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1. At JD a Nhit i Atef The time required for of a non GSO satellite passing through the main beam of a GSO earth station antenna depends on mutual location of earth and space stations of the GSO network as well as on orbital parameters of the non GSO network Determination of the exact value Af in general is hampered The value of At should be computed at the location where the time for a non GSO satellite to pass through the GSO main beam is smallest Since this occurs when a GSO earth station is located directly under a GSO space station pass time At could be determined by equations 2 and 3 see Fig 2 w a 0 where 5 34B arsin gt sin 3 oun 3 a la cos a sin 0 071 ANETTA non GSO satellite angular velocity of rotation around the Earth at the minimum operational altitude degrees s for multiple orbits the greatest such should be selected Earth rotation angular velocity at the equator degrees s i orbit inclination degrees Q3qp GSO earth station antenna 3 dB beamwidth degrees Re Earth radius km h orbit altitude km see Note 1 NOTE 1 In the case that the constellation has multiple values of A for different sub constellations or planes the lowest value should be used In the case of elliptical orbits the minimum operating height should be used The Np value defines simulation accuracy The higher the Np value the higher the accuracy of the final
2. Calculate 6 arcsin amp geo R 0 180 arcsin sin B R h 03 180 6 E 85 D R h a sin 0 Dz 2D sin te 2 D3 Dy cos 180 02 Then calculate the value 2 ta Bere 4 R h Dy 2 sin 180 85 which can be used in equation 2 to calculate the step size to use 2 2 Total simulation run time This section describes the calculation of number of time steps for the epfd and epfdy algorithms specified in Part D The basic approach first considers constellations with repeating and non repeating ground track separately where systems that use repeating ground tracks use station keeping to ensure that the satellites follow a single Earth trace For example in the case of a 6 h orbit there will be minor launch errors and perturbations that would make the orbit drift unless station keeping was used operationally to ensure the track repeats Administrations therefore must indicate to the BR whether station keeping is used to maintain a single track 10 Rec ITU R S 1503 FIGURE 4 Geometric parameters involved in the equations GSO satellite 1 i Non GSO Non GSO satellite satellite 1503 04 Some constellations have different values for inclination height or eccentricity between the planes In this case it is assumed that to maintain coverage the constellation would be designed so that the separation between planes does not change signifi
3. plane for which the epfd level may have large variations close to in line interference and where a fine quantization of the region is required The second part of the numerical procedure performs the calculations in the regions of the 6 plane for which the epfd level has smooth variations allowing for a coarser quantization Finding the 0 plane regions associated with potential quasi in line interference RPII corresponds to defining regions such that when the reference satellite is inside one of these regions in line interference events involving one or more of the satellites in the constellation may occur The important point here is to guarantee that when the reference satellite is not inside any of these regions in line interference does not occur and a coarser quantization grid can be used The regions of potential in line interference RPII are usually defined as rectangular regions around points of potential in line interference PPII These PPI can be found using the methodology described in Part D 6 3 Once the potential occurrence of quasi in line interference is detected the reference satellite is inside one of the potential in line interference regions it is important to identify which satellites and earth stations are involved in it This way epfd computations could be made considering that only a few interference entries those associated with the in line interference event have to be re computed when the reference
4. Determine the location of all other satellites in the constellation there are two possible constellation configurations according to the expressions in Part D 6 2 Sub step 8 2 Repeat Steps 9 to 19 for each of the two configurations Step 9 Step 10 Step 11 Step 12 Step 13 Step 14 Step 15 Step 16 Step 17 Step 18 Step 19 Step 20 Step 21 Step 22 4 2 6 Set epfd 0 Repeat Steps 10 to 18 for all non GSO space stations Determine if this non GSO space station is visible to the GSO satellite using the algorithm in Part D 5 4 2 If the non GSO space station is visible to the GSO satellite then do Steps 13 to 18 Calculate e i r p dB W BW f of non GSO space station in direction of GSO satellite using the e i r p mask in Part C 3 Calculate Gry receive relative gain dB at GSO satellite using relevant gain pattern specified in algorithms in Part D 5 5 Calculate D distance km between the non GSO space station and the GSO satellite using the algorithm in Part D 5 4 1 Calculate the spreading factor Lpg 10 log 4x D 60 Calculate epfdis for this non GSO satellite epfdisi e i r p Lrs Gry Gmax Increment epfd by epfd s Locate in the epfd histogram the bin corresponding to the value of epfdis and add PROB 2 to it Generate the epfdj CDF from the epfd PDF using the algorithm in Part D 7 1 2 Compare epfdis statistics with limits using algorit
5. Nrun max N rep Nrracks Then the total run time is Trun Nrun P repeat So the number of time steps is then Nsteps round Trun Tstep to nearest integer below 2 2 2 Non repeating orbits In this case the longitudinal spacing between successive ascending node passes must be examined so that there are sufficient tracks within the main beam The time step size and number of time steps can be used to determine how far a particular orbit will have processed within the run The same numbers can be used to determine how many time steps are required for the orbit to drift around the equator The orbit period can then be used to work out the difference between tracks The constant that specifies the required number of points within the main beam can be used to specify the number of tracks though the main beam required i e Nyack Nhits If the gap between tracks is too large or too fine resulting in either insufficient samples or excessive run times respectively then artificial precession can be used It is expected that station keeping drift should cancel out in the long term and so would not be required for these calculations The result should be like Fig 6 FIGURE 6 Non GSO satellite track 1503 06 In Fig 6 it can be seen that the result would be a series of tracks within the main beam of the GSO earth station that is sufficiently fine to resolve the main beam and produces sufficient samples to generate the req
6. The same criteria should be used when sampling the pfd mask 2 4 Methodology The pfd mask is defined by the maximum pfd generated by any space station in the interfering non GSO system and as a function of the parameters defined either in option 1 or option 2 For the generation of the pfd mask the cells in the non GSO satellite footprint are located according to the beam pointing utilized by the non GSO system For satellites with steerable antennas the satellite can point to the same area of the Earth throughout its track through the sky These cells are fixed relative to the Earth s surface For satellites that have antenna pointing angles fixed relative to the satellite the cell pattern is the same relative to the satellite but is moving relative to the Earth 2 4 1 Option 1 Option 1 has been described for a pfd mask defined as a function of the separation angle A as an example If the pfd mask is provided as a function of the X angle the following calculation remains the same replacing a with X angle 34 Rec ITU R S 1503 The pfd mask is defined as a function of the separation angle between this non GSO space station and the GSO arc as seen from any point on the surface of the Earth and the difference AL in longitude between the non GSO sub satellite point and the GSO satellite The angle o is therefore the minimum topocentric angle measured from this particular earth station between the interfering non GSO space station and
7. Calculate the parameters required by the pfd mask either lat or X Along or lat azimuth elevation as required using the definition of angles in Part D 5 1 Using the pfd mask for the selected non GSO satellite calculate pfd lat a or X Along or pfd lat azimuth elevation at the GSO earth station using the non GSO satellite pfd mask as specified in Part D 3 6 Calculate off axis angle p at GSO earth station between the line to the GSO satellite and the non GSO satellite Calculate Gry Receive gain in dB at GSO earth station using relevant gain pattern specified in algorithms in Part D 5 5 Calculate epfd for this non GSO satellite using epfd pfd a Grx Gmax where Gmax is the peak gain of the GSO earth station antenna Sort the epfd contributions of the non GSO satellites Repeat Step 22 for the N lat largest epfd contributions on this list plus those satellites within the exclusion zone where N lat is the maximum operating non GSO satellites at the latitude of GSO ES considered corresponding to the maximum number of satellites allowed to transmit at the same frequency towards the same area on the ground fulfilling the GSO exclusion zone and minimum elevation angle requirements as defining by for the non GSO system Increment epfdy by the epfd value Locate in the epfdy histogram the bin corresponding to the value of epfdy and add PROB 2 to it Generate the epfd CDF from the epfd PDF
8. _ TUE en XG yay YG Ze ZN zg VA kl Uv x6 wn yG Zn z0 and p2 Zan 9 Yen VO 2GEn z0 JA xy xg ww VO Zw z6 The GSO earth station position can either be x kl xy XG XG x k2 xy XG xG y kllyy vo YG or y k2 y YG Ye z kl zy ZG 26 z k2 zy ZG 26 The correct GSO earth station position is the one for which gt gt gt PG is minimum and will be recorded only if NG PG That is to say xy x Yy y Zy z has to be minimum and point P is recorded only if xg xy YG YN zg Zy lt xg x yg y7 ZG 2 3 Maximum epfd geometry for non inline situation 3 1 Using o angle In this case the maximum epfdy occurs for a GSO earth station placed at a point on the Earth for which the angle between the non GSO satellite and the GSO satellite equals Qo The system of equations that has to be satisfied to determine the GSO earth station location is then Jer as and exe sino a 9 lan esl The unknown parameters of this set of equations are x y Z the coordinates of the GSO earth station in the geocentric reference As x y z only depends on the latitude and longitude of the GSO earth station the unknown parameters can be reduced to two by applying the changes of reference x Re cos lat cos long y Re cos lat sin long Re sin lat Z The set of equ
9. 3 Generation of e i r p masks 3 1 Generation of earth station e i r p masks 3 1 1 General presentation The earth station e i r p mask is defined by the maximum e i r p as a function of the off axis angle generated by an earth station The non GSO earth station is located in a non GSO cell which is served by a maximum number of non GSO space stations The density of non GSO earth stations which can operate co frequency simultaneously is also used as an input to the calculation 3 1 2 Mitigation techniques description The mitigation technique implemented within the non GSO system should be accurately explained in this section in order to be fully modelled in the calculation of the epfdt see Part C 2 2 3 1 3 Earth station antenna pattern The earth station antenna pattern used needs to be identified to calculate the earth station e i r p mask 3 1 4 Methodology Step 1 The earth station e i r p mask is defined by the maximum e i r p radiated in the reference bandwidth by the earth station as a function of the off axis angle and is given by ES EIRP O G 0 P where ES EIRP equivalent isotropic radiated power in the reference bandwidth dB W BW ep 0 separation angle between the non GSO space station and the GSO space station at the non GSO earth station degrees G 6 earth station directional antenna gain dBi maximum power delivered to the antenna in the reference bandwidth dB W BW BW a
10. B 1503 09 The coordinates of the point M at the Earth s surface are a b in the antenna plane A B corresponding to 01 14 in the polar reference The coordinates of the point C centre of the cell i are A B in the antenna plane A B and 6 in the spherical reference Rec ITU R S 1503 33 For satellite antenna gain patterns with functional descriptions i e equations the gain into the point M may be computed directly from the coordinates C A Be and M a b For other patterns the satellite antenna gains are provided in a grid of A B points The point M a b may be located between four points of the grid A B Thus it is necessary to evaluate the gain at the point M knowing the gain for the four points P1 G1 P2 G2 P3 G3 and P4 G4 PI GI P2 G2 P3 G3 P4 G4 1503 09bis The four gains are weighted by the distances between P and M before being added up If a bj are the A B coordinates of point P and d j 1 4 the distance of point P to the point M then dj f a aj b b Ifd 0 then G M G P else sabe d J m 4 gt as ii and 4 G F G M 1Ologio X m V10 10 j l The G M is then the gain of the non GSO satellite antenna illuminating beam i in the direction of the point M The sampling of the non GSO satellite antenna pattern should be adapted so that interpolation does not lead to significant approximation
11. Step 10 Update position vectors of GSO satellite using algorithm in Part D 5 3 Step 11 Step 12 Step 13 Step 14 Step 15 Step 16 Step 17 Step 18 Step 19 Step 20 Step 21 Step 22 Step 23 Step 24 Rec ITU R S 1503 61 Set epfdy 0 Repeat Steps 13 to 23 for all non GSO earth stations Determine if this non GSO earth station is visible to the GSO satellite using the algorithm in Part D 5 4 2 If the non GSO earth station is visible to the GSO satellite then do Steps 15 to 23 Repeat Steps 16 to 23 for the maximum number of non GSO satellites that can be tracked Select the i th satellite away from the GSO arc that is above minimum elevation angle and not inside the GSO exclusion zone If the algorithm has selected a satellite then do Steps 18 to 23 Calculate ES EIRP dB W BW p of non GSO earth station in direction of GSO satellite using non GSO earth station e i r p mask in Part C 3 REP_EIRP ES EIRP 10log o NUM ES Calculate Gry receive relative gain dB at GSO satellite using relevant gain pattern specified in the algorithms in Part D 5 5 Calculate D distance km between the non GSO earth station and the GSO satellite using the algorithm in Part D 5 4 1 Calculate the spreading factor Lpg 10 log 4x D 60 Calculate epfdt for this non GSO satellite epfd REP_EIRP Lrg Gry Gmax Increment epfdt by epfdf Increment epfd statistics by this
12. total interference power over all axial ratios and polarization ellipse orientations is a very small net increase in the received interference power in the BSS antenna of 0 048 dB The bounds of any cross polarization contributions that are very unlikely to Then where p d Neo pfd co Neross pfd _cross and where P i BW ef be reached are from 30 dB to 3 dB N N cross pfd 10 log 5 192 469 10 5 zoersel l J pfd radiated by a non GSO space station dB W m2 in the reference bandwidth index of the beams illuminated in the polarization considered maximum number of beams which can be illuminated simultaneously in the polarization considered pfd produced at the point considered at the Earth s surface by one beam in the polarization considered dB W m2 in the reference bandwidth index of the beams illuminated in the opposite polarization to the polarization considered maximum number of beams which can be illuminated simultaneously in the opposite polarization to the polarization considered pfd produced at the point considered at the Earth s surface by one beam in the opposite polarization to the polarization considered dB W m2 in the reference bandwidth pfd co P G 10 logy 4 T d maximum power emitting by the beam i in the reference bandwidth dB W BW ep reference bandwidth kHz 32 Rec ITU R S 1503 G gain generated by the beam i in the polarization considered at
13. 325 BWE BW 4 2 4 6 File formats File formats should be in ASCII text format to allow visual inspection and modification of the input parameters to the routines It would also be acceptable to have the input parameters in a binary database format if a graphical interface is provided to view and modify input parameters before running the simulation 4 2 5 Algorithms and calculation procedures In the calculation of the dual time step for the epfd computation Ncoarse 1 66 Rec ITU R S 1503 4 2 5 1 Time simulation approach To calculate epfd values from one non GSO system into one GSO system satellite the following algorithm should be used The algorithm can be used on multiple GSO systems in parallel if required Step 1 Read in parameters for non GSO system as specified in Part D 4 1 4 2 Step 2 Read in GSO parameters as specified in Part D 4 1 4 3 Step 3 If required calculate worst case GSO location using algorithm in Part D 4 1 2 Step 4 Initialize statistics by zeroing all bins of epfdj values Step 5 If required calculate number of time steps and time step size using algorithm in Part D 4 1 3 and hence calculate end time If a dual time step algorithm is included then use Sub step 5 1 otherwise Ncoarse 1 all the time Sub step 5 1 Calculate coarse step size Teoarse Tfine Neoarse Step 6 Repeat Steps 7 to 19 for all time steps If a dual time step algorithm is included then repeat Sub step
14. 4 Per each interval of AL the iso a line can be defined by a set of n points My for k 1 2 n To determine the maximum pfd corresponding to a given value of a it is necessary to calculate the maximum pfd at each of the points Max for k 1 2 2 The maximum pfd at a given My is determined by first finding the pfd contributed by each cell toward My taking into account the dependency of the sidelobe patterns on the beam tilt angle The maximum pfd contributions toward Ma are then summed with the number of contributions constrained by the physical limitations of the space station Out of the Nprtal cells that can be seen within the coverage area of the space station under a minimum elevation angle for communication only Nco can be illuminated at the same frequency bandwidth in one sense of polarization and Ns in the other sense of polarization This characterizes the limitation of the antenna system on the non GSO space station To calculate the mask in one polarization the cells which can be illuminated in the polarization concerned are identified and the cross polarization level is considered for other cells Rec ITU R S 1503 35 Out of these Nco and Necross cells only a given number can be powered simultaneously This characterizes the limitation of the repeater system of the non GSO space station If applicable the limitations in terms of frequency reuse pattern and polarization reuse pattern also need to be clarified If
15. 6 1 to Step 17 until end time is reached Sub step 6 1 If itis the first time step then set Tstep Tine Sub step 6 2 Otherwise if there are less than Ncoarse steps remaining then set Tstep Thine Sub step 6 3 Otherwise if the any of the a angles for the last time step were within coarse of the exclusion zone angle then set the Tstep Tyine otherwise use Tstep Teoarse Step 7 Update position and velocity vectors of all non GSO satellites using algorithm in Part D 5 2 Step 8 Update position vectors of GSO satellite using algorithm in Part D 5 3 Step 9 Set epfd 0 Step 10 Repeat Steps 10 to 18 for all non GSO space stations Step 11 Determine if this non GSO space station is visible to the GSO satellite using the algorithm in Part D 5 4 2 Step 12 Ifthe non GSO space station is visible to the GSO satellite then do Steps 13 to 18 Step 13 Calculate e i r p dB W BW of non GSO space station in direction of GSO satellite using the e i r p mask in Part C 3 Step 14 Calculate Gry receive relative gain dB at GSO satellite using relevant gain pattern specified in algorithms in Part D 5 5 Step 15 Calculate D distance km between the non GSO space station and the GSO satellite using the algorithm in Part D 5 4 1 Step 16 Calculate the spreading factor Lpg 10 log 4n D 60 Step 17 Calculate epfd for this non GSO satellite epfdisi e i r p LFs Gryx Gmax Step 18 Incr
16. GSO arc there are at least three different ways of modelling a non GSO system based on a cell architecture Cell wide observance of a non operating zone a beam of a non GSO space station is switched off if the separation angle between this non GSO space station and the GSO arc at any point of the non GSO cell is less than ag GSO arc avoidance angle Cell centre observance of a non operating zone a beam of a non GSO space station is switched off when the centre of the cell sees this non GSO space station at less than Og from the GSO arc A satellite based reference a beam of a non GSO space station turns off when a satellite based reference angle X is less than Xo The reference angle X is the angle between a line projected from the GSO arc through the non GSO space station to the ground and a line from the non GSO space station to the edge of the non GSO beam Other mitigation techniques may be used by a non GSO system which are not listed here Information on these tech niques will be provided by the non GSO administration for the description and verification of the pfd mask Figs 8a and 8b define the amp angle and the X angle FIGURE 8a Overhead beam view of satellite based exclusion angle GSO arc projection line x GSO projection zone a x beam turned off when edge within GSO projection zone 1503 08a 2 3 pfd calculation 2 3 1 pfd calculation The pfd radiated by a non GSO space station
