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GPS-Guided Real-time Aerial Surveillance System Design

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1. The wooden frame is flexible tough and resilient however not as strong as the more expensive carbon fibre which could also be used Figure 4 shows the complete frame hardware and the flight control board mounted and optimized for x configuration Fig M us University of Applied Sciences ures 24 25 26 27 and 28 in appendix 1 show a model of the quad copter the simplici ty of quad rotor design in terms of material and structure The hardware is suitable in architecture and electronics for many other types of vehicles different in shape align ment or type of configuration The flight control board is marked to indicate where the front of the craft and board orientation defers with type of configuration selectable from the flight control board programming display menu Building everything from scratch would have meant using a Computerized Numerically Controlled CNC router to ma chine all the parts For simplicity it was preferable to build the quad copter part by part including brushless motors and propellers as can be seen in appendix 1 The type of motors used was Turnigy L2210 1400 Bell with voltage specification 7 4 11 1 volts powered by 3 cell LiPo battery The motors have speed specification of 1400 rpm v a current on no load of 1 1 amperes max current of 24A and a maximum power of 210 Watts The motor is relatively lightweight about 50 grams a 3 mm shaft size 28 mm shaft length motor size of 28 mm x 17 mm and can
2. munication link and getting data from a constellation of satellites certainly sounds very interesting but attaining the goals of the project would prove to be a much more difficult task All challenges would have to be overcome and serious problems solved As a result the project was divided into various blocks or subsystems each design exam ined analysed and tested separately making sure that everything would fit together and work as one system when combined at the end of each phase As already mentioned during the quad copter design several parameters such as aer odynamics torque on the motors propellers size and pitch thrust lift stability vibra tions and other technicalities related to flight control were carefully considered In the case of a quad rotor there are complex manoeuvres that involve a whole bailiwick of calculations that are still to be fully understood by some hobbyists engineering stu dents and other enthusiasts However the use of the advanced kk2 0 flight controller which has more efficient control gave the system the required stability thereby making autopilot control easier It all came down to getting the gyro accelerometer and auto levelling settings of the FC right These were some of the most difficult and most im portant settings to effect and they play a vital role in the stability balance and control of the quad copter Also the GPS device and the HMC5883L magnetometer electronic compass were first made
3. ware to the onboard processor using a specialized 6 pin USBasp AVR Programmer Another flight control board or flight controller the KK2 0 Multi rotor Flight Control shown in figure 6 has much more flexibility more advanced functions and has a Liquid Crystal Display LCD which makes it easier to use The flight controller feeds signals to the Electronic Speed Controllers ESCs which in turn control the angular velocity or rotational speed of the motors thereby changing the flight dynamics of the quad copter Unlike the previously mentioned HK Multi rotor Flight Control Version 2 1 board where HK is an abbreviation of HobbyKing the KK2 0 Flight Controller is equipped with an Atmega324PA processor 22 21 Top view 3D view Figure 5 Three dimensional array of Murata type Piezoelectric Gyroscope sensor modules as mounted on HK Multi rotor Flight control board version 2 1 Signals from the radio receiver Rx Receiver are fed into the processor via four input connectors on the flight control board These inputs are labeled aileron elevator throt tle and rudder sometimes abridged as Ail Ele Thr and Rud are Pulse Width Modu lated PWM signals The signals pulse widths drive the Electronic Speed Controllers which control the speeds of each motor and initiate an up or down a forward or back ward and or a left or right motion of the quad copter 22 21 The full mechanism of motion of the quad copter will be discussed subsequently
4. P University of Applied Scien 16 headers GPGGA GPGSA GPGSV and GPRMC as in figure 11 was chosen for its simplicity and ease of use and interfacing properties that would hence render its im plementation in the project less complex 7 PuTTY ESETT Trigger Horiz onta 1O 4 t I e CHI ew fore zZz00ms ONM ME OCT CH2 fWDIV 25087 A 0 0768 A gt pw lt gt 5c gt EEE SerTrrinGcs BMF Figure 11 The uPatchi00 C4 TxDO raw output no GPS data Screenshot and TxDO blue and 1PPS Red waveform as seen on the oscilloscope VBAT provides power to enable the receiver to store the almanac and the ephemeris data The almanac data comprises constant transmissions of approximate positions of the satellites whereas the ephemeris data contains the precise positions of the satel lites Without VBAT the receiver s memory is erased each time the main power VDD is turned off 7 8 13 56 The antenna for the GPS receiver is characterised by its operation on a 28x28 mm ground plane meaning the uPatch100 C4 patch antenna is tuned at 3 MHz above the centre frequency of 1575 MHz to 1578 MHz hence countering any effects that may result from the usually plastic casing The asynchronous UART serial communica Helsinki Met li University of Applied Sciences 17 tion port is 4800 bps at 3 0V CMOS level signal no parity eight data bits and 1 stop bit with an xxx N 8 1
5. PWMs UARTSs and PGAs can be placed just with a simple drag and drop gesture and inter connected with a click of the mouse button 9 1 8 A customized Autopilot Control board specially designed for the purpose of carrying out this project is shown in figure 16 The board was carefully designed to fit on the PSoC evaluation board like a shield as illustrated in appendix 2 so that the CY8C29466 24PXI chip controller IC on the board connects in an appropriate manner with the com ponents on the autopilot shield The chip is encased in a 28 pin integrated circuit DIP package with the ability to connect to three output ports that is Port O PO port 1 P1 and port 2 P2 P2 has a 14 pin connector to which the Liquid Crystal Display LDC 0 T M University of Applied Sciences 21 can be connected These ports are also shown on the autopilot shield or board PO and P1 are 10 pin ports eight pins are for data and two are for powering externally con nected components Port 2 is reserved for LCD connection by default However some pins on PO have been modified for use as connectors to the motors and could be used for this purpose as well Receiver Connector X Y Inclinometers Gain control potentiometer Port 1 Connector Connections to motors via Flight Controller Figure 16 Autopilot control board and its features The characteristics of the C29466 24PXI chip controller are optimum therefore making it a suitable c
6. 2 Role of Software in Navigation 4 Results 4 1 System Guidance and Coordination 4 2 M2M Telemetry OooanWnk oa FB C CO PP N CO N N 9 11 14 15 17 19 22 22 23 24 25 26 29 29 29 31 33 33 34 M a University of Applied Sciences 4 3 Autopilot Manual Mode Selection 35 4 4 Autonomous Navigation 35 4 5 Video Transmission and Reception 36 5 Discussion 38 5 1 Motivation 38 5 2 Strengths and Challenges 38 6 Conclusions 40 References 41 Appendices Appendix 1 Project Progress Photo Gallery Appendix 2 Hardware Schematic Diagrams and Components Appendix 3 Software Components and Code Appendix 4 Useful Images of Hardware Testing Measurements and Readings P University of Applied Sciences 1 Introduction The concepts and technologies applied in aerial surveillance involving autonomous and Global Positioning System GPS based guided systems may be related but they are not very new There are many companies engineers inventors engineering students and hobbyists who at some point had an idea or actually carried out some kind of pro ject using GPS technology Most companies focus on the military surveillance applica tion of the GPS for autonomous aerial vehicles inventors seek new ways in which the technology might increasingly be used for civilian purposes On the other hand hobby ists are motivated by the quest for fun and thus the focus is more on Radio Controlled or RC type prototype pr
7. 65675039289 De Bothezat helicopter ground testing open fields men hanging on side Accessed 08 Feb ruary 2013 13 McNamara J GPS for Dummies 2 Edition Hoboken NJ 07030 5774 Indianap olis Indiana Canada John Wiley amp Sons 2008 P University of Applied Sc 42 14 SIMCom Wireless Solutions C Ltd SIM900 Specifications online Changning District Shanghai P R China SIM Technology Group 2012 URL http wm sim com producten aspx id 1019 Accessed 16 March 2013 15 HobbyKing Turnigy L2210 1400 Bell Style Motor 210w Specifications online California USA Hextronik Limited 2012 URL http www hobbyking com hobbyking store uh_viewltem asp idProduct 18 544 Accessed 22 March 2013 16 Pulsar Electronics PVT Ltd SIM900 GSM GPRS Module Product Specifica tions online Malad W Mumbai 400064 Maharashtra India Pulsar Electron ics PVT Ltd 2012 URL http pulsarele tradeindia com sim900 gsm gprs module 1451822 html Accessed 01 April 2013 17 Luise M Dardari D Falletti E Satellite and Terrestrial Radio Positioning Tech niques A signal processing perspective The Boulevard Langford Lane Kidling ton Oxford OX5 1GB UK Academic Press 201 1 18 EngineersGarage AT Commands GSM AT command set online B 3 Jai Ja wan Colony 1 JLN Marg Jaipur 302018 EngineersGarage 2012 URL http www engineersgarage com tutorials at commands page 2 Ac cessed 03 April 2013 19 SIMCom Wireless sol
8. CH3 CH1 Trimmer Trimmer Radio Transmitter Controller Figure 19 Diagram of a 6 channel 2GHz RC transmitter left and receiver right The radio transmitter stick controller has two control sticks that control two channels each These sticks can move vertically up and down covering one channel and hori zontally left and right covering the other channel as shown in figure 19 The left stick controls channels three and four CH3 and CHA while the right stick controls CH1 and CH2 The stick controller plays an important role during manual operations it is used to Helsinki Metropolia University of Applied Sciences 29 steer the quad copter to move left or right up or down and speedup or slowdown by moving the sticks The left stick is particularly important as the rudder channel CH4 is also used to arm the flight control board 3 2 6 Programming the Autopilot and Flight Control The autopilot is the unit that takes control and manages the flight and control of the quad copter when manual operations are switched off First the 2 4GHz FM modulated RC Transmitter shown in figure 19 with the receiver is programmed in such a way that one of the switch channels CH5 or CH6 is used for switching the manual opera tions ON or OFF Most transmitters come with user manuals from the manufacturer with detailed but simple steps for programming user customized functions however the receiver requires no programming at all The pro
