IRA：Whether staID and location information are in dqpsk？

[cyqsir]

Whether staID and location information are in dqpsk？Is the timestamp decoded or added manually？Whether bpsk is useless for decoding IRA？Whether there is documentation for the code package detailed description？
Thank you for your answer！

[schneider42]

The unique word (UW) is sent as BPSK (0x789). The actual data is DQPSK.

We decode the UW also as DQPSK (it's simply easier that way) that's why you see a bunch of '00' and '11' at the start of the frame.

The timestamp is based on the the time the capture started an the sample number (from the SDR) where the unique word of the frame starts. It is not something transmitted by the satellite. If you have a GPSDO with 1 PPS, a supported SDR (USRP) and enabled this in the config (https://github.com/muccc/gr-iridium/blob/master/examples/usrp-b2x0-uhd.conf#L13), the timestamp is based on GPS time.

[schneider42]

Please let us know if you have further questions.