1. Communication Subsystem

2. Introduction Hardware Protocol Description Interface Examples Test Link Budget Conclusion

3. Table of Contents Hardware Protocol Description Interface Examples Test Link Budget Conclusion

4. Hardware OSSS Vital Part Testing MIL-STD-1540 Power Interface?

5. Specifications Frequency: 430-450 MHz Bitrate: 9600 baud Voltage: 3.3-5 V and 7.5-12 V Power output: 2W@9.6V Current Drain: Transmitting: 940mA@2W Receiving: 60mA Mass: 100 g

6. Interface

7. Ground Station Modem from OSSS No Final Solution Yagi Antenna  16 dB gain NOVA Rotor Control Price  10.000 - 20.000 Kr. Brian Lodahl from KOM

8. Table of Contents Hardware Protocol Description Interface Examples Test Link Budget Conclusion

9. Requirements Flawless Link Support Call-names Pause / Resume Prioritizing Channels Half Duplex

10. Layer Structure

11. AX.25 Error Detection Supports Call-names Supports Half Duplex Connections Widely Used Well Documented

12. T55X Structure

13. T55X Transport Layer Channels 16 Channels Priorities Fixed Priorities Pause / Resume

14. Example Application Channel 2Channel 1 De-Mul Scheduler Channel 1 Channel 2 Application Data-A Packet-A1 Data-B Packet-A2 Packet-B1 Packet-A2 Data-A

15. Table of Contents Hardware Protocol Description Interface Examples Test Link Budget Conclusion

16. Interface Callback Functions Receive Data Receive Events / Beacon Send Connection Less Data Send Data Connect / Disconnect Complete API on WWW www.control.auc.dk/~01gr555/api/

17. Table of Contents Hardware Protocol Description Interface Examples Test Link Budget Conclusion

18. Start Communication while(true) do sendConLess(housekeeping) sleep(rtt+ct) if status=CONNECTED then break sleep(30 s) Satellite: SetupCall-back(handleEvent(type, data)) handleEvent(type,data) { If type=DATA_RECEIVED then store(data) connect } Ground Station:

19. Sequence Chart Ground applications Ground protocol Satellite protocol Satellite applications sendConLess Lost in space getStatus sendConLess getStatus handleEvent connect 30 sec

20. Send/Receive Start: createChannel(8,receiveImage) createChannel(2,commandChannel) Main:....... sendData(2,Take Picture)........ Callback: receiveImage(data){ Save(data) sendEventToAdmin(Received Image) } Ground Station:

21. Send/Receive Start: createChannel(8,imageChannel) createChannel(2,receiveCommand) Callback: receiveCommand(data){ if data=’take image’ then takeImage sendData(8,image) } Satellite:

22. Time Synchronization Several Solutions Connection Less Channel With Estimation No Requirements Yet

23. Table of Contents Hardware Protocol Description Interface Examples Test Link Budget Conclusion

24. Modelling and Verification Why? Short Implementation Test Time New Protocol Satellite What: SDL Modelling Exhaustive Testing Code Generation Tools: ObjectGeode

25. Table of Contents Hardware Protocol Description Interface Examples Test Link Budget Conclusion

26. Link Budget Link Budget equation or Ebno EIRP: (Equivalent Isotropically Radiated Power) G/T: Quality factor of receiver

27. Link Budget Max distance to satellite Using Pythagoras: Inserting into the equation

28. Effective Throughput I frame size: 24 - 276 bytes 23 bytes overhead S frame size: 19 bytes

29. Effective Throughput Data: Beacon:

30. Table of Contents Hardware Protocol Description Interface Examples Test Link Budget Conclusion

31. Work So Far: Analysis / Design / Modelling / API Hardware To Do: Implementation Verification / Test Purchase from OSSS Ground Station