9. PO 6 Port 0 6 StdCPU Hi POMI Port_0_7 StdCPU Hi P1 0 Port 1 0 GloballnOd P1 1 Port 1 1 GloballnOd P1 2 Port 1 2 GloballnOd P1 3 Port 1 3 GloballnOd P1 4 Port_1_4 GloballnOd v P1 5 Port 1 5 GlobalOutC r output Ready Figure 34 A Screenshot of Chip level configuration and component blocks placement in the PSoC Designer Program for partial programming Created with PSoC Designer 29 Helsinki Metropolia University of Applied Sciences Appendix 3 2 6 Software Components and Code void readGPS Nmea v id int i907 l1ht Plaga if UART cGetChar Bputreriug 2 5 i l while Flag burrer i 9UARL CeetChar DelaySOuTimes 10 if Buffer i S amp amp i gt 0 Flag 0 else itt j UART CPutString Cir inBurrlerg T UART Putstring Butter void main void char vLI s AE char vnL2 sem Initialize UART CPutString r nWelcome to PSoC UART GPS test program vlel Venn LCD Position 0 0 7 LCD PrCstring Poot GPS Sftarringil while getNavSignals Navigate readGPS Nmea decode select sentence ProcessCoordinates if atoi Quali 1 ato1i Quali 2 ato1 Qual1 3 Print else if strcmp Quali vL1 7 20 Print else clsBuffer Helsinki Metropolia University of Applied Sciences Appendix 3 3 6 Software Components and Code void decode void int comma 0 char cTok
10. PrCotrang 3 LCD Positroni2L4 Display the data on the LCD LCD PrString Z axis Convert the float to Ascii in order to display it on the LCD LCD PrCotrang LCD Position 1 1 7 LCD PECOUTInNG tact 7953 LCD Position 1 8 LCD Prstring tGa float heading amp 1stacus 7 Convert the float to Ascii in order to display it on the LCD LCD PrCotrang W LCD Position 3 i Display the data on the LCD LCD PrCotring i deus 53 LCD POSTCLOni 29 LCD Prstrtungirtoat tlest heading Degs siStatus Convert the float to Ascii in order to display it on the LCD LCD Prestrang j3 DelaylOmsTimes 5 j Listing 6 Raw code Helsinki Metropolia University of Applied Sciences Appendix 4 1 2 Useful Images of Hardware Testing Measurements and Readings di Paratiex USE Osolloscope p J gt n Parallax USB Oscih bci md j Max Voltage 329V Max Voltage v MinVoltage 20ms 70m Min Voltage 15 Pk Pk Voltage s 331v Pk Pk Voltage V Mean Voltage 03V RMSV 500 ma Period Frequency 305V Max Voltage 479 V MaxVoltage mv Min Voltage 150mv MinVoltage Pk Pk Voltage 493V Pk Pk Voltage Mean Voltage 230mv Mean Voltage 211V RMSV 337V RMSV 000s Period 1840 ms Period 0Hz Frequency i 5434 Hz Frequency 500 0 ms Pulse Width US 120ms Pulse Width 5000 ms Pulse Width 1720 ms Pulse Width 5096 Pos Duty Cycle 656 Pos sane Figure 3
11. The multi rotor flying object was designed as desired went through vigorous testing and finally flew Stabilizing the system was a problem but important adjustments were made to optimize the system A smooth flight was necessary for easy stirring and con trol thus any interferences or vibrations that might disturb imaging via the close circuit television CCTV camera mounted on the quad copter had to be eliminated Secondly it was required to design a system to acquire and parse data from the GPS receiver via the PSoC programmable System on Chip controller and take care of the improvisation of SIM900 GPRS module for M2M telemetry Getting the module to send text messages was not particularly difficult However sending the coordinates directly to the autopilot was a problem This problem was overcome and the module was set to send the GPS coordinates to one mobile phone after which they were retrieved and programed into the autopilot The ability to function within the mobile phone network enhanced the flexibility made the system less susceptible to interferences during communication and minimised other technical constraints Finally with the quad copter GPS receiver and surveillance camera ready a control program was designed to monitor guide the system and process the data and infor mation Once the GPRS sends a signal the GPS coordinates are read into the main program as destination coordinates The quad copter then takes off while the
12. char delim s cTok strtok Buffer delim while cTok NULL Switch comma case 0 header cTok break case 1 data0 cTok break case 2 datal cTok break case 3 data2 cTok break case 4 data3 cTok break case 5 data4 cTok break case 6 data5 cTok break case data6 cTok break case 8 data7 cTok break case 9 data8 cTok break case 10 data9 cTok break comma ct t CTOk Strtok NULL delim Delay5SOuTimes 10 void Select sentence void int done 1 phar dL p char _GGA GPGGA Global Positioning System Fix Data char BMCLIS GPBMC while done if strcmp header GGA 0 UTC datab lat datal ulat data2 lon data3 ulon data4 Quali data Sat data Alti data8 uAlti data9 else 1r stromp header RMC 0 UTC data0 Quali datal lat data2 ulat data3 lon data4 ulon datab5 ptrHeading data7 Date data8 done 0 kj EEE Helsinki Metropolia University of Applied Sciences Appendix 3 4 6 Software Components and Code void getAngle void LIDAT dy dx dy dace latl dx cos p17 18U lacl lon2 lonl angle atan2 dy dx void ProcessCoordinates void Char fTok Shear din z2 char dlimlb miz char fltBuff x float tmpO0 0 0 tmpl 0 0 float pFracl 0 0 pIntl1 20 0 pFrac2 0 0 pInt2 20 0 float iData0 20 0 iDatal 0 0 iData2 0 0 iData3 0 0 int in
13. deliver a thrust of 880 grams The main body frame was bought in pieces as a kit and then the quad copter was built by assembling and gluing the prefabricated pieces shown in appendix 1 together to form a strong wooden frame as in figure 4 The flight control board also comes as a complete module with sensors processor and preinstalled firmware all that is left to do is to connect the motors radio receiver and autopilot 15 3 1 3 Flight Control Board The flight control board is a unit whose purpose is to stabilize the quad copter while in flight It provides the ability to connect a radio receiver allowing for manual control and also a possible attachment of an autopilot for autonomous navigation Onboard inertial sensors or gyroscopes and accelerometers are used to detect signals generated as a result of the various degrees of movement of the vehicle on which the flight control board is mounted The HK Multi rotor Flight Controller Version 2 1 board has three of such gyroscopes mounted so that they operate at right angle to each other in the x y and z axes orientation respectively in a three dimensional space as shown in figure 5 The gyroscope senses and passes roll pitch and yaw motion signals to an At mega168PA processor 21 Most flight control boards are programmable or can be flashed with the Firmware pro vided by the manufacturer In some cases the user can also upload customized soft P University of Applied Sc 10
14. differ syntactically The basic command syntax is made up of a command and an argument whereas the S parameter syntax involves a command an index to the S register and the value to be assigned to the register As for extended commands they operate in several modes as Test Read Write and Execution Com mands The syntax and example of such commands are illustrated in listing 1 It is im portant to note that all AT command lines must begin with the prefix AT and to end or terminate a command line a carriage return CR is entered The SIM900 AT Com mand manual explains in much greater detail how to use or implement these com mands Therefore explanations are limited to the scope of this project 18 2 19 12 13 Test command Syntax AT lt command gt Example AT ATD Read Command Syntax AT lt command gt Example AT CBC Write Command Syntax AT lt command gt 1 value DU GAVE d N value Example AT CSCA 4 358468946311 120 Execute Syntax AT command 1 parameter zs parame ter N paramerver Example AT CMSS 1 7 3584689463117 120 Listing 1 Syntax for Test Read Write and Execute AT Commands Adapted from Engineers Garage 18 2 and SIMCom 19 218 228 These commands are essential in the programming of the SIM900 GPRS GSM module and are used in the project to send instructions and communicate with SIM900 GPRS GSM module via the RS 232 or USB interface depending on the type or version of the devic
15. forms of M2M telemetry which is the role and opera tion of the SIM900 GPRS GSM device One role is to send GPS coordinates of the location of a dedicated sensor through the GSM mobile network to a mobile phone and or a similar or appropriate device thereby completing the both machine to machine and the machine to man aspect simultaneously This is how the system receives the destination coordinates for the Quad Copter This is accomplished by programming the SIM900 GPRS with a C language program embedded with already discussed special commands known as AT Commands It is not just the sending of information to a mo bile phone that is important since information can still be parsed directly into the sys tem s program It is nonetheless important to note that the main goal was to get infor mation to as many people as possible especially if such information came in the form of a disaster warning P University of Applied Sc 35 4 3 Autopilot Manual Mode Selection There are two modes of flight control operation the Manual mode and the automated or Autopilot mode The quad copter is started and armed in the manual mode Also in this mode the instructions are sent via the radio receiver and the user has total control over the quad copter whereas in the automated mode instructions are from the autopi lot program Thus the autopilot takes control of the flight Information from the GPS device and other sensors are used to form algorithmic solu
16. in table 2 There are other sentences from which data can be extracted however the GPRMC is a good ffe University of Applied Sciences 23 example for demonstration of the process It can be seen from table 2 that the GPRMC identifier contains information about the time latitude longitude ground speed mag netic variation and the date The date is current whereas the time is the Universal Time Coordinate and if need be the actual time in the location of use must be calculated ac cordingly Table 2 Full description of the GPRMC sentence ment Format data pall mE Pea GPS Transit data ee o validity A ok V invalid or TIU Milla 6012 4688 N 60 12 4688 N 60 124808 N 50 00000 a ono Speed in knots Speed over groundin Knas X X a Variation Magnetic variations in degrees in degrees For checking transmission errors It should be noted that other sentences can be analysed and described in a similar manner as the GPRMC described in table 2 above 3 2 2 Parsing Data from NMEA Sentence In section 3 2 1 with reference to listing 2 there was an analysis of procedure for storing the required sentence into the buffer thus the content of the buffer must be parsed to retrieve the information from the string of data in it Listing 3 shows a section of code responsible for the parsing process whereby the content of the buffer is parsed using the string tokenizing function strtok Since each
17. informative parameter in the NMEA sentence which itself begins with is separated from the other by a comma the to kenizing function uses the and characters as delimiters The switch case structure of the program selectively stores each parameter in the appropriate variable After all the selection and parsing is done the result will be header GPRMC sentence identifier while data0 to data9 152741 UTC time 15 27 41 A validity indicator 6012 4688N Latitude 60 degrees 12 4688 minutes North 02439 7964E Longitude 24 degrees 39 7964 East 000 0 knots speed in knots 000 0 true course 281212 fe sity of Appli 24 date 28 12 2012 respectively in that order Now that information has been extracted it is stored and used according to the demand by the autopilot The autopilot program constantly updates the GPS information cTok strtok Buffer delim while cTok NULL switch comma case 0 header cTok break case 1 data0 cTok break case 2 data1 cTok break case 3 data2 cTok break case 10 data9 cTok break j comma cTok strtok NULL delim Delay50uTimes 10 Listing 3 A section of code required to parse the NMEA sentence string store in the buffer The GPS data is stored in string format Thus in order for the program to be able to use these data the functions itoa and ftoa are used to convert the string to an integer and float respectively In this forma
