Observation 14507168: SENTINEL-1 (98261)

Satellites & Observations Observations
1

Regarding Observation 14507168 …Is the posted HEX data, the complete set or a subset of the received data? Our SENTINEL-1 transmitted beacon msg should be 1 KB (1,024 Bytes). Does the receiving SatNOGS GS perform “frame trimming/data manipulation” on the ground?

2

No, my guess false positives because there is no information on how to decode the frames.

Jan | PE0SAT

3

Thanks Jan. Would you please elaborate on your comment “my guess false positives.”

4

The transmitter defined and used for this observation is GMSK 50000 for some reason the FSK flow-graph detects signals and is outputting some hex values.

But at the same time this can’t be correct because we have no details on the signals send by SENTINEL-1, I even wonder if the 50000 baud-rate is correct.

Jan | PE0SAT

5

Thanks Jan. Here is the summary of our UHF SDR features:

  • The radio chip used is the AT86RF215 and so a lot of the parameters are based on its capabilities.

  • 402.000 MHz half-duplex

  • GMSK at 50 kbps, BT=0.5

  • NRZL

  • Using the SFD-16 PPDU:

    • Preamble - 8 bytes of 01010101

    • SFD 2 bytes 0x7209

    • PHR Header 2 bytes - Upper 5 bits all 0, lower 11 bits frame length

    • FCS CRC32 at the end of the frame

  • Inside the PPDU is a single USLP frame.

1 Like