[time-nuts] nuts about position

[Peter Monta]

Jim Lux writes:



> But another poster did comment on "why not use the telescope" you could
> precision point to a series of stars and calculate using celestial nav
> where you are.  Although, that might be painful to the 1 meter sort of
> accuracy - the "tables" probably don't really account for deviations from
> ellipsoid and so forth.


I took a shot at this recently, using the optical signal available from
GPS, Project Echo style:

http://fer3.com/arc/m2.aspx/Navigating-with-GPS-optically-PeterMonta-jan-2018-g41217

It would be difficult to get to 0.3 meter, though.  More like 15 meter
single shot, maybe 5 meter with averaging.

As the other responses point out, this is routine for GNSS surveying.  A
few hours of dual-frequency GPS data is enough for accuracy of a few
centimeters.  If reference stations such as CORS are available, the "rapid
static" solvers cut the needed session time to 20 or 30 minutes.  Set up a
reference mark in a clear area, get its position, then use a total station
to do optical ties to other local marks like the telescope mount.

Cheers,
Peter