18. into handheld devices and tested separately as shown in appendix 4 Even the quad copter was tested without the autopilot Once it was certain that every part worked separately they were put together into one unit and tested again as a complete system When the system is working perfectly a signal simulating an event for example some form of fire or smoke was generated the signal was fed into the Arduino GPRS sys tem mimicking sensors detecting some activity Once the threshold had been reached the Arduino driven GPRS module sent an SMS containing the GPS coordinates of the distress location The coordinates are received on a GSM mobile device then immedi ately programmed into the autopilot The autopilot program defines and sets these co ordinates as a destination and then calculates the distance to the location and bearing using current position coordinates and the coordinates of the destination The receiver on the quad copter receives the incoming signal and the quad copter takes off guided automatically by the GPS coordinates to the target location while an operator monitors the situation on a computer monitor in real time P University of Applied Sc 40 6 Conclusions The aim of this project was to design a GPS guided aerial real time surveillance sys tem with improvised GPRS for M2M Telemetry The project was divided into three main sections the first of which was to designing a GPS guided flying object quad copter
19. of the destination relative to origin Next the program calculates the Origin to Destination OD distance compares it with the Current to Destination CD distance If the former and latter are equal the quad copter is still at the origin the program calculates the heading to destination but if the latter is less than the forma the quad copter is closer to destination However this is just a summary of the many variables in consideration during the course calculations and navigation process The software also updates the origin each time the quad copter moves to a new on course P University of Applied Sc 36 position Each new on course position then becomes the new origin point O and the cycle of checking coordinates and distances start again The detailed mechanism and role of software has been discussed in section 3 3 2 and a summarized tabular form of the navigation process is illustrated in table 3 Table 3 Summary of the process of Navigation of the Quad Copter Observation Compare Heading Quad Copters pre Action to be taken current and status dicted or expected destination and con position coordinates ditions OD CD Not equal True Origin or home Calculate Heading and pro ceed to destination towards destination to destination OD CD Not equal Wrong Off course Reverse direction and acquire new heading recalculate bearing and distance or Home It should be noted that there are several other scena
20. operator checks that all is fine and that there is a clear live video feed on the monitor The Radio controlled transmitter is then switched off This action starts the autopilot program and the quad copter continues its flight to the destination If within the range of the video transmitter aerial images would be seen on the monitor The operator could switch on the radio controlled transmitter to turn off the autopilot and regain manual control of the vehicle Thus the aim and all the goals set in the beginning of the project were met and the system works as required However this project should not be considered exhaus tive it stands more for an improvised approach to aerial surveillance providing a sim pler solution to a greater problem Possibly with time more research will be carried out more advanced technological solutions will be sought in case they do not already exist and are unaffordable M University of Applied Sc 41 References 1 PosiTim Global Navigation Satellite Systems GNSS GNSS Overview online D 64342 Seeheim Jugenheim Germany PosiTim May 2010 URL http www positim com navsys_overview html Accessed March 4 2013 2 Garmin Ltd The GPS satellite system online Olathe KS 66062 3426 Kansas City USA Garmin Ltd 2013 URL http www8 garmin com aboutGPS Accessed April 22 2013 3 Zogg J M GPS Basics Introduction to the System Application Overview GPS X 02007 online CH 8800Thalwil Switzerland u b
21. right Helsinki Metropolia University of Applied Sciences Appendix 3 1 6 Software Components and Code File Edit View Project Interconnect Build Debug Program Tools Window Help nusdg mXEY ut APPR e Os 8 gt gt EGR 9G Global Resources PSoC_G v 2 X Power Settin 5 0V 24MHz CPU Clock SysClk 8 p 32K Select Intemal PLL Mode Disable Sleep Timer 512 Hz VC1 SysClk 12 VC2 VC1 h 2 VC3 Source VC1 VC3 Divider 52 SysCik Sour Intemal SysCIk 2 Dis No Analog Powe SC On Ref Low Ref Mux Vdd 2 Vdd 2 ana Iti t 5 1bX Port 0 6 Port 1 O Selects the nominal operation voltage and System Clock SysCik source fro Parameters UART 2X Name UART User Module UART 3 Version 53 Clock vc3 RX Input Row_1 0 TX Output Row 2 LJ TX Interupt M TXRegEmpty ClockSync Sync to SysClk RxCmdBuffer Enable RxBufferSize 127 CommandTem 13 Param_Delimit 10 lgnoreCharsBe 1 Name Indicates the name used to identify this User Module instance m Pinout PSoC GPS Guided 4 X PO 0 Port 0 0 GlobalOutE PO 1 Port 0 1 GlobalOutE PO Port_0_2 GlobalOutE PO 3 Port 0 3 GlobalOutE PO 4 Port 0 4 StdCPU Hi PO 5 Port 0 5 StdCPU Hi
22. 5 GPGSA A 2 02 04 10 13 04 0 03 9 00 9 01 GPG5V 3 1 12 02 24 315 37 04 45 263 51 07 10 192 28 10 32 289 48 70 GPG5V 3 2 12 13 63 230 40 16 11 106 00 20 36 136 25 23 77 114 31 7A GPG5V 3 3 12 25 00 352 00 29 03 014 00 30 25 079 22 31 19 041 27 74 GPRMC 152741 A 6012 4688 N 02439 7964 E 000 0 000 0 281212 A 79 GPGGA 152742 6012 4689 N 02439 7965 E 1 04 03 9 00052 5 M 044 5 M 66 GPG5A A 2 02 04 10 13 04 0 03 9 00 9 01 GPG5V 3 1 12 02 24 315 37 04 45 263 51 07 10 192 26 10 32 289 48 7E GPG5V 3 2 12 13 63 230 40 16 11 106 00 20 36 136 00 23 77 114 25 78 GPG5V 3 3 12 25 00 352 00 29 03 014 00 30 25 079 25 31 19 041 26 72 pem mc DP t Figure 22 Sample of raw data from the GPS device showing all four NMEA sentences and their data content The quad copter was designed and configured to eliminate any complications associ ated with the mechanical transmissions applied in the rotor head cyclic and collective pitch change control systems Despite being more gust sensitive the quad copter uses a more complex harmonised rotor speed control and systematic thrust adjustments on each of the four rotors to achieve lift stirring and manoeuvring Several tests crashes Helsinki Metropolia University of Applied Sciences 34 and readjustments were made to get the system working At first it was difficult to get the autopilot to take control and there was too much shaking One of the motors seemed
23. 5 Left Screenshot of the waveforms on the oscilloscope GPS receiver output CH1 1PPS output CH2 Right Screenshot of the waveforms on the oscilloscope radio receiver output signal CH1 PSoC autopilot output signal CH2 ES TM pice Figure 36 Left GPS receiver connection to UART and PSoC during a successful test Time Latitude and Longitude are displayed on the LCD Right The uPatch100 GPS re ceiver undergoing tests for use in navigation as a handheld device or portable sys tem Helsinki Metropolia University of Applied Sciences Appendix 4 2 2 Useful Images of Hardware Testing Measurements and Readings H Yn TF T FY 71 ia Reguta Regulator 1 1 v4 3 E x DEA ad A bod sa a E EMI FI http prj fiz Tat I T KTA TETTT 5 AITF 1411 l TTT11 tamm A JUN Figure 37 A photo of HMC5883L 3 axis magnetometer on a PSoC board during testing for use as compass Helsinki Metropolia University of Applied Sciences
24. Components O F Sree a aa O DOOD 9 i Metropolia mon PSoC Based Quad Rotor Control Shield Ms wW o010101010101030101010101010 f gn 610160101010101010 01610 ATO Appendix 2 1 2 2x101920202020202 JIL X52 20101010101010 M Lj Figure 30 Left The Autopilots PCB Schematic logic Diagram Created with Pads Suit Pads logic 28 Right A Diagram showing the composite layer of the PCB layout of the Figure 31 autopilot Adapted from Pads Suit Pads layout 28 Tamugri k meeceeeeeeeoeeeeee C Jan 2013 e 000o Metropolia e e Gyro e e ccon 5 e e nooo CHi gee feo eec CH2 Mee ececc00000 u3 u2 ut CH3 Mee Yaw Roll Pitch 8S m m eal CH4 Heo ee e 8 7 7 OS TP det 64S STS eem PO eecc00000BF ececccc0600H ececc00000H PSoC Based Quad Rotor Control Shield The Autopilots Bottom Layer PCB Layout diagram Created with Pads Suit Pads layout 28 Helsinki Metropolia University of Applied Sciences Hardware Schematic Diagrams and Components Appendix 2 2 2 Figure 32 PSoC Chip controller demo board and Autopilot board shield plugged in Arduino UNO aware LL LA awd Alan ON L RM 5 a LE Mon ta on OO EI oa 16X2 LCD 0 uu M PULLS LL Figure 33 A picture of an Arduino uno demo board left and The SIM900 GPRS shield plugged in
25. DisableGInt Delay5OuTimes 2 I2Cm fSendStart Addr I2Cm WRITE Do a write I2Cm TWELtEe Datad Jar i 12Cm fWritei Datal I2Cm Write Data2 jf 1Z2Cm IWrite Datas Pi I2Cm fWrite Data4 7 I2Cm fWrite Data5 I2 m SendStop I2Cm fReadBytes Addr DataBfer 6 I2Cm CompleteXfer if DataBfer 0 PX axis DataBrer U lt lt 8 DataBrer 1 rY axis DataBrer 2 lt lt 8 DataBrer 3j rZ axis DataBfer 4 lt lt 8 DataBfer 5 else strcpy DataBfer NULL lItoa X axis rX axis 10 Helsinki Metropolia University of Applied Sciences Appendix 3 6 6 itoalr axis ry axis 10 ItOa A QXXS rTA2 akties Ly declin Ang 139 6 1000 0 zy mrad milliradians tO tads 8degs east is tdeclination heading at n2f ator Y axis ADOL X 2x15 headingt declin Ang if heading lt 0 heading 2 pi Correct for when signs are reversed if heading gt 2 pi heading 2 pi Check for wrap due to addition of declination heading Degs heading 1 3 180 pi Convert radians to degrees for readability cGsprintf tstr S T1 4f heading Degs jJ LCD Position s l Display the data on the LCD LCD Prstring XxX axis Convert the float to Ascii an order to display it on the LCD LCD Preotrang LCD POSTCLIOn UL 8 Display the data on the LCD LCD Pr5tring Y axis Convert the float to Ascii zn order to display it on the LCD LCD
26. IM900 GPRS that are beyond the scope of this project 3 1 6 GPS Receiver Retrieving data from the satellites requires an appropriate GPS receiver that is sizable and easy to interface with a microcontroller The uPatch100 is a 28 x 28 x 7 0 mm W x L x H the antenna inclusive device built on a Sony chip set CXA3355 RF and CXD2956 Baseband high performance architecture The module has two regulated 3 3V to 5 5V supplies an 8 pin external connection described in table 1 and one Uni versal Asynchronous Receiver Transmitter UART port that can be preconfigured for 4800 or 9600 bps and for RS232 or CMOS signal levels Devices of the type uPatch100 R4 are configured for RS232 level at 4800 bps while uPatch100 C4 is for CMOS level at 4800 bps or bps Table 1 Input output Pins on uPatch100 GPS receiver module Adapted from Fastrax Ltd Technical Interface Description uPatch100 GPS Receiver 8 4 GND Gromd Power and Signal ground 1 1 1 1PPS 1 Pulse Per Second Output CMOS level 2 GPIO9 Satellite Fix indicator output CMOS level 2 4 16 VBAT Power 3 3V to 5 5V Backup Battery Power 8 ix i Eight different NMEA sentences are possible with the uPatch100 four of which are shown in figure 11 However the output can be customized using NC SONY ASCII protocol command The upatch100 C4 picture and block diagram shown in figure 12 operates at 4800 bps and outputs four NMEA 0183 V3 0 sentences indicated by the
