3 ms·
Ok, so by which physical method do they have better telemetry?
by SiempreViernes 7y ago
Ok, so by which physical method do they have better telemetry?
- DuskStar 7y agoActive transponders on the satellite itself. GPS fixes. Other observations from the satellite. Controlling the target makes some problems a lot easier.
- SiempreViernes 7y agoGPS appears to not give great online performance in LEO[1], and transponders is just slightly easier radar, not a fundamental difference. Do they have really good star trackers on their sats? [1]: https://space.stackexchange.com/questions/563/in-leo-what-is-the-precision-of-gnss-based-position-compared-to-traditional-met https://space.stackexchange.com/questions/563/in-leo-what-is...
- dtkav 7y agoThey don't need great online performance, they need offline performance for orbit determination. Once they have a good orbit fit, they will propagate it to predict the probability of collision a few days in advance.
- dtkav 7y agogps (NORAD is using radar)
- debatem1 7y agoDefinitely GPS, probably star trackers too. Not a good idea to have a single point of failure on position knowledge when your whole scheme depends on putting small beams in the right places.
- SiempreViernes 7y agoThey do seem to have star trackers, but rely on NORAD for other satellites Details towards the end: https://techcrunch.com/2019/05/24/spacex-reveals-more-starlink-info-after-launch-of-first-60-satellites/ https://techcrunch.com/2019/05/24/spacex-reveals-more-starli...
- dtkav 7y agostar trackers are not used for orbit determination (position). They are used to determine the attitude (orientation). GPS works extremely well in low earth orbit.
- Rebelgecko 7y agoHow do you pull a TLE (or any sort of ephemeris other than rotation/attitude) out of star tracker data?