On Thu 2023-12-28T09:23:30+ Poul-Henning Kamp hath writ:
> Also: When&where celestial navigation is possible, most vessels
> travel a lot further than 50 meters during the time it takes to make
> a measurement of the necessary precision.
As noted by ION
https://www.ion.org/Museum/item_view.cf
Warner Losh writes:
> Still, even 50m can be a lot if you are flying over a narrow mountain pass
> in a plane that can't just fly super-high above it...
Celestial navigation requires you to be able to see something through the
windows.
If that is an option the sane pilot would look at t
Jim outlines a calculation I've done many times. But there's a similar
calculation for GNSS systems (GPS, Galileo, Beidou, etc). If you want to use
GNSS to determine positions on Earth's surface to accuracy of a few metres, the
system needs an estimate of current UT1 accurate at least to a few
On Wed, Dec 27, 2023 at 6:04 AM Jim Lux wrote:
> Let’s back of the envelope the impact of a 1 second error in a longitude
> sight.
> The Sun moves 360 degrees in 86400 seconds. A one second error is then
> about 0.004 degree. But in equatorial km, let’s assume 40,000 km
> circumference, so 40,00