17. ITU R S 1503 15 The roles of the administration of the non GSO network and the BR are discussed in Part A 2 1 The first of the above functions Function 1 is performed by the administration of the non GSO network and parameters used for that function are provided to the BR to corroborate the pfd masks in support of its role in performing Function 3 Detailed parameters are needed by the BR in support of Function 2 1 2 Scope and overview This section identifies inputs to the software in four main paragraphs Paragraph 2 of Part B defines all of the inputs to facilitate design of the BR databases Paragraphs 3 to 5 of Part B describe the inputs in terms of their use within the three software functional elements Function 1 Generation of pfd masks 3 of Part B Function 2 Comparison of epfd levels with limit values 4 of Part B and Function 3 Checking of submitted parameters for self consistency 5 of Part B Note that in the following tables square brackets in variable names indicate an index for that variable and not tentative text 13 Cross references to relevant Parts The following Table indicates the relevant Parts of this Annex where input and database parameters generally are applied More detailed cross references for specific parameters are provided in 2 of Part B Software function Relevant Parts of this Annex where parameter inputs are applied Function 1 Generation of pfd e i r p masks 1 4
18. Re earth radius PQ y z GSO earth station coordinates in this reference S xs ys zs GSO satellite coordinates in this reference N xy Yn ZN non GSO satellite coordinates in this reference Rec ITU R S 1503 43 2 Downlink in line geometry This section describes calculation of the position of the GSO earth station for the in line maximum epfdy algorithm described in Part C 1 The calculation uses the non GSO satellite position and the GSO satellite position for the maximum epfd using the geometry below FIGURE 15 Projection of the geometric in line situation GSO earth station acceptable position for in line event GSO satellite GSO earth station rejected position for in line event Non GSO satellite GSO arc 1503 15 The GSO earth station is at the interception of the sphere of equation 5 and the line passing by the GSO satellite and non GSO satellite gt gt GP k GN with ke R that is to say x xg k xy XG y yG k yn Ye 6 zZ 2G k zy ZG Equations 5 and 6 lead to xg k ty P 0G k Oy yg Eg k En zG R then K ty x6 vy YG y 20 kG xy XG yg Wn IG 2G Zw 20 xG G 2G Re D The resolution of 7 gives two solutions kl and k2 determined as follows If A A xGg xy xG VGN Yo 2G Zn 2G 4 xy XG On vo Zw 20 2 2 2 2 ag yG z6 Re 44 Rec ITU R S 1503 then
19. Sub step 6 1 to Step 22 until end time is reached otherwise repeat Steps 7 to 22 until end time is reached Sub step 6 1 Ifit is the first time step then set Trey Tine Sub step 6 2 Otherwise if there are less than Ncoarse Steps remaining then set Tstep Thine Sub step 6 3 Otherwise if the any of the a or X angles for the last time step were within rsr of zero or rsr 2 Step 7 Step 8 Step 9 Step 10 Step 11 Step 12 Step 13 Step 14 Step 15 Step 16 Step 17 Step 18 Step 19 Step 20 Step 21 Step 22 Step 23 Step 24 Step 25 3 5 2 of the exclusion zone angle Qo or Xo then set Tstep Tyine otherwise set Tstep Tcoarse Update position vectors of all earth stations based on coordinate system in Part D 5 1 Update position vectors of all GSO satellites based on coordinate system in Part D 5 2 Update position and velocity vectors of all non GSO satellites based on coordinate system orbit prediction model and station keeping algorithm in Part D 5 3 Set epfd 0 Select all non GSO satellites visible to the GSO earth station using the algorithm in Part D 5 4 1 Repeat Steps 13 to 18 for each visible non GSO satellite Calculate the parameters required by the pfd mask either lat or X Along or lat azimuth elevation as required using the definition of angles in Part D 5 1 Using the pfd mask for the selected non GSO satellite calculate pfd lat a or
20. X Along or pfd lat azimuth elevation at the GSO earth station using the non GSO satellite pfd mask as specified in Part D 3 6 Calculate off axis angle at GSO earth station between line to the GSO satellite and the non GSO satellite Calculate Gry Receive gain dB at GSO earth station using relevant gain pattern specified in algorithms in Part D 5 5 Calculate epfdy for this non GSO satellite using epfdy pfd a Gax Ging Where Gmax is the peak gain of the GSO earth station antenna Sort the epfd contributions of the non GSO satellites Repeat Step 21 for the N lat largest epfdy contributions on this list plus those satellites within the exclusion zone where N lat is the maximum number of operating non GSO satellites at the latitude of GSO ES considered corresponding to the maximum number of satellites allowed to transmit at the same frequency towards the same area on the ground fulfilling the GSO exclusion zone and minimum elevation angle requirements as defining by for the non GSO system Increment epfd by the epfdj value Increment epfdy statistics by epfdy for this time step by Tstep Tfine entries Generate the epfd CDF from the epfd PDF using the algorithm in Part D 7 1 2 Compare epfdy statistics with limits using algorithm in Part D 7 1 Output results in format specified in Part D 7 3 Analytical method approach To calculate epfdy values from one non GSO system into on
21. any point in the GSO arc The objective of the mask is to define the maximum possible level of the pfd radiated by the non GSO space station as a function of the separation angle between the non GSO space station and the GSO arc at any point on the ground per interval of AL At each point of the non GSO satellite footprint the pfd value depends on the configuration of the spot beams which are illuminated by the satellite the maximum number of co frequency beams which can be illuminated simultaneously the maximum number of co frequency co polarization beams which can be illuminated simultaneously the maximum power available at the satellite repeater The proposed methodology for the generation of the pfd mask is explained in the following steps Step 1 At any given time in the field of view of a non GSO space station Noral is the maximum number of cells that can be seen with the minimum service elevation angle Step 2 In the field of view of the non GSO space station it is possible to draw iso at lines i e the points on the surface of the Earth which share the same value of a see Figs 10 and 11 FIGURE 10 Field of view of a non GSO space station Option 1 B Exclusion zone lal lt A degrees 1503 10 Step 3 Along the iso a line define intervals of AL difference in longitude between the non GSO sub satellite point and the point on the GSO arc where the a or X angle is minimized Step
22. by any interested parties without reference to any specific development methodology 46 Rec ITU R S 1503 1 3 Overview This section is structured into the following paragraphs 2 General requirements of the algorithm such as constants and environment 3 Defines the epfd algorithm 4 1 Defines the epfdr algorithm 4 2 Defines the epfd algorithm 5 Defines the core geometry and algorithms used by both epfd calculations including gain patterns 6 Specifies details of the analytic method 7 Specifies the output formats and process to obtain a go no go decision Note that where square brackets are included as part of a parameter name this indicates an index into an array not tentative text 1 4 Cross references This section is part of an overall document and the following Parts give additional information Part A Fundamental constraints and basic assumptions This Part relates to the two basic approaches in the SRD in particular the calculation of time step for the time simulation approach and the choice of the reference satellite longitude and latitude increments in the analytical method approach Part B Parameters of non GSO systems This Part gives the complete list of required parameters from which a sub set of parameters is used as inputs to the epfd software sections Part C pfd mask definition This Part gives further information about the definition and format of the pfd mask used for epfd calcu
23. data section administration Block a Block b Input to software for calculation Input to software for generation Input to software for self P XSS 3 epfd statistics and of pfd e i r p masks consistency tests pia gt A limit compliance checking y vy Calculation Determination of the maximum section Testing of the reliability of epfd GSO earth station gt the software output a location and associated pointing directions Block 2 Block 3 l Calculation of pfd e i r p fdei Calculation of the epfd statistics a mask m p rg gt gt and limit compliance checking gt mas en Block 1 Block 4 Pass or fail decision Step 1 Step 2 1503 01 1 1 3 Allocation of responsibilities between Administrations and the BR for software employment Taking into account significant complexity regarding specific features of different non GSO system configurations in the software it would seem appropriate to impose some burden of responsibility relevant to testing for epfd limits on administrations notifying appropriate non GSO systems Therefore the examination procedure for meeting epfd limits would consist of two stages The first stage would include the software development Block 1 and conducting all the calculations by the administrations notifying non GSO systems The stage would also include estim
24. epfdrt If a dual time step algorithm is included then the step below should be used Sub step 24 1 Increment epfdr statistics by the epfdt for this time step by Ts rep Tyine entries Step 25 Step 26 Step 27 4 1 6 2 Generate the epfdt CDF from the epfdt PDF using the algorithm in Part D 7 1 2 Compare epfdt statistics with limits using algorithm in Part D 7 1 Output results in format specified in Part D 7 2 Analytical method approach To calculate epfdt values from one non GSO system into one GSO system satellite the following algorithm should be used The algorithm can be used on multiple GSO systems in parallel if required Step 1 Step 2 Step 3 Step 4 Step 5 Step 6 Step 7 Step 8 Step 9 Step 10 Read in parameters for non GSO system as specified in Part D 4 1 4 2 Read in GSO parameters as specified in Part D 4 1 4 3 If required calculate maximum epfd GSO location using algorithm in Part D 4 1 2 or other suitable method If required calculate locations of non GSO earth stations using algorithm in Part D 4 1 5 Initialize statistics by zeroing all bins of epfdt values Make a partition of the non GSO reference satellite p 0 plane Repeat Steps 8 to 25 for each element cell of the 0 plane partition Calculate the probability PROB of finding the non GSO reference satellite inside the cell according to the expression in Part D 6 1 Place the non GSO reference s
25. guarantees that the data published are also the data used in these examinations The BR considers this important for both the notifying administration and for administrations the services of which may be affected by the new station For its regulatory and technical examination of satellite networks the BR has only used so far on a regular basis software developed for GSO networks However when software for pfd calculations that works on non GSO networks becomes available the same principle should apply This is not only for the convenience of the BR but to ensure consistency and transparency towards administrations Rec ITU R S 1503 87 PART G Software development and maintenance 1 Software product development approach 1 1 Methodology The methodology used in the software product development approach should be described in the software documentation 1 2 Validation Validate conformity of the software results with the equations described or referenced in this text 2 Software user interface Software should comply with the BR interface requirements as in Part F 2 3 Software documentation and maintenance 3 1 Software requirements specification The software documentation should refer to the relevant sections of this Recommendation 3 2 Requirements implementation The purpose of this Recommendation is to state how the requirements of this Recommendation are to be implemented in the software 3 3 User manual The purpose
26. if the non GSO satellites operate in the exclusion zone and have a maximum epfdy at amp 0 then calculate the latitude and the longitude of the GSO earth station at the point on the Earth for which the angle between the non GSO satellite and the GSO satellite equals to ag see geometry calculations in the Annex to Part C 42 Rec ITU R S 1503 Step 10 If the non GSO satellites operate in the exclusion zone and have a maximum epfdJ at amp 0 then calculate the latitude and the longitude of the GSO earth station at the intersection of the 0 line to the Earth see geometry calculations in the Annex to Part C Step 11 Store GSO network location 2 Determination of GSO network location for maximum epfd The epfdy produced by the emissions of all the earth stations of a non GSO system operating in the FSS is evaluated at any point of the geostationary arc For duration purposes it is not possible to calculate epfdt statistics for all possible space station locations and pointing directions Thus it is necessary to define a method to determine the location where the maximum epfd occurs The epfd7 is dependent on the density of the non GSO earth station which are visible from the GSO space station with regard to its antenna aperture The difference in free space losses from the GSO space station between a non GSO earth station at the GSO sub satellite point and a non GSO earth station at 10 elevation is about 1 2 dB which is se
27. of the user manual is to tell the user how to run different tests to obtain certain results Given the complexity of these tests they need to be given in detail 3 4 Maintenance and upgrade The fact that part of the software and not only the data depend on the characteristics of the system puts unusually high demands on the maintainability of the software PART H Procedures for the evaluation of a candidate software The following steps should be followed for the evaluation of a candidate software Step 1 Evaluate the operational environment of the software This evaluation should consider whether the software runs on 32 bit Window platforms Windows 95 98 Windows NT version 4 0 Windows 2000 or higher versions The software should be able to run without any problem after the end of the year 1999 This evaluation should also consider memory and hard disk requirements input and output files storage requirements software portability etc Relevant parts of Part F of this Recommendation should be used as the guidelines 88 Rec ITU R S 1503 Step 2 Evaluate software compliance evaluate compliance with the constraints and basic assumptions units constants earth model Evaluate if the software uses the definitions formats and units of non GSO orbit and systems parameters test points and inputs for self consistency tests Relevant parts of Parts A and B of this Recommendation should be used as the guidelines Step 3 Evaluate calcula
28. on multiple GSO systems in parallel if required Step 1 Read in parameters for non GSO system as specified in Part D 4 1 4 2 Step 2 Read in GSO parameters as specified in Part D 4 1 4 3 Step 3 If required calculate maximum epfd GSO location using the algorithm in Part D 4 1 2 Step 4 If required calculate locations of non GSO earth stations using the algorithm in Part D 4 1 5 Step 5 Initialize statistics by zeroing all bins of epfdy values Step 6 If required calculate number of time steps and time step size using the algorithm in Part D 4 1 3 and hence calculate end time If a dual time step algorithm is included then use Sub step 6 1 otherwise Ncoarse 1 all the time Sub step 6 1 Calculate coarse step size Teoarse Tfine Neoarse Step 7 Repeat Steps 8 to 24 for all time steps If a dual time step algorithm is included then repeat Sub step 7 1 to Step 22 until end time is reached Sub step 7 1 If it is the first time step then set Tstep Tyine Sub step 7 2 Otherwise if there are less than Ncoarse Steps remaining then set Tstep Tyine Sub step 7 3 Otherwise if any of the a angles for the last time step were within coarse of the exclusion zone angle then set the Tstep Tine otherwise use Tstep Teoarse Step 8 Update position vectors of all earth stations using algorithm in Part D 5 1 Step 9 Update position and velocity vectors of all non GSO satellites using algorithm in Part D 5 2
29. satellite changes its location inside the considered potential in line interference region This measure could save a substantial amount of computer time when a large number of interference entries are present b Given the position of the reference satellite finding the position of all other satellites in the constellation block 3 in the diagram in Fig 27 is a problem that has two possible solutions This is due to the fact that two different orbital planes having the same inclination can contain the reference satellite Both solutions have to be taken into account in the proposed procedure In the case of circular orbits finding these solutions do not constitute a complex task since the altitude of the satellites is previously known For satellites in elliptical orbits this is a more complex procedure since the satellite altitudes change with time see Part D 6 2 6 1 Probability of the reference satellite being inside a rectangular cell The probability of finding the reference satellite inside a rectangular cell say cell j in the plane defined by PE Pm Py 9 Om Om can be obtained by using the probability density function in expression 34 and is given by em Saen f cm Fe 1 for Om 20 Oy gt 0 P DD fe Sm On fen FOND for On lt 0 Oy 20 38 TU en f t en fn ey FG for 0 lt 0 Oy lt 0 with 0 for oo lt X ST f x l he a 7 l arctan e for T lt XST 39
30. satellite point the azimuth angle defined in Part D 5 4 3 the elevation angle defined in Part D 5 4 3 Whatever parameters e g amp angle X angle are used to generate the pfd mask the resulting pfd mask should be converted to one of the format options above Because the non GSO space station can generate simultaneously a given maximum number of beams it should be taken into account in order to better fit the system design and not be too constraining for non GSO systems The mitigation techniques used by the non GSO system such as the GSO arc avoidance are implemented in the calculation of the pfd mask The GSO arc avoidance defines a non operating zone on the ground in the field of view of a non GSO space station The location of this non operating zone on the ground will move as a function of the latitude of the non GSO sub satellite point To get a more accurate model of a non GSO system the latitude of the non GSO sub satellite point is taken as a parameter to the pfd mask calculation Use of amp or X angle pfd masks implies that the same definition of GSO angle is used for exclusion angle in the calculation of epfd 30 Rec ITU R S 1503 2 2 Mitigation techniques description The mitigation technique implemented within the non GSO system should be accurately explained in this section in order to be fully modelled in the calculation of the epfdt With regard to the use of a non operating zone around the
31. shared between runs The Table could be queried so that the required values can be used depending upon non GSO system frequency Rec ITU R S 1503 63 For each set of limits the following would be defined as specified in Part B 2 2 Frequency band start FSTART IS GH Frequency band end FEND IS Z Applicable Region 1 REGIONI IS Applicable Region 2 REGION2 IS Applicable Region 3 REGION3 IS Part D 5 5 GSO half power beamwidth Array of NEPFD IS epfd values EPFD IS I dB W m BW Array of NEPFD IS percentages PC IS I From the EPFD IS I arrays the number of bins and bin ranges can be calculated using Step 1 Calculate EPFD IS MIN minimum value in EPFD IS I array Step 2 Calculate EPFD IS MAX maximum value in EPFD IS I array Step 3 Calculate EPFD IS START by rounding EPFD IS MIN to nearest 10 dB below Step 4 Calculate EPFD IS END by rounding EPFD IS MAX to nearest 10 dB above Step 5 Number of bins EPFD IS END EPFD IS START Sp This will give a set of bins that are of size Sg bin size specified in Part D 2 5 and are below and above the epfdj limits required 4 2 2 Determination of maximum epfd configuration The maximum epfd location of GSO satellite and beam centre is defined in Part C 4 2 3 Calculation of run steps 4 2 3 1 Time simulation approach A single time step and number of time steps are calculated using the algorithm in Part A 4 2 3 2 Analytical approach The longi
32. step and simulation duration values generated by the software against the predicted values This checking could be done for example through a comparison with results obtained with the analytical method CDF generation Using sets of test input files with known CDF results verify the CDF generation software Go no go decision process Using sets of CDF test input files verify the accuracy of the go no go decision process Should multiple implementations be available then sensitivity analysis could be used to evaluate them and their output can be compared to ensure consistency 86 Rec ITU R S 1503 2 Evaluation of the epfd 1 statistics obtained by the BR These are tests which will be performed automatically by the software as part of each run to confirm that the run did find the worst case interference events epfd value for 100 time the epfdy value for 100 time obtained during the run should be compared with a value calculated from analysis of the non GSO constellation The obtained value should be within 0 X dB of the expected value In cases in which the time simulation method is used a software based on the analytical method described in Part D 6 can if applicable be used as an option to verify the reliability of the obtained statistical results 3 Verification of the pfd masks The pfd masks are inputs to the BR validation tool to be provided by the notifying administration to the BR together with the soft