27. Tamugri King Asa Musoro GPS Guided Real time Aerial Surveillance system Design New Approach with Improvised GPRS for M2M Telemetry Helsinki Metropolia University of Applied Sciences Bachelor of Engineering Information Technology Bachelor s Thesis 6 May 2013 ffi a University of Applied Sciences Abstract Author s Tamugri King Asa Musoro Title GPS Guided Real time Aerial Surveillance System Design New Approach with Improvised GPRS for M2M Telemetry Number of Pages 43 pages 4 appendices Date 06 May 2013 Bachelor of Engineering Degree Programme Information Technology Specialisation option Embedded Systems Engineering Instructor Anssi Ikonen Project Supervisor Aerial surveillance has become a vital part of security law enforcement and even warfare whereby unmanned aerial vehicles fitted with cameras provide real time surveillance A multi rotor helicopter was the vehicle of choice in this project and has a history that goes beyond the Archimedes and the Leonardo Da Vinci era Nowadays new technologies have scaled down these multi rotor aerial vehicles many mini versions exit and have become increasingly agile The inclusion of wireless technology in surveillance and linking the sys tem to the GPS and the mobile network was vital in order to meet the goals of this project The goal of this project was to design a GPS Guided real time aerial surveillance system Three subsystems were combined in terms of tech
28. acceleration of gravity in tilt sensing and dynamic acceleration acceleration resulting from motion shock or vibration applications 25 1 25 5 7 ADXL377 ourpur 320 OUTPUT g REFERENCE ACCELERATION g Figure 9 Functional Block Diagram for ADXL377 3 Axis High g Analog MEMS Accelerometer and Output linearity over the Dynamic range Copied from Analog Device ADXL377 Datasheet 25 1 5 The ADXL377 accelerometer senses 200g full scale range with low power at 300 uA and 1 8 to 3 6V it has a shock resistance of up to 10000g and it is a user adjusta ble bandwidth accelerometer 25 5 7 The half power bandwidth of which is given by BW _ 21 f 3dB 21x32kQ0xC Simplified as BW sap ion Where fgw is the half power bandwidth 32kO is the nominal value 15 of the internal resistor Rrut and Cy Cy and C are recommended to have a minimum ca pacitance of 1000pF 25 5 7 ffe us University of Applied Sciences 14 3 1 5 SIM900 GPRS Module The General Packet Radio Service GPRS refers to the standard overseeing wireless communications having working speeds of up to 115 kbps The service includes a sig nificant range of bandwidths efficient for sending and receiving data appropriately Such data could be in form of Web browsing and or messaging Instant Messaging IM electronic mail e mail SMS or Multimedia Messaging MMS and possibly other forms of data Bottom View Top vi
29. are then manages the flight and stabilises the system using data from the sensors and signals from the PWM thus giving the autopilot a smooth functionality The rest of the raw code for the entire program is listed in listing 6 in appendix 3 Helsinki Metropolia University of Applied Sciences 33 4 Results 4 1 System Guidance and Coordination The system is said to be GPS guided as a result it must be able to acquire GPS infor mation with relative ease Figure 22 shows a copy of the resulting NMEA sentence and GPS information from the output of the GPS receiver The information is in the form of a string so in order to use the information the system was designed to be able to select the appropriate sentence identifier and retrieve the necessary information Each sen tence identifier is slightly different from the other and may not contain all the infor mation needed however the system was programmed to select all identifiers of sen tences that contain longitude latitude altitude heading time speed and date which are essential for guiding the quad copter Marg io ee eae sentence information Notepac File Edit Format View Help GPG5V 3 2 12 13 63 230 40 16 11 106 00 20 36 136 00 23 77 114 00 7F GPGSV 3 3 12 25 00 352 00 29 03 014 26 30 25 079 00 31 19 041 00 75 GPRMC 152740 A 6012 4687 N 02439 7962 E 000 0 000 0 281212 A 71 GPGGA 152741 6012 4688 N 02439 7964 E 1 04 03 9 00052 5 M 044 5 M 6
30. ation System with Timing and Ranging Global Positioning System It was developed by the U S United States Department of Defence DoD There were as many as 24 fully operational satellites in 1994 that completed the GPS space segment orbiting the earth at about 20 000 km above sea level on six different orbital planes inclined at 55 These satellites are constantly rotat ing completing the orbits twice in less than 24 hours at speeds roughly 11 300 km h Most satellites GPS satellites inclusive are powered essentially by solar energy alt hough there might be backup batteries on board should in case there is a solar eclipse Figure 2 shows a pictographic illustration of how these satellites are positioned in orbit 1 2 3 9 12 There are many other systems in operation developed and used by other countries some of which might also have global coverage such as Russia s GLONASS acronym for Globalnaya Navigatsionnaya Sputnikovaya Sistema or Global Navigation Satellite System the European Union s Galileo Positioning System which is also a GNSS Global Navigation Satellite System and China s global system called COMPASS nav igation system also known as BeiDou Navigation Satellite System BDS 1 4 17 40 The first satellite system also known as Transit became operational in 1964 prior to the introduction of the GPS Consequently the first GPS satellite was launched in 1978 to be used for military purposes however in 1984 the GPS wo
31. cedure is basically to assign specific functions to the channels CHX on the transmitter for example CH4 could be as signed to Rudder CH3 to the Throttle CH2 assigned to the Elevator and CH1 to Ailer on After programming customized functions into the transmitter it is ready to control the quad copter and switch between manual and autopilot functionality In order to carry out the necessary controls for flight and navigation the autopilot must be able to communicate with the four rotors that provide the trust and hence the lift For this reason the autopilot is connected to the flight control board and the radio receiver will then be connected via the autopilot to the flight control board or flight controller FC Each channel is plugged into the FC in their respective corresponding sockets then signals would be received from the transmitter or directly from the autopilot with relative ease 3 3 Analysis of Main Subsystem Operation 3 3 1 Quad copter Flight Dynamics In order to fully describe the flight dynamics of a quad rotor much more complex anal ysis of various mathematical models would have to be considered however a simpler way to describe it will be in terms of rotor dynamics This means that almost every movement would be associated with the rotation of the motors or rotors If all four ro tors rotate with the same speed the quad copter hovers and increasing the speed on ffe University of Applied Scien 30 ea
32. ch rotor causes the quad copter to fly vertically upwards In contrast any slight in crease or decrease in the rotational speed of any one of the rotors will change the dy namics As figure 20 shows the speed of the rotors is one of the determining factors in which direction or how the quad copter flies po ae Right z A Right roll lockwise frist ei I A Left roll P A Backward pit Forward pitch gt Hover Speed lt Hover Thrust gt gt Hover Thrust lt Hover Speed gt Hover Thrust Figure 20 Quad rotor flight mechanism and dynamics based in x type alignment or configura tion As figure 20 illustrates an increase in the speed of rotors 1 and 4 slightly above hover creates a moment that results in the quad copter moving to the right Likewise increas ing the speed of rotors 2 and 3 creates a left roll that results in the quad copter moving to the left To achieve a clockwise or right yaw motion the two adjacent clockwise ro tating motors 1 and 3 speeds are slightly increased above hover speed A left yaw counter clockwise rotation is effected by an increase in speed of rotors 2 and 4 this way various degrees of movements can be realized The total vertical thrust on the quad copter is given as the sum of all individual thrusts on the rotors Therefore For F F F F The total torque is algebraic sum of the torques on each rotor express
33. d bearing and also control the quad copter when operating in Autopilot mode A description of the process of acquiring and processing the NMEA sentence from the GPS receiver in relation to the role of the software in navigation is demonstrated by the flow chart in figure 21 After checking the validity of the data the latitude and longitude are extracted as dis cussed in section 3 2 2 the coordinates are used to calculate the distance to the loca tion First the destination coordinates must be predefined then the systems starts the course calculation program subroutine This subroutine checks that the coordinate have been acquired it will then proceed to calculate the bearing and set a course To set the course the system yaws to a specific angle to a reference plane usually the north which is the bearing The distance to location is constantly checked by pro cessing information of the current position coordinates with respect to the destination Metropolia University of Applied Sciences 32 Since the bearing and distance to location has been calculated and a course set the autopilot program starts the navigation subroutine Considering figure 17 OABCO form a rectangle whose sides represent the bounds within which the quad copter must navi gate The function of the navigation subroutine is to keep the quad copter within these bounds To do that it must constantly calculate new bounds as the quad copter ap proaches the destinati
34. data format As shown in figure 11 the uPatch100 C4 TxDO ter minal also shown in the bock diagram figure 12 will output a burst of signals every second which means all four NMEA sentences are sent within a span of a second or every 1PPS pulse The waveform of the 1PPS signal compared with the TxDO can be seen in appendix 4 gt mI System Connector wDD VET C e GPS BB XRESE xd GNO Loc me TXDO river FIX Figure 12 Picture of the top and bottom view of the uPatch100 C4 GPS receiver module and block diagram right Adapted from Fastrax uPatch100 Technical Interface Descrip tion ver 3 2 8 7 In applications where more NMEA sentences are required the uPatch100 is limited and simply updating the firmware might not help However there are newer versions of GPS receivers of the same series which are capable of outputing more sentences 3 1 7 Aerial Surveillance System Surveillance cameras vary in type shape size and function and there are a wide varie ty of tiny micro or mini cameras and there are many others commercially available It is expected that the quad copter may attain an average height of 30 meters since the altitude antenna height from sea level is retrieved from the GPS data It will therefore be required that the surveillance camera be robust enough to withstand vibrations Helsinki Metropolia University of Applied Sciences 18 shock and acquire clear images at high altit
35. dex 0 sStrocartirltburrt bar strcat fltBuff dlm strcat fltBu uft Lon tTok strrtok rltBurr dlim while fTok NULL switch index case 0 iData0 atoi fTok break case 1 iDatal atoi fTok break case 2 iData2 atoi fTok break case 3 iData3 atoi fTok break index fTok strtok NULL dlim cmp 1Data0 0 01 pFracl modf tmpO amp pIntl jf Gale lat mins tmol 1Datal 0 U00 pFracl tmpl 4 add lat mins tmpt iData2 0 01 pFrac2 modf tmpO amp pInt2 calc lon mins tumpl iData3 0 0001 pFrac2 tmpl add lon mins LAT pIntl pFracl1 600 lat in degs dec LON pInt2 pFrac2 60 lon in degs dec EEE Helsinki Metropolia University of Applied Sciences Appendix 3 5 6 Software Components and Code void distance void fleet dlat dlon sglat Salon lat2 2LAT lon2 2LON distO 20 distA 0 distB 0 dlat lat2 latl dlon lon2 lonl sqlat dlat dlat sqlon dlon dlon disto SaqQrb isqglat sglon distA lon2 10on1 distB lat2 lat1 j void ReadCompass void reads the Data from the HCM5883L and stores it in the variable iDataBuffer Variables used to convert the Hex Data data into Decimal format char CSer int iStatus radix dec i unsigned char fRst Pleat declin Ang tData heading heading Degs char DateBfer rX ax1i5 rY axisS rA axis X axis lD0 Y axis 10 2 a xis ri0 MSC
