Raw Data Protocol
SI synchronizes transmissions with observatory rotation (nadir pulse)
SI must transmit a full package of data between nadir pulses
- Header based SI packet structure
- No Data Code - transmitted to CIDP if there is not data this rev.
- Packet Header - informs CIDP data is present
- Request Header - Tells CIDP service request is in packet
- HK Header - Separates SI HK telemetry from raw data
- Raw Data Header - Tells CIDP that raw data follows
- Each header is followed by a word count to allow CIDP to parse packet
- Entire packet terminated with a checksum
- Packet may be made up of Request, HKTEL, Raw Data or any combination of the three
- CIDP verifies packet structure with checksum and word counts