33. the non GSO beam the difference AL in longitude between the non GSO sub satellite point and the point on the GSO arc where the o or X angle is minimized Option 2 The pfd mask is defined by pfd_mask satellite ande latitude Az EI the non GSO satellite 2 Part C i the latitude of the non GSO sub satellite point the azimuth angle defined in Part D 5 4 3 the elevation angle defined in Part D 5 4 3 4 3 Non GSO uplink pfd mask Mitigation technique Description of non GSO cell wide observance of non operating zone or cell centre 2 2 Part C observance of non operating zone text defining mitigation techniques used for uplink and downlink directions of transmission or others ES_EIRP 6 Non GSO earth station e i r p as a function of the off axis angle 3 1 Part C ES TRACK Maximum number of co frequency tracked non GSO satellites 4 1 4 2 Part D ES MINELEV Minimum elevation angle of the non GSO earth station when it is transmitting degrees 4 1 4 2 Part D ES_MIN_GSO Minimum angle to GSO arc degrees 4 1 4 2 Part D ES DENSITY Average number of non GSO earth stations km 4 1 4 2 Part D ES DISTANCE Average distance between cell or beam footprint centre km 4 1 4 2 Part D 4 4 pfd compliance test points 4 4 1 Points identified by notifying administration Points should be provided by the administration as the most sensitive maximum epfd points that would cause the gr
34. the point considered at the Earth s surface dBi d distance between the non GSO space station and the point considered at the Earth s surface if the non GSO satellite antenna gain is in isoflux d is the altitude of the non GSO space station m and pfd_cross B G_cross 10 logio 47d where G_cross cross polarization gain generated by the beam j illuminated in the opposite polarization to the polarization considered at the point considered at the Earth s surface dBi It is expected that the parameters used to generate the pfd e i r p mask correspond to the performance of the non GSO satellite over its anticipated lifetime 2 3 2 Satellite antenna gain at the point considered at the Earth s surface The objective of this section is to determine the gain in the direction of a point M at the Earth s surface when the satellite antenna points towards a cell i The antenna coordinate can be defined by four ways of the coordinate system Q spherical coordinate v u sin B cos v sin 8 sin B A 9 cos p B 0 sin Az El sin El sin 9 sin tan Az tan 8 cos As an example the following calculations are performed in the antenna reference A B The sampling of the non GSO antenna pattern should be adapted so that interpolation does not lead to gain level significantly different from real values Figure 9 presents the geometry in the antenna plane A B FIGURE 9 Antenna plane A
35. where A 59 with given by equation 3 for epfd epfdt calculations and by equation 4 for epfdj calculations Although the above mentioned values for the longitude and latitude increments as well as the size of the RPII were shown to be adequate in several exercises they may have to be adjusted Very large earth station with very narrow beams would require a decrease in the latitude and longitude increment size but would allow for a smaller RPI On the other hand earth stations with a broad beam would allow for larger values of the longitude and latitude increments but would require a larger RPII 6 4 Finding the PPII In the case that the optional fine grid is used then the following points are to be noted 6 4 1 Uplink interference epfdt For each GSO interfered with satellite test point the following steps should be used in determining the PPII in the case of epfdt calculations Step 1 For each interfering non GSO network earth station identify the position of the interfering network satellite that is in line with the considered earth station and the GSO interfered with satellite Step 2 Place the reference satellite at this position and determine the position of all other satellites in the constellation for the two possible configurations according to Part D 6 2 Step 3 These Nyon GsOearthstations X Nnon GSOsatellites X 2 satellite positions form the set of PPIIs It should be noted that the switch off alg
36. 1 Part D REGION3 DOWN Applicable in Region 3 3 1 Part D P Maximum power emitting by the non GSO satellite antenna beam i dBW in the reference 2 3 1 Part C bandwidth G Non GSO satellite antenna gain dBi 2 3 1 Part C G_cross Cross polarization non GSO satellite antenna gain dBi 2 3 1 Part C Neo Maximum number of co frequency co polarization beams 2 3 1 Part C Ner ss Maximum number of co frequency cross polarization beams 2 3 1 Part C ANTENNA POINTING Description of antenna pointing method of the non GSO satellites e g steerable fixed cells 2 4 1 and 2 4 2 Part C on the Earth fixed relative to satellite s direction of motion fixed relative to lines of longitude 3 2 3 3 3 Rec ITU R 8 1503 19 epfd calculations FSTART_IS Frequency band start where epfd applied GHz 4 2 1 Part D FEND IS Frequency band end where epfd applied GHz 4 2 1 Part D REGION1 IS Applicable in Region 1 4 2 1 Part D REGION2 IS Applicable in Region 2 4 2 1 Part D REGION3 IS Applicable in Region 3 4 2 1 Part D non_GSO_SS_EIRP e i r p per non GSO space station dBW in the reference bandwidth RIFBW 4 2 4 2 Part D Detailed data on mitigation technique s employed Description of mitigation technique used including all aspects affecting calculation of pfd masks 3 4 3 4 1 3 4 2 4 1 pfd spatial reference system Uplink direction of transmission Mi
37. 2 2m tan x 2 k T k 1 for m lt x lt and where sinb Cm arcsin 0 40 sin 6 and in cy arcsin x Oo 41 sind Rec ITU R S 1503 79 In the case of circular orbits 0 lin equations 40 and 41 and since e 0 gt k 1 equation 39 is reduced to 6 2 0 for o lt x lt T f x t z for T lt XST 2 T l for nm lt x lt Finding the position of all satellites in the constellation In this section the following notations and definitions are used Yy Satellite phasing between planes Angle between the intersections of adjacent orbit planes and the equatorial plane Major semi axis of the elliptical orbit o Argument of the perigee Unitary vector in the z axis direction r Orbit radius circular orbit True anomaly of the reference satellite in constellation configuration measured from the line of nodes True anomaly of the reference satellite in constellation configuration Eccentric anomaly of the reference satellite in constellation configuration Mean anomaly of the reference satellite in constellation configuration Eccentric anomaly of the i th satellite in the j th orbital plane corresponding to constellation configuration Unitary vector in the direction of the i th satellite in the j th orbital plane corresponding to constellation configuration Vector of the position of the i th satellite in the j th orbital plane corresponding to con
38. 49 Step 4 Calculate EPFD DOWN END by rounding EPFD DOWN MAX to nearest 10 dB above Step 5 Number of bins EPFD DOWN END EPFD DOWN START Sz This will give a set of bins that are of size Sp bin size specified in Part D 2 5 and are below and above the epfdy limits required 3 2 Determination of maximum epfd configuration The algorithms to determine the location of the GSO earth station and satellite that corresponding to the maximum epfd configuration are given in Part C 3 3 Calculation of run steps 3 3 1 Time simulation approach The fine time step is calculated using the algorithm in Part A together with the calculation of the number of time steps Dual time step option In order to improve simulation performance an option to the algorithm is to implement two time steps A coarse time step would be used except when any non GSO satellite is near one of the two conditions exclusion angle amp or X 0 exclusion angle amp or X edge of exclusion zone Figure 17 shows where to use the finer time step FIGURE 17 GSO earth station Exclusion zone for non GSO satellite Track across exclusion zone GSO arc GSO satellite 1503 17 The algorithm in Part D 3 5 1 shows the optional steps for dual time steps as sub steps i e 5 1 5 2 6 1 6 2 6 3 and 22 1 A coarse step size is used for non critical regions far from the GSO earth station main beam axis and exclusion zone boundaries This step size is de
39. GSO constellation into a GSO downlink It is assumed that each non GSO satellite has a pfd mask From the pfd for each satellite the aggregate epfd at an earth station of a GSO system is calculated This is repeated for a series of time steps or reference satellite positions in the analytical method until a distribution of epfd is produced This distribution can then be compared with the limits to give a go no go decision Figure 16 shows the geometry with constellation of non GSO satellites and test GSO satellite transmitting to a GSO earth station 48 Rec ITU R S 1503 FIGURE 16 1503 16 3 1 Configuration parameters This sub section specifies the parameters required for all epfd calculations defined in the RR This would be a data set of N sets of limits that can be shared between runs The Table could be queried so that the required values can be used depending upon non GSO system frequency These constants as described in Part B 2 2 are GSO_ES_ PATTERN One of those in Part D 5 5 Array of NEPFD DOWN epfd values EPFD DOWN I dB W m BW Array of NEPFD DOWN percentages PC I From the EPFD DOWN Jarrays the number of bins and bin ranges can be calculated using Step 1 Calculate EPFD DOWN MIN minimum value in EPFD DOWN I array Step 2 Calculate EPFD DOWN MAX maximum value in EPFD DOWN I array Step 3 Calculate EPFD DOWN START by rounding EPFD DOWN MIN to nearest 10 dB below Rec ITU R S 1503
40. GSO earth station were directly below the GSO satellite see Fig 3 then the value of the minimum simulation time increment could be calculated using equations 1 and 2 In that case a width of the non GSO earth station antenna main beam should be taken instead of that of the GSO earth station antenna main beam rs _____Non GSOSS EN 34B 4 Nef X Z X iS K Non GSO Es 1503 03 TABLE 4 Input data Orbit altitude degrees Rec ITU R S 1503 9 2 1 4 Algorithm of determining the uplink simulation time increment Calculation algorithm Step 1 Input the data listed in Table 4 Step 2 For satellites with different altitude and inclination calculate the simulation time increments by equations 1 and 2 Step 3 Select a simulation time increment 2 1 5 Description of the procedure for determination of minimum inter satellite simulation time increment The time step size for epfdj calculations is derived by considering that there should be at least Nj time steps during which the non GSO satellite is within the main beam of the GSO satellite Given that the shortest time step is when the beam at the GSO is pointed as far as possible away from the sub satellite point and given the following Re radius of the Earth h height of non GSO orbit Rgeo radius of geostationary orbit Q3qp half power beamwidth of GSO beam Then the time step can be calculated using the following algorithm see Fig 4
41. GSO earth stations are then determined by the points on the Earth for which the angle between the non GSO satellite and the GSO satellite equals Xo 13 Algorithm for the research of maximum epfd locations In the following paragraph all a angles can be replaced by an X angle Step 1 If non GSO satellites are switched off in the exclusion zone then go to Step 2 else go to Step 4 Step 2 Determine the non GSO satellite latitude non GSO lat and Along the difference between the non GSO space station longitude and the GSO space station longitude for which PFD a Aq Along LOI is maximum ong max Step 3 Store Along non GSO lat Go to Step 6 Step 4 If max PFD a Qg Along an pfd a 0 Along gt 0 long max then the maximum epfdy occurs at amp Og else the maximum epfd occurs at amp 0 Sub step 4 1 Determine the non GSO latitude non GSO lat and Along the difference between the non GSO space station longitude and the GSO space station longitude for which G O max PFD Q Qg Along Along is maximum if maximum epfdJ occurs at amp 0 PFD a Q9 Along is maximum if maximum epfd occurs at a 0 Along Step 5 Store non GSO lat Along Step 6 Select the first non GSO satellite which is at the latitude non GSO lat Step 7 Store the non GSO satellite longitude Step 8 Calculate the GSO satellite longitude Step 9 If non GSO satellites are switched off in the exclusion zone or
42. PRECESS Precession rate 3 4 4 4 1 4 4 and 4 2 4 4 Part D 18 Rec ITU R S 1503 3 2 Non GSO RF parameter inputs 3 2 1 Earth stations non GSO ES PATTERN Non GSO earth station antenna pattern 3 3 Part C P Maximum power at the input to the non GSO earth station antenna in the reference 3 4 Part C bandwidth dBW FSTART_UP Uplink frequency band start GHz 4 1 1 Part D FEND UP Uplink frequency band end GHz 4 1 1 Part D REGION1_UP Applicable in Region 1 4 1 1 Part D REGION2_UP Applicable in Region 2 4 1 1 Part D REGION3_UP Applicable in Region 3 4 1 1 Part D ES_TRACK Maximum number of co frequency tracked non GSO satellites 4 1 4 2 Part D ES_EIRP e i r p per non GSO earth station dBW in the reference bandwidth RAFBW 4 1 4 2 Part D ES_MINELEV Minimum elevation angle of the non GSO earth station when it is transmitting degrees 4 1 4 2 Part D ES_MIN_GSO Minimum angle to GSO arc degrees 4 1 4 2 Part D ES DENSITY Average number of non GSO earth stations co frequency with GSO link km 4 1 4 2 Part D ES DISTANCE Average distance between cell or beam footprint centres stations co frequency with GSO 4 1 4 2 Part D link km 3 2 2 Satellites FSTART DOWN Downlink frequency band start GHz 3 1 Part D FEND DOWN Downlink frequency band end GHz 3 1 Part D REGION DOWN Applicable in Region 1 3 1 Part D REGION2 DOWN Applicable in Region 2 3
43. Part C Function 2 Calculation of cumulative time distributions of epfdy and epfd 1 6 Part D N Common BR database parameters 2 1 Parameters provided by administration of the non GSO system Annex 1 to Part B details the existing and future RR Appendix S4 parameters of any non GSO FSS constellation to be provided by administrations to the BR for coordination request or notification processing 2 2 BR supplied inputs and database parameters Sp Bin size for quantizing epfd statistics 0 1 dB 2 5 3 4 5 and 4 1 4 5 Part D REGION1 UP Applicability of Region 1 yes or no 4 1 1 Part D REGION DOWN Applicability of Region 1 yes or no 3 1 Part D REGION2 UP Applicability of Region 2 yes or no 4 1 1 Part D REGION2 DOWN Applicability of Region 2 yes or no 3 1 Part D REGION3_UP Applicability of Region 3 yes or no 4 1 1 Part D REGION3 DOWN Applicability of Region 3 yes or no 3 1 Part D 16 Rec ITU R S 1503 REFBW Reference bandwidth for epfd calculations kHz 3 1 Part D NEPFD_DOWN Number of epfdy points 3 1 Part D EPFD DOWN RR IJ Array of NEPFD_ DOWN values dB W m in reference bandwidth from Article S22 of 3 1 Part D the RR DOWN PC RR IJ Array of NEPFD DOWN percentages from Article S22 of the RR 3 1 Part D RAFBW Reference bandwidth for epfdy calculations kHz 4 1 1 Part D NEPFD_UP Number of epfdy points 4 1 1 Part D EPFD_UP_RRI I Array of NEPFD_
44. Rec ITU R S 1503 1 RECOMMENDATION ITU R S 1503 FUNCTIONAL DESCRIPTION TO BE USED IN DEVELOPING SOFTWARE TOOLS FOR DETERMINING CONFORMITY OF NON GEOSTATIONARY SATELLITE ORBIT FIXED SATELLITE SYSTEM NETWORKS WITH LIMITS CONTAINED IN ARTICLE S22 OF THE RADIO REGULATIONS Resolutions 130 WRC 97 and 538 WRC 97 2000 The ITU Radiocommunication Assembly considering a that for the use of non geostationary systems in the fixed satellite service non GSO FSS systems in certain frequency bands including bands covered by Appendices S30 S30A and S30B WRC 97 adopted provisional power limits and included these limits in Table S22 1 of Article S22 of the Radio Regulations RR and Annex 1 to Resolu tion 130 WRC 97 and Annex to Resolution 538 WRC 97 b that these frequency bands are currently used or planned to be used extensively by geostationary satellite systems GSO systems c that to perform the regulatory examination of such non GSO FSS systems the Radiocommunication Bureau BR requires a software tool that permits the calculation of the power levels produced by such systems on the basis of the specific characteristics of each non GSO FSS system submitted to the Bureau for coordination or notification as appropriate d that GSO FSS and GSO broadcasting satellite service BSS systems have individual characteristics and that interference assessments will be required for multiple combinations of antenna characteristics interfere
45. S4 has been updated the BR will proceed with including them on the notice forms and in the database 22 Rec ITU R S 1503 FIGURE 7 non geo orbit s_beam phase s_as_stn grp Lo e_as_stn emiss assgn e srvcls Y T srv_cls srv_area 1503 07 TABLE 8 ApS4 II notified data for non GSO system ctry exe T Symbol indicating kilohertz K megahertz M or gigahertz G 50 EENES Name of the transmitting or receiving station stn name X X X X X X e_as_stn EJ Associated earth station ey EJ Symbol of the country or geographical area in which the station is located Code indicating if the earth station is specific S or typical T x Degree part of longitude coordinate of the station expressed in degrees minutes and seconds Longitude direction indicator East E or West W Minute part of longitude coordinate of the station expressed in degrees minutes and seconds long_sec Second part of longitude coordinate of the station expressed in degrees minutes and seconds Latitude direction indicator North N or South S Second part of latitude coordinate of the station expressed in degrees minutes and seconds noise _t C 10 c 5 96 Total receiving system noise temperature expressed in kelvins referred to the output of the receiving antenna gain C 10 c 2 99 9 Maximum i
46. SO system would be used where the definitions of the parameters are specified in Part D 5 3 1 at the time of the start of the simulation Note that in the Table below the indices N are present to indicate that there would be a different value for each satellite and the N th value corresponds to the N th satellite For the pfd mask it indicates that the pfd data is structured in such a way that the pfd N entry is a reference that points to a particular sub set For example each satellite in the constellation could reference the same pfd lat az el pfd lat X Along or pfd lat a Along table Parameter description O N degrees Longitude of ascending node Argument of perigee WIN degrees Because of the use of a pfd mask the number of antennas on the satellite and the non GSO RF link parameters are not necessary for epfd calculation However each satellite could have an individual pfd mask and so for each satellite there would be a reference into the pfd mask database Each satellite must have an independent set of six orbital parameters for orbit definition and subsequent propagation 3 4 3 GSO system parameters The GSO system parameters can be taken from either the algorithm in Part D 3 2 or entered values In that case the following parameters specified in Part B 2 1 are used G50 stl Toate 50 LONG GSO earth station latitude GSO ES LAT GSO earth station longitude GSO ES LONG Reference earth statio
47. The PDF shall be converted into a cumulative distribution function CDF which records for each pfd level the number of simulation time steps at which that pfd level was exceeded normalized by the total number of simulation time steps When the analytical method is used a PDF of the pfd is directly determined This PDF records the probability of occurrence of each pfd level These probability values correspond to the percentage of time that the pfd level would occur in an infinite time observation interval This PDF can also be converted into a CDF 7 1 2 Production of the CDF The process detailed in Part D 3 5 generated a PDF of the pfd values This PDF shall be converted into a CDF which records for each pfd level an estimate of the percentage of time during which that pfd level is exceeded 84 Rec ITU R S 1503 For each pfd value the CDF shall be calculated by where 7 1 3 CDF 100 1 SUM PDF min PDF PDF PDF table entry for a pfd value of X dB normalized so that the total sum for all PDF is 1 Comparison procedure The next stage is the comparison of the pfd limit values in the RR with those in the probability table Step 1 Step 2 Step 3 Step 4 Step 5 Perform Steps 2 through 4 for each specification limit i Read the pfd value probability pair J and P from the database If the pfd value J has a higher precision than Sg currently 0 1 dB round J to a lower value with a maximum pre
48. UP values dB W m in the reference bandwidth from Article 22 of 4 1 1 Part D the RR UP PC RR IJ Array of NEPFD UP percentages from Article S22 of the RR 4 1 1 Part D F DOWNgat Downlink transmit centre frequency GHz 3 4 2 Part D Nfreq Number of frequency regions 3 4 2 Part D GSO_SEPARATION Separation between GSO satellite test points 1 2 5 Part D GSO LONG GSO satellite longitude s degrees 3 4 3 and 4 1 4 3 Part D GSO ES LAT GSO earth station latitude degrees 3 4 3 Part D GSO ES LONG GSO earth station longitude degrees 3 4 3 Part D GSO ES PATTERN Reference gain pattern of the GSO earth station from among those specified in Part D 3 4 3 Part D 5 5 GSO ES D ANT Earth station antenna diameter 3 1 and 3 4 3 Part D BS LAT GSO boresight latitude 4 1 2 and 4 1 4 3 Part D BS LONG GSO boresight longitude 4 1 2 and 4 1 4 3 Part D ES F Uplink frequency GHz 4 1 4 2 Part D GSO SAT PATTERN GSO satellite reference antenna gain pattern and related parameters selected from among 4 1 1 and 4 1 4 2 Part D those in Part D 5 5 2 GSO SAT PEAKGAIN GSO satellite peak gain 4 1 1 Part D GSO SAT BEAMWIDTH GSO satellite half power beamwidth 4 1 1 Part D Rec ITU R S 1503 17 RIFBW Reference bandwidth for epfd calculations kHz 4 2 1 Part D NEPFD IS Number of epfd points 4 2 1 Part D EPFD IS I Array of NEPFD IS values dB W m in the re