36. dinates bearing and distance calculations were acceptable and the system was able to navigate to within a few metres of the destination Hence the sys tem has potential for use as a simple surveillance system due to its versatility and low cost Keywords GPS Telemetry Surveillance Quad Copter Bearing Waypoints Heading NMEA Flight Controller GPRS Quad rotor ESC P University of Applied Sc Contents 1 Introduction 2 Theoretical Background of the System 2 1 Quad Rotor Aerial Vehicle 2 2 GPS Fundamentals 2 2 1 Background and Introduction 2 2 2 Devices Concept and Application 2 3 The SIM900 GPRS Module 2 39 1 GPRS GSM Basics 2 3 2 Technical information and Application 2 3 3 SIM900 GPRS GSM AT Commands 3 System Description and Design 3 1 Hardware Description and Design 3 1 1 Basic System Blocks 3 1 2 Quad copter Design and Mechanism 3 1 3 Flight Control Board 3 1 4 Sensors Features and Characteristics 3 1 5 SIM900 GPRS Module 3 1 6 GPS Receiver 3 1 7 Aerial Surveillance System 3 1 8 Autopilot Design 3 2 Software Description Design and Implementation 3 2 1 Acquiring GPS NMEA sentences for Information 3 2 2 Parsing Data from NMEA Sentence 3 2 3 Activating the Sim900 GPSR GSM Communication 3 2 4 Acquiring Heading and Calculating Bearing 3 2 5 Software Management of Navigation and Control 3 2 6 Programming the Autopilot and Flight Control 3 3 Analysis of Main Subsystem Operation 3 3 1 Quad copter Flight Dynamics 3 3
37. e system to an external trigger to an operator and is also programed to link to the GSM mobile network The system could hence be also used as a very versatile low cost improvised disaster warning system P University of Applied Sc 2 Theoretical Background of the System 2 1 Quad HRotor Aerial Vehicle Many modern surveillance systems deploy some kind of aircraft or vehicle which in this case is a mini multi rotor aerial vehicle The history of multi rotor aerial vehicles as some suggest started with Chinese toys in 400BC and Archimedes scientific princi ples of 200BC 11 4 In 1483 there was Leonardo Da Vinci s sophisticated design of hovering machine the so called aerial screw or air gyroscope widely considered by some experts as the helicopter s ancestor 10 4 Then George Cayley came with his 1843 designed multi rotor hovering aircraft called the aerial carriage 10 5 Although Oemichen 1920 24 and de Bothezat made successful autogiros the focus would be on de Bothezat s 1922 quad rotor as one of the earliest quad rotor helicopters 11 4 The quad rotor helicopter has come a long way However it is the efforts of today s en gineers engineering students hobbyists and enthusiasts that have made this magnifi cent machine what it is The innovative curiosity and enthusiasm over quad rotors is evident in the numerous designs and different types and all other mini versions that exist Figure 1 Pictorial example of a
38. e used Helsinki Metropolia University of Applied Sciences 3 System Description and Design 3 1 Hardware Description and Design 3 1 1 Basic System Blocks The flight control board or flight controller FC the Programmable System on Chip PSoC chip controller board the Autopilot board and the SIM900 GPRS module are the hardware blocks They are supported by gyroscopes and accelerometers on the FC the electronic compasses and GPS receivers connected to the PSoC and the Ar duino uno demo board running the GPRS shown in figure 10 below and figure 33 in appendix 2 Flight Control Board Radio 2x3 axis gyros and 3 axis Search Track Position accelerometer Renee GPS Receiver Manual input Main System s Processing and Control Unit SIM900 GPRS module CCTV Receiver Flight Control Program Process managing Program PSoC chip Controller Processor Arduino Camera Video Autopilot GPRS shield Transmitter Figure 3 A general block diagram of the Main System GPS receiver uPatch100 captures a stream of data known as National Maritime Elec tronic Association NMEA sentences from a constellation of satellites that constitute the space section of the GPS navigation system For proper 3D tracking about four satellites are required but then a valid fix must be achieved The process managing M University of Applied Sciences program is
39. ect This phenomenon the Coriolis Force Effect is triggered when an angular rate causes vibrations in the sensor These vibrational changes are converted into electrical impulses which are amplified and sent to the output pin on the sensor s break out board ready for processing 3 1 2 Signal Conditioning Config C Signal PC Seria 23 L Conditioning Interface 24 CO Signal S Register VLOGIC GND REGOUT Figure 8 ITG 3200 Integrated Triple Axis Digital Output Gyroscope Block Diagram and chip Adapted from InvenSense Product catalogue 23 Alternatively to the Murata analogue piezoelectric gyroscope the InvenSense MEMS single chip 3 axis gyroscope such as the ITG 3200 in figure 9 integrates MEMS and Helsinki Metropolia University of Applied Sciences 13 CMOS technology through wafer level bonding It is an x y and z axis ultra sensitive 14 LSBs per sec digital output angular rate sensor miniaturized into a single tiny chip with an IC 400 kHz serial interface Having multiple gyroscopes certainly allows for more flexibility and a much greater degree of freedom of movement and control In addition to two gyroscopes the flight controller has a 3 axis accelerometer on board The ADXL377 is a 3 axis high g Analogue MEMS Accelerometer which is also a good example of an Analog Device Inc accelerometer It provides analogue output voltage signal proportional to acceleration It is capable of measuring static
40. ed as Ta ee oy ee T qn The moment due to a force on a body is defined as the product of the force and the perpendicular distance from the turning point to the point on the line of the application of the force Therefore the moment due to each rotor is given by ASO Helsinki Metropolia University of Applied Sciences 31 M Pot yaw M igh roll I T4 T T3 M teft roll I t T3 T t T4 M reont pitch I T2 E T3 T4 Mback piten Ta T4 T4 T2 The blade or rotor speed at hover is given by 27 30 v kyy p 2p The rotational speed or rotor angular velocity is given by v w r where v is the linear velocity and r is the radius of rotation The acceleration is calculated as follows for linear acceleration v a r which implies the angular acceleration is given by a r Therefore the torque which is related to the angular acceleration is given by T a Where is the moment of inertia considered the moment of a moment The lift is given by L C 5 pv A where L is lift in Newton N C is the lift coefficient p is the density of the fluid medium in kg m v is velocity due to the fluid medium in m s and A is the area of the body given in m 3 3 2 Role of Software in Navigation The software controls almost every aspect of the autopilot s functionality from the ac quisition of GPS data to processing the data calculate distances an
41. er with an operating frequency of up to 2 4 GHz 4 channel input recording 30 frames per second images capture and AVI file format compatible with Windows Media Player The device is USB 2 0 compatible with an in P University of Applied Sciences 19 terface transmission rate of 480 Mbps an image resolution of 720 576 or 1440 1152 pixels for a moving image automatic brightness adjustment functionality and other ad vanced digital video control functions 26 1 2 A sample of the video image transmitted from the wireless camera and received by the ES 601WS wireless USB DVR which is also shown in figure 23 The Eye Sight Technology application software is called Mul tiViewer The MultiViewer is a 4 Channel surveillance software compatible with Win dows having Joint Photographic Experts Group JPEG image format snapshot from video function and can be configured to attach and email images to a specified address 26 1 5 Figure 14 A wireless USB DVR Adapted from Eye Sight Technology Co Ltd 26 1 5 The wireless USB DVR adapter will work on any computer provides the right drivers and the application software are installed 3 1 8 Autopilot Design The base of the autopilot hardware is the Programmable System on Chip PSoC board and CY8C29466PXI microchip controller unit The PSoC chip is based on a powerful Harvard Architecture 24 MHz 32 bit accumulator and a low powered high speed M8C core processor With a relatively l
42. esign is created in the chip level configuration section of the PSoC designer program as figure 18 illustrates There three main types of functional blocks in the chip level configuration the 16 bit Timer 8 bit PWM and UART The UART block connects to the GPS receiver and pro vides an interface between the GPS receiver and the PSoC program ensuring its ability to monitor retrieve organize and use the GPS data Each timer block connects to a channel on the radio receiver and provides the means by which signals from the re ceiver are channelled through the autopilot to the flight controller The timer uses the PSoC timer interrupt and time capture functionality to measure the pulse width of the M University of Applied Sciences NO 7 signals for the radio receiver The time capture function is demonstrated by listing 5 The software checks the status of a flag while it compares the time difference between the rising edge and the falling edge of the pulse 7 GIO p7 GE mie m Sas a EIER Gi amp Gi aig L1 a aa CN NT CN T amp e le pelje elje s m u zx u lmu s u Figure 18 Screenshot of the chip level configuration of project software Created with PSoC Designer 29 oince the signals are pulse width modulated signals an interrupt is triggered on every rising edge of and stopped on the falling edge The period is then used to calculate the pulse width These calculations are done internally in the auto
43. ew d z ON PREZ nin HESS iE 2122270099527 L LLL EE FCC ID uto evi214209 E 09R0 asm ses nili Ld L4 LIT L Am Ld ld LJ AU a e Ld e P C B SIM Card Holder SIM900 Module Figure 10 Snapshots of the SIM900 GPRS shield showing the bottom and top views with its main features The GPRS module chosen for this project has the required characteristic and incorpo rates a SIM900 on a Printed Circuit board PCB to form a GPSR shield as shown in figure 10 The device was made by SIMCom as a complete Quad band GSM GPRS module designed on a single chip processor integrating AMR926EJ S core It is relia ble and has the following general characteristics which are also specific to what the project requires 14 16 Quad Band 850 900 1800 1900 MHz GPRS multi slot class 10 8 GPRS mobile station class B Compliant to GSM phase 2 2 Class 4 2 W 850 900 MHz Class 1 1 W 1800 1900MHz Dimensions 24 24 3mm Helsinki Metropolia University of Applied Sciences 15 Weight 3 4g Control via AT commands GSM 07 07 07 05 and SIMCOM enhanced AT Commands SIM application toolkit Supply voltage range 3 2 4 8V Low power consumption 1 0mA sleep mode Operation temperature 40A C to 85A C 14516 These characteristics are the bases for which the module was chosen There are many more features functions and advanced characteristic of the S
44. he bearing of the destination requires the GPS coordinates of the origin or current position and the destination coordinates Then the two point coordinate technique is used to calculate the angle between the line through the points OB and the vertical line through the origin OA or with respect to the North which is the bearing Considering figure 17 the origin of the graph is xoyg but the flight starts at point O and the destination is at point B the distances OB OA and OC considering a flat surface are given by the equations m dog OB J x x1 y y1 do OA 4 Ca x1 y 91 doc OC 4 x x1 O1 8 OD Equations 1 2 and 3 are formulated based on the geometry of Cartesian coordinate since the coordinates used are latitudes and longitudes A 2 4 Sie lor a C duicixuur ru dE AI LE iL J mic E EE E EE C EE i 9 htk x2y2 c WENN C ZZ ZZ ZZ LM T i p H FT 1 j 2 ae ere AER dl semis es ee me ic es ts samp E cr lip ee le x ms sai xs je i em eas en en se ses a cn Gd a n ee Sew ot semi ces enews ma um d 141 lI Ho i a B y oO x P e 1 o Cxo Yo 1 d Figure 17 Graphical illustration for calculations involving bearing and distance using two point coordinates The tangent of the angle a is the length of the opposite side OC or AB divided by that of the adjacent side OA The bearing is then calculated b
