3 ms·
11 dB is pretty impressive, especially if you are just looking at the Doppler shift in the carrier. Which actually begs the question, can you decode anything (
by jdiez17 5y ago
11 dB is pretty impressive, especially if you are just looking at the Doppler shift in the carrier.
Which actually begs the question, can you decode anything (e.g. satellite ID) from the downlink/idle signal? If not, how do you figure out which satellite a given signal came from?
My first guess would be that you can fit an orbit to the Doppler shift, find the closest TLE set from space-track.org, and assume that the signal came from that satellite. Then propagate the orbit to the observation epoch and that should give you a fairly accurate guess of the satellite's actual location. Or do you do something completely different?
- piannucci 5y agoWhat you describe with finding the closest TLE is pretty much what they did. We use a highly directional antenna (~1-2 degree beam) and some tracking software, so it’s not ambiguous. I’ve been able to demodulate and reconstruct about 100 subcarriers’ worth of signal, but until recently I couldn’t record the entire bandwidth. Now we’ve got our hands on one of those awesome RFSoCs with 2 Gsps ADC, so it might be possible to decode more. But unknown error correction, bit interleaving, so it’s a tall order. We’d have to get lucky.