Calculation of radio electrical coverage in Medium‐Wave
Contents
1. Calculate Figure 3 4 2 Field Calculation at single points Windows TX and RX ALLEE Conductivity J database Conductivity DataBase Germany Hgh Resolution Transmitter 1 Guard Interval us Name Latitude OO0d0O0mOO N Longitude O00d00mOOsE Freq MHz Power KW Gain dB Gain dB Antenna Heigh m Antennas Heigh m Polarization Vertical Polarization Vertical Receiver data Figure 3 4 3 Parameters to configure the simulation 16 Calculation of radio electrical coverage in Medium Wave Frequencies Marcos Crego Garc a Data must be inserted in the format specified at user interface This implies inserting the configuration with the correct units but also inserting latitude and longitude coordinates as specified The format specified for both coordinates 1s next Latitude generally it is set from 90 what is 90 0 00 to 90 being the Equator the 0 reference In the notation used in this application latitude ranges over 90d00m00sS equivalent to 90 and 90d00m00sN equivalent to 90 Longitude generally it takes values between 180 what is 180 0 00 and 180 In the format used in this project longitude ranges over 180d00m00sW 180 to 180d00m00sE equivalent to 180 Field strength calculation at one receiver due to one or several transmitters only has sense when all the transmitters are working at the same frequency and polarization This fact2. O00d00m00sN O00d00m00sE 0 0 0 0 0 0 Name Latitude Longitude Freq MHz Power KV Gain dB Polarization Transmitter 6 TS DDOAD0OmOOs kN O00d00m00sE 0 0 0 0 0 0 Antenna Heigh m 0 Vertical M Name Latitude Longitude Freq MHz Power KAN Gain dB TX6 OOOd00m00sN O00d00m00sE 0 0 0 0 0 0 Antenna Heigh m 0 Polarization Vertical v Receiver 1 Name Latitude Receivers Configuration Mot used Oo00d00m00sNh OOOd00mO00sE Receiver 2 Name Latitude Not used OO00d00m00sN Receiver 3 Name Latitude Not used Q OdOOmOOsN Receiver 4 Name Latitude Not used O00d00m00sN O00d00m00sE Receiver 5 Name Latitude Not used O00d00m00sN OO0d00m00sE Receiver 6 Name Latitude Not used O00d00m00sN OO0d00mO00sE Longitude Longitude OO0d00m00sE Longitude O00d00m00sE Longitude Longitude Longitude Antenna Heigh m 0 Antenna Heigh m 0 Antenna Heigh m 0 Antenna Heigh m 0 Antenna Heigh m 0 Antenna Heigh m 0
3. gt SS 1 i pr uU di i PNA eos MN 4 DL a RI il RUP NINE RUNNIN at Lo L AZLA AAA aii Intensidad de campo dB 1V m X NN a mi AAS ANE p ORIS AC ERR ANNA N vi NAIA AANA TEN D NN t AURA INUIT AAA fooo D v SUI NU L O LIST A NN p 9 JUS CZ CN IS TN o Sf At A AAA HHS AUVAVAVAVAVAU Vay A uA Z L4 te 008 NUN AS LN SL ek 2 MHz 150 m 1 5 MHz 200 m D km Inversa de la distancia Figure 3 2 1 Example of ITU R P 368 9 Recommendation BL d 5 x 3 D lt gt an EA BH SE NS LTT somes IT de 22m hi WI Sim Ma SS a ee ee oe bite 10000 m 20 khe 5000 m 1 bhi 20 000 m Imensidad de campo Bi V jm CREE A AA A Gur Ru rT o a P1 n ee MW hi i TITRES UNN i m M s n 2 i ns l RM RNS E Ss o NN Sak Illi E mu mm i LM E X VEL ii X AR th d N ill i UN Me T Bons sitit ii Sih iu Nim Su MIO NDS Nis io f Aff ii dis N i w A NE HIA resto K RN hN RNI IN aa i PENN NS n A C j a E AA TN INS eh we Wish an l NA TINA a ON TR 1i MANN ORA ma um t i d ANNO Figure 3 2 2 ITU R P 368 9 Rec Remarkable parameters 11 Marcos Crego Garc a 30 kHz 10000 m 20 kHz 15 000 m 15 kHz 20000 m 10 kHz 30000 m ur NULLE il NNEC
4. si ee Rangek m iver RX Field profile between a Transmitter TX and a Recei Figure 3 4 10 23 Calculation of radio electrical coverage in Medium Wave Frequencies Marcos Crego Garc a Elevation profile Eley ation m Rang k m Figure 3 4 11 Elevation profile over the sea between a Transmitter and a Receiver Also the application shows a waitbar so the user can have an estimation of the remaining time for the calculations GRWAVE has a slow and complex algorithm and grwave m has to create and reading two files in each calling so simulations will last several hours for big maps and high resolution It is useful in this case to know the remaining time to finish simulation The code controlling a waitbar 1s shown in the next figure 24 Calculation of radio electrical coverage in Medium Wave Frequencies Marcos Crego Garc a Starting waitbar ye x waitbar 0 Please wvait k will be the status bar so it is started to zero k 0 printing an advice set x name Estimating remaining time total number of iterations of the loop is calculated total size mapcob 1 size mapcob 2 E ESES loop for fila 1 1 size mapcob 1 with clock the actual instant is stored into tO tO clock instrucctions Waitbar will be updated for each element of the loop calculated update the waitbar to advance k k 1 waitbar k total calculate the ti
5. When having Scale Factor 1 results match exactly but with a scale factor lower than one the field obtained with the map at one point only gives an approximation of the real field and it will not match with the final field calculated by the profile In this way coverage maps can be considered as an approximation of the field strength in an area due to a 21 Calculation of radio electrical coverage in Medium Wave Frequencies Marcos Crego Garc a transmitter but to know the exact field strength at one point 1t must be chosen the first option of the application field strength Coverage Map 10 0 10 20 30 40 50km pa a a S E O D aooo Munich Figure 3 4 8 Coverage results in the area of Nurnberg 22 Marcos Crego Garc a Calculation of radio electrical coverage in Medium Wave Frequencies Height M ap e c u 43 5 en i pun 1 1 i 1 1 1 Q 1 1 1 2 F 2 3 1 1 1 1 1 gt 1 1 1 1 1 1 A ras NA Comi 1 i 1 1 i e i e i r 1 1 1 1 V i i i x rr q 1 i 1 1 1 EP i i i E 1 a fF tt 3 E 1 1 1 1 1 2 1 1 1 1 1 a a 1 1 1 1 q 2 T u 1 z 1 e nmi 1 e i gt i QQ 1 m I 4 L I L L I T LR ee a O X Figure 3 4 9 wiAneap 3
6. as 1t was said before a Correction Factor must be applied after calling GRWAVE when using other power or antenna gain Binary and source code files are available at the ITU R Website 28 Calculation of radio electrical coverage in Medium Wave Frequencies Marcos Crego Garc a GRWAVE has a MSDOS command window interface to insert data needed but also allows the user to insert data into a file following a fixed format In the same way results obtained can be printed by GRWAVE either in the screen or into a text file The option chosen to communicate Matlab with GRWAVE was using the binary and the system command from Matlab and input and output text files to insert configuration and reading data The full instruction used to call GRWAVE 1s ergrw res system grwave lt data inp gt data out The instruction system command execute operating system command and return the result on success or an explanatory message of error in other case In this case command to execute is GRWAVE which must be located in the same directory of the application and data inp and data out are the names of the input and output directory respectively Both input and output files are text files with a format specified by GRWAVE Instruction Manual GRWAVE An example of the input file data inp 1s shown below HTT 9 146930e 001 HRR 9 8675476e 001 IPOLRN 1 FREQ 0 909000 SIGMA 0 008000 EPSLON 14 000000 dmin 1 231949e 001 dmax 1 3
7. map over this function is applied If the map 1s elevation map z will be an elevation vector d Vector of distances of every point of z to the first point located in vectors Lat and Lon in this case the transmitter lat and lon Similar to d but containing the latitude and longitude over the map of each element of z 54 Calculation of radio electrical coverage in Medium Wave Frequencies Marcos Crego Garc a Figure 3 5 20 Example of mapprofile b Resizem This function has two different sintaxis depending on the data available for the resize submap RESIZEM map r c method submap sublegend RESIZEM map SF maplegend method This function 1s used to increase or decrease the number of points and so on the resolution of the map The new size can be provided for the elements of row and columns desired r c or by giving a Scale Factor For example a Scalefactor 0 5 means that should be taken 1 of each two points of the original map for example Interpolation method can be the same than mapprofile This is the function used to reduce the grid of field strength from the high resolution conductivity map The variable returned is the submap created what is a map with the same latlim and lonlim than the original but with different number of points and so different resolution As the resolution in points and degrees 1s different the first maplegend element of variable submap will be different than the maplege
8. 17 High resolution Germany conductivity database 48 Figure 3 5 18 High resolution South Korea conductivity database 49 Figure 3 5 19 Graphical example of the map varlables ooooooocnnnncccccnnnnnononononnnnss 32 Figure 3 5 20 Example of mapprofll6 oooooonnnnnccccccnnnnnnnnnnnnnnnnnnnnnonnnnnncnnnnnnnnnnonnnnnoss 55 Pitre 3 002 T Example OP Tesi Zen dadas 56 Figure 3 5 22 Example Of Map eins cese eh te tertia an ne Y hee e a e Eu RE 57 Figure 23235 loadmap M parta Code iia 59 Figure 3 6 1 Example of coverage at 0 909 MHz Vertical polarizati0N 61 Figure 3 6 2 Example of coverage at 24 MHz Vertical polarization 62 Figure 3 6 3 Example of coverage at 0 909 MHz Vertical polarizati0N 63 Figure 3 6 4 Example of coverage at 0 909 MHz Horizontal polarizati0n 64 Calculation of radio electrical coverage in Medium Wave Frequencies Marcos Crego Garc a Resume of the Final Career Project Technical Industrial Engineering Title Calculation of radio electrical coverage in Medium Wave Frequencies Keyword Groundwave propagation coverage conductivity field strength ISI ITU R Author Marcos Crego Garc a Director Prof Dr Thomas Lauterbach Georg Simon Ohm Hochschule Nurnberg Codirector Mois s Serra Date February 2009 Resume The aim of this project is