45. hoice for this project All required modules are in one chip and versatility is guaranteed which is also important for autopilot functionality Signals from the radio receiver are interfaced with each of the internal blocks these control signals can then be processed and controlled by the PSoC ImageCraft C software Every one of the different signals from the receiver is captured by a timer module in the chip level con figuration shown in figure 18 A timed interrupt is generated each time there is a change in the level of the incoming pulse from the receiver Based on this time the pulse width is calculated The calculated pulse width is then written into the PWM which in turn outputs a pulse with the same characteristics as the input pulse In doing so the autopilot program has control over the quad copter since it can channel signals from the receiver to the flight controller in the manual mode and also send control sig nals to the controller in the auto navigation mode P University of Applied Sciences 22 3 2 Software Description Design and Implementation 3 2 1 Acquiring GPS NMEA sentences for Information As discussed in section 3 1 6 when powered the upatchi00 GPS receiver module out puts a burst of data every second as a series of character strings called the NMEA Sentences as illustrated in figure 11 and figure 22 Once the required sentence has been captured it is stored in a buffer Every NMEA sentence begins with a
46. ially enhanced re ceivers 13 54 56 P University of Applied Sciences 2 3 The SIM900 GPRS Module 2 3 1 GPRS GSM Basics The main function of the GPRS GSM module is to send an alert with the corresponding coordinates of the location of an impending disaster accident or event If there is an incident depending on the type nature and significance of the incident specialised sensors would be triggered accordingly For example a gas leak would trigger a gas sensor and an earthquake would trigger an earthquake sensor Signals reaching speci fied thresholds are then dispatched along with the GPS coordinates of the location via the GPRS system into the GSM network Using AT Commands the GPRS device is programed to send an SMS Short Message Service and is optimized for M2M teleme try Important information could be transmitted or broadcast through the GSM network to any mobile phone or to another appropriate device A simple SIM card enhances the system s communication range and gives it access to the GSM mobile network Figure 10 shows a SIM900 GPRS module programmable with AT commands and designed as a shield to fit on the Arduino Uno demo board The incorporation of the SIM900 GPRS module in the project is vital and also important since it links the whole system to the GSM mobile network Different forms and formats of data or information would easily be broadcasted to every mobile phone in a given area Depending on what shows up in
47. in section 3 under the hard ware description and analysis The KK2 0 flight controller has two built in 3 axis single chip gyroscopes and a single chip 3 axis accelerometer system simultaneously giving it an increase in stability and P University of Applied Sciences 11 the added advantage of having an auto leveling functionality This function requires that the sensors be properly calibrated and the vehicle must be sitting on a leveled plane surface Also in the auto level settings the P gains and l gains must be set so as to maintain some degree of control over the quad copter during flights The additional onboard LCD screen and built in firmware or preinstalled software allows for an easy setup Most functions that is the Craft type selection the motor layout and direction of rotation ESC calibrations radio receiver test sensor test roll pitch and yaw gains PI editor sensor calibration mixer editor and more functions are set with just a simple click of buttons selections from a menu and following the onscreen prompts 21 22 3 Axis gyroscopes 3 axis accelerometer Motors output channels Receiver input channels Programming E LJL 8i connection s s ara s a 3 9 _ Menu navigation and function selection buttons Figure 6 KK2 0 Multi rotor LCD Flight Control Board Adapted from HobbyKing 22 As can be seen from figure 6 above there are up to five receiver input channels and eight motor
48. lox ag October 2001 URL http faculty ksu edu sa hbilani SE412books GPS basics u blox en pdf Accessed 12 March 2013 4 van Diggelen F A GPS Assisted GPS GNSS and SBAS Norwood MA USA Artech House 2009 5 Reece ME Global Positioning System online New Mexico USA New Mexico Institute of Mining and Technology April 2000 URL http infohost nmt edu mreece gps history html Accessed 2 March 2013 6 Murata manufacturing Co Ltd product specification manual Angular Rate Sensors ENC Series ENC 03R Tokyo Japan Murata Manufacturing Co Ltd 2011 7 Fastrax Ltd uPatch100 OEM GPS Receiver Module Datasheet revision 1 0 Van taa Finland Fastrax Ltd 2004 8 Fastrax Ltd Rev 3 2 Technical Interface Description uPatch100 GPS Receiver Vantaa Finland Fastrax Ltd 2005 9 Cypress Semiconductor Corporation PSoC Programmable System on chip Ref erence manual TRM PSoC TRM Document No 001 14463 Rev G online oan Jose CA 95134 USA Cypress Semiconductor Corporation 2013 URL http www cypress com doclD 42666 Accessed 30 April 2013 10 Castillo P Lozano R Dzul AE Modelling and Control of Mini Flying Machines London Springer Verlag London Limited 2005 11 Leishman JG Principles of Helicopter Aerodynamics USA Cambridge University Press 2006 12 CriticalPast Testing of De Bothezat helicopter in open fields online Dayton Ohio USA CriticalPast LLC 2013 URL http www criticalpast com video
49. ls and wit This meant that the project could be considered farfetched notwithstanding the fact that each phase mentioned could by itself consti tute a separate project However the system sees several possible and potentially save civilian applications in disaster regions as an early warning system For instance sending aerial images of a disastrous wild fire as a warning directly to every active mo bile phone in a nearby community and tracking wildlife remotely with a GPS guided quad copter fitted with a camera providing a bird s eye view Not only can one monitor events in real time but the location of the event can also be pinpointed The potential bestowed by such a successful project leaves a feeling of satisfaction for creating something difficult but very useful and very affordable 5 2 Strengths and Challenges The challenges involve in the design of any flying object are many and vary however the technicalities associated with controlling a quad rotor are equally enormous Cer tainly using a readymade flight control board simplified the task and diminished the tedium inherent in the hardware design This meant that the many aerodynamic calcu lations were eliminated Ensuring the stability of the Quad Copter during flight is of prime importance given that it must have the ability to hover at a considerable altitude Thus the propellers and motors must be meticulously balanced Establishing a com M University of Applied Scien 39
50. nology design and in operation to achieve one unique system The principal objectives of the project were to design a GPS guided aerial vehicle or quad copter and seconaly to design program for SIM900 GPRS module improvised for M2M telemetry thirdly mount a camera on the quad copter and design a control program for monitoring guiding and stabilizing the system while in flight The quad copter was at the centre of the hardware design since it was the surveillance vehicle It was built from a kit containing pieces of the frame motors kk2 0 flight controller propellers and ESCs The required GPS information was captured with the uPatch100 GPS receiver and pro cessed in the PSoC chip controller and software platform M2M telemetry was achieved with GPRS module programmed on the Arduino platform with AT commands and actuated to send GPS coordinates as SMS The three subsystems combining GPS GPRS and wireless surveillance camera on a quad copter were controlled by the autopilot or manual ly with radio transmitter controller The PSoC autopilot program managed the navigation from origin to destination as the aerial images are transmitted and monitored from a dis tance Manual testing was easy but engaging the autopilot program was difficult Thus the autopilot program was optimized with the auto levelling function on the flight controller A smooth flight was obtained in good weather and the system worked as expected The course tracking GPS coor
51. ojects Engineering students might want to apply their newly acquired knowledge prove their worth to prospective employers or carry out the most exciting school project Whatever the motivation may be the GPS technology has been used extensively in a variety of applications Many of such applications would involve Space airplane car and pedestrian navigation and surveillance systems However this project differs from the rest in that there is a slight difference in the approach and the improvisation techniques used in carrying it out The goal of this project is to design a GPS guided real time aerial surveillance system with an improvised application of General Packet Radio Service GPRS for Machine to machine and or machine to man M2M telemetry The project is divided into three main parts that involve Designing a gyro stabilized aerial vehicle or flying object a Quad Copter with three dimensional 3D flight capability Programming a SIM900 GPRS module configured for M2M telemetry Mounting a surveillance camera on the quad copter and design a control pro gram for monitoring guiding and tracking the system while in flight The quad copter fulfils the project s requirement for an aerial vehicle providing the means by which the surveillance camera becomes airborne giving a bird s eye view of the area under surveillance Also the GPS component is there to track and guide the quad copter while the GPRS component links th
52. on the navigation bounds reduce in dimension too The current location become the new origin and the area of the rectangle OABCO reduces the distance proximity to the axes lines OA and OC must decrease progressively at the same pace If the distance OA is significantly shorter than OC the system will pitch to compensate and vice versa keeping the quad copter on the course OB till the destina tion when all dimensions converge to zero distance Start Course calculatio Start navigation Adjust pitch and Yaw to heading bearing acquired Course Set distance to destination and proximity to axes OK Get Destination Coordinates And Calculate current coordinates m Received Coordinates X NO OK NMEA Parse NMEA Sentence ee found YES Process data AllData Processed YES YES Calculate bearing and Set a course And Start navigation Current Destination Stop Destination Reached Distance 0 Maintain Heading or course to destination Start GPS Figure 21 Diagram of a flowchart demonstrating the role of software in the navigation process The motors are controlled by pulses from the pulse width modulator PWM blocks in the chip configuration of the PSoC designer in conjunction with the program to deter mine when and how long a pulse should be sent to the flight controller The flight con troller s firmw