49. ameters as specified in Part B 2 1 would be used OS eer Region One of 1 2 or 3 The filing administration can supply a set of earth station frequency applicable region The ITU database of limits can be searched to extract those applicable for each set 4 2 4 3 GSO system parameters The GSO system can be either calculated or use worst case parameters using the algorithm in Part D 5 2 or entered values The required parameters as specified in Part B 2 1 are GSO satellite longitude GSO SAT LONG GSO boresight latitude BS LAT GSO boresight longitude BS LONG GSO reference gain pattern GSO SAT PATTERN One of those in Part D 5 5 Rec ITU R S 1503 65 These parameters are defined in Part D 5 1 and 5 2 4 2 4 4 Run parameters The run parameters can be either calculated using the algorithm in Part D 4 1 3 or entered values For the time simulation approach the required parameters are Number of time steps NSTEPS Precession mechanism J2 or Admin Supplied or Artificial For the analytical method approach the required parameters are related to increments in the reference satellite position Longitude step for the coarse grid PHISTEPCG degrees 4 2 4 5 Other parameters The run would also use the epfd limits database from Part D 4 1 1 to get three defining parameters for the epfdis statistics Starting value for epfd bins EPFD_IS START dB W m BW Bin size Pan D
50. and lunar attraction medium drag for satellite solar radiation pressure etc The function description of software in this Annex accounts orbit perturbations only due to the Earth oblateness It is motivated by the fact that effect of other perturbing factors is significantly less The Earth s oblateness causes secular and periodic perturbations of ascending node longitude and orbit perigee argument Part D describes expressions to account the Earth s oblateness effect The orbits of some repeating ground tracks can be very sensitive to the exact orbit model used Administrations could also provide the BR with their own independently determined average precession rates that could be used by the software instead of the values calculated using the equation in Part D 2 System requirements Two approaches are described in this Annex analytical method and time simulation time simulation in which interference levels are evaluated at each time step and the analytical method in which interference levels are evaluated at increments of the position longitude and latitude of a non GSO network reference satellite Paragraph 2 1 and 2 2 of Part A refer to the choice of time steps and the total number of time steps to be used in the time simulation approach Paragraph 2 3 of Part A refers to the choice of the longitude and latitude increments to be used in the analytical method approach 2 1 Simulation time increment and accuracy The simulat
51. angle is valid must be given In this case it is the start of the simulation i inclination angle This is defined as the angle between the plane of the orbit and the equatorial plane The orbit and position of the non GSO satellite within the orbit is then defined by further parameters as shown in Fig 24 FIGURE 24 Non GSO satellite U S Nn L VAN Pj Perigee Apogee Line of ascending node nx Semi major axis a 1503 24 The shape of the orbit is defined by a Ry R 2 18 e Ra Rp Ra Rp 19 where a semi major axis e eccentricity R distance from the centre of the Earth to the satellite at apogee Rp distance from the centre of the Earth to the satellite at perigee The position of the perigee within the orbit plane is defined by argument of perigee angle between the line of the nodes and perigee The position of a non GSO satellite within the plane at a particular time is defined by vo angle between perigee and specified point on orbit For circular orbits can be set to zero and vg assumed to be the same as the argument of latitude defined as Ho Vo 20 72 Rec ITU R S 1503 Other useful terms are pale 21 M E esin E 22 tan Ia H tan 23 2 l e 2 Raok 24 1 ecos v T 2na fu 25 where p focal parameter E eccentric anomaly M mean anomaly T period of orbit R distance from centre of Earth to satellite when satelli
52. applicable the power allocated to one cell may vary taking into account the elevation angle relative to this cell for example FIGURE 11 View in 3D of the iso 0 line AZ iso line Oper longon oso 4 es Along GSO arc tt eef 1503 11 Step 5 The generation of the pfd mask also needs to take into account accurately the mitigation technique implemented within the non GSO system With regard to the use of a non operating zone around the GSO arc there are three different ways of modelling a non GSO system based on a cell architecture cell wide observance of a non operating zone a beam is switched off when one point on the Earth sees a non GSO satellite within og of the GSO arc In this particular case any beam illuminating a cell which is crossed by an iso line corresponding to a value a lt ag is switched off cell centre observance of a non operating zone a beam is switched off when the centre of the cell sees a non GSO satellite within og of the GSO arc In this case any beam illuminating a cell with its centre inside the non operating zone bounded by the two iso Q lines is switched off if a satellite based reference is chosen a beam of a non GSO space station turns off when the angle X is less than Xo The reference angle X is the angle between a line projected from the GSO arc through the non GSO space station to the ground and a line from the non GSO space station to the edge of the non GSO b
53. approach The analytical method can be used to evaluate the statistical behaviour of interference e g epfd in environments containing non GSO networks In the following paragraphs the analytical method is applied to evaluate the statistical behaviour of the epfd levels produced by a non GSO network into receivers earth station or satellites of GSO networks 76 Rec ITU R S 1503 Methodology Let us consider an interference environment involving one non GSO interfering network and one or more GSO victim networks The approach being considered in this method to assess interference in such an environment takes into account the fact that once the position of one particular satellite here referred to as the reference satellite in the non GSO interfering constellation is known the epfd levels affecting the receivers in GSO satellite networks considering that all systems parameters are given can be uniquely determined It further assumes that the positions of this reference satellite is characterized by a random vector Based on these assumptions epfd levels can be seen as random variables that are deterministic functions of the random position x 0 7 longitude and latitude 8 of the non GSO reference satellite and therefore their probability density functions can be determined from the probability density function px of the position longitude and latitude of the reference satellite For a satellite placed in elliptical o
54. as well as epfd limits The calculation section is designed for estimations required to examine notified non GSO systems compliance with the epfd limits The calculation section is based on a concept of a downlink power flux density pfd mask see Note 1 an uplink effective isotropic radiated power e i r p mask see Note 2 and inter satellite e i r p mask see Note 3 NOTE 1 A pfd mask is a maximum pfd produced by a non GSO space station and is defined in Part C NOTE 2 An e i r p mask is a maximum e i r p radiated by a non GSO earth station and is a function of an off axis angle for the transmitting antenna main beam NOTE 3 An inter satellite e i r p mask is a maximum e i r p radiated by a non GSO space station and is a function of an off axis angle for the boresight of the non GSO space station Rec ITU R S 1503 3 A pfd e i r p mask is calculated in Block 1 based on the notified non GSO system parameters delivered from the initial data section Block 4 tests the aggregate interference produced by non GSO network stations for meeting epfd limits The verification in Block 4 is effected on the basis of the non GSO system constellation characteristics from the initial data section a pfd e i r p mask from Block 1 and output data from Block 3 The output data are verified for validity in Block 2 FIGURE 1 Parameters of a non GSO system delivered by a notifying Initial data available at the BR Initial
55. at any point on the Earth s surface is the sum of the pfd produced by all illuminating beam in the co frequency band Some non SFO systems have tracking antennas which point to cells fixed on the Earth s surface and do not move with the spacecraft However since the pfd mask is generated with respect to the non GSO location assumptions must be made in the development of the pfd mask Making the simplifing assumption that the cells move with the spacecraft can lead to inaccurate geographic distributions of epfd levels It was noted that as non GSO systems use mitigation techniques there will be no main beam to main beam alignment Therefore de polarization effects mean that both co polarization and cross polarization contributions must be included as sources of interference Rec ITU R S 1503 31 FIGURE 8b Relationship between geometries for satellite based exclusion angle X and ground based angle A in case of interference from non GSO into GSO networks Point on GSO arc that minimizes Ol Non GSO satellite Non GSO ES Non GSO exclusion zone 1503 08b This implementation of the pfd mask explicitly accounts for both co polarization and cross polarization from non GSO satellites into GSO earth stations for like types of polarization circular to circular or linear to linear Isolation between systems of different types of polarization circular to linear is not directly covered A study has shown that the average
56. atellite at the centre of the cell Determine the location of all other satellites in the constellation there are two possible constellation configurations according to the expressions in Part D 6 2 62 Rec ITU R S 1503 Step 11 Repeat Steps 12 to 25 for each of the two configurations Step 12 Set epfdt 0 Step 13 Repeat Steps 14 to 24 for all non GSO earth stations Step 14 Calculate if this non GSO earth station is visible to the GSO satellite using the algorithm in Part D 5 4 2 Step 15 If the non GSO earth station is visible to the GSO satellite then do Steps 16 to 24 Step 16 Repeat Steps 17 to 24 for the maximum number of non GSO satellites that can be tracked Step 17 Select the i th satellite away from the GSO arc that is above minimum elevation angle and not inside the GSO exclusion zone Step 18 Ifthe algorithm has selected a satellite then do Steps 19 to 24 Step 19 Calculate ES EIRP dB W BW a of non GSO earth station in direction of GSO satellite using non GSO earth station e i r p mask in Part C 3 REP EIRP ES_EIRP 10log NUM_ES Step 20 Calculate Gry receive relative gain dB at GSO satellite using relevant gain pattern specified in the algorithms in Part D 5 5 Step 21 Calculate D distance km between the non GSO earth station and the GSO satellite using the algorithm in Part D 5 4 1 Step 22 Calculate the spreading factor Lpg 10 log 4n D 60 Step 23 Calcu
57. ation of a mask for pfd e i r p produced by interfering non GSO network stations The mask would account for all the features of specific non GSO systems arrangements The first stage would be finalized with delivering the pfd e i r p mask in analytical or documented formats to the BR Moreover the notifying administration would provide the BR with the software used in Block 1 for the pfd e i r p mask estimation the complete software description and parameters from Block a as well as any additional information that is useful to regenerate the pfd e i r p mask The information mentioned shall also be available for other administrations The second stage calculations would be effected at the BR The second stage would feature the following operations Definition of the maximum epfd geometry of a GSO space station and an earth station of that network Block 3 It would ensure verification of sharing feasibility for a notified non GSO network with any GSO network in the FSS and BSS epfd statistics estimation Block 4 Software results verification for validity Block 2 Making a decision on interference compliance with epfd limits Block 4 The estimations are based on the non GSO system parameters Block a delivered by a notifying administration and the initial data Block b available at the BR 4 Rec ITU R S 1503 Any administration may use software that uses the algorithms defined in this Annex together with data on th
58. ations 8 and 9 has two unknown parameters and therefore a single solution Rec ITU R S 1503 45 3 2 Using an X angle In this case the maximum epfdy occurs for a GSO earth station placed at a point on the Earth for which the angle at the non GSO satellite between the GSO earth station and the line projection from the GSO satellite through the non GSO satellite to the surface of the Earth is equal to Xo If Pin line is the line projection from the GSO satellite through the non GSO satellite to the surface of the Earth then the system of equations that has to be satisfied to determine the GSO earth station location is then NG NEin line cos Xp 10 Re PVF ame and NG NP mo sin X TELE 11 re Fane The set of equations 10 and 11 has two unknown parameters and therefore a single solution PART D Software for the examination of non GSO filings 1 Introduction 1 1 Scope The scope of this section is to specify part of a software requirements document SRD for a computer program that can be used by the BR to calculate whether a specific non GSO system proposed by an administration meets epfd limits This section defines two approaches time simulation in which interference levels are evaluated at each time step and the analytical method where interference levels are evaluated at increments of the position latitude and longitude of a reference satellite see Part D 6 1 2 Background T
59. cantly For the case of repeating ground tracks this means that there will be a single repeat period for the constellation This is the time for all satellites within the constellation to return to the same position relative to the Earth and each within the constraints of station keeping For the case of non repeating ground tracks there will be a single period for all the orbit planes to process around the equator This approach is to be used for constellations with both circular and elliptical orbits Table 5 shows the input parameters used in all constellation types TABLE 5 Input data EE In both cases the time step can be calculated using the method described above The number of time steps should be at least Nmin Ns X 100 100 maximum in the Tables of Article S22 of the RR less than 100 So for example for the 99 999 case the number of steps would be Nmin 1000000 Rec ITU R S 1503 11 2 2 1 Repeating orbits For those orbits specified as being repeating the orbit predictor has to be accurate to ensure repeatability Thus there is an option for administrations to specify the exact longitude precession rate with respect to a point mass orbit predictor that ensures the orbit would repeat The definition and use of this parameter is in Part D With this parameter a simulated orbit would be repeated but in reality there would be a slight drift due to longitudinal station keeping errors This effect is modell
60. cision of 0 1 dB From the CDF find P the probability that pfd value J was exceeded as obtained by the software If P lt P then record Pass the CDF complies with this specification point Else record Fail the CDF does not comply with this specification point The final stage is the comparison of the maximum pfd value recorded during the software run with the limit specified for 100 time if any From the CDF find the maximum pfd value recorded during the software run Jma Compare it with the pfd limit specified for 100 time J100 If Imar lt Jing then record Pass the CDF complies with this specification point If Jmax 2 J100 then record Fail the CDF does not comply with this specification point 7 1 4 Decision process If a Pass result was recorded for all of the specification limits then the non GSO network complies with the specification If any Fail results were recorded then the non GSO network does not comply with the specification 7 2 Background information to decision The background information required is pfd data generated in the software run including antenna diameter and reference antenna pattern table of specification limits for various antenna diameters and reference antenna pattern 7 3 Format for output The output format shall be statement of the result of the test summary table CDF table for information only 7 3 1 Statement of the result of the comp
61. cond order compared to the density of non GSO earth stations In the mean time the further from the sub satellite point the GSO satellite is pointing the larger the beam size illuminated on the ground In the case where the GSO satellite antenna discrimination is taken into account the pointing direction of the maximum epfdy corresponds to a case where there is a high density of non GSO earth stations within the GSO coverage area and a maximum number of contributors in the far side lobes Therefore the maximum epfdt will occur for a GSO space station pointing far from the sub satellite point Then the GSO space station located at a longitude of 50 E and pointing towards a direction at 42 5 N corresponds to one of the maximum epfd7 locations This calculation has been achieved by assuming that the edge of the coverage area is at an elevation of 10 and that a GSO antenna aperture of 4 in the 14 11 GHz band is used In the 30 20 GHz band the GSO space station is located at a longitude of 50 E and pointing towards a direction at 50 9 N which corresponds to a minimum elevation angle of 20 and a GSO antenna aperture of 1 55 3 Determination of GSO network location for maximum epfdis The location of the GSO space station and its pointing direction remains the same as for the computation of the epfdt see Part C 2 ANNEX 1 TO PART C 1 In line geometry Let the system be considered in the geocentric reference Let
62. d the equator namely Trun Tperiod Norbits Step 13 The total number of time steps is then Nsteps Round Tyun Tstep to nearest integer below 2 3 Longitude and latitude increments for use in the analytical method approach In the analytical method approach see Part D 6 the position longitude and latitude of a non GSO network reference satellite is varied in some specified increments covering the range of all possible values of longitude and latitude These longitude and latitude increments play a role similar to that of the time step in the time simulation approach and have to be chosen to guarantee precise results The choice of these parameters should be done according to the guidelines in Part D 6 3 and 6 4 PART B Parameters of non GSO system 1 Introduction 1 1 Background Certain parameters for a non GSO network and other data must be specified in order to accomplish the requisite software functions Function 1 Calculate the pfd masks for the non GSO satellites downlink and the e i r p mask for the earth stations transmitting to those satellites uplink Function 2 Apply the e i r p mask in the calculation of uplink epfdy levels and downlink equivalent pfd epfd levels cumulative time distributions of epfdt or epfdy Function 3 Determine whether the pfd e i r p mask levels are consistent with basic transmission parameters of the non GSO network only in the case of dispute Rec
63. de of the non geostationary satellite above the surface of Distances gt 99 999 km are expressed as a the Earth or other reference body km product of the values of the fields perigee and perig exp see below e g 125 000 1 25 x 10 perig exp A 4 b 3b Exponent part of the perigee expressed in power of 10 To indicate the exponent give 0 for 10 1 for en 2 for 10 etc ref ret body EEE EN Code for the reference body about which the satellite orbits for the reference body about which the satellite orbits nbr _sat A 4 b 4 9 4 Number of non geostationary satellites used in an identical non geostationary orbit A 4 b 5 99 x Number ofnon geostationary orbital planes o Number of non geostationary orbital planes of non geostationary orbital planes A 4 b 1 999 9 ii Inclination angle of the satellite orbit with respect to the plane of the ee Equator 9 COSTS ALI A TABLE 8 continued Items in ore SE eee aaa EE A 4 b 5 999 99 Angular separation in degrees between the ascending node and the vernal CG equinox inclin_ang A 4 b 5 999 9 x Inclination angle of the satellite orbit with respect to the plane of the Equator A 4 b 5 9 5 Semi major axis of the satellite orbit kilometres perig arg A 4 b 5 999 9 x Angular separation degrees between the ascending node and the perigee of an elliptical orbit A 4 b 5 999 9 Initial phase angle of the satellite in the orbital plane el stn_ type C 10 X x Type
