OrcaSat Ground Station telemetry Decoder for Elec400s @ UBC
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Frequency: 433Mhz
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Modulation: GFSK
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Bandwidth: 15kHz
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Callsign: TBD
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Link Layer: AX.25
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Baud Rate: 9800 bit/s
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TLE: TBD
AX.25 does not encode NRZ 1's and 0's, instead is issues NRZI(non return to zero inverter). NRZI encodes a 0 bit as a change from mark to space and a 1 is encoded as no change. To decode we will have to convert a NRZI signal to a bit sequence.
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Bit-Order: Leas-significant-bit first.
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Flags: starts and end each package. 0x7E or: 01111110. It is the only place in the packet in which 6 consecutive 1s appear.
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FCS: for error correction/detection they are the checksum to determine the integrity of the packet.
| Flag | Dest. Addr | Src. Addr. | Digipeter Addr. | Control Field | ID | Information Field | FCS | Flag |
|---|---|---|---|---|---|---|---|---|
| 1 | 7 | 7 | 56 | 1 | 1 | 256 | 2 | 1 |
- AX.25 stream - BistreamGenerator.py
- Helper Functions - helperLib.py
- Decode Sample - decoderMain.py
- OOT implementation for GNURadio
- GUI and command creation
- Automation
- USRP Connection
- CubeSat Live Test.