53. output channels The fifth input channel is reserved for auxiliary functions while the extra four motor output not used in this project are reserved for use in other types of multi rotor vehicles with more than four rotors 3 1 4 Sensors Features and Characteristics As earlier discussed there are two main types of sensors used to maintain balance and stabilisation when the quad rotor is in flight These sensors include the gyroscope and the accelerometer The HK Flight Control Version 2 1 board integrates only three single axis gyroscopes whereas the more advanced HK KK2 0 Multi rotor Flight control board has both two 3 axis gyroscopes and one 3 axis accelerometers The former uses P University of Applied Sciences 12 three Murata analogue piezoelectric gyros while the latter uses single chip 3 axes In venSense MEMS technology type gyroscopes and the advanced Analog Device accel erometers Figure 7 shows a detailed circuit diagram of a Murata ENCO3 MB analogue gyroscope Low Pass Filter fc 1KHz I High Pass Filter 4 7u fc 0 3Hz ENCO3 MB Sensor Simple Amplifier circuit Figure 7 ENCOS MB Sensor single axis gyroscope Adapted from Murata Manufacturing 6 1 3 The ENCOS3 MB Sensor gyroscope is used to sense gyroscopic or angular move ments of the quad copter on the x y and z axes This gyroscope is miniaturised ultra lightweight angular rate sensor whose operation principle is based on the Coriolis force eff
54. ow operation voltage range of 4 75 to 5 25 V the CY8C29466 24PXI PSoC unit can work at extended temperatures ranging from 40 C to 125 C The MCU is mounted on a PSoC board as shown in figure 15 The chip has 12 rail to rail analogue blocks of 14 bit Analogue to Digital Converters P University of Applied Sciences 20 ADCs 9 bit Digital to Analogue Converters DACs and a variety of Programmable Gain Amplifiers PGAs The PSoC MCU is very advanced Programmable filters and comparators complement the analogue blocks with 16 digital blocks supplying 8 to 32 Bit timers counters and Pulse Width Modulators PWMs Cyclical Redundancy Check CRC and Pseudo Random Sequence PRS modules and up to four full duplex or eight half duplex Universal Asynchronous Receiver Transmitters UARTs and multiple SPI masters or slaves 9 1 LCD Connector Voltage selection jumpers CY8C29466 24PXI Mini Programmer connector MCU External power connector Ports 0 and 1 Figure 15 Picture of a PSoC Board and its features All features and blocks described are built in on a single Integrated circuit IC and connectable to all intrinsic Global input output peripherals GPIO and also to external ports on the PSoC board 9 1 It is possible to build complex peripherals just by com bining different blocks together This can be done in the chip level configuration of the PSoC designer application software where various modules such as timers
55. pilot program giving it considerable control over the pulse width and hence the speed of the motors and amount of thrust There are four timer blocks each connected to a corresponding re ceiver channel from channel 1 CH1 to channel 2 CH2 respectively The PWM block Helsinki Metropolia University of Applied Sciences 28 channels the signals from the receiver to the flight controller in a controlled manner as the autopilot program would allow In the manual mode the autopilot would feed the pulse width of the receiver signal directly into the PWM which will in turn generate an identical signal to be fed into the flight controller if Flagl amp FALLING EDGE 1 CaptureNegEdge 1 Timerlo CH1 wReadCompareValue Timerl6 CH1 FUNC LSB REG amp 0x80 Flagl amp FALLING EDGE 1 Pulsewidth 1 CapturePosbdge 1 CaptureNegbdge I Flagl DATA AVAILABLE 1 Listing 5 Section of code demonstrating the timer interrupt calculation of pulse width of an input signal from the radio receiver On the other hand the autopilot program causes the PWM to generate signals that would be fed into the flight controller which then controls the flight of the quad copter There are four PWM blocks that connect to four inputs on the flight controller the ailer on elevator throttle and rudder Aerial Dual Rate Handle Receiver CHS CH6 Switch Switch Signal Battery Antenna trimmer V C 6CH Transmitter Timmer
56. quad rotor shown in an X configuration This project would require an agile aerial vehicle and the most suitable design would be a multi rotor vehicle well known to many hobbyists as a quad copter It is a quad rotor helicopter and therefore for simplicity the term quad copter was adopted for use in the rest of the project The quad rotor in consideration here is a small agile versatile multi directional flying object with four rotating propellers mounted on four electric motors arranged so that they are aligned in a squared x formation as shown in figure 1 ffe us University of Applied Sciences The design is nothing near in size like de Bothezats machine but it has been scaled down to a few tenths of centimetres The type of alignment use is x type alignment or x configuration meaning the alignment is squared and x shaped as illustrated in ap pendix 1 Changing the alignment means the firmware must also change and will also require making adjustments to motors connections hence altering their direction of rotation The dynamics of the quad rotor can be mathematically related to Euler and Newtonian laws of motion of a rigid body Together these laws better describe the combined dynamics of translational and rotational motions of a rigid body 2 2 GPS Fundamentals 2 2 1 Background and Introduction The GPS is a satellite navigation system GPS simply means global positioning system also known as NAVSTARGPS that is Navig
57. rios for navigation apart from the example in Table 3 The compass on the autopilot is also useful in navigation The sys tem and also align itself along latitudes or longitude so as to get to its destination De pending on the accuracy of the GPS device the craft or the quad copter could be off by a few meters from the target location However corrections can be made to get the quad copter within two meters of the target 4 5 Video Transmission and Reception The importance of the video transmitted by the surveillance camera and that of the information it may carry cannot be over emphasised The surveillance was simplifies with the use of a camera which already had and inbuilt transmitter and a range that was good enough within 100 metres in open air Transmission is initiated as soon as the system is turned on The camera starts capturing and instantly begins transmitting video images At the end the reception is via a USB Close Circuit Television CCTV signal receiver connected to a laptop computer with the appropriate software installed The system is set up tuned to the selected channel and fine tuned for brighter and sharper images The operator or user could also choose which system to use the Metropolia University of Applied Scie 37 Phase Alternating Line PAL system or the American National Television System Committee NTSC system If required the wireless camera s lens can also be adjust ed when it is out of focu
58. s 2013 04 13 16 53 00 Figure 23 A screenshot of aerial video sample streaming via Eye Sight Technology Mul tiViewer software graphic display interface Possible improvements that can be made on the system are first the lens could be changed into a wide range view type of lens to deliver a view angle of about 115 up to 130 and secondly the camera could be replaced by one with a much higher and bet ter resolution Helsinki ft olia University of Applied Sciences 38 5 Discussion 5 1 Motivation Venturing into a very technical project such as this was very bold daring as some would say it was a difficult project Nevertheless there was a very strong enthusiasm and willpower to proceed and see the project through to the end There was probably an anxiety and thrill to undertake a project which by every indication was likened to rocket science Assuredly many would agree a project of the likes of rocket science is always exciting or at least sounds so which means it might also have been a good motivation in this case The three phases involved acquiring and parsing the required NMEA sentences from the GPS module designing the autopilot and also modelling and designing the quad copter The quad copter had to be flexible enough to be au tonomously controlled by an autopilot capable of navigating with GPS coordinates The successful implementation of each phase required programming mathematical and engineering ski
59. sign so as listing 1 shows the if UART_cGetChar line looks for the beginning of the sentence string denoted by the dollar sign However the program will miss that charac ter and start storing from the second character Thus the buffer is initialized so that the first element in it is always a sign to maintain the starting character of each sen tence in doing so the program will always know where a sentence begins void readGPS Nmea void 1f UART cGetChar 4 B ffer 0 9 171 while Flag Buffer i UART cGetChar DelaySOuTimes 10 if Buffer i S amp amp i gt 0 Flag 0 else itt j UART CPutString XArinBurrers 97 UART PUCString Butter Listing 2 A piece code for getting data from the GPS sensor module upatch100 C4 Now that the buffer already contains at index zero the index is reinitialized to one and the rest of the characters in the sentence are indexed into the buffer until the be ginning of the next sentence At this point the content of the buffer is similar to the fol lowing format GPRMC hhmmss A lIll Il a yyyyy yy a x x x x ddmmyy x x a hh Where GPRMC is the header representing the sentence type or sentence identifier that always follows the character as in the following example of a complete sentence with information GPRMC 152741 A 6012 4688 N 02439 7964 E 000 0 000 0 281212 A 79 The full description of the information in the sentence has been given
60. t Technology Co Ltd ES 601WS WIRELESS USB DVR User Manual V1 0 Hong Kong Eye Sight Technology Co Ltd 2009 2 Reg Austin Unmanned Aircraft Systems UAV Design Development and De ployment Hoboken NJ USA John Wiley and sons Ltd Publications 2010 28 Pads Suit The PADS Evaluation Circuit computer program Version 9 2 Wil sonville OR Mentor Graphics Corporation 2010 29 PSOC Designer computer program Version 5 3 San Jose CA Cypress Semi conductor Corporation 2013 P University of Applied Sciences Appendix 1 1 3 Project Progress Photo Gallery Figure 24 Parts and Components Used in Quad Copter construction eee p _ m ee uox Figure 25 Assembled quad copter frame arms Yo Helsinki ft olia University of Applied Sciences Appendix 1 2 3 Project Progress Photo Gallery Figure 26 Fully assemble frame top and 3D views Figure 27 Completed x configuration quad copter with motors ESCs and Propellers A UT os Metropolia University of ied Sciences Appendix 1 3 3 Project Progress Photo Gallery Figure 28 Completed x configuration quad copter with motors ESCs Propellers Battery and Flight controller Right and frame no propellers autopilot connected left Figure 29 Test flight video screenshots Helsinki Metropolia University of Applied Sciences Hardware Schematic Diagrams and
61. t the program is able to use the values to carry out the required calculations 3 2 3 Activating the Sim900 GPSR GSM Communication The sim900 is activated using AT commands once the SIM card has been inserted It is also recommended to use the default pin code during testing if it is not deactivated When all is set the procedure for setting the SMS mode is as follows AT lt CR gt initiates Attention AT CPIN 1234 lt CR gt enters the pin code AT CMGF 1 lt CR gt set the SIM900 to SMS text mode AT CMGS 358xxXxXxXxXXXxx lt CR gt Enters the destination phone number gt message to be sent here lt Ctrl z gt pess control z after message Listing 4 AT command syntaxes for sending SMS to a specific phone number The commands in listing 4 above are inserted into a C language code as a string of characters which are then sent to the SIM900 via a terminal program Alternatively the commands could be defined within a C language code to be actuated at specific mo University of Applied Sciences 25 ments The code would then be simply compiled and uploaded into the Arduino GPRS shield unit For the purpose of this project the SMS message to be sent will be specific GPS coordinates that would be preprogramed in the software 3 2 4 Acquiring Heading and Calculating Bearing The Heading is acquired by reading the electronic compass or by getting course made true value from the GPS receiver Calculating t
