Comment by spwa4
16 hours ago
More to the point, to do that to this number of satellites on this big an area you'd need nuclear power plant levels of power, and it would only degrade GPS a bit (their clocks slowly desync when uplink is blocked)
16 hours ago
More to the point, to do that to this number of satellites on this big an area you'd need nuclear power plant levels of power, and it would only degrade GPS a bit (their clocks slowly desync when uplink is blocked)
My understanding was that each satellite broadcasts a coarse ephemeris for the whole network, and that that “almanac” isn’t accurate for very long (on the order of weeks). Without uploads to the satellites, those almanacs will go stale.
I don’t think the almanacs are necessary for the system to work, in theory. But I believe they’re commonly used by receivers to narrow down the range of possibilities when trying to find a PRN match for a signal they’re getting.
(I’ve dealt with GPS and similar navigation signals for work but am not an expert, this is just the impression I’ve gotten over a few years)