9. 2 3 4 50067 9 3 4 5 6 709 4 i 1 10 100 Sooo 10 000 istanc DEZ SS I 2 MH 150 m 1 MHz 200 m mim 661b L IA A Se GS SS Figure 3 5 5 GRWAVE result vs ITU R graphics result 3 5 2 Millington Method GRWAVE can only be called when having one conductivity between transmitter and receiver This means that when several conductivities appear Millington method must be applied This method requires the knowledge of the parts of the path with different conductivity But not only conductivity data and paths are needed Also the data of antenna height to enter the ITU R GRWAVE is referred to effective antenna height Effective height 1s defined at the ITU R P 368 9 as the height of the antenna over the mean height of the path between transmitter and receiver so the entire path must be had in account 33 Calculation of radio electrical coverage in Medium Wave Frequencies Marcos Crego Garc a So before calling Millington method two previous calculations must be done effective heights of transmitter and receiver antenna and the characteristics of each path of one single conductivity To find out the conductivity paths a line between transmitter and receiver must be done over the conductivity map Using the mapping toolbox it can be created this line with an interpolation to the nearest conductivity as shown in the figure TX HAHAHAHA RX ol 02 0
10. Given a position in a matrix by its row and column this function returns its latitude and longitude Setpostn Given a latitude and longitude returns the position in the matrix as row and column 53 Calculation of radio electrical coverage in Medium Wave Frequencies Marcos Crego Garc a 3 5 5 3 Most used functions Some examples of the most important functions for this application are a Mapprofile z d lat lon mapprofile map maplegend Lat Lon method This useful function creates the interpolated line between a receiver and a transmitter to calculate the paths for Millington Both Lat and Lon are 2 elements vector containing the information of both latitude and longitude of the two point to join with a interpolated line In this project these two points used to be the transmitter and the receiver so these two vectors used to have the sintaxis Lat latTX latR X Lon lonTX lonRX Method 1s the interpolation method to be used that can be nearest bilinear or bicubic In case of conductivities values are fixed so nearest 1s the interpolation needed In case of elevation profiles it should be more accurate interpolate the value of height at one point with another method Bilinear method has been chosen in this case The values returned are Z A vector of interpolated values between transmitter and receiver The origin of the data contained in this vector conductivities elevations etc depends on the
11. ScaleFactor Latlim Lonlim worldmap Latlim Lonlim contourfm mapg mapglegend colormap pink 40 Calculation of radio electrical coverage in Medium Wave Frequencies Marcos Crego Garc a Figure 3 5 10 GLOBE elevation data for Nurnberg area There is no digital conductivity database in high resolution There is a digital conductivity database coming from a vegetation database with poor resolution and not having in account rivers and lakes with good conductivity and so very important However ITU R provides a detailed atlas of conductivities in its ITU R P 832 2 Recommendation ITU R P 832 2 This atlas cover almost all the world except Germany so for this project high resolution conductivity database must be created also The conductivity data of Germany terrain 1s fully documented at Internet CONDUCT Here the image containing the map of the conductivities can be downloaded but this map yields several problems It has no latitude and longitude references and the image has poor resolution so it has to be pre processed 41 Calculation of radio electrical coverage in Medium Wave Frequencies Marcos Crego Garc a The first step 1s editing the map with one image editor and cleans the pixels to obtain pure colours for each zone of conductivity RGB code of each zone is assigned to one conductivity establishing the relationship between colours and conductivities Figure 3 5 11 Cleaning the image with an
12. and longitude are specified into headers text files that must be downloaded with the elevation tiles To deal with GLOBE database and being capable of extract a region of the world even if it is separated in tiles MATLAB Mapping Toolbox MATLAB can be used with the function globedem mapg mapglegend globedem c globe ScaleFactor Latlim Lonlim This command specifies Matlab c globe The directory where the files of GLOBE are stored both elevation tiles and headers ScaleFactor The Scale Factor that 1s the resolution desired 1 means maximum resolution 1 km between points of the matrix returned Latlim and Lonlim These two variables specify the limits of latitude and longitude of the region desired 39 Calculation of radio electrical coverage in Medium Wave Frequencies Marcos Crego Garc a Data returned are mapg The map containing the elevation data of the area selected by Latlim and Lonlim mapglegend The reference vector or maplegend of all map which will be specified in the Mapping Toolbox section GLOBE returns the elevation of the points over the sea and the sea marked with a NaN This must be changed inside the application to assign sea a zero elevation An example of the maps returned by GLOBE for the area of Nuremberg 1s shown in next figure Example of the command ScaleFactor 1 Latlim 48 50 Lonlim 10 5 12 5 mapg mapglegend globedem c globe
13. being able to plot the field profile between the transmitter and the receiver Adapting the system to be able to calculate the effect of the Inter Symbol Interference ISI and the electric field resulting at one receiver in a scenario of several transmitters And packaging all this calculations into an easy to use Graphical User Interface In the figures below some examples of the results desired are shown Calculation of radio electrical coverage in Medium Wave Frequencies Marcos Crego Garc a E dB uV m TX red and RX blue position Coverage Map Koln 3 01 121dB uVim Frankfurt 12 2238dB uV m Transmitter 0 1KW a Example of Coverage Map b Example of field calculating results over an scenario with several receivers and transmitters Figure 3 1 1 Examples of the maps obtained Field profile 100 a TM CNET A CES NR ES y A A MESE MERE RI d mE M m MN E usd A Ts Sc aile d Field at Receivers RENS A NNNM NEN NM SEMEN Nuremberg 71 668787 dB uV m Frankfurt 12 223787 dB uV m mp TU pU joe eee um Munich 25 103787 dB uV m 70 A A NM Koln 3 011213 dB uV m T SN RT ee 8 15 20 25 3 Rangek m o th e a Figure 3 1 2 Examples of profiles and results printed on screen Calculation of radio electrical coverage in Medium Wave Frequencies Marcos Crego Garc a 3 Project exposure This chapter is the main chapter of this document where all the details of the
14. of conductivity In this case two options were possible the first one should be ignore that intermediate points and keep on calculating the field strength with the other points with conductivity defined and the second option should be do not calculate the field strength at all In the first case Millington s Method and GRWAVE should give a value but since there are intermediate points where there is no information of 50 Calculation of radio electrical coverage in Medium Wave Frequencies Marcos Crego Garc a conductivity the result 1s not reliable and it yields to a very inaccurate result To avoid inaccuracies and reliabilities the second option has been chosen so in these cases field strength will not be calculated Code Error 4 Error in Map Application deals with two different types of databases high resolution and low resolution database When choosing low resolution one the user can choose any area of the world desired to calculate for example the coverage with no problem because any part of the world can be trimmed from a worldwide map However high resolution databases have exact limits of latitude and longitude and if the user choose a region a receiver or a transmitter falling out of this range the application will not be able to calculate the field strength with the database desired by user and so on it will exit 3 5 5 Mapping Toolbox Matlab Mapping Toolbox MATLAB is a huge set of functions to a
15. project are explained To do so some introduction of Groundwave propagation should be given first followed by a project description and detailed software development as well as several practical examples are exposed 3 1 Groundwave propagation The Groundwave propagation method has special relevance at HF communications in the 10 KHz 30 MHz frequency band When the height of the transmitter antenna operating at these frequencies is small in comparison with its wavelength A Groundwave propagation appears In the lowest frequencies of the band this propagation method can even reach hundreds of Kilometres given worldwide coverage with a very low bandwidth but very useful for maritime rescue applications The most important property of the Groundwave propagation is that it propagates parallels to the ground In this way the attenuation will depend strongly on the terrain constants conductivity and permittivity as well as other factors like polarization antenna height distance and frequency Over non homogeneous paths the use of vertical polarization 1s the only practical approach because the ground quickly absorbs horizontal polarization Even vertical polarization suffers high attenuation over poor ground Paths over the sea or including the sea have diminished losses because the increased sea conductivity Radiation over a smooth spherical surface is a radio electrical problem that has an analytical solution The radiated f