64. define which approach is used 4 1 Option 1 The four dimensional pfd mask database format should be the following one number n 1503 12a Rec ITU R S 1503 39 4 2 Option 2 The four dimensional pfd mask database format should be the following one number n 1503 12b PART Maximum epfd location of GSO network 1 Maximum epfd location of the GSO earth station pointing towards the GSO satellite for epfd calculation The solution proposed to define a maximum epfd location of the GSO earth station is based on a pfd mask referenced by latitude of the non GSO space station angle to GSO arc a or satellite angle X see Fig 13 and the difference between the longitude of the GSO satellite and the longitude of the non GSO sub satellite point Along FIGURE 13 Representation of the maximum epfd situation Earth s surface r GSO arc Non GSO satellite Line a ennn al GSO satellite 3 1503 13 To take into account the different values that the RR Article S22 limits may have for different latitudes throughout this section maximum epfd should be understood as maximum epfd limit The highest peaks of downlink interference may occur either Situation 1 When a non GSO satellite side lobes passes through the main beam of a GSO earth station or Situation 2 When a non GSO satellite main beam passes through the side lobes of the GSO earth station 40 Rec ITU R S 1503 FIGURE 14 Representat
65. e GSO system earth station the following algorithm should be used The algorithm can be used on multiple GSO systems in parallel if required Step 1 Step 2 Read in parameters for non GSO system as specified in Part D 3 4 2 Read in GSO parameters as specified in Part D 3 4 3 54 Step 3 Step 4 Step 5 Step 6 Step 7 Step 8 Step 9 Step 10 Step 11 Step 12 Step 13 Step 14 Step 15 Step 16 Step 17 Step 18 Step 19 Step 20 Step 21 Step 22 Step 23 Step 24 Step 25 Step 26 3 6 Rec ITU R S 1503 If required calculate maximum EPFD GSO location using algorithm in Part D 3 2 Initialize statistics by zeroing all bins of epfdy values Make a partition of the non GSO reference satellite 9 plane Repeat Steps 7 to 23 for each element cell of the p 8 plane partition Calculate the probability PROB of finding the non GSO reference satellite inside the cell according to the expression in Part D 6 1 Place the non GSO reference satellite at the centre of the cell Determine the location of all other satellites in the constellation there are two possible constellation configurations according to the expressions in Part D 6 2 Repeat Steps 11 to 23 for each of the two configurations Set epfd 0 Select all non GSO satellites visible to the GSO earth station using the algorithm in Part D 5 4 1 Repeat Steps 14 to 19 for each visible non GSO satellite
66. e non GSO networks to estimate statistics for interference into its own GSO networks and check for compliance with epfd limits It would assist in solving probable disputes between the BR and administrations concerned The elements of the software block diagram discussed are presented hereinafter in detail The Parts are as follows Part A Basic limitations and main system requirements for the software as a whole are presented Part B Non GSO networks parameters and initial data for Blocks a and b are discussed Part C Definitions and estimation algorithms for pfd e i r p masks relative to non GSO network earth and space stations are presented Specifics of those masks applying in simulation is also discussed Block 1 Part C This part deals with procedures to define the maximum epfd location of GSO network stations Part D The part deals with general requirements on the software related to examination of non GSO networks notifications algorithms to estimate epfd statistics and the format for output data presentation Part D covers issues of Blocks 3 and 4 Parts EH These parts define requirements on the software related to valuation of delivered software and to verification of the software output on validity Block 2 Parts F G The software documentation and follow up operational environment and interface requirements and other matters are described 1 2 Units of measurement To provide for adequate simula
67. eam Step 6 The maximum pfd value corresponding to a given value amp within an interval of AL is pfd a AL maxg 1 2 n pfd Mg x Step 7 The location of an iso o line hence the value of the maximum pfd along this line depends on the latitude of the non GSO sub satellite point Therefore a set of pfd masks will need to be provided each corresponding to a given latitude of the sub satellite point Step 8 A set of pfd masks may be needed one per non GSO satellite 36 Rec ITU R S 1503 2 4 2 Option 2 The pfd mask is defined in a grid in azimuth and elevation per latitude of the non GSO sub satellite The objective of the mask is to define the maximum possible level of the pfd radiated by the non GSO space station in this azimuth elevation grid At each point of the non GSO satellite footprint the pfd value depends on the configuration of the spot beams which are illuminated by the satellite the maximum number of co frequency beams which can be illuminated simultaneously the maximum number of co frequency co polarization beams which can be illuminated simultaneously the maximum power available at the satellite repeater FIGURE 12 Field of view of a non GSO space station Option 2 ry Elevation Azimuth 1503 12 The proposed methodology for the generation of the pfd mask is explained in the following steps Step 1 At any given time in the field of view of a non GSO space
68. eatest interference to GSO networks In addition the methodology used to determine those points should be provided This includes locations of GSO satellites GSO satellite antenna boresight and GSO earth stations Rec ITU R S 1503 21 4 4 2 Points determined by BR in pre processing Points should be determined by the BR and an indication of the methodology used to determine the points should be provided 5 Inputs to software for self consistency tests Data from Part B 3 and Annex to Part B ANNEX 1 TO PART B This Annex 1 to Part B presents the actual format of the RR Appendix S4 database which should be updated to include the parameters needed Table 8 lists the current RR Appendix S4 information for non GSO satellite systems currently included in the BR space networks system database and the associated database for graphical data Graphical Interference Management System GIMS The relationship between the database tables is shown in Fig 7 New alphanumerical or graphical data elements used for processing pfd calculations involving non GSO satellite networks would certainly be required and should be identified defined as to their format and location in the data structure of the BR databases and added to this Table The list of such additional elements should eventually serve as a basis for administrations contributions on additional or modified information to be added to RR Appendix S4 at the forthcoming WRC Once RR Appendix
69. ed by mechanisms such as random sampling or linear drift in orbit as discussed in Part D It is expected that station keeping changes within the orbit plane would make no difference and so are not included The result should be like Fig 5 FIGURE 5 Non GSO satellite track GSO ES main beam i 1503 05 In Fig 5 it can be seen that the result would be a series of samples within the main beam of the GSO earth station that is sufficiently fine to resolve the main beam includes station keeping drift and produces sufficient samples to generate the required statistics TABLE 6 Input data Given the following parameters Nmin minimum number of time steps required for statistical significance Prepeat time period that the constellation repeats s Tstep time step s Nrracks number of tracks through the main beam 5 as specified by Recommendation ITU R S 1325 For this case the time step should not exactly divide the constellation repeat period If Nrepsteps P repeat Tstep is an integer then calculate a revised time step equal to Ld T step L step N repsteps JN repsteps 12 Rec ITU R S 1503 Calculate the time period required to get the minimum number of time steps for statistical significance Tsig Nin Tstep This corresponds to the following number of constellation repeats Nrep round Tsig Prepeat to nearest integer above The number of repeats of the constellation is the largest of Nep or Niracks 1
70. elocity vectors around the Z axis by the required angle using rotation matrix x cos sin6 0 x y sin cosd 0 y 33 z 0 0 1 Z to rotate by angle 6 NOTE 1 The software should check the orbit precession rate supplied under item a for self consistency with the other input parameters 5 4 Geometry 5 4 1 Satellite visibility check Two stations whether earth stations or satellites are visible if the direct distance between them is less than the sum of the distance to the horizon for each station using the spherical Earth model described in 5 1 5 4 2 Angle to GSO arc Figure 25 shows the definition of the o angle and X angle FIGURE 25 Non GSO satellite Earth station aL le Geostationary arc Test point P 1503 25 The Figure shows a test earth station and non GSO satellite For each test point P on the GSO arc there is a line from the earth station that intersects that point There is then an angle a between that line and a line from the earth station to the non GSO satellite The amp angle is the minimum of all the test points i e a min Q Similarly for each test point P on the GSO arc there is a line from the non GSO satellite that intersects that point There is then an angle X between that line and a line from the earth station to the non GSO satellite The X angle is the minimum of all the test points i e X min X 5 4 3 Satellite azimuth and elevation Fi
71. ement epfdis by epfdj Sub step 19 Increment epfd s statistics by this epfd s If a dual time step algorithm is included then the step below should be used Sub step 19 1 Increment epfd s statistics by the epfdis for this time step by Tstep fine entries Step 20 Generate the epfd CDF from the epfdj PDF using the algorithm in Part D 7 1 2 Step 21 Compare epfdj statistics with limits using algorithm in Part D 7 1 Step 22 Output results in format specified in Part D 7 2 4 2 5 2 Rec ITU R 8 1503 67 Analytical method approach To calculate epfdj values from one non GSO system into one GSO system satellite the following algorithm should be used The algorithm can be used on multiple GSO systems in parallel if required Step 1 Step 2 Step 3 Step 4 Step 5 Step 6 Step 7 Step 8 Read in parameters for non GSO system as specified in Part D 4 1 4 2 Read in GSO parameters as specified in Part D 4 1 4 3 If required calculate worst case GSO location using algorithm in Part D 4 1 2 Initialize statistics by zeroing all bins of epfdi values Make a partition of the non GSO reference satellite p plane Repeat Steps 7 to 19 for each element cell of the p plane partition Calculate the probability PROB of finding the non GSO reference satellite inside the cell according to the expression in Part D 6 1 Place the non GSO reference satellite at the centre of the cell Sub step 8 1
72. evation angle relative to this cell for example Rec ITU R S 1503 37 Step 3 The generation of the pfd mask also needs to take into account accurately the mitigation technique implemented within the non GSO system With regard to the use of a non operating zone around the GSO arc there are three different ways of modelling a non GSO system based on a cell architecture cell wide observance of a non operating zone a beam is switched off when one point on the Earth sees a non GSO satellite within ag of the GSO arc In this particular case any beam illuminating a cell which is crossed by an iso line corresponding to a value a lt ag is switched off cell centre observance of a non operating zone a beam is switched off when the centre of the cell sees a non GSO satellite within og of the GSO arc In this case any beam illuminating a cell with its centre inside the non operating zone bounded by the two iso 0 lines is switched off ifa satellite based reference is chosen a beam of a non GSO space station turns off when the angle X is less than Xo The reference angle X is the angle between a line projected from the GSO arc through the non GSO space station to the ground and a line from the non GSO space station to the edge of the non GSO beam Step 4 A set of pfd masks may need to be provided as a function of the latitude of the sub satellite point Step 5 A set of pfd masks may be needed one per non GSO satellite
73. f reference bandwidth kHz 38 Rec ITU R S 1503 Step 2 Assuming that the non GSO cells are uniformly distributed on the Earth s surface the simultaneous co frequency transmit non GSO earth stations are evenly distributed over the cell Therefore the interferer can be located at the centre of the cell to perform the simulation 3 2 Generation of space station e i r p masks The space station e i r p mask is defined by the maximum e i r p generated by a non GSO space station as a function of the off axis angle between the boresight of the non GSO space station considered and the direction of the GSO space station 3 2 1 Methodology The space station e i r p mask is defined by the maximum e i r p radiated in the reference bandwidth by the space station as a function of the off axis angle and is given by NGSO SS EIRP O G 6 P where NGSO SS EIRP equivalent isotropic radiated power in the reference bandwidth dB W BW 0 separation angle between the boresight of the non GSO space station and the pointing direction of the GSO space station degrees G 6 space station antenna gain pattern dBi corresponding to the aggregation of all beams P maximum power in the reference bandwidth dB W BW BW if reference bandwidth kHz 4 Format of the pfd mask This structure allows an administration to supply the data with fewer degrees of freedom if desired dimension of the pfd mask less than 4 The file format would
74. ference bandwidth 4 2 1 Part D IS PC I Array of NEPFD IS percentages 4 2 1 Part D IS F Frequency for epfdis calculation GHz 4 2 4 2 Part D For the analytical method only PHISTEPCG Longitude step for the coarse grid degrees 3 4 4 Part D THETASTEPCG Latitude step for the coarse grid degrees 3 4 4 Part D PHISTEPFG Longitude step for the fine grid degrees 3 4 4 Part D THETASTEPFG Latitude step for the fine grid degrees 3 4 4 Part D 3 Non GSO system inputs to software All data algorithms test points and methodologies used for generation of the pfd masks shall be provided to the BR to verify the submitted pfd masks for archival purposes in the case of dispute 3 1 Non GSO orbit parameters Neat Number of non GSO satellites 3 4 2 and 4 1 4 2 Part D Neollatitude Maximum number of non GSO satellites operating co frequency at latitude lat 3 4 2 Part D A N Semi major axis of orbit km 3 4 2 and 4 1 4 2 Part D E N Eccentricity of orbit 3 4 2 and 4 1 4 2 Part D I N Inclination of orbit degrees 3 4 2 and 4 1 4 2 Part D O N Longitude of ascending node of orbit degrees 3 4 2 and 4 1 4 2 Part D WIN Argument of perigee degrees 3 4 2 and 4 1 4 2 Part D VIN True anomaly degrees 3 4 2 and 4 1 4 2 Part D W delta Station keeping range for ascending node 3 4 2 and 4 1 4 2 Part D H_MIN Minimum operating height km 3 4 2 Part D ORBIT_
75. fine steps to coarse steps to ensure that a coarse step is never larger than the target topocentric size of 1 5 3 3 2 Analytical approach The longitude and latitude steps for the position of the reference satellite are chosen according to the procedure in Part D 6 3 3 4 Inputs and file formats 3 4 1 Input parameters The term input is a generic term that can include input files or input provided by the user through some graphic interface or prompting by the software This section contains a description of the input parameters that are necessary to perform the epfd analysis The following subsections contain tables of the required inputs for the non GSO system parameters GSO system parameters run parameters statistical parameters and file formats 3 4 2 Non GSO system parameters The following parameters as specified in Part B 2 1 would be used TE o e Sweats o a EC EE EE a Orbit has repeating ground track maintained by station keeping Yes or No Administration is supplying specific node precession rate Yes or No 7 Station keeping range for ascending node as half total range W delta degrees The filing administration can supply a set of satellite frequency applicable region The ITU database of limits can be searched to extract those applicable for each set Rec ITU R S 1503 51 For each satellite the following parameters specified in Part B 2 1 Parameters provided by administration of the non G
76. fined as a topocentric angle coarse 1 5 This coarse step size is used for all antenna beamwidths and all non GSO systems There are two possible fine step regions because of the two possible maximum epfd locations of a non GSO a Whenanon GSO satellite is near the main beam the fine step region FSR is defined as a fixed topocentric angle from the axis of the GSO earth station beam X or amp 0 IfD A gt 100 set the edge of the first sidelobe region to Q of the GSO earth station pattern 9 15 85 D A 0 6 50 Rec ITU R S 1503 _ If D A lt 100 set the edge of the first sidelobe region to that defined in the GSO earth station pattern or 95 A D The off bore angle for the fine step region is defined as the greater of 3 5 or Orsr 1 max 3 5 1 b When a non GSO satellite is near the exclusion zone the fine step region measured from the boundary of the exclusion zone X Xo or amp Mi is defined as PFSR 2 Qcoarse The size of the coarse step needs to be an integer multiple of fine steps for statistical purposes Since the coarse step size is constant the ratio of coarse steps to fine steps is dependent only upon the beamwidth of the GSO earth station 3qp This ratio is defined as Neoarse Floor Nnits coarse 3dB where floor is a function that truncates the decimal part of the ratio and outputs the integer part of the ratio This produces a conservative ratio of
77. formations can be done such as using the universal variable x defined by a vt 32 dt r 5 3 3 Non GSO satellite orbit station keeping An important aspect to station keeping is to simulate multiple passes of the non GSO satellite through an earth station s main beam with slightly different crossing directions As changing the position within the plane does not effect this then the main parameter to vary is the longitude of the ascending node The approach proposed is to give range Waerta in longitude of ascending node At the start of the simulation all stations in the constellation have this parameter offset by Wgeltg During the simulation this field would increase to 0 at the run s mid point and then increase to W gelta This is implemented by rotating the station s position and velocity vectors around the Z axis by the required angle as specified in Part D 5 3 4 5 3 4 Forced orbit precession The standard orbit prediction algorithm is based upon point Earth mass plus correcting factors for Jy perturbations There are two cases where this requires to be over ridden a where administrations supply a detailed value of the orbit precession rate with respect to a point Earth mass to ensure a repeat ground track b for non repeat orbits where an artificial precession rate is used to ensure the required spacing between equatorial passes 74 Rec ITU R S 1503 This is achieved by rotating the non GSO satellite position and v
78. gure 26 shows the definition of the azimuth and elevation angles used for the non GSO satellite Rec ITU R S 1503 75 FIGURE 26 Z Az El 90 Az El ve ve Y Az El 0 0 Se ea X Az El 90 0 1503 26 It should be noted that direction of the cartesian X Y Z vectors in this diagram are X ve in the East direction from the non GSO satellite Y towards the centre of the Earth from the non GSO satellite Z ve towards the North direction from the non GSO satellite 5 5 Gain patterns This section defines the gain patterns used in the algorithms for earth stations and satellites Note that all formula include the peak gain so where relative gain is required the peak gain should be subtracted 5 5 1 GSO earth station gain patterns 5 5 1 1 FSS earth station gain pattern The FSS earth station gain pattern to use is specified in Recommendation ITU R S 1428 5 5 1 2 BSS earth station gain pattern The BSS earth station gain pattern to use is specified in Recommendation ITU R BO 1443 5 5 2 GSO satellite gain pattern The values of peak gain and half power beamwidth and the antenna reference radiation pattern to use are specified in RR Article 22 5 5 3 Non GSO earth station gain pattern These data would be supplied as part of non GSO filing either in the form of tabulated values or as references to standard patterns defined in ITU R Recommendations 6 The analytical method
79. hat would be radiated regardless of what resource allocation and switching strategy are used at different periods of a non GSO system life The concept of satellite based reference angle could be used to calculate the pfd mask 2 Generation of satellite pfd masks 2 1 General presentation The satellite pfd mask is defined by the maximum pfd generated by any space station in the interfering non GSO system as seen from any point at the surface of the Earth A four dimensional pfd mask is recommended for use by the BR verification software and is defined following one of the two options Option I As a function of the non GSO satellite the latitude of the non GSO sub satellite point the separation angle amp between this non GSO space station and the GSO arc as seen from any point on the surface of the Earth The o angle is therefore the minimum topocentric angle measured from this particular earth station between the interfering non GSO space station and any space station in the GSO arc or the separation angle X which is the angle between a line projected from the GSO arc through the non GSO space station to the ground and a line from the non GSO space station to the edge of the non GSO beam the difference AZ in longitude between the non GSO sub satellite point and the point on the GSO arc where the a or X angle is minimized Option 2 As a function of the non GSO satellite the latitude of the non GSO sub
