3 ms·
That number doesn’t tell much without knowing the background noise on the L-bands out there. It would also be interesting to know whether they achieved this wit
by slow_typist 2y ago
That number doesn’t tell much without knowing the background noise on the L-bands out there. It would also be interesting to know whether they achieved this with commercial Gnss receivers.
- querbu 2y agoSince the high gain antenna is pointed at the entire earth, the noise temperature is similar earth temperature. Semi-custom gnss receiver, they collect mostly correlator outputs, and 2.5 seconds of raw IQ
- slow_typist 2y agoAngular size of the earth should be about 2 degrees. That is about nothing compared to the beam width of a 15 dB antenna. So space noise is definitely a factor here. However they made it work, and could have used an antenna with much more gain (think voyager dish) if necessary. Probably the idea behind the experiment is to track rovers on the surface where the antenna is only roughly pointed at earth - without the complexity and energy budget coming with a rotator.
- zokier 2y ago> It would also be interesting to know whether they achieved this with commercial Gnss receivers They used Qascom QN400 receiver.
- slow_typist 2y agoThanks. Using your info I found a masters thesis from 2022 on the subject: https://www.researchgate.net/publication/368292806_Study_of_high_sensitivity_GNSS_receivers_for_space_applications_and_lunar_missions https://www.researchgate.net/publication/368292806_Study_of_... And there is a Qascom company profile: https://italianspaceindustry.it/listing/qascom/ https://italianspaceindustry.it/listing/qascom/