16. radio electrical coverage in Medium Wave Frequencies Marcos Crego Garc a By Millington programmed Matlab function the field strength returned is directly Et 17 70 dB uV m approximately equal to the field strength calculated manually with two graphics The second test using ITU R Graphics for vertical polarization at 1 MHz low frequencies Ef El dl E2 d1 E2 d1 d2 58 El dl 64 E2 dl 77 E2 d1 d2 71 Eb E2 d2 El d2 El d1 d2 66 E2 d2 81 El d2 70 El d1 d2 55 Et Ef Eb 2 62 dB uV m By Millington the field strength returned is directly Et 62 14 dB uV m approximately equal to the field strength calculated manually with two graphics 38 Calculation of radio electrical coverage in Medium Wave Frequencies Marcos Crego Garc a 3 5 3 Elevation and conductivity database Due to the nature of the Groundwave propagation it is needed to know the terrain conductivity and the antenna height and so digital conductivity and elevation or topography databases are required Nowadays there 1s no digital High Resolution Conductivity Database available However there is available a digital Global Elevation Terrain database with a resolution of one km available at NOAA s Project Website GLOBE GLOBE 1s an atlas elevation database World data are separated into several tiles to be able to manage them each tile representing an area of the world The limits of latitude
17. the conductivity map selected switch lower Country case germany load germany mat case korea load korea mat otherwise load conduct mat end having in map the global database this instruction trims the range of latitude and longitude required and return results overvritting map and map maplegend maptrims map maplegend Latlim Lonlim if ScaleFactor is lower than one matrix must be reduced map maplegend resizem map ScaleFactor maplegend load the elevation map at maximum resolution scalefactor 1 mapg mapglegend globedem c qlobe 1 Latlim Lonlim elevation of the sea is changed form NaN to 0 mapgi findi isnan mapy 0 fit the size of the elevation map to be the same than the conductivity map mapg resizem mapg size map bilinear Figure 3 5 23 loadmap m partial code After selecting database it has to be trimmed to select only the region specified by range limited in latlim and lonlim If the high resolution database 1s selected and latitude and longitude ranges over several degrees it is possible to have a huge matrix so it can be resized by a scale factor if its value is lower than one At this point conductivity database is already done To load the elevation database from GLOBE GLOBE files must be recorded into the path c globe the application makes the calling to globedem with the same latit
18. to accomplish an application software based on Matlab to calculate the radioelectrical coverage by surface wave of broadcast radiostations in the band of Medium Wave MW all around the world Also given the location of a transmitting and a receiving station the software should be able to calculate the electric field that the receiver should receive at that specific site In case of several transmitters the program should search for the existence of Inter Symbol Interference and calculate the field strength accordingly The application should ask for the configuration parameters of the transmitter radiostation within a Graphical User Interface GUI and bring back the resulting coverage above a map of the area under study For the development of this project it has been used several conductivity databases of different countries and a high resolution elevation database GLOBE Also to calculate the field strength due to groundwave propagation it has been used ITU GRWAVE program which must be integrated into a Matlab interface to be used by the application developed Calculation of radio electrical coverage in Medium Wave Frequencies Marcos Crego Garc a 1 Introduction This project deals with radioelectrical propagation in the frequency band of Medium Wave In this band of frequencies between 10 KHz and 30 MHz the main propagation method 1s Surface Wave or Ground Wave Propagation There are two different ways to calculate the electri
19. vectors of distance and terrain constraints d flipdim MDIST 1 sig flipdim MSIGMA 1 epslon flipdim MEPSLON 1 Effective height of the terrain in sense rx gt tx hh h 2 end calculating total field strength Et EdB 1 EdB 2 2 end 3 del function Figure 3 5 8 MillingtonH m source code As the field returned is a result of several callings to GRWAVE it should be also normalized so the correction factor must be later applied 36 Calculation of radio electrical coverage in Medium Wave Frequencies Marcos Crego Garc a To check 1f Millington was working well several test have been made In the test normalized field strength was calculated with no height data in account so the Matlab function should return the same field than the graphics and Millington manual method should do Here are two of the tests done one for the highest side of the frequency band 30 MHz and the other one for an approximation of the lower extreme of the frequency band 1Mhz o 0 003 80 0 0 03 e 40 Figure 3 5 9 Millington example for testing Matlab function Using ITU R Graphics for vertical polarization at 30 MHz the highest frequency available Ef El d1 E2 d1 E2 d1 d2 20 El dl 30 E2 dl 25 E2 d1 d2 15 Eb E2 d2 El d2 El d1 d2 16 E2 d2 34 El d2 38 El d1 d2 20 Et Ef Eb 2 18 dB uV m 37 Calculation of
20. 2008 67 Calculation of radio electrical coverage in Medium Wave Frequencies Marcos Crego Garc a GLOBE THE GLOBAL LAND ONE KM BASE ELEVATION PROJECT GLOBE A 30 arc second 1 km gridded quality controlled global Digital Elevation Model DEM NOAA http www ngdc noaa gov mgg topo globe html Consultation October 2008 GRWAVE GRWAVE USER MANUAL Software concerning Tropospheric Propagation Ground wave propagation GRWAVE International Telecommunication Union Radiocommunication Sector ITU R Study Group 3 SG 3 Radiowave propagation http www itu int ITU R index asp category documents amp link rs 3 amp lang en Consultation October 2008 ITU R P 368 9 ITU R P 368 9 RECOMMENDATION Ground wave propagation curves for frequencies between 10 kHz and 30 MHz Approved on February 2007 in force ITU R P 832 2 ITU R P 832 2 RECOMMENDATION Atlas mundial de la conductividad del suelo Approved on July 1997 in force 68 Calculation of radio electrical coverage in Medium Wave Frequencies Marcos Crego Garc a MATLAB MATHWORKS Mapping Toolbox User s Guide Analyze and visualize geographic information http www mathworks com access helpdesk help toolbox map Consultation October 2008 69 Calculation of radio electrical coverage in Medium Wave Frequencies Marcos Crego Garc a Appendix List of abbreviations BOF CF dB DLL Dmax Dmin DRM Dstep E E
21. 3 4 Figure 3 5 6 Acquiring the stretches of the path of the same conductivity Once the path and all their conductivities are obtained they must be grouped into stretches of the same conductivity The receiver should be placed in each one of these points to calculate the Millington method described above As effective height depends on the path effective antenna height for receiver and transmitter should be different in every point when field is calculated So for each point of the final path effective height must be calculated for transmitter and receiver 34 Calculation of radio electrical coverage in Medium Wave Frequencies Marcos Crego Garc a TX Effective height of antenna TX and RX gt Mean height of the path Figure 3 5 7 Calculation of the effective height After calculated the paths Millington method can be called This function MillingtonH m is responsible for requesting GRW AVE several times depending on the number of paths of different conductivity It returns the value of field strength at the receiver also normalized The detailed code is shown below This function has as input parameters the system configuration frequency polarization etc and several vectors with the terrain constants MSIGMA MEPSLON and a vector of distances of each value to transmitter MDIST When MillingtonH m is called it is supposed to be under ITU R conditions so the field strength can
22. 31949e 001 dstep 1 go stop Figure 3 5 2 Example of GRWAVE input data file data inp Where HTT Effective height of the Transmitter m HRR Effective height of the Receiver m 29 Calculation of radio electrical coverage in Medium Wave Frequencies Marcos Crego Garc a IPOLRN Polarization 1 for vertical and 2 for horizontal FREO Frequency in MHz SIGMA EPSLON Condutivity S m and permitivity of the terrain dmin Distance km where the field needs to be calculated dmax and dstep are required but not used and take values next to dmin With the command go GRWAVE starts calculating the field strength and after that it returns to the input file and when reading the command stop it exits GRWAVE and returns the control to the Matlab command Windows Units of Frequency heights conductivity and distance must be respected because this is the way of calling GRWAVE Before exit GRWAVE store the results into a file data out with the format shown in next figure GRwAVE RELEASE 2 AT 23 10 1985 wweww w COPYRIGHT C GEC PLC 1985 A RE CCIR Personal Computer version 1989 study Group 5 IWP5 1 GRWAVE COMPUTES FIELD STRENGTH DISTANCE VARIATIONS FOR A HOMOGENEOUS CURVED EARTH WITH EXPONENTIALLY DECREASING REFRACTIVE INDEX ATMOSPHERIC CONSTANTS REFRACTIVITY 2315 00 N UNITS SCALE HEIGHT 7 350 KM GROUND CONSTANTS RELATIVE PERMITTIVITY CONDUCTIVITY 8 0000D 05 VERTICAL POLARISATIO