80. his section assumes that the following approaches are used epfdy calculation Each non GSO satellite has a pfd mask and the pfd for each satellite is used to calculate the aggregate epfdy at an earth station of a GSO system This is repeated for a series of time steps or reference satellite positions in the analytical method until a distribution of epfd is produced This distribution can then be compared with the limits to give a go no go decision epfd calculation The Earth is populated with a distribution of non GSO earth stations Each earth station points towards a non GSO satellite using pointing rules for that constellation and transmits with a defined e i r p From the e i r p and off axis gain pattern for each earth station the epfdt at the GSO can be calculated This is repeated for a series of time steps or reference satellite positions in the analytical method until a distribution of epfdy is produced This distribution can then be compared with the limits to give a go no go decision epfd calculation From the e i r p and off axis angle for each space station the epfdis at the GSO space station can be calculated This is repeated for a series of time steps or reference satellite positions in the analytical method until a distribution of epfd is produced This distribution can then be compared with the limits to give a go no go decision The SRD provides detailed algorithms that would allow it to be implemented in software
81. hm in Part D 7 1 Output results in format specified in Part D 7 2 Outputs The result of the algorithm is two arrays of size NEPFDj as specified in Part D 4 1 in format Array of NEPFD_IS EPFD values EPFD_IS_CALC I dB W m BW Array of NEPFD_IS percentages PC_CALC I where PC_CALC I is percentage of time EPFD IS CALC I is exceeded 68 Rec ITU R S 1503 5 Geometry and algorithms This section describes the geometry that defines the core algorithms used in the software One aspect is the conversion into a generic cartesian vector based coordinate system The precise orientation of the X vector is not specified in this Recommendation to allow alternative implementations by developers The axis chosen should not impact the results as satellite and Earth coordinates are defined relative to the Earth To aid developers examples coordinate systems are used to show how to convert to and from generic vectors 5 1 Earth coordinates system Figure 20 shows the reference coordinate system for earth stations FIGURE 20 Vector Z axis A Earth station Vector XY plane O origin 1503 20 The Earth is defined as a sphere with radius as specified in Part D 2 5 Re The Earth rotates around an axis the Z axis at a rate defined in Part D 2 5 Qe Perpendicular to the Z axis crossing the Earth at the Equator is the XY plane Earth stations are located on this sphere based upon two ang
82. if a graphical interface is provided to view and modify input parameters before running the simulation 3 5 Algorithms and calculation procedures The operating non GSO satellites are those outside the exclusion zone above their minimum operating elevation angle and transmitting towards i e height above or equal to MIN OPERATING HEIGHT the GSO earth station The maximum number of operating non GSO satellites is the maximum number of non GSO satellites allowed to transmit co frequency towards the same area on the ground 3 5 1 Time simulation approach To calculate epfdy values from one non GSO system into one GSO system earth station the following algorithm should be used The algorithm can be used on multiple GSO systems in parallel if required Step 1 Read in parameters for non GSO system as specified in Part D 3 4 2 Step 2 Read in GSO parameters as specified in Part D 3 4 3 Step 3 If required calculate the maximum epfd GSO location using the algorithm in Part D 3 2 Step 4 Initialize statistics by zeroing all bins of epfdy values Step 5 If required calculate number of time steps and time step size using algorithm in Part D 3 3 and hence calculate end time If a dual time step algorithm is included then use Sub step 5 1 otherwise Ncoarse 1 all the time Sub step 5 1 Calculate coarse step size Tooarse Tyine Neoarse Step 6 Rec ITU R S 1503 53 If a dual time step algorithm is included then repeat
83. ion of the two situations of maximum epfd geometry oe GSO space station l l l l F l l l l Situation 1 Fa X r Situation 2 S Non GSO a y exclusion zone P A Non GSO ra operating zone 8 x l r l k I ki k I N 3 t E A x rr S F r E I s oo w l ge in Dn hd ze Non GSO satellite 7 ad i side lobes to GSO f ae Pi G a earth station i A f 2 f l main beam Non GSO satellite main beam weg g to GSO earth station side lobes PA a a N t GSO earth station 1503 14 The maximum epfdy occurs in situation 1 only when non GSO satellites are switched on in the exclusion zone The maximum epfd in situation 2 can occur either when non GSO satellites are switched on or off in the exclusion zone For non GSO satellites that are on in the exclusion zone whether the maximum epfdy occurs in situation 1 or situation 2 depends on which of the following level is the highest for the non GSO system studied pfd a 0 or X 0 AL _pfd a O or X Xo AL gt G 8 Ginax where off axis angle at the GSO earth station Qo angle between the GSO arc and the non GSO satellite at the edge of the exclusion angle 1 1 Non GSO system with satellites switched on in the exclusion zone The worst in the sense of deepest non GSO interference is driven by the maximum single satellite interference Situation 1 Maximum epfd is for an in line situation The in line case for single
84. ion terms The Earth s oblateness causes orbit plane shift along the ascending node longitude and perigee argument shift Since three orbital parameters i p e are constant during satellite motion two parameters Q and would vary with time Rec ITU R S 1503 73 Perigee argument is defined as o M t 28 where o perigee argument at an initial moment perigee argument precession rate A current value of an ascending node longitude is defined as Q Q0 Q 29 where Qo ascending node longitude at an initial moment Q ascending node longitude precession rate The conversion to generic cartesian based vector would depend upon the direction of the X vector For an example coordinate system and for circular orbits the satellite motion expression in the geocentric inertial reference system could be defined as x R cos v cos Q sin v sin Q cos Z y R cos v w sin Q sin v cos Q cos i 30 Z Rsin v sin i A satellite motion in an elliptical orbit is non uniform therefore the Kepler expression and a concept of a mean anomaly would be used in the model to define the real anomaly as a function of time Since an explicit dependence of the true anomaly on time is unavailable so the numerical methods of solving the below expressions were used for its definition The expression is M E t to 31 a As use of the E and M are not recommended for all types of orbits trans
85. ion time increment is one of the most important parameters for determination of a distribution function of interference from non GSO networks on the basis of the simulation model Its specified value should guarantee absence of cases when high level short term interference exceeding an acceptable level is missed and is not considered 6 Rec ITU R S 1503 Otherwise results of simulation analysis will be inaccurate and sometimes erroneous The decrease of a simulation time increment allows to increase accuracy of obtained results but at the same time results in increase of total number of simulation time increments and amount of required calculations The description of calculation algorithms for simulation time increment in uplink and downlink is shown below 2 1 1 Description of the procedure for determination of minimum downlink simulation time increment The value of simulation time increment should guarantee acquisition and description of the most short term interference scenarios with required accuracy The high level short term interference is caused by emission of a non GSO space station which is in line situation a non GSO satellite passes through the main beam of a GSO earth station antenna Therefore one method for determining a simulation time increment Afef could be based on ensuring the required number AN of pfd estimations during the time interval At when a non GSO satellite passes through the main beam of a GSO earth station antenna
86. ity B in equation 44 is usually given by 2m B N satelliteperplane Rec ITU R S 1503 81 Step 3 Determine the location vectors of the satellites in the two constellation configurations by pr e ul where 2 a l e gh 2 1 ecos v and uj cos of p Mj u sin a M by with b uxn and cos jy sin jy 0 M sinjw cosjy 0 0 0 1 The angle y is usually given by 2T N planes y In the particular case of circular orbits since the true anomaly the eccentric anomaly and the mean anomaly are all the same and since a r and e 0 k 1 Steps 2 and 3 simplify to Step 2 al iB jr Step 3 P rus where u cos a M u sin a M by with b ux ny and cos jy sin jy 0 M sinjw cosjy 0 0 0 1 82 Rec ITU R S 1503 6 3 Choosing the longitude and latitude increments for the fine and coarse grids The 8 plane quantization grid should be sufficiently fine to detect fast variations of the epfd levels that occur near to in line interference situations However a fine quantization of the whole 9 plane could result in an excessively large computer time So the numerical implementation of the analytical method can as an option be split in two parts The first part performs the calculations in the regions of the 6 plane in which the epfd level may have large variations close to in line interference and where a fi
87. late epfdt for this non GSO satellite using the REP_EIRP value calculated in Part D 4 1 5 epfdt REP_EIRP Lfs Gry Gmax Step 24 Increment epfdy by epfdy Step 25 Locate in the epfdt histogram the bin corresponding to the value of epfdt and add PROB 2 to it Step 26 Generate the epfd CDF from the epfdy PDF using the algorithm in Part D 7 1 2 Step 27 Compare epfdy statistics with limits using the algorithm in Part D 7 1 Step 28 Output results in format specified in Part D 7 2 4 1 7 Outputs The result of the algorithm is two arrays of size NEPFD as specified in Part D 4 1 1 in format Array of NEPFD_UP EPFD values EPFD_UP_CALC I dB W m BW Array of NEPFD UP percentages PC CALC IJ where PC CALC I is percentage of time EPFD UP CALC I is exceeded 4 2 epfdis software description This section describes the algorithm to calculate epfdig from non GSO space stations into a GSO uplink From the e i r p and off axis angle for each space station the epfdj at the GSO space station can be calculated This is repeated for a series of time steps or reference satellite positions in the analytical method until a distribution of epfdj is produced This distribution can then be compared with the limits to give a go no go decision 4 2 1 Configuration parameters This sub section specifies the parameters required for all epfdj calculations This would be a data set of N sets of limits that can be
88. late the longitudinal spacing between successive ascending passes through the equatorial plane S given the Earth s rotation rate Q 0 250684 degrees min Spass Q2 Q Pn degrees The equations above apply to circular orbits For elliptical orbit systems where the calculations above would be significantly different the value of Spass should be supplied by the administration Step 5 From the GSO earth station beamwidth and height S eg can be calculated using equation 3 20 Sea Ta tracks Step 6 Calculate the number of orbits to fully populate around the equator taking into account that each plane has ascending and descending nodes N 180 orbits req 14 Rec ITU R S 1503 Step 7 Round Norbits to next highest integer Step 8 Calculate total angle orbit has rotated round during this time Stotal Norbits Spass Step 9 Calculate the number of multiples of 360 that this corresponds to rounding up to nearest integer above N360 1 Sota mod 360 Step 10 Calculate the separation between planes that this corresponds to 5 360 N 369 actual 7 Norbits Step 11 To ensure that the orbit drifts with the required precession rate the following additional artificial precession should be included Sartificial Sactual Spass degrees orbit or Sartificial Dartificial Tr degrees s period Step 12 Part D gives more information on how this parameter is used The total run time is then the time to process aroun
89. lations Part C Maximum epfd geometry This Part gives information about how to calculate the locations of the GSO earth station and satellite that gives the maximum epfd Part F Operational environment for the software This Part gives further information about platform requirements and the operating system under which the software is expected to run Part H Procedures for the evaluation of the candidate software This Part gives further information about the user interface requirements 2 General requirements 2 1 Software environment The software should match the environment defined in Part F 2 2 Implementation requirements The criteria used to evaluate candidate software are defined in Part H Rec ITU R S 1503 47 2 3 Program interfaces It is preferable that the program shall read data electronically but it should also be possible to enter data from the keyboard Output should be either electronic format or printed via printer configured for the PC 2 4 Algorithm constants The algorithms should use the following constants as specified in Part A Fundamental constraints and basic assumptions for the simulation radius of the Earth radius of the geostationary orbit gravitational constant Ja parameter speed of light angular rate of rotation of the Earth 2 5 General assumptions and limitations It is assumed that pfd masks are used to define the transmit radio characteristics of
90. les Latitude angle between line from centre of Earth to earth station and XY plane Longitude angle as shown in Figure 21 FIGURE 21 Earth station S ve longitude Positive ei Reference longitude 0 vector Z axis 1503 21 Rec ITU R S 1503 69 Earth stations are assumed to have constant position in time The orientation within the XY plane of the X and Y axes is not specified in this Recommendation as all locations are referenced to the Earth rather one particular inertial frame This allows different implementations to use different reference points if required without impacting on the results One possible implementation is what is described as the geocentric inertial system For this example case conversion from geographic coordinates is achieved using Long arccos a ifx2 0 11 Long arccos ifx lt 0 12 x y Z Lat arctan 13 x y If this example coordinate system is used then the conversion from geographic coordinates into geocentric inertial system coordinates is x R cos lat cos long 14 y R cos lat sin long 15 z R sin lat 16 where x y Z coordinates in the geocentric inertial system long geographic longitude lat geographic latitude In this example geocentric inertial reference system the equation for motion of a mass point on the Earth s surface would be as x R cos lat cos lon Qot y Re cos lat sin lo
91. levels with the RR Article S22 limits pass fail go no go decision etc Part D of this Recommendation should be used as the guideline Step 11 Evaluate availability of DLL files and or COM for possibility of use with other applications Step 12 Evaluate upgrade and maintenance of software Evaluate possibility and ease of trouble shooting maintenance and upgrade by the user and the definition of a set of tests to be conducted when the BR software or its operating environment are modified or upgraded This should also include regression evaluation i e whether unchanged blocks of the software are not affected by modifications to other blocks Part E 4 and Part G 3 4 should be used as the guidelines Step 13 Evaluate software applicability to all cases of interest The software should be able to handle all types of non GSO systems including systems with long repeating tracks and constellations with slow precession rates Rec ITU R S 1503 89 Step 14 Evaluate reliability sensitivity and accuracy evaluate how the results reflect the expected system behaviour reliability of the results orbit projection offset angles CDF generation go no go decision maximum epfd value epfd value for 100 time etc calculation accuracy versus step size and sensitivity to input constants Part E and Part D 6 should be used as the guidelines Software can be evaluated from functional testing considerations or structural testing considera
92. liance test The overall conclusion of the evaluation Pass or Fail as defined in Part D 7 1 4 shall be output Rec ITU R S 1503 85 7 3 2 Summary table The summary Table shall show the following data pfd value Probability ay Probability J and P pfd value probability specification values from the database where Pass fail test result Py probability value from the probability table 7 3 3 Probability table The output shall include for information the calculated CDF which was used in the decision making process PART E Testing of the reliability of the software outputs 1 Evaluation of the computation accuracy of the candidate software These tests could be performed by the software developer and the results supplied to the BR along with the candidate software Software functions to be evaluated Orbit projection Using a set of simplified parameters which result in a defined repeat period run the software for the required simulation interval and check the actual satellite vectors against the predicted values Offset angles Using appropriate sets of earth station and satellite locations check the actual beam offset angle values against the predicted values The sets of test data should cover the most complex trigonometrical cases for example sites around longitude zero and longitude 180 Time step and simulation duration Using appropriate sets of non GSO network parameters check the time
93. m run configuration 58 Rec ITU R S 1503 4 1 4 2 Non GSO system parameters The following parameters as specified in Part B 2 1 would be used Parameter description Parameter name Number of non GSO satellites Neat Orbit has repeating ground track maintained by Yes or No station keeping Administration is supplying specific node Yes or No precession rate Station keeping range for ascending node as half Waetta degrees total range For each satellite the following parameters specified in Part B 2 1 would be used where the definitions of the parameters are specified in Part D 5 3 1 at the time of the start of the simulation Note that in the Table below the indices N are present to indicate that there would be a different value for each satellite and the N th value corresponds to the N th satellite NE Each satellite must have an independent set of six orbital parameters for orbit definition and subsequent propagation To define the characteristics of non GSO earth stations the following parameters as specified in Part B 2 1 would be used Parameter description Parameter name Maximum number of co frequency tracked non ES TRACK GSO satellites Earth station e i r p mask ES_EIRP dB W BW er Number of frequency regions Nyreg Region One of 1 2 or 3 Central transmit frequency Minimum elevation angle ES MINELEV Minimum angle to GSO arc ES MIN GSO Average numbe
94. n Qet 17 z R sin lat where lat geographic latitude of the mass point on the Earth s surface lon geographic longitude of the mass point on the Earth s surface t time Qe angular rate of rotation of the Earth 5 2 GSO satellite coordinate system The geostationary arc is a circle in the XY plane at a distance of Reo from the Earth s centre where Roog is specified in Part A 1 3 Individual geostationary satellites have location on this circle defined by a longitude as shown in Fig 22 70 Rec ITU R S 1503 FIGURE 22 GSO satellite Positive vector Z axis ve longitude Reference longitude 0 1503 22 Geostationary satellites are assumed to have constant longitude in time The conversion to and from vectors can use the same algorithms as in the section above by setting the latitude to zero 5 3 Non GSO satellite coordinate system 5 3 1 Non GSO satellite orbit parameters This section defines the parameters that specify an orbit for non GSO satellites Non GSO satellites move in a plane as shown in Fig 23 FIGURE 23 Orbit satellite Equatorial plane Line of the nodes 1503 23 Rec ITU R S 1503 71 The plane of the orbit is referenced to the Earth by two angles Q longitude of ascending node This defines where the ascending orbit plane intersects the equatorial plane As the orbit is fixed in inertial space while the Earth rotates a time reference for which this
95. n gain pattern GSO ES PATTERN One of those in Part D 5 5 Earth station antenna diameter GSO ES D ANT The latitude and longitude of the GSO satellite and earth station are defined in Part D 5 2 and 5 1 3 4 4 Run parameters The run parameters can be either calculated using the algorithm in Part D 3 3 or entered values For the time simulation approach the required parameters are Number of time steps NSTEPS Po Precession mechanism J2 or Admin Supplied or Artificial 52 Rec ITU R S 1503 For the analytical method approach the required parameters are related to increments in the reference satellite position Parameter description Parameter name Parameter units Longitude step for the coarse grid PHISTEPCG Latitude step for the coarse grid THETASTEPCG Longitude step for the fine grid PHISTEPFG Latitude step for the fine grid THETASTEPFG 3 4 5 Other parameters The run would also use the epfdy limits database from Part D 3 1 to get three defining parameters for the epfdy Statistics Parameter description Parameter name Parameter units Starting value for epfd bins EPFD DOWN START dB W m BW ep Number of epfd bins Bin size Part D 2 5 dB W m BW ref 3 4 6 File formats File formats should be in ASCII text format to allow visual inspection and modification of the input parameters to the routines It would also be acceptable to have the input parameters in a binary database format
