Several vessels regularly work the poles and their data is publicly available. Here's one from the Healy on a cruise that went to 75N ( at least). I haven't looked at the data to know how much is there, but at a minimum I should think you could look for gaps in the timestamp.
http://www.marine-geo.org/tools/search/Files.php?data_set_uid=11624 I used to work on the Palmer and never saw a glitch in our systems based on latitude, although we used them for basic nav only (no 'science' done with the signals). We worked both poles and at times (very rarely - only for drilling operations when we were on DP) had corrections sent to the ship via satellite (Furgro corrections if I recall correctly). Not sure that the Military wouldn't have been very interested in polar nav even in the early days of GPS - Subs were regularly transiting and hiding in the arctic and I've got to think they might have wanted to pop up for a fix now and again, even with MRU's/gyros. That said, a friend of mine regularly worked on the arctic ice sheet in the 70-90's and most of his navigation was celestial via theodolite. He did, however, have an opportunity to test one of the earliest GPS's on the ice before it was decommissioned. Knowing the magnitude of what he had, he asked and was able to keep the front panel. I tried to send pics of it to the list a year or so ago, but they bounced (size I guess). I've tried to attach a smaller version to this email. Front what I can tell, this is the 21st GPS produced. Brent [image: Inline image 1] On Tue, Aug 15, 2017 at 6:22 AM, David J Taylor via time-nuts < [email protected]> wrote: > The satellite orbits only go so far north? If you are far enough north for > that to be a problem, can you pick up the satellites across the pole? > > I have several days of NMEA log files from 68 N. I think it will be simple > after I have done it, but it may be a while before I get time to plot them. > Does anybody have (non-Windows) code to that? > =========================== > > Hal, > > GPS worked fine for me on a cruise including 80 degrees north. > > Cheers, > David > -- > SatSignal Software - Quality software written to your requirements > Web: http://www.satsignal.eu > Email: [email protected] > Twitter: @gm8arv > _______________________________________________ > time-nuts mailing list -- [email protected] > To unsubscribe, go to https://www.febo.com/cgi-bin/m > ailman/listinfo/time-nuts > and follow the instructions there. >
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