23. N 12 319 13 319 1 000 MINIMUM DISTANCE MAXIMUM DISTANCE DSTEP FREQUENCY 909 MHZ 91 5 98 8 TRANSMITTER HEIGHT RECIEVER HEIGHT DISTANCE FIELD STRENGTH KM DBCUVM 12 32 82 89 13 32 81 97 Li e 00 stop Program terminated 30 14 000 SIEMENS METRE KILOMETRES KILOMETRES KILOMETRES METRES METRES BASIC TRANSMISSION LOSS DB CF 33 04 54 56 CR 00 Figure 3 5 3 Example of GRWAVE output data file data out Calculation of radio electrical coverage in Medium Wave Frequencies Marcos Crego Garc a This file has all the information of the configuration in the header and the value desired is near the bottom of the file so it means that to be able to read the data desired the file pointer must be located first at the beginning of the corresponding line GRWAVE always print two values of field strength but the only one needed is the first one In the example below data required should be 82 89 dB uV m Next figure shows an extract of the reading data instructions programmed at the grwave m Matlab function grvave system callback ergrw res system grwave lt data inp gt data out E open data out for reading fid fopen data out r ndata number of chars of the header ndata 1169 put the pointer ndatos chars after the begining of the file fseek fid ndata bof reading row a fscanfi fid f f f 3 1 3 data required is the seco
24. NANT NNN SUID NOIA NAM M M Nil 4 56789 10000 wani odures ap pepisumuj o Depends on the Conductivity Depends on the Frequency Depends on the Distance Calculation of radio electrical coverage in Medium Wave Frequencies Marcos Crego Garc a As the figure shows they are only valid over the frequency range from 10 KHz to 30 MHz for vertical polarization and antennas over the ground ITU R P 368 9 Over those frequencies GRWAVE still gives an approximation of the field strength but it is not accurate and reliable so it 1s not recommended using it out of this range From the graphics it can be seen that field strength diminish with frequency so groundwave propagation is not a relevant propagation mechanism with big distances in the HF band ITU R graphics and ITU R GRWAVE return normalized field strength for a transmitter using a power of 1 KW over a short monopole antenna 3 dB gain antenna so it will be necessary applying a Correction Factor CF to be able to use any other transmitter power of antenna gain COMMERCIALFM The field strength the power in KW and the antenna gain are related by the Power Density S as shown in the equations 3 2 1 to 3 2 4 To de normalize the expression returned by GRWAVE both real field and GRWAVE field can be compared In this way dividing SreaL Scrwave the correction factor is obtained The Correction Factor CF expression 1s shown in e
25. UV C Universitat de Vic Escola Polit cnica Superior Final Career Project Calculation of radio electrical coverage in Medium Wave Frequencies Marcos Crego Garc a Technical Industrial Engineering Director Prof Dr Thomas Lauterbach Vic February 2009 Calculation of radio electrical coverage in Medium Wave Frequencies Marcos Crego Garc a Index of contents Resume ot the Final Career Projet din ana 5 SA bs ELE eiut dite tede babe LE ve itis ue uid bee 5 2 WODICC UV Sette tan Mec utudicat A M tans Ubi Mte cd Un Mi tni ut 7 9 IBPOICCEC X DOSULE iE E N eee a 9 SL COUN Wave propa S iiO Mii 9 32 A A toma asl oath 10 9 3 Nom Homogeneous PaSa ean aT o Pet te bs ob eir 13 DAY POPC CU CSC ii 10 Osc T M 14 3 9 SONAE de VelODEDODE Go pecie E peuie d etute eite i Peste tomus ebute tveeaauadadaiatnvebaemasee 26 35 1 GRWAYVYE Matlab AMT aCe eiii 28 3 542 Male om MEN di 33 3 5 3 Elevation and conductivity database ocooononooonooonononcnnnnnnnnnnnnnonnnnnos 39 39A DOE errors Te ute iia 50 30 25 Mapping LoOlDOX adsense 51 3 6 Practical examples ido 60 A INI O AO 65 A E 66 6 Bibliography and Telete l6 6 Sai 67 Appendix Last oF abDEeVIdlHlOflS sado 70 Calculation of radio electrical coverage in Medium Wave Frequencies Marcos Crego Garc a Index of figures Figure 3 1 1 Examples of the maps obtained eese 8 Figure 3 1 2 Examples of profiles and results printed on scr
26. adio electrical coverage in Medium Wave Frequencies Marcos Crego Garc a finding positions inside x for RGB codes uno find x 1 164 x 2 15 J x 3 225 J dos find x 1 O amp X 2 143 x 3 250 J tres find x 1 21 J x 2 66 x 3 3 I J cuatro findi x 1 77 x 2 215 x 3 22 Je cinco find x 1 252 x 2 5 amp x 3 5 LE 134 seis find x 1 O amp X 2 255 x 3 146 siete find x 1 137 x 2 234 x 3 98 J ocho find x 1 164 x 2 1 amp X 3 1 E E nueve find x 1 10 J x 2 87 J x 3 144 J diez find x 1 255 x 2 140 x 3 19 J je once find x 1 242 x 2 85 J x 3 138 J J doce find x 1 250 x 2 241 x 3 3 1 14 trece find x 1 153 x 2 84 J x 3 9 TE catorce find x 1 237 x 2 235 x 3 143 J Je quince find x 1 102 x 2 8 amp X 3 141 diezsei find x 1 54 J x 2 147 x 3 17 Je negro f
27. ation of radio electrical coverage in Medium Wave Frequencies Marcos Crego Garc a Coverage Map 50 0 495 43 0 485 Figure 3 6 1 Example of coverage at 0 909 MHz Vertical polarization 61 Calculation of radio electrical coverage in Medium Wave Frequencies Marcos Crego Garc a Coverage Map Figure 3 6 2 Example of coverage at 24 MHz Vertical polarization The second comparison is between both vertical and horizontal polarization As it can be seen in the colour bar the horizontal polarization decreases dramatically at little distance from transmitter 62 Calculation of radio electrical coverage in Medium Wave Frequencies Marcos Crego Garc a Coverage Map 50 0 425 490 485 40 0 10 20 30 4 50km LL LLL A A O IJ 480 N 10 Figure 3 6 3 Example of coverage at 0 909 MHz Vertical polarization 63 Calculation of radio electrical coverage in Medium Wave Frequencies Marcos Crego Garc a Coverage Map Figure 3 6 4 Example of coverage at 0 909 MHz Horizontal polarization 64 Calculation of radio electrical coverage in Medium Wave Frequencies Marcos Crego Garc a 4 Conclusions The software developed fits with all the objectives Matlab interface for GRWAVE has been done Fitting to the ITU R Recommendations o With homogeneous paths o With non homogeneous paths and Millington method o With frequency and elevation ITU R limits Calculate areas of coverage fields due to a single transmitt
28. b Ef Et EPSLON EXE FREQ G GLOBE Beginning of file Correction Factor Decibels Dynamic Linking Library binaries functions inserted into a file Maximal distance Minimal distance Digital Radio Mondiale Step in distance to calculate dmax based on dmin East to refer to field strength Et is used Back Field Field in direction receiver to transmitter used in Millington Forward Field Field in direction transmitter to receiver used in Millington Total reciprocal field returned by the Method of Millington e Permittivity of the terrain Executable file Frequency Antenna gain Global Land One km Base Elevation GLOBE Project 70 Calculation of radio electrical coverage in Medium Wave Frequencies GRWAVE GUI HF HRR HTT IPOLRN IST ITU R JPG KW MEX MF MW NaN NOAA PNG Marcos Crego Garcia MSDOS software to calculate the field strength due to Groundwave propagation Guided User Interface High Frequency Effective height receiver antenna Effective height transmitter antenna Polarization Inter Symbol Interference International Telecommunication Union Radiocommunication Section Joint Photographic Experts Group Image format Kilowatts Matlab interface to be able to call Fortran or C codes in Matlab Medium Frequency Medium Wave North Not a number Organization in charge of GLOBE project Transmitter power Portable Network Graphics Image format 71 Calc
29. be calculated To do so the program first calculate the field in direction transmitter to receiver forward and once it 1s calculated it flips all the vectors to reverse them and do the calculations again to obtain the receiver to transmitter field strength back After obtaining both values the arithmetic mean 1s made and the total field 1s returned 35 Calculation of radio electrical coverage in Medium Wave Frequencies Marcos Crego Garc a function Et MillingtonH MIPOL MFREO MEPSLON MSIGMA MDIST MHTief h EdB 2 element vector Ef Eb EdB geros 1 2 distances for non homogeneous paths d MDIST terrain vector constraints at the path sig MSIGMA epslon MEPSLON Effective height of the terrain in sense tx gt rx hh h 1 1 amp this loop vill calculate field Ef and Eb for j 1 1 2 setup value EdB 3 O 2 to calculate the lengths of the homogeneous paths i do the cumulative sum d cumsum d millington for i 1 1 length d 1 EdB 3 EdB j grwave MIPOL MFREOQ epslon i sig i d i MHTZXef j hh i EdB j EdB 3 grwave MIPOL MFREQ epslon i 1 sig i ri d i MHTXef j hh i end adding the last element of millington outside the loop EdB j EdB j grwave MIPOL MFREOQ epslon length d sig length d d length d MHTXef j hh length d to be able to calculate field strength in sense rx gt tx i flip the
30. c field due to Groundwave propagation The set of graphics provided by the ITU R P 368 9 Recommendation each one for different frequencies and terrain conductivity and permittivity With ITU R GRWAVE a MSDOS based software used by ITU to obtain the graphics showed at Rec ITU R P 368 9 which allows calculating the field at one point over a path with one conductivity given a transmitter and a receiver Although ITU R Graphics and GRWAVE are recognized methods by ITU R they have limitations like These methods do not have in account topographical data very important in this type of propagation due to its nature detailed description of groundwave propagation can be found at chapter 3 1 Millington method for Non Homogeneous paths calculations become tedious and complicated when calculating the field over paths with several different conductivities Calculation of radio electrical coverage in Medium Wave Frequencies Marcos Crego Garc a 2 Objectives The aim of this project 1s the development of a software tool based on ITU R Recommendation and ITU R GRWAVE that will eliminate these limitations by Calculating the electric field keeping the ITU R P 368 9 Recommendations with ITU R GRWAVE Introducing topographical data of the terrain under study Introducing high resolution conductivity maps Performing automatic calculations of radio electrical coverage at one region Making calculations at one single point