96. nation of how requirements are implemented the purpose of each segment of the software with references to the related part of this Recommendation Part G 3 3 of this Recommendation should be used as the guideline Step 8 Evaluate consistency with the overall approaches used by the BR use of ITU terminology and definitions adherence to the BR input BR supplied input and database parameters and output file requirements interface with the BR databases alphanumerical or graphical requirements for interface with existing BR software etc Relevant parts of Part F 3 4 3 7 4 1 4 4 2 4 4 2 6 and 4 1 7 of Part D should be used as the guidelines Step 9 Evaluate if the software meets requirements and that results conform to the equations described or referred to in this Recommendation for the generation of space station pfd masks the generation of earth station e i r p masks calculations of pfd mitigation techniques considerations earth station and satellite antenna gain considerations worst locations of GSO network that give maximum epfd Parts C and C of this Recommendation should be used as the guidelines Step 10 Evaluate if the software performs the specified functions and that results conform to the equations described or referred to in this Recommendation for the examination of non GSO filings calculation of cumulative epfd distributions the geometries used in epfd calculations including gain patterns comparison of epfd
97. nce levels and probabilities e that designers of satellite networks non GSO FSS GSO FSS and GSO BSS require knowledge of the basis on which the BR will make such checks f that such tools may be already developed or under development and may be offered to the BR recommends 1 that the functional description specified in Annex 1 be used to develop software tools calculating the power levels produced by non GSO FSS systems and the compliance of these levels with the limits contained in Table S22 1 of Article S22 of the RR 2 that Annex 1 Part H be considered as a basis by the BR for the evaluation of candidate software supplied by administrations NOTE 1 Radiocommunication Study Group 4 will take the lead role in consultation with Radiocommunication Study Group 11 in the future maintenance of this Recommendation in particular to modify it as required to be able to determine compliance with further requirements called by ITU R 2 Rec ITU R S 1503 ANNEX 1 CONTENTS Page Part A Fundamental constraints and basic assumptions cccccecceescessceseceseceseccecaeecaeecaeeeeeeneceeeeeenseenseeeaeenaeenaes 2 Part B Parameters of non GSO System nanne snor enne enne enneenseenneenseenseenverneesneesmenseenneenneenseenneenneenneenseensennenn 14 Part C Generation of pfd eirp Tasks nn vetreserves benden te ev 29 Part C Maximum epfd location of GSO network anas oneenenvenernenvenernenvenennenveneenenvenennene
98. ndition the position of all other satellites in the constellation are determined Once the position of all satellites are known the epfd level s into the desired test point or points is evaluated To generate the probability distribution of a quantized version of these quantities the obtained value is quantized to the nearest quantization level and the probability of finding the reference satellite inside the considered cell obtained using the probability density function in equation 34 is added to current value of probability associated to the corresponding quantization level This procedure is then repeated for all partition cells and the so obtained histogram is integrated to generate the desired CDF The flowchart in Fig 27 illustrates the procedure described above It reflects the algorithm and calculation procedures presented in Part D 3 5 2 and 4 1 6 2 Rec ITU R S 1503 77 FIGURE 27 Flow chart of the analytical method Take a cell in the partition of the interfering non GSO network 8 plane say cell j Determine the probability P of finding the non GSO network reference satellite inside the cell j Place the non GSO network reference satellite at the centre of the cell j Determine the location of all other satellites in the constellation there are two possible constellation configurations associated with a given position of the reference satellite For the two possible constellation configuration
99. ne quantization of the region is required These regions are referred here as RPII The second part of the numerical procedure performs the calculations in the regions of the plane in which the epfd level has smooth variations allowing for a coarser quantization It is suggested that the longitude and latitude increments Agyand AO for the fine grid be chosen such that Apr lt and Ady lt 7 10 where is the geocentric angle defined by equation 3 for epfdt calculations and by equation 4 for epfdis calculations The longitude and latitude increments Aq and A6 for the course grid should be chosen as Ag 1 59 and A0 1 59 with given by equation 3 for epfd7 calculations and by equation 4 for epfd calculations Finding the plane regions associated with potential quasi in line interference RPI corresponds to defining regions such that when the reference satellite is inside one of these regions in line interference events involving one or more of the satellites in the constellation may occur The important point here is to guarantee that when the reference satellite is not inside any of these regions in line interference does not occur and a coarser quantization grid can be used The RPI are defined as a regions usually rectangular around PPI These PPII can be determined using the methodology described in Part D 6 4 It is suggested that the RPII be defined by a Ax A degree square region around the PPIIs
100. nnenvenennennenven 39 Part D Software for the examination of non GSO filings ennn anne ener enne rneesneesvenseerneernenseenseenseenneeenseensennenn 45 Part E Testing of the reliability of the software outputs anna oneeneenveneenvernenneeneenvenveneenvenvenvenvenvenneen 85 Part F Operational environment for the software nennen ven envenvenvenvenvenneenenneeneenvenvenvenvernvenvenvenvencenneen 86 Part G Software development and maintenance nne enernvenvenvenvenvenneenenneenvenenneeneenvenvenvenverevenvenvenvencenneen 87 Part H Procedures for the evaluation of a candidate software ennn eneenvenvencennern enne evenvenneencenvenvenneen 87 Functional description of software for use by the BR in checking compliance of non GSO FSS systems with epfd limits PART A Fundamental constraints and basic assumptions 1 General 1 1 Software composition 1 1 1 Purpose The software algorithm described in this Annex is designed for its application by the BR to conduct examination of the non GSO FSS system notifications for their compliance with the validation limits specified by the RR 1 1 2 Software block diagram The block diagram of the software algorithm described in this Annex is shown in Fig 1 It consists of two sections that of initial data and that of calculation The initial data section contains the whole set of parameters relevant to the notified non GSO system a set of reference GSO system parameters
101. of the associated space station geostationary G or non geostationary N Pe 999 99 Nominal longitude of the associated space station give for West In degrees from 179 99 to 180 00 for East COSTS ALI WN LT TABLE 8 end Items in ore wie pert RS Appendix me te aus X 4 Designation of the satellite antenna beam ang alpha 999 9 Satellite beam orientation B 4 a B 4 b X 12 mn e fi Code identifying a beam as either transmitting E or receiving R Pe B 4 a B 4 b oe Number of the attachment for the radiation pattern diagram gain B 4 a 99 9 x Maximum isotropic gain of the antenna dB with one decimal position copolar gain for plans Satellite beam orientation Antenna radiation pattern indicated by a reference to the appropriate ITU R x x Recommendation x E 9 fx Maximum e i r p at 4 kHz Maximum e i r p at 1 MHz f Average e i r p at 1 MHz For non standard antennas For non standard antennas Service area Symbol of the country or geographical area Nature of service and class of station for the group of frequency assignments Class of station Nature of service 87 COSTS ALI A Rec ITU R S 1503 29 PART C Generation of pfd e i r p masks 1 Definition The purpose of generating pfd masks is to define an envelope of the power radiated by the non GSO space stations and the non GSO earth stations so that the results of calculations encompass w
102. orithm should ensure that the non GSO earth station does not transmit towards non GSO satellites that are in the exclusion zone and so the use of the fine grid for the uplink may not be necessary Rec ITU R S 1503 83 6 4 2 Downlink interference epfdJ For each GSO network interfered with earth station test point the following steps should be used in determining the PPII in the case of epfd calculations Step 1 Identify the position of the interfering network satellite that is in line with the considered interfered with GSO network earth station test point and the GSO satellite serving it Step 2 Place the reference satellite at this position and determine the position of all other satellites in the constellation for the two possible configurations according to Part D 6 2 Step 3 These Nyon GsOsatellites X 2 satellite positions form the set of PPIIs 6 4 3 Inter satellite interference epfd For each GSO interfered with satellite test point the following steps should be used in determining the PPII in the case of epfd calculations Step 1 Let Nesosatellitebeams denote the number of co frequency beams in the interfered with GSO satellites being considered For each of these beams identify the position of the interfering non GSO satellite that is on the beam axis Step 2 Place the reference satellite at this position and determine the position of all other satellites in the constellation for the two possible configu
103. r of non GSO ES per km ES DENSITY km Average distance between cell or beam foot print ES DISTANCE centres D The filing administration can supply a set of earth station frequency applicable region The ITU database of limits can be searched to extract those applicable for each set Rec ITU R S 1503 59 41 4 3 GSO system parameters The GSO system can be either calculated or use worst case parameters using the algorithm in Part D 4 1 2 or entered values The required parameters as specified in Part B 2 1 are Parameter description Parameter name Parameter units GSO satellite longitude GSO_SAT_LONG GSO bersih ade BS LAT GSO boresight longitude BS LONG degrees GSO reference gain pattern GSO_SAT PATTERN One of those in Part D 5 5 These parameters are defined in Part D 5 1 and 5 2 4 1 4 4 Run parameters The run parameters can be either calculated the using algorithm in Part D 4 1 3 or entered values For the time simulation approach the required parameters are Parameter description Parameter name Parameter units Time step TSTEP s Number of time steps NSTEPS Precession mechanism J2 or Admin Supplied or Artificial For the analytical method approach the required parameters are related to increments in the reference satellite position 4 1 4 5 Other parameters The run would also use the epfdy limits database from Part D 4 1 1 to get three defining parameters for the epfd stati
104. rations according to Part D 6 2 Step 3 These Ngsgsatellitebeams X Nnon GSOsatellites X 2 Satellite positions form the set of PPIIs 6 5 Additional use of fine grids Fast variations of epfd can also occur when satellites approach the boundary curve that characterize the exclusion angle zone in the 8 p plane In the vicinity of this boundary curve exclusion zone vicinity regions EZVR fine grids could be also used to better detect these fast variations The following steps should be used to determine these EZVR Step 1 Determine in the coarse grid which cells contain the exclusion zone boundary curve Let us say that the number of cells satisfying this condition is Ngz Step 2 For each of these Ngz cells place the reference satellite at its centre and determine the position of all other satellites in the constellation for the two possible configurations according to Part D 6 2 and identify the coarse grid cells containing them Step 3 These Nez X Nyon GSOsatellites X 2 coarse grid cells will constitute the set of coarse grid cells inside which a finer grid is to be used 7 Structure and format of results 7 1 Go No go decision 7 1 1 Overall description of the decision process When time simulation is used the simulation produces a probability distribution function PDF of the pfd The PDF records for each pfd level the number of simulation time steps at which that pfd level occurred divided by the sum of all bins
105. rbit around the Earth when the argument of the perigee equals 7 2 this probability density function see Note 1 is given by 2 k 1 e cosO 2 sin for _ lt lt 58 pO FT an ein 8 sin 1 47 sin 5 1 K7 gO wee A 0 otherwise where 5 angle between the orbital plane and the equatorial plane k l e 35 l e e denoting the orbit eccentricity and g cos sin sin sin osin 36 where is the argument of the perigee Using equation 34 it is possible for example to obtain the probability of having a satellite inside any given region in the sky In the particular case of circular orbits e 0 gt k 1 equation 34 is reduced to 1 cos for lt O lt Px 0 4 27 sin 8 sin PERDER 37 0 otherwise NOTE 1 A general expression for this probability density function valid for any elliptical orbit satellite has been developed and is under consideration by Radiocommunication Working Party 4A Procedure to obtain the epfd CDFs For simplicity let us assume that only a single non GSO network is involved in the interference environment The longitude and latitude of the reference satellite of this non GSO satellite network takes values on a 6 plane T lt psSn 6 lt 6 lt 5 In a first step this plane is finely partitioned into small rectangular cells For each of these partition cells it is assumed that the reference satellite is located at its centre and for this co
106. results Rec ITU R S 1503 7 FIGURE 2 GSOSS 3 X GSO ES Se gt N SS satellite station ES earth station 1503 02 Selection of Np value could be based on Recommendation ITU R S 1325 which recommends the Nj value of 5 and greater In a case when a non GSO network satellite constellation consists of satellites with different orbital parameters it is necessary to determine a simulation time increment for each type of the orbits concerned and to define a minimum one TABLE 3 Input data Parameter Designation Units Orbit inclination degrees 2 1 2 Algorithm of determination of downlink simulation time increment Calculation algorithm Step 1 Input the data listed in Table 3 Step 2 For satellites with different altitude and inclination calculate the simulation time increments by equations 1 and 2 Step 3 Select a simulation time increment 8 Rec ITU R S 1503 2 1 3 Description of the procedure for determination of minimum uplink simulation time increment High level short term uplink interference would be caused by emissions from a non GSO earth station during an in line event when a GSO SS would be in the main beam of a non GSO earth station antenna The required number Nj of epfdt measurements should be effected within the period of the GSO satellite staying in the main beam of the non GSO earth station antenna to ensure acquisition and definition of the in line event If the non
107. rth is populated with a uniform distribution of non GSO earth stations Each earth station points towards a non GSO satellite using pointing rules for that constellation and transmits with a defined e i r p From the e i r p and off axis gain pattern for each earth station the epfdt at the GSO can be calculated This is repeated for a series of time steps or reference satellite positions in the analytical method until a distribution of epfdt is produced This distribution can then be compared with the limits to give a go no go decision Figure 18 shows the geometry with population of non GSO earth stations transmitting to a constellation of non GSO satellites together with a test GSO satellite receiving from a GSO earth station FIGURE 18 a Pay f3 RS NN i TRG rd Po A SANG P A 1503 18 56 Rec ITU R S 1503 4 1 1 Configuration parameters This sub section specifies the parameters required for all epfdt calculations defined in the RR This would be a data set of N sets of limits that can be shared between runs The Table could be queried so that the required values can be used depending upon non GSO system frequency For each set of limits the following would be defined as specified in Part B 2 2 Frequency band start GHz Frequency band end GHz Applicable Region 2 REGION2 UP Yes or No Reference bandwidth kHz Array of NEPFD UP epfd values EPFD UP IJ Array of NEPFD UP percentages PC UP IJ From
108. s evaluate the epfd levels L first configuration and L second configuration reaching the considered test point Locate in the test point epfd histogram the bins corresponding to the values L and L and add to each of these bins the value P 2 Have all the cells in the 9 plane partition been considered Take another cell in the interfering non GSO network plane partition j 1 Generate the CDF from histogram End 1503 27 78 Rec ITU R S 1503 Concerning the procedure described in the previous paragraphs the following additional comments are pertinent a Although the partition of the 6 plane into rectangular cells need not to be a grid type of partition the used of grid type partitions is convenient for implementation purposes However to avoid a prohibitive amount of required computer time when applying the proposed analytical method to complex situations involving a large number of earth stations and satellites the following points should be taken into account The 9 plane quantization grid should be sufficiently fine to detect fast variations of the epfd levels that occur near to in line interference situations However a fine quantization of the whole 8 plane could result in an excessively large computer time So the numerical implementation of the analytical method could as an option be split in two parts The first part performs the calculations in the regions of the
109. satellite interference is when a non GSO satellite is in the main beam of the GSO earth station Le when a 0 or X 0 However it could in principle be up to half a time step out Rec ITU R S 1503 41 The downlink pfd mask can be examined to determine the latitude of the sub satellite point and the difference in longitude Along at which the maximum pfd occurs for a 0 or X 0 The intersection of the amp 0 or X 0 line with the Earth is a set of maximum epfdy locations Situation 2 Maximum epfd is for a non GSO satellite main beam passing through the side lobes of the GSO earth station antenna The methodology used to achieve the maximum epfd situation will be the same as for non GSO satellite switching off in the exclusion zone 1 2 Non GSO system with satellites switched off in the exclusion zone The maximum epfdy for single satellite interference is when a non GSO satellite is closest to the exclusion zone of the GSO earth station i e when amp 9 or X X0 The downlink pfd mask can be examined to determine the latitude of the sub satellite point and the difference in longitude Along at which the maximum pfd occurs for amp 09 or X Xo Therefore this criteria determines the latitude of the non GSO satellite contributing maximum epfdy Lat non GSO and the difference between the longitude of the non GSO sub satellite point and the longitude of the GSO satellite when it occurs The locations of the
110. sotropic gain of the antenna expressed in dB with one decimal position bmwdth C 10 c 3 999 99 x Angular width of radiation main lobe expressed in degrees with two decimal positions lat deg x Degree part of latitude coordinate of the station expressed in degrees minutes and seconds i x Minute part of latitude coordinate of the station expressed in degrees minutes and seconds COSTS ALI A ET TABLE 8 continued Items in ae e_as stn Associated earth station cont Recommendation senen NE re se oo jemen Nature of service and class of station for an associated earth station e_srvels stn_cls x Class of station code x Nature of service code a aes Emission nat_srv VT COSTS ALI U TABLE 8 continued Items i in PC es eee eee a bdwdth 9 8 Assigned frequency band expressed kHz PO Date of bringing into use Date in yyyymmdd format Flag indicating that for the set of emissions associated to a list of frequency assignments the maximum peak power and maximum power density values provided are of type C 8 b Number of the attachment indicating the reason for minimum peak power and minimum power density C 8 c information being absent polar_type za Receiving system noise temperature Symbol indicating the type and the direction of polarization where applicable in case of circular or elliptical polarization Number of the attachment for the service area diagram Number of
