Post #3665299
2026-07-08 06:07 UTC
@tomjennings@tldr.nettime.org GPS is timing correlation of transmissions from N of M satellites.
If you know your location fairly accurately you can get time from that. If you know the time fairly accurately you can get location from that. If you know neither you’re in coldstart, which is very slow, because you have to guess at which satellites you might see, on which frequencies, when. And do successive approximation of time and location.
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@ewenmcneill@cloudisland.nz 2026-07-08 06:07
@tomjennings@tldr.nettime.org Airplane mode for ages likely triggers “no known location” :-/ The fastest way out is probably to set the time “fairly close” from some other source (eg pocket watch, or even solar noon with longitude correction). And then hopefully cold start will have a reasonable idea which satellites to expect. (As Nick notes it’s possible phones expect decent RTC and won’t do full “know nothing” cold start of old devices.)