31. een 8 Figure 3 2 1 Example of ITU R P 368 9 Recommendation suus 11 Figure 3 2 2 ITU R P 368 9 Rec Remarkable parameters sssuussss 11 Figure 3 3 1 Example of Method of Millington with a path of two conductivities 13 Figure 5 4 15 Start Menu WO is 15 Figure 3 4 2 Field Calculation at single points Windows usesesssese 16 Figure 3 4 3 Parameters to configure the simulation eeeeeeeeeseessseessee 16 Figure 3 4 4 Field Calculation Results offered eeeeessssessssussss 18 Figure 34 92 Coverage caleulati n 3VIDdOW ida 20 Figure 244 6 CONMSUraton parameter ias 20 Figure 3 4 7 Example of configuration and Waltbar cccccccnonoooononanonccnncnoncnnnnnnnnnnnnnos 21 Figure 3 4 8 Coverage results in the area of Nurmberg ooooonnnnnononononononononnnnnononononononoss 22 Figure 3 4 9 Elevation map in the area of Nurnberg oooooconncnnononononnnnnononononnnnnnnnnnnnononos 23 Figure 3 4 10 Field profile between a Transmitter TX and a Receiver RX 23 Figure 3 4 11 Elevation profile over the sea between a Transmitter and a Receiver 24 Figure 3 4 12 Control code of a WADE e edet Ern letto eerte tome vue dus 25 Figure 3 5 1 Flow chart of the application eene 28 Figure 3 5 2 Example of GRWAVE inpu
32. elds are calculated assuming a homogeneous path so graphics or GRWAVE can be applied 13 Calculation of radio electrical coverage in Medium Wave Frequencies Marcos Crego Garc a As 1t can be seen in this example for only two conductivities six different consults to ITU R graphics or six calls to GRWAVE are needed This means a very tedious process and it becomes even more tedious because generally there are more than two conductivities between Transmitter and Receiver especially when they are far enough 3 4 Project description As it was said in the first chapter the aim of this project 1s to accomplish next objectives Suit the method of calculation to the ITU R P 368 9 for groundwave field strength coverage Include topographical data Include conductivity maps to be able to process the coverage under one area and fields profiles automatically Extend the GRWAVE to calculate the field in one point receiver due to one or several transmitters checking if there is ISI or not Create an easy to use graphical user interface to simplify the methods described at ITU R Rec To achieve these objectives it has been chosen Matlab as the programming tool due to its Mapping Toolbox that allows dealing with maps and coordinates data expressed in latitude and longitude which are the nature way to express the location of a radio station Moreover the version chosen has been Matlab 7 R14 because the plot of the coastal l
33. er operating in a site Calculate field strength at single points receivers due to one or several transmitters Checking in case of several transmitters if there should be ISI at one point or not Printing data at the screen when needed A graphical interface make the application easy to use saving data at binary mat files to be able to load them after the simulation 1s done in Matlab to have a data post process Radioelectrical conclusions obtained from the data observed from several simulations are Vertical polarization 1s stronger than horizontal polarization in every path and distance between transmitter and receiver At low frequencies elevation and conductivity terrain 1s negligible and coverage diagrams are very rounded At high frequencies conductivity and elevation affect strongly to the Groundwave propagation and distance of coverage and so field strength 1s reduced dramatically in comparison to low frequencies Antenna elevation has its influence over the field calculated so the transmitter site must be the highest site inside the area of coverage 65 Calculation of radio electrical coverage in Medium Wave Frequencies Marcos Crego Garc a 5 Future guidelines This project could be expanded in several ways Adding more countries to the high resolution conductivity database This point was not made at this Project due to time restrictions Matlab is optimized to work with matrix Dealing with files at
34. homogeneous paths Calling GRWAVE from Matlab Programming ITU R P 368 9 Recommendation for non homogeneous paths Programming method of Millington This means the previous obtaining of the path between two points in a map conductivity interpolation and effective heights The nature of the project means working with maps so it is needed to use Matlab Mapping Toolbox which will be discussed in the last place This project works with two databases terrain conductivity and permittivity and elevation database Both are necessary data to call GRWAVE following the instructions from the ITU R Loading conductivity and elevation maps The flow diagram 1s shown below P Calculation of radio electrical coverage in Medium Wave Frequencies Marcos Crego Garc a Main program Field calculation Coverage calculation 3 2 For each RX For each Load Check without Load oint of the Maps RX with ISI Maps P ISI 4 a Calculate paths map TX RX 6 b Millington Et V E 2 E Figure 3 5 1 Flow chart of the application 3 5 1 GRWAVE Matlab interface ITU R GRWAVE is software developed in FORTRAN to estimate the field produced for Groundwave propagation The results obtained are only reliable under certain conditions of frequency and height ITU R P 368 9 which are fully contemplated in the program The field strength given 1s normalized to a transmitter power of 1 KW and an antenna gain of 3 dB so
35. ield can be expressed as a sum of terms with amplitudes in function of frequency terrain constrains polarization distance and Calculation of radio electrical coverage in Medium Wave Frequencies Marcos Crego Garc a antenna height This 1s the analytical solution provided by ITU R GRWAVE GRWAVE The estimation of the Groundwave field strength given at one point depends on the nature of the path between transmitter and receiver In this way two different methods are defined by ITU R Recommendation Method for homogeneous paths and Millington s Method for Non Homogeneous paths ITU R P 368 9 3 2 Homogeneous paths The ITU R Rec 368 9 defines a homogeneous path as the path between the transmitter and the receiver when there 1s only one terrain conductivity between them In this case both ITU R Graphics or ITU R GRWAVE can be used directly to calculate the field strength at the receiver As shown in the figure below ITU R graphics depend on frequency terrain constrains and range and so appropriate curve must be selected 10 Calculation of radio electrical coverage in Medium Wave Frequencies Curvas de propagaci n de la onda de superficie tierra 6 3 x 10 S m 40 IR RI O II onannan a HHA SL A Ie He Sul A I dou AUI AT js is i e a NL EE un NS ISSN SHR T OPS gt Sira Y 234 mb Li imm HIT se 4 i mit i a ti i al SS q
36. image editor Sea has been assigned to white colour while non defined areas remain in black The second step is obtaining the latitude and longitude limits using Germany image from ITU R P 832 2 Recommendation So to achieve that with the image editor a new image is made with two layers the first one bottom the ITU R image from Germany containing the latitude and longitude references and the second layer containing the coloured conductivity map In this way conductivity map is adjusted to ITU R map and it is trimmed following the guides of the ITU R Layer and it 1s achieved a new image with conductivity data and latitude and the longitude limits already set 42 Calculation of radio electrical coverage in Medium Wave Frequencies Marcos Crego Garc a Figure 3 5 12 Setting latitude and longitude limits Now we have the image cut with references known the third step is loading the image into Matlab and converting the image into a map format Matlab can load images in different formats PNG format has been chosen because of the high definition of its pixels and colours It can not be JPG format because of the fading of the colours To be able to convert colours to conductivities pure colours are needed With the instruction imread germany png the image created germany png is loaded as a matrix of three dimensions or layers Red Green and Blue corresponding to RGB Code With the matrix loaded a simple Matlab script
37. ind x 3 1 0 J i x 2 7 7 0 J x 3 0 Je blanco find x 1 255 x 2 255 x 3 255 J Figure 3 5 14 Converting image to conductivity database II Now we have the position inside the matrix founded for each colour the colours must be assigned to one conductivity This is made by the next set of instructions assign conductivities to the colours map negro Nal black non defined conductivity data map blanco 5000e 3 white sea map uno 20e 3 map dos 10e 3 map tres 13e 3 map cuatro 6e 3 map cinco 4e 3 map seis te 3 map siete 5e 3 map ocho 5 5e 3 map nueve 6e 3 map diez 4 5e 3 map once 3 5e 3 map doce 3e 3 map trece 2e 3 map catorce 1e 3 map quince 2 5e 3 map diezsei 6 5e 3 Figure 3 5 15 Converting image to conductivity database II 45 Calculation of radio electrical coverage in Medium Wave Frequencies Marcos Crego Garc a Permittivity 1s also needed for this project because it has strong influence on the terrain properties It is no needed having another matrix of the same dimensions of map with the parameters of the permittivity There is only one permittivity for each conductivity and conductivity values are known for a specific map so permittivity can be stored in a matrix of two rows one being the conductivities sigma of the map and the other