62. the section of software that coordinates the signalling between the autopilot and the FC It also works with the flight control program that channel the GPS coordi nates acquisition program with the autopilot and FC during navigation Figure 3 also shows a camera block which represents the surveillance camera and video transmitter and the radio receiver that channels signals from transmitter to the autopilot and flight controller 3 1 2 Quad copter Design and Mechanism As mentioned in section 2 1 a quad copter is a like a quad rotor helicopter with two of its rotors rotating in the clockwise direction while the other two rotate in the counter clockwise direction There are various techniques involved in the design of a quad copter and whatever the design be it simple complex or sophisticated the physics and basic principles that make the object fly are the same The quad copter basically con sists of four propellers mounted on four rotating motors therefore a simple design of a mini version of the object will require a sizable frame structure The frame must be ro bust enough to handle all forces and vibrations subjected to it and also support the weight of the motors and battery attached to it Propeller Motor connection Flight Control board Receiver a i E gt Figure 4 A picture of the Quad copter structure and other hardware including version 2 1 of the HK Multi Rotor Flight control board
63. the surveillance information the ability to send lifesaving preventive warnings to everyone is assured 2 3 2 Technical information and Application The SIM900 module is a Quad band GSM GPRS module is built on a single chip pro cessor platform The integrated AMR926EJ S core is cost effective and its small size offers an added advantage to users 14 The SIM900 module also complies with the GPRS standards in terms of interface and operations within the GSM GPRS 850 900 1800 1900MHz frequency ranges It is also optimized for voice and other forms of data transfer including text and images The module is 24 mm x 24 mm x 3 mm in dimensions power consumption is low and is designed to meet almost any re quirements for M2M applications 14 P University of Applied Scien 2 3 8 SIM900 GPRS GSM AT Commands The definition of AT Command may vary but it is mostly defined as a machine code or instructions that are used to activate features on a modem in this case the SIM900 GPRS GSM module A series of machine instructions used to activate features on an intelligent mo dem Developed by Hayes Microcomputer Products and officially known as the Hayes Standard AT Command Set it is used entirely or partially by most every modem manufacturer AT is a mnemonic code for ATtention which is the prefix that initiates each command to the modem 20 AT Commands are sometimes classified as basic S parameter and extended however all three categories
64. tions to complex mathemat ics involved in every instance of the quad copter s movements Without the GPS infor mation the system will be unable to function well in the autopilot mode It is important to note that the system prior to every flight will start in the manual mode Then after arming the system typically with the rudder stick of the radio handset transmitter or stick controller the autopilot can then be engaged with the flip of a switch on the radio stick controller handset After the autopilot has been engaged the system will be on armed but there will be no lift off until there is valid fix on the GPS data as indicated by the valid fix indicator and until the system has acquired valid GPS coordi nates of both origin and destination To disengage the autopilot the switch is flipped again and control of the craft is returned to manual mode There is however a safety mechanism to switch from the autopilot mode to the manual mode if there was an error Alternatively the system would simply drop lift and the hovering rotor speed and land itself 4 4 Autonomous Navigation Navigation is by the coordinate system and also significantly dependent on the quad copter dynamics and the autopilot s response The GPS receiver provides information about the speed of the craft the heading altitude and the coordinates in the form of latitudes and longitudes This information is sent to the autopilot program which first calculates the bearing
65. udes There are however a few other speci fications with which the camera must comply That is it must be a wireless camera lightweight small in size and powered by a supply of about 5 volts with a good resolu tion The First Person View FPV cameras associated with many hobbyists and RC plane enthusiasts are best suitable for projects such as this Nevertheless a more prac tical and less expensive solution was found Figure 13 shows a snapshot photo of a 2 4 GHz Wireless Pinhole Camera with a built in Li Battery a 62 degree view and DC 5 volts 80mA input for power and battery charging The charge and power are selectable by slide switch The camera poses a CMOS sensor optimized for PAL NTSC systems with a resolution 628x582 PAL and 510x452 NTSC The minimum illumination is 1 5 Lux F1 5 and the gain control is automatic with transmission frequency and a power of ISM 2400 MHz 2483 MHz and 10 mW respectively Figure 13 Multiple views Snapshots of a 2 4GHz Wireless Pinhole surveillance Camera To complete the surveillance system a proper unit is needed to capture the video transmitted from the wireless camera It is required that the unit be a wireless unit which can be connected to the universal serial bus interface The wireless Universal Serial Bus Digital Video Recorder Wireless USB DVR is a suitable choice and has the required characteristics Figure 14 shows a wireless USB DVR model ES 601WS a wireless audio visual USB DVR receiv
66. uld be made available for M University of Applied Sc civilian use too The system constantly undergoes improvements whereby new better and more accurate satellites are being launched to replace older satellites Modernisa tion efforts for the GPS III began in 2008 and the first upgraded satellites are expected to go online by 2014 5 Figure 2 A Diagram of the GPS Satellite Array or Constellation Adapted from Garmin Ltd 2 lt should be noted that the GPS satellite representation in figure 2 is used only as an example to show the positioning of navigation satellites in orbit 2 2 2 Devices Concept and Application The GPS global Positioning System would be incomplete without the user applica tions and GPS receivers These are devices that enable users to receive signals from the GPS satellites and use them for positioning locating navigating and surveying GPS receivers could be classified into five categories consumer military mapping and resource commercial transportation and survey models The C A code Coarse Acqui sition code also known as SPS Standard Positioning Service refers to the signals received by civilian and or other consumer GPS receivers Conversely the Precision code P code also known as Precise Positioning Service PPS is resistant to jamming and spoofing Therefore it is used for military applications particularly by the U S mili tary With this code transmissions are encrypted and require spec
67. unbalanced and there was no sense the system was actually following the GPS data despite the valid fix indicator being on There was a limitation in the PSoC chip in that there was not enough space in the chip level configuration for the placing of the number of blocks needed for the system However a workaround was found by using 8 bit PWM blocks rather that 16 bit block which require more space Also if the weather is windy more power was required to stabilize the system and the risk of crashing increases Thus it would be recommended to fly the quad copter under rela tively favourable atmospheric conditions especially when operating in the autopilot mode 27 40 The hardware setup is a step by step procedure that begins with settings on the flight controller FC to the calibration The flight controller s function menu made setup easi er thus sensor calibration for gyros and accelerometers stick scaling for the transmit ter radio controller pitch roll and yaw gains ESC calibration and auto level settings are done by simple selecting functions from a menu 4 2 M2M Telemetry Telemetry is M2M and for all cases that is Machine to Man and Machine to Machine Communications between camera and receiver RC transmitter and receiver qualify as Machine to machine component and there are not as important compared communica tions involving the SIM900 GPRS module What is of utmost importance is the aspect of the system that deals with both
68. utions Ltd SIM900 AT Command Manual V1 03 shanghai China SIMCom Wireless solutions Ltd 2010 20 PC Magazine Encyclopedia Definition of AT command set online New York USA The Computer Language Company Inc 2013 URL http www pcmag com encyclopedia term 38080 at command set Ac cessed 05 April 2013 21 HobbyKing HobbyKing Multi Rotor Control Board V2 1 Atmega168PA online California USA Hextronik Limited 2012 URL http hobbyking com hobbyking store 19534 HobbyKing Multi Rotor C ontrol Board V2 1 Atmega168PA html Accessed 09 April 2013 22 HobbyKing HobbyKing KK2 0 Multi Rotor LCD Flight Control Board online California USA Hextronik Limited 2012 URL http hobbyking com hobbyking store 24723 Hobbyking KK2 O0 Multi r otor LCD Flight Control Board html Accessed 22 March 2013 23 nvenSense ITG 3200 Integrated Triple Axis Digital Output Gyroscope Overview online Sunnyvale California USA InvenSense Inc 2013 URL http invensense com mems gyro itg3200 html Accessed 10 April 2013 24 Greer A Layne C Certificate Mathematics A Revision Course for the Caribbean UK Nelson Thornes Ltd 2001 25 Analog Devices Inc Small Low Power 3 Axis 200 g Accelerometer ADXL377 datasheet online Norwood MA 02062 9106 U S A Analog Devices Inc 2012 URL http www analog com static imported files data_sheets ADXL377 pdf Ac cessed 13 April 2013 P University of Applied Sc 43 26 Eye Sigh
69. y taking the arctangent of the M University of Applied Sciences 26 result 24 The same formula would apply if the coordinate were replaced with latitudes and longitudes from the GPS data The latitudes will replace the x coordinates while the longitudes will replace the y coordinates Considering equations 1 2 and 3 were for calculations on a flat surface however the earth s surface is spherical so a more accurate calculation of the distance OA OB and OC that takes into consideration the curved surface or spherical nature of the earth is given by X2 X1 y2 Y lt 2 Z tte dog OB 2R arcsin sin 2 cos x cos x sin 2 In terms of latitude lat and longitude lon dog 2R arcsin sin E cos lat cos lat sin a 4 7 The value of R is the radius of the earth about 6 371 kilometres and equation 4 is a derivative of the Haversine formula Following from equations 2 and 3 the bearing is then calculated from the dis tances as follows b a arctan doc do4 Where b is the bearing in degrees a tO the vertical the great circle cosine ap proach will be b a arctan 2 sin lon lon cos lat cos lat sin lat sin lat cos lat cos lon lon 3 2 5 Software Management of Navigation and Control The operation of hardware such as the GPS receiver Magnetometer and other autopi lot functionalities are managed by the software The software d

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