111. station Nyo q is the maximum number of cells that can be seen with the minimum service elevation angle Step 2 For each point M Az EI determine the maximum pfd The maximum pfd at a given Mg is determined by first finding the pfd contributed by each cell toward M Az El taking into account the dependency of the sidelobe patterns on the beam tilt angle The maximum pfd contributions toward My are then summed with the number of contributions constrained by the physical limitations of the space station Out of the Noral cells that can be seen within the coverage area of the space station under a minimum elevation angle for communication only Nco cells can be illuminated at the same frequency bandwidth in one sense of polarization and N 9s cells in the other sense of polarization This characterizes the limitation of the antenna system on the non GSO space station To calculate the mask in one polarization the cells which can be illuminated in the polarization concerned are identified and the cross polarization level is considered for other cells Out of these Nco and Necross cells only a given number can be powered simultaneously This characterizes the limitation of the repeater system of the non GSO space station If applicable the limitations in terms of frequency reuse pattern and polarization reuse pattern also need to be clarified _ If applicable the power allocated to one cell may vary taking into account the el
112. stellation configuration Distance from the centre of the Earth of the i th satellite in the j th orbital plane corresponding to constellation configuration 42 80 Rec ITU R S 1503 Consider a geocentric geostationary system of rectangular coordinates in which the x and y axis belong to the equatorial plane and the z axis points to the north Let u denote the unitary vector pointing to the reference satellite location and p pbe the vector characterizing the position of the i th satellite in the j th orbital plane corresponding to constellation configuration 1 2 The following steps are to be used in determining the locations p e G 9 Neatelliteperplane LJ 95 sNplanes L 1 2 of all satellites in the two constellation configurations Step 1 Let u ux Uy Uz ie and calculate for 1 2 the unitary vectors n defined by cu cos dy uy Uy ny ay 43 cos with muur cos 8 fuy u2 02 sin Bu cos 8 ag wesw Step 2 Let k be the unitary vector in the z axis direction and calculate the following quantities for 1 2 w k Xn x denotes the cross product Ye arccos sgn u T denotes transpose and sgn denotes the signum function v w Mop Qn E 2arctan tan v 2 l e k 1 M Ey esin Ep M M i B j A 44 Ej M 2 Lo ne sin hari n l wl 2arctan ktan Ej X 2 af 7 v 45 Note that the quant
113. stics Starting value for epfdy bins EPFD UP START dB W m BW Number of epfd bins N BINS EE 60 Rec ITU R S 1503 4 1 4 6 File formats File formats should be in ASCII text format to allow visual inspection and modification of the input parameters to the routines It would also be acceptable to have the input parameters in a binary database format if a graphical interface is provided to view and modify input parameters before running the simulation 4 1 5 Production of non GSO earth station distribution To produce the distribution of non GSO earth stations the following method should be used Step 1 Calculate the number of actual operating non GSO earth stations that the representative earth station will represent using NUM ES ES DISTANCE ES DISTANCE ES DENSITY Step 2 Calculate e i r p to use for each representative non GSO earth station using REP EIRP ES EIRP 10logio NUM ES Step 3 Define the GSO service area as the region enclosed by the contour representing a relative gain of 15 dB Step 4 For every distance ES DISTANCE in latitude and distance ES DISTANCE in longitude within the service area defined in Step 3 locate a representative non GSO earth station with radiating with REP_EIRP 4 1 6 Algorithms and calculation procedures 4 1 6 1 Time simulation approach To calculate epfdt values from one non GSO system into one GSO system satellite the following algorithm should be used The algorithm can be used
114. te is at position v These can be used by the algorithm to predict the future position of the non GSO satellite as described in 5 3 2 5 3 2 Non GSO satellite orbit predictor Given the orbital elements in the section above standard orbit mechanics can be used to predict the position of the satellite at future times In addition there are two additional precession factors for the ascending node and argument of perigee as described below Orbit pecession in acending node longitude The rate of ascending node longitude secular drift is defined as _ Ja cos i pop It follows from the above that polar orbits have zero precession rate and equatorial ones have a maximum precession rate With direct satellite motion i lt 90 the ascending node shifts to the west to Q decreasing and with reverse satellite motion i gt 90 it shifts to the east to Q increasing Q 26 Perigee argument precession Perigee argument secular shift rate is defined as re Ja cos i 1 mS 2p la u Perigee argument precession rate at i 0 and i 180 is maximum For ij 63 26 06 or i2 116 33 54 the precession rate is zero If i lt 1 or i gt ip then the perigee precession is along a satellite motion direction and if ij lt i lt i then it is in the opposite direction 27 Other precessions such as periodic perigee argument precession rate are not taken into account since their effect is negligible Use of precess
115. tellite 1503 19 The algorithm in Part D 4 6 1 shows the optional steps for dual time steps as sub steps i e 6 1 6 2 7 1 7 2 7 3 and 24 1 A coarse step size is used for non critical regions far from the GSO earth station main beam axis and exclusion zone boundaries This step size is defined as a topocentric angle coarse 1 5 This coarse step size is used for all antenna beamwidths and non GSO systems The size of the coarse step needs to be an integer multiple of fine steps for statistical purposes Since the coarse step size is constant the ratio of coarse steps to fine steps is dependent only upon the beamwidth of the non GSO earth station 3qp This ratio is defined as Neoarse Floor Nnits coarse 934B where floor is a function that truncates the decimal part of the ratio and outputs the integer part of the ratio This produces a conservative ratio of fine steps to coarse steps to ensure that a coarse step is never larger than the target topocentric size of 1 5 4 1 3 2 Analytical approach The longitude and latitude steps for the position of the reference satellite are chosen according to the procedure in Part D 6 3 4 1 4 Inputs and file formats 4 1 4 1 Input parameters This section defines the input parameters for a particular non GSO system scenario In this case input is a generic term that could include files or user input Information is required for non GSO system GSO syste
116. the EPFD UP I arrays the number of bins and bin ranges can be calculated using Step 1 Calculate EPFD UP MIN minimum value in EPFD UP I array Step 2 Calculate EPFD UP MAX maximum value in EPFD UP I array Step 3 Calculate EPFD UP START by rounding EPFD UP MIN to nearest 10 dB below Step 4 Calculate EPFD UP END by rounding EPFD UP MAX to nearest 10 dB above Step 5 Number of bins EPFD UP END EPFD UP START Sg This will give a set of bins that are of size Sg bin size specified in Part D 2 5 and are below and above the epfd limits required 4 1 2 Determination of maximum epfd configuration The maximum epfd location of the GSO satellite and beam centre is defined in Part C 4 1 3 Calculation of run steps 4 1 3 1 Time simulation approach A single time step and number of time steps are calculated using the algorithm in Part A Dual time step option In order to improve simulation performance an option to the algorithm is to implement two time steps A coarse time step would be used except when any non GSO satellite is near the edge of the exclusion zone Note that there is no need to check for the central line representing a 0 as non GSO earth station does not transmit to the non GSO satellite within the exclusion zone Rec ITU R S 1503 57 Figure 19 shows where to use the finer time step FIGURE 19 GSO earth station Exclusion zone for non GSO satellite Track across exclusion zone GSO arc GSO sa
117. the attachment for the spectrum mask diagram Maximum total peak envelope power dBW or maximum aggregate power dBW supplied to the input of the antenna Number of the attachment for the type of modulation and multiple access Sequence number associating a particular service area diagram with the group Name of the service area In case of linear polarization the value of the angle degrees measured anticlockwise in a plane normal to the beam axis from the equatorial plane to the electric vector of the wave COSTS ALI U ST TABLE 8 continued ZE o prd_ddd A4 b 2 Day part of the time elapsing between two consecutive passages of a non geostationary satellite through a point in its orbit prd_hh A4 b 2 x Hour part of the time elapsing between two consecutive passages of a non geostationary satellite through a point in its orbit prd_mm A4 b 2 ia part of the time elapsing between two consecutive passages of a non geostationary satellite through a point in its orbit apog A 4 b 3a a 99 The farthest altitude of the non geostationary satellite above the surface of Distances gt 99 999 km are expressed as a the Earth or other reference body km product of the values of the fields apogee and apog exp see below e g 125 000 1 25 x 10 apog exp A4 b 3a Exponent part of the apogee expressed in power of 10 To indicate the exponent give 0 for 10 1 for 10 2 for 102 etc perig A 4 b 3b 9 5 99 The nearest altitu
118. the non GSO satellites The Earth is assumed to be a sphere with orbit prediction algorithm based upon single point mass plus Jy factor A general limitation on the generation of epfd statistics as described in Part B 2 2 is Bin size Sp 0 1 dB To be consistent with evaluation algorithm in Part D 7 13 epfd values calculation for each time step should be rounded to the lower values with a maximum precision of 0 1 dB The calculation of angle to GSO arc a and X as described in Part D 5 4 2 are based upon a number of test points with specified separation between them Separation between GSO test points GSO SEPARATION 2 6 Frequency selection Separate frequency values will generally be required for assessment of epfd levels into each service FSS and BSS in each of the frequency bands within a service Let F_ down up is denote the list containing the set of frequency values to be tested The following procedure shall be employed to determine the set of values in F_ down up is Step 0 Empty the F_ down up is list Step 1 For each service FSS and BSS repeat Step 2 Step 2 For each set of limits repeat Step 3 Step 3 For each antenna diameter repeat Steps 4 and 5 Step 4 Find the lowest frequency which is shared by GSO and non GSO Step 5 Add that frequency to the list of values in F_ down up is to be tested 3 epfdy software description This section describes the algorithm to calculate the epfd from a non
119. tigation technique Description of non GSO cell wide observance of exclusion zone or cell centre observance 2 2 Part C of exclusion zone text defining mitigation techniques used for uplink and downlink directions of transmission or others Downlink direction of transmission Mitigation technique Description of non GSO cell wide observance of exclusion zone or cell centre observance 2 2 Part C of exclusion zone text defining mitigation techniques used for uplink and downlink directions of transmission or other Inputs to software for calculating epfdt and epfdy and limit compliance checking Non GSO orbit parameter inputs See Part B 3 1 20 Rec ITU R S 1503 4 2 Non GSO downlink pfd mask MIN EXCLUDE Exclusion zone angle 3 4 2 Part D Option 1 f The pfd mask is defined by pfd_mask satellite latitude or X AL th 2 tellit 2 Part C e non GSO satellite the latitude of the non GSO sub satellite point the separation angle a between this non GSO space station and the GSO arc as seen from any point on the surface of the Earth The angle is therefore the minimum topocentric angle measured from this particular earth station between the interfering non GSO space station and any space station in the GSO arc or the separation angle X which is the angle between a line projected from the GSO arc through the non GSO space station to the ground and a line from the non GSO space station to the edge of
120. tion results and to avoid errors a common measurement units system is used in Table 1 for the software description The list of measurement units for the basic physical parameters is shown in Table 1 TABLE 1 The system of measurement units for basic physical parameters used for the software performance description Distance Anal Linear rotation velocity Angular rotation velocity Frequency GHz Frequency bandwidth Power dBW Power spectral density Average number of co frequency non GSO earth stations per unit area epfd epfdy or epfd Antenna gain dBi Geographical position on the Earth s surface Rec ITU R S 1503 5 1 3 Constants The functional description of the software for examination of non GSO networks notification at the BR uses the following constants constants related to the Earth TABLE 2 Constants related to the Earth Parameter Notation Numerical value Units Radius of the Earth 6 378 145 km Radius of geostationary orbit Reo 42 164 2 Gravitational constant 3 986012 x 10 Speed of light 2 99792458 x 105 km s Angular rate of rotation of the Earth 41780745823 x 103 Earth rotation period 86 164 09054 Factor of the Earth non sphericity 2 634 x 1010 1 4 The Earth model The force of the Earth attraction is the main factor to define a satellite orbital motion Additional factors include orbit variations due to the Earth s oblateness and its mass distribution irregularities solar
121. tions Both test evaluations are essential and used here In functional testing the software is regarded as a black box It is subjected to an input and its output is verified for conformance with the specifications In this case the user concern is in what the software should do and not in the implementation details i e how it is done In structural testing the details are considered If the source code is made available then the software programming language programming style comments within program control methods and coding details are of concern Table 10 may be used as a guidance for the evaluation of a candidate software For each evaluation step use a score of 1 to 10 where 10 represents excellence or complete satisfaction and 1 represents complete dissatisfaction or no availability TABLE 10 Software evaluation table Operational environment s Step 1 Possibility of use with other applications Friendliness of software steps Flexibility and user interaction steps Consistency with BR approaches sees J Error handling and software recovery steps Upgrade and maintenance Sepia Documentation user manuals Step 7 ee Compliance constraints and basic assumptions Step 2 EN Execution time and stress testing
122. tions run time under usual and large volume loads such as number of satellites the ability to consider more than one constellation and evaluate calculation run time at different step sizes e g minimum simulation uplink downlink time increment for the simulation method or minimum longitude and latitude increments for the analytical method Relevant parts of Parts A and E of this Recommendation should be used as the guidelines Step 4 Evaluate whether the software is user friendly ease of use intuitive availability of online help indicator for run progress in terms of percentage completed and availability of software technical support Step 5 Evaluate error handling and software recovery determine clarity of error messages and whether errors can be detected and corrected Determine if software can return to operational status after failure and adequacy of backup data Step 6 Evaluate software flexibility software ability to provide results at intermediate calculation stages users should be able to pause or cancel a run and save the results to a file at any stage during simulations user ability to enter data from keyboard and or input files and graphic interfaces user ability to use different parameters and models system parameters reference antenna patterns etc Step 7 Evaluate documentation and clarity and completeness of user manual s availability of clear and complete set of user manuals flow charts examples in manuals expla
123. tude and latitude steps for the position of the reference satellite are chosen according to the procedure in Part D 6 3 4 2 4 Inputs and file formats 42 41 Input parameters This sub section defines the input parameters for a particular non GSO system scenario In this case input is a generic term that could include files or user input Information is required for non GSO system GSO system run configuration 64 Rec ITU R S 1503 4 2 4 2 Non GSO system parameters The following parameters as specified in Part B 2 1 would be used Parameter description Parameter name Number of nan GS0 satelite Orbit has repeating ground track maintained by Yes or No station keeping Administration is supplying specific node Yes or No precession rate Station keeping range for ascending node as Waelta degrees half total range For each satellite the following parameters specified in Part B 2 1 would be used where the definitions of the parameters are specified in Part B 5 3 1 at the time of the start of the simulation Note that in the Table below the indices N are present to indicate that there would be a different value for each satellite and the N th value corresponds to the N th satellite EE CPS Each satellite must have an independent set of six orbital parameters for orbit definition and subsequent propagation To define the characteristics of non GSO earth stations the following par
124. uired statistics Rec ITU R S 1503 13 TABLE 7 Input data GSO earth station antenna 3 dB beamwidth degrees Required number of tracks of a non GSO satellite passing through the main N racks beam of a GSO earth station antenna Jn the case of calculating run length for epfd In the case of epfd and epfd epfdy calculate p using the beamwidth of the non GSO earth station as specified in its e i r p mask using the calculation in equation 3 epfd calculate using the beamwidth of the GSO satellite in the calculation in equation 4 Two parameters are required Spass longitudinal spacing between successive ascending passes through the equatorial plane Sreg required resolution of passes through the equatorial plane based upon GSO earth station beam size These are calculated using the following steps Step 1 Calculate nodal regression rate of the non GSO orbit Q using the following equation Q 6 91951 x 10 3 x Re a 5 cos i degrees min where i orbital inclination degrees Step 2 Calculate the satellite s Keplerian period P assuming a circular orbit and no orbital perturbations P 84 48905 a R 5 min Convert this to seconds to get T period Px 60 Step 3 Calculate the satellite s nodal period P accounting for the Earth s oblateness Py Px 1 0 75 Jo 6 5 sin i Re a min where Jy is the first order Earth oblateness term 0 001082636 dimensionless Step 4 Calcu
125. using the algorithm in Part D 7 1 2 Compare epfdy statistics with limits using algorithm in Part D 7 1 Output results in format specified in Part D 7 3 pfd mask calculation The pfd mask is defined as a table of pfd values for various angles and latitudes It can be assumed that at or X angles increase from zero as the definition of amp or X in Part D 5 4 2 results in o or X that are greater than or equal to zero Note that the latitude range should be Minimum Maximum where is the inclination of the non GSO satellite s orbit Rec ITU R S 1503 55 In general the azimuth elevation or ot or X angles calculated at each time step will be between two values in the arrays In this case linear interpolation between pfd values should be used The mask that is closer in latitude to that of the reference satellite should be used Part C gives more information about the format and sampling of the pfd mask 3 7 Outputs The result of the algorithm is two arrays of size NEPFD DOWN as specified in Part D 3 1 in format Array of NEPFD_ DOWN epfd EPFD_DOWN_CALC I dB W m BW ep values Array of NEPFD DOWN PC CALC I percentages where PC CALC I is percentage of time EPFD DOWN CALC I is exceeded 4 Software description 4 1 epfdt software description This section describes the algorithm to calculate epfdt from non GSO earth stations into a GSO uplink It is assumed that the Ea
126. ware used for its calculation the complete software description and parameters The information required to generate the pfd mask could be made available to interested administrations to be used in case of dispute 4 Re testing of the BR software after any modifications or upgrades A set of tests should be defined for use on any occasions when the BR software or its operating environment has been modified or upgraded Such tests could include a some or all of the tests defined in Part E 1 for the initial evaluation of the computational accuracy of the candidate software b repetition of a representative set of evaluations of actual non GSO filings and comparison of the results obtained by the original and modified software systems PART F Operational environment for the software 1 Operating system The software shall run on 32 bit Window platforms under the Microsoft Windows NT version 4 0 or later and Microsoft Windows 95 98 or higher versions 2 Interfaces to existing software and databases The BR captures all incoming notices related to space services into one central database for alphanumeric data SNS and into another database for graphical data GIMS such as antenna diagrams and service areas These databases are used for the publication of the data on CD ROM in the Weekly Circular and its Special Sections They are also used to provide input data to software packages performing RR Appendix 29 and pfd examinations This

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