38. ine and politics frontiers 1s more accuracy The project has been divided in two differentiated parts the one for the scenarios with several transmitters and receivers and the one for coverage calculation The program allows the user to choose the option desired or even both options as shown in the next figure 14 Calculation of radio electrical coverage in Medium Wave Frequencies Marcos Crego Garc a Starting Menu Selectthe options desired Field Calculation Figure 3 4 1 Start Menu Window In case of both options chosen the first window to be open is the corresponding to Field Calculations because coverage calculations take a long time to finish and it is probably that it 1s only needed the field at one receiver instead of one region The window that appears in this case is shown in the figure below and it is formed by the configuration of six transmitters and the configuration of six receivers Transmitters and receivers are stored in Matlab into a vector of structures Transmitters data are the name of the site the position given by its latitude and longitude in format 000d00m00sN being d degrees m minutes s seconds N North the frequency in MHz the power in KW the antenna gain dB the antenna height in metres and the polarization Receiver s data are stored in the same way storing name to recognize them at the map latitude and longitude coordinates and antenna height It is needed als
39. is checked by the graphical interface previously to launching the application The application gives the results of the calculation in two formats graphical and text printed by screen Graphical data allow the user to locate visually the transmitters and receivers and text data allows to copy data to a file 17 Calculation of radio electrical coverage in Medium Wave Frequencies Marcos Crego Garc a TX red and RX blue position 2 arnamburg g pBO Se3edB uvim 1K wy Transmitters to be used Nuremberg even Koln 145317 4B UW im Field at Receivers Hamburg 60 883788 dB uV rm Frankfurt 13 707902 dB iuV m 91370 79dB uVim Munich 25 109699 dB uV m Koln 14 531749 dB uV m uremberg AKW a Results over a map b Results printed on Matlab screen Figure 3 4 4 Field Calculation Results offered When having a scenario with several transmitters with long distances between them and DRM system there can appear Inter Symbol interference at one receiver In presence of ISI the field returned by the application and the GRWAVE is not reliable and so it 1s not calculated So in order to avoid useless calculations the application checks previously for the presence of ISI DRM 18 Calculation of radio electrical coverage in Medium Wave Frequencies Marcos Crego Garc a There will be ISI when IdI d2 gt Guard Interval s x c m s 3 4 1 Being dl distance between transmitter 1 a
40. llow the management and representation of maps A map in Matlab is a NxM matrix with a reference vector called maplegend or refvec 3 5 5 1 Common variables This maplegend is very important and provides next information explained using as an example the maplegend of the Germany s conductivity database maplegend 120 55 6 The first element of maplegend gives the number of elements cells per grade In this case horizontal longitude resolution should be 120 columns per degree while latitude resolution should be 120 rows per degree 51 Calculation of radio electrical coverage in Medium Wave Frequencies Marcos Crego Garc a The second element gives the Latitude in degrees of the upper left corner of the map and the third element gives the Longitude of the upper left corner of the map This is graphically shown in the next figure Matlab mapping toolbox versions until Release 2007b version take maps with the same resolution in latitude and in longitude so the first element of the maplegend resolves the resolution in both dimensions this not means square matrix A map without maplegend will be interpreted as a simple matrix containing simple data never as a map But when working with maps there are three more variables very frequently used LatLim that is a 2 elements vector with latitude limits of the map Lonlim that is the 2 elements vector with longitude limits of the map and ScaleFactor value rela
41. me to simulate one cell substracting actual time clock with init time t0 ti etimel clock tO j remaining time in seconds to calculate remaining cells number of remaining cells total k t res secZhr ti total K pass the seconds to string and put as the waitbar title set x name streat Remaining time timezstr t res T ae ae ae ae ae ao ao ao ao co ao ao e ao ao e e ao e ao ao ao ao ao ao e ao ao ao ao am end 3 of the loop closing waitbar closelx Figure 3 4 12 Control code of a waitbar In this example extracted from coverage m function variable total represents the total number of cells of the coverage map rows x columns It will be decreased at every iteration of the loop The instruction etime calculates the difference in seconds between two instants of time As clock gives the actual time of the operating system the instruction etime clock t0 provides the time between t0 and now able to give us an 25 Calculation of radio electrical coverage in Medium Wave Frequencies Marcos Crego Garc a estimation of the time needed to process one cell and so on the time remaining to process the remaining cells Functions etime and clock are Matlab reference functions available in the basic Matlab toolbox However the instr
42. nd element of vector a Figure 3 5 4 Extract of instructions from grwave m After creating the input file with the configuration desired not at the figure the system calling to GRWAVE is done Figure 3 5 4 1s an extract of the real code where all the operations with files are checked for errors After calling GRWAVE the function opens the output file to read the data Before reading the data the file pointer 1s set at the beginning of the line desired There are approximately 1169 chars at the header having in account carrier returns so the 3l Calculation of radio electrical coverage in Medium Wave Frequencies Marcos Crego Garc a pointer is moved 1169 chars from the beginning of the file bof with the command fseek This 1s indeed an approximation and in the real function several validations of the position are done because sometimes GRWAVE inserts some more characters so an approximation is done When the pointer is correctly located the function reads the file with the command fscanf and returns in a a vector of tree elements in column format The field strength should be the second one that 1s the data returned by grwave m function So Matlab GRWAVE interface is a file grwave m that creates the input file calls GRWAVE and reads the data of the output file Dealing with text files decreases the simulation speed After programming grwave m routine it must be tested with ITU R graphics to contrast b
43. nd of map This is why it is very 55 Calculation of radio electrical coverage in Medium Wave Frequencies Marcos Crego Garc a recommendable calling resizem in the second format to return the new sublegend or submap legend Figure 3 5 21 Example of resizem c Maptrims submap sublegend maptrims map maplegend Latlim Lonlim This function given a map a maplegend and a region limited by 1ts latitude and longitude limits trims a map to extract a submap of the area defined When working with conductivity database all Germany map is loaded but generally only a small area is needed This instruction extracts the area desired from the original map returning the submap with its reference vector sublegend 56 Calculation of radio electrical coverage in Medium Wave Frequencies Marcos Crego Garc a EUN o ee saat aie 525 L xemba utg 47 5 Dortmund Halle Saale GERMANY Kaln elpz Hamburg Frankfurt Ludwigshafen Am IH lrnberg Stuttgart trasbp urg Munich p e Y ow Zurich Figure 3 5 22 Example of maptrims d Plotting maps functions To plot the maps needed in this project next functions were used Worldmap Creates de new figure with the axes Also paints the main cities with their name Contourfm Plots de data into the figure making grouping the data into contours Scaleruler Plots the scale used to measure distances in a map Textm Wri
44. nd receiver d2 distance between transmitter 2 and receiver Guard interval in seconds Guard interval defined by DRM standard c speed of light at the vacuum 3x10 m s With a default guard interval of 2666 us the minimum difference of distance needed to have ISI is 800 km far enough to cover a wide region without ISI DRM The second option is the coverage calculations This option allows the user to define a region of the space where to calculate the map of coverage and to configure only one transmitter inside of it It must be pointed that transmitter must be inside the coverage region to validate configuration and start the calculations The window in this case 1s the one showed in next figure As it can be seen a transmitter and the region under study must be configured Also the application allows configuring a receiver but this 1s optional If the receiver 1s configured the application will calculate both the coverage over the region and the field profile between transmitter and receiver To have an idea of the heights of each one application also plots the terrain heights profile between transmitter and receiver 1n this case Examples of results given by this option are shown in Figure 3 4 8 to Figure 3 4 11 There is another parameter related with the grid of the field strength the scale factor The scale factor is related with the maximum number of points where the field strength will be calculated If the scale factor is 1
45. o a conductivity database from the terrain under the transmitters and the receivers There are two options detailed in chapter 3 5 3 for the conductivity database a high resolution database only available for few countries and a low resolution database containing the conductivity of the entire world but giving a very low accuracy 15 Calculation of radio electrical coverage in Medium Wave Frequencies Marcos Crego Garc a TX and RX Configuration Conductivity DataBase Guardinterval us Germany High Resolution gt Transmitter 1 Name Latitude Longitude Freq MHz Power KV Gain dB Polarization Transmitters Configuration OO0d00m00sN O00d00m00sE Antenna Heigh m 0 TX1 0 0 0 0 0 0 Vertical X Transmitter 2 Name Latitude Longitude Freq MHz Power KV Gain dB Antenna Heigh m D Polarization TX2 BO OdOO0mOO0sN O00d00m00sE 0 0 0 0 0 0 Transmitter 3 Name Latitude Longitude Freq MHz Power KV Gain dB Polarization TX3 O00d00m00sN O00d00m00sE 0 0 0 0 0 0 Antenna Heigh m 0 Vertical X Transmitter 4 Name Latitude Longitude Freq MHz Power KAN Gain dB Antenna Heigh m D Vertical X Polarization Transmitter 5 TX4
46. ongitude from 6 to 14 South Korea Latitude from 33 to 39 and Longitude form 126 to 130 49 Calculation of radio electrical coverage in Medium Wave Frequencies Marcos Crego Garc a 3 5 4 Code errors returned The application exits when certain errors appear These errors are not produced by an application malfunction and they are the result of checking the input configuration of the system The input data are verified at the User Interface but also at the beginning of some functions This has been made in this way to make the functions independent of the guided user interface and 1n this way be able to improve and add functionalities to it in the future So errors returned are next Code Error 0 Non error code The returning of a zero means that the simulation has finished correctly Code Error 1 Error in Frequencies This error will appear when calling Millington function with a frequency out of the range of the ITU R that 1s with a frequency lower than 0 1 MHz or higher than 30 MHz Code Error 2 Error in Elevation This error will appear when checking paths to call Millington function it 1s detected some possible elevation that does not match with ITU R maximum available Code Error 3 Error in the conductivities of the path between transmitter and receiver Due to the nature of the conductivity high resolution database it 1s possible to have in the path a non defined value
47. oth results and be able to check whether the function 1s correct Several probes have been made and results are given in the table below and an example in the next figure Frequency o distance ITU R Graphics GRWAVE 20 MHz o 1 80 distance 100km 30 dB uV m 30 54 dB uV m 20 MHz o 0 003 e 80 d 100km 6 7 dB uV m 7 06 dB uV m 20 MHz o 0 01 80 d 100km or 2 dB uV m 1 23 dB uV m 20 MHz o 0 001 e 15 d 100km 8 dB uV m 7 44 dB uV m 20 MHz o 0 0001 e 15 d 100km 19 dB uV m 18 70 dB uV m 32 Calculation of radio electrical coverage in Medium Wave Frequencies Marcos Crego Garc a as de propagaci n de la onda de superficie tierra O 3 x 10 Sim 40 o a e MER MHz 200m 750 kHz 400 m La 500 kHz 600 m e 5 EET L RA LU um cal Field from ITU R BS mn IA e amo Graphics AUS S Am i i TERRI 40 dB uV m ERN x T TM oL m M uu TR AN Rote sumo ia i ERA Ska inem TTIR NES MAL 3 Ns No ME Mun SN SSI UNS A Field returned from GRWAVE 40 05 A Sr iy
48. quation 2 2 4 S E Zo PXGxk 4x r P x G x k 4n 3 2 1 SREAL SGRWAVE PngAL X Great Porwave X Gorwave 3 2 2 Errar Ecrwave X V PngAL X GreaL 3 3 2 3 Palou 3 2 4 12 Calculation of radio electrical coverage in Medium Wave Frequencies Marcos Crego Garc a 3 3 Non Homogeneous paths The ITU R P 368 9 Recommendation defines a non homogeneous path as the path between the transmitter and the receiver with two or more conductivities between them In this case data contained in the graphics must be used following the Method of Millington described at the Recommendation This method implies several calculations over several graphics both in Transmitter to Receiver direction as in the inverse Receiver to Transmitter direction As an example with a path of only two conductivities as shown in the figure the total normalized field strength at the receiver should be the one at equation 3 3 3 61 1 O2 2 T R d2 Figure 3 3 1 Example of Method of Millington with a path of two conductivities Ef El d1 E2 d1 E2 d1 d2 3 3 1 Eb E2 d2 E1 d2 El d1 d2 3 3 2 Et Ef Eb 2 3 3 3 The f field is the Forward Field in the direction Transmitter to Receiver Eq 3 3 1 while the Eb field 1s the Back Field 1n the opposite direction Receiver to Transmitter Eq 3 3 2 Both of them must be calculated to obtain the Reciprocal Total Field t The intermediate fi
49. t data file data IMp ooooonnncnccnnnnnnnnnnnnnnnnos 29 Figure 3 5 3 Example of GRWAVE output data file data out sss 30 Figure 3 5 4 Extract of instructions from grwave m eese 3l Calculation of radio electrical coverage in Medium Wave Frequencies Marcos Crego Garc a Figure 3 5 5 GRWAVE result vs ITU R graphics reSUlt ooooooononononnnnoononanonononnnnnnnnnnnnos 33 Figure 3 5 6 Acquiring the stretches of the path of the same conductivity 34 Figure 3 5 7 Calculation of the effective Dai 35 Figure 3 5 8 Millington H m source CO savin tesicesscvsaretsautiudecuvarveaduleibeeduamhseidieectlatars 36 Figure 3 5 9 Millington example for testing Matlab function 2d Figure 3 5 10 GLOBE elevation data for Nurnberg area eseesessesssse 4 Figure 3 5 11 Cleaning the image with an image editor seeeeeesssussse 42 Figure 3 5 12 Setting latitude and longitude limits oi eter Hd 43 Figure 3 5 13 Converting image to conductivity database I 44 Figure 3 5 14 Converting image to conductivity database 1I 45 Figure 3 5 15 Converting image to conductivity database II 45 Figure 3 5 16 Converting image to conductivity database Sig ep matrix III 46 Figure 3 5
50. te strings into a map given a latitude and longitude Plotm Plots an element into a map with its latitude and longitude 57 Calculation of radio electrical coverage in Medium Wave Frequencies Marcos Crego Garc a e Unit conversion functions and others Mapping Toolbox also has several functions to convert from one format to another as Deg2km Converts degrees to km Str2deg Converts a string 00d00m00sN for example into latitude in degrees Distance Measures distance in degrees from two elements given by their latitude and longitude Time2str Converts timing format to a string Etime Calculates the difference between two time vectors in seconds 3 5 5 4 Application function LOADMAP The application has to load several maps Most of the requests to maps are done in the function loadmap so here will be explained an extraction of its code to show how to deal with maps In the first instance database must be loaded The database selected by user is stored in the variable Country which can take the values of Germany Korea or other In the two first cases high resolution databases will be loaded In any other case low resolution will be the one selected So loadmap first check with a case sentence the value of the variable Country to load one database or the other as shown in the figure below 58 Calculation of radio electrical coverage in Medium Wave Frequencies Marcos Crego Garc a loading
51. ted with the resolution between 2 maps Corner coordinates Latitude 552 u hj Z 7 7 50 o N Longitude limits LonLim 6 14 ea HH a a e m Figure 3 5 19 Graphical example of the map variables 22 Calculation of radio electrical coverage in Medium Wave Frequencies Marcos Crego Garc a 3 5 5 2 Resolution of a Map Another important question 1s how to calculate the resolution 1n degrees or kilometres of one map If the map has been obtained from GLOBE to maximum resolution then by the characteristics of GLOBE it is known that the resolution 1s 1 km and 120 cells per degree To calculate the resolution of any map the maplegend is the only element needed to calculate the resolution in degrees or in Km of a map So on the resolution in degrees can be calculated as Resolution 1 maplegend 1 3 5 5 2 1 And the resolution in Km can be calculated using Mapping Toolbox as Resolution Km deg2km Resolution 3 9 5 2 2 Functions referring to maps used to have a common header structure with the variables seen before In this project most used dealing with maps were Globedem Load GLOBE maps from a directory Resizem Resize a map with a scale factor or to a size desired Mapprofile Given two points inside a map create the interpolation line joining them with distances latitudes and longitudes of each them Maptrims Trims an area from a bigger map Setltin
52. the corresponding permittivity epsilon This matrix is called sig ep and it exists in every conductivity database file updating conductivity permitivity relationship matrix sig ep 5000e 3 81 E De 3 17 10e 3 14 13e 3 15 6e 3 13 4e 3 12 7e 3 13 5e 3 13 5 5e 13 8e 3 14 4 5e 12 3 5e 11 je 3 11 2e 3 10 le 3 ds 9e 10 6 5e 1 Nal NaN Figure 3 5 16 Converting image to conductivity database Sig ep matrix III Not all the conductivities have an exact permittivity assigned In this case there is needed and approximation so an interpolation between the nearest must be done There is a four and very important step calculating the maplegend of our map Dealing with maps in Matlab requires a reference vector for every map the maplegend or refvec This vector gives information about the resolution in degrees of the map and the latitude and longitude of the upper left element of the matrix as detailed in next 46 Calculation of radio electrical coverage in Medium Wave Frequencies Marcos Crego Garc a chapters The procedure to achieve a maplegend from a map coming from an image 1s quite difficult and inaccurate To avoid inaccuracies the maplegend will be taken the equivalent map of GLOBE and to do so a GLOBE map should be created for the same limits of latitude and longitude The maplegend of GLOBE will be created in calling to GLOBEDEM instruction After that conductivity map 1s resized to
53. the GLOBE map In this way both maplegends should be the same and the obtaining of the maplegend of the conductivity map 1s done As conductivity database has been created from GLOBE and both have same resolution this means that the resolution should be also 1Km with Scale Factor of 1 accurate enough to groundwave propagation The same procedure can be followed to complete the database with other countries conductivities defined in the ITU R Recommendation In this project due to time restrictions only two countries have been digitalized Germany and South Korea Resulting conductivity maps are shown in next figures 47 Calculation of radio electrical coverage in Medium Wave Frequencies Marcos Crego Garc a Figure 3 5 17 High resolution Germany conductivity database 48 Calculation of radio electrical coverage in Medium Wave Frequencies Marcos Crego Garc a Figure 3 5 18 High resolution South Korea conductivity database They do not fit exactly to the maps plotted by Matlab because the source of the images is different than the one in Matlab To obtain an exact database by this method Matlab maps Germany images and ITU R images should fit exactly and that 1s very difficult to achieve These maps have exact limits of latitude and longitude Out of this range they can not be used and 1t must be use the low resolution database instead Limits for these databases are Germany Latitude from 47 to 55 and L
54. the main function GRWAVE decreases dramatically the application speed This could be solved partially modifying GRWAVE source code in Fortran and making a MEX file to be able to work with a binary DLL at Matlab instead of working with files The application has been developed in Matlab and right now Matlab 7 R14 1s needed to be executed Another improvement should be assembling a EXE file to make the application independent from Matlab Add tools for DRM Calculations or for any other specific system working in this frequency band All this improvements have not been made at this project by time restrictions 66 Calculation of radio electrical coverage in Medium Wave Frequencies Marcos Crego Garc a 6 Bibliography and references CONDUCT BRUMMER Walter ber die Ausbreitung von Lang und Mittelwellen Germany conductivity image map in HF Frequencies to be load as a database http members aon at wabweb radio grundl3 htm Consultation November 2008 COMMERCIALFM MOLLO J C Campos electromagn ticos Determinaci n de la zona de protecci n a las personas por transmisiones de FM comerciales INTI Electr nica e Inform tica http www inti gov ar sabercomo sc23 inti9 php Consultation December 2008 DRM MAT AS Jos Mar a La Radio Digital Terrestre en Europa Eureka 147 y DRM www sincompromisos com Documentos Radiocomunicacion Radio Digital Terrestre pdf Consultation December
55. the resolution is maximum and the field matrix will have the same resolution than the conductivity matrix This implies very large simulations so it 1s useful to set the scale factor with values under 1 0 5 0 1 etc Minimum scalefactor value 1s 0 05 19 Calculation of radio electrical coverage in Medium Wave Frequencies Marcos Crego Garc a Coverage Maps Calculation Conductivity DataBase Germany High Resolution x Transmitter Coverage Area Name TX Latitude FROM 000d00m00sN TO poDdOOmDOsN Latitude O00dDOmOOsN Longitude FROM ooodo0moose TO o00dO0mO0sE Longitude OD0ADOmO0sE Scale Factor 1 Max 0 05 Min 1 Frea MHz 0 0 Power KW 00 Receiver optional Receiver data Gain dB 00 Name are optional k In case of Antenna Heigh m 0 Latitude UUIERUUS non empty Receiver Longitude ODOJOOMDOSE the field profile mem between TX and olarization vertical M RX should e Antenna Heigh m 0 calculated Calculate Figure 3 4 5 Coverage calculation window Coverage Maps Calculation a E Conductivity Conductivity DataBase Germany High Resolution database Name Coverage area Latitude Longtude Freq MHz Power KW Gain dB Antenna Heigh m Transmitter data Receiver data Polarization Vertical Figure 3 4 6 Configuration parameters 20 Calcula
56. tion of radio electrical coverage in Medium Wave Frequencies Marcos Crego Garc a _ Coverage Maps Calculation Conductivity DataBase Germany High Resolution y Transmitter Coverage Area Name TX Latitude FROM 48d00m00sN TO 50d00m00sN Latitude 49d1Sm28sN Longitude FROM 40d30m OsE TO 12d30mO0sE inci 11d22m28sE Scale Factor 1 Max 0 05 Min go7 Freq MHz 0 909 Receiver optional Power KW 04 About Field Profiles Gain dB 7 Name RX Remaining time 00 10 18 A O gt Latitude 490270005 ected Longitude 1idO4mOOsE i Polarization Vertical E E 2 Calculate Figure 3 4 7 Example of configuration and waitbar If the scale factor is set to a very low value and the resulting field matrix is very little application will resize field map and so scale factor to a minimum number of rows and columns to be able to plot a map and to have accuracy results In this way the smaller dimension of the matrix has been established in 11 rows or columns by empirical data result of several simulations There can appear inconsistencies between the field strength observed at one point at the map and the exact field strength given by the profile for example This 1s due to the resolution grid of the coverage map where the field strength is calculated
57. uction time2str is only available in the Mapping Toolbox as one of the huge amount of conversion between units function Furthermore to work with the data resulting once the simulation is made the program stores the data acquired into three different files in mat binary format FieldData mat saves the variables resulting from the simulation of several transmitters and receivers CoverageData mat saves the coverage maps and data resulting from coverage simulation SimulationData mat that saves all variables available in the workspace To load the data once the simulation is finished type load filename mat in the Matlab command windows or workspace to access the data 3 5 Software development The application consists on several functions developed in Matlab All of them converge in two primary functions oadmap in charge of loading conductivity and elevation maps and MillingtonH the function in charge of the field calculation at one point given one transmitter and one receiver This function implements Millington s Method of calculation which implies the calculation of the paths of different conductivity between transmitter and receiver and several callings to the Matlab GRWAVE Interface 26 Calculation of radio electrical coverage in Medium Wave Frequencies Marcos Crego Garc a The main steps followed in the software development of the application were these Programming ITU R P 368 9 Recommendation for
58. ude and longitude limits than for the conductivity map The result is stored into a matrix called mapg map from Globe and with its maplegend mapglegend 29 Calculation of radio electrical coverage in Medium Wave Frequencies Marcos Crego Garc a GLOBE database marks the sea level as a NaN to differentiate from the rest of the elevations We need to work with entire numbers so it 1s needed to change the NaN by for example a zero This is made with the instruction find to locate de index having a NaN To be accurate it 1s needed that elevation map and conductivity map have the same resolution rows and columns So this 1s why the last instruction 1s included to resize GLOBE map to the same size than the conductivity map 3 6 Practical examples The Groundwave propagation 1s very important in the lowest part of the frequency band and in vertical polarization To demonstrate those facts lets compare the coverage results 1n both cases with a practical example At the first instance the coverage for low and high frequencies 1s compared The figures below show that at low frequencies the effect of the conductivity and or the elevation of the terrain and antennas are negligible But as the frequency 1s increased both effects turn important and coverage 1s reduced dramatically As the colours of the map are relative there 1s attached the colour bar to indicate the field strength assigned to each colour 60 Calcul
59. ulation of radio electrical coverage in Medium Wave Frequencies SIGMA IX Range from transmitter to receiver Receiver Power density or South if talking about latitude O Conductivity of the terrain Transmitter West 2 Marcos Crego Garc a
60. would find the index of the matrix corresponding to the known Photoshop colours and assign them to their conductivity Next figures show extracts of the source code used to create de database from the png format 43 Calculation of radio electrical coverage in Medium Wave Frequencies Marcos Crego Garc a nd lonlir 2 defining latlim a latlim 47 55 J lonlim 6 14 loading the image of germany x imread germany png setting up map as a 2 map zeros size x 1 Figure 3 5 13 Converting image to conductivity database I The instruction imread loads the image in brackets to Matlab in the format described above This means that x will be a matrix NxMx3 being each of the three dimensions a RGB code correspondingly The variable map is then create to a zero matrix with the same size than one layer of x so it will be a NxM matrix Once the image is loaded the script looks for the elements having a specific code This search is made with instruction find of Matab and the index returned are stored into several vectors For example if having a find R 3 amp G 255 amp B 123 s Will store in vector a all the indexes of a matrix expressed as elements of a very big vector so that indexes can be selected at variable map in this way map a 5 to assign all the elements of map at the positions indicated by a the value 5 44 Calculation of r
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