[time-nuts] OT - GPS and North

Bruce Griffiths bruce.griffiths at xtra.co.nz
Sun Nov 22 00:37:21 UTC 2009


Neville Michie wrote:
>
> When you think of time specifications from GPS, the GPS system is a 
> poor way to find north.
> Even with a base line of 1000 metres you only have a fraction of a 
> degree.
> The GPS system may be useful to get accurate time to simplify a star 
> observation, from a known (GPS)
> position on this planet, but finding north is still a problem because 
> of the accuracy of a small
> number of observations from a star fix.
> Gyrocompasses take some time to get a measurement
> ( one hour) but even their estimate of North  cannot match the 
> precision that the GPS system can get us with time.
> cheers, Neville Michie
If you are taking star shots a stellar compass can easily provide a 
boresight pointing accuracy of a few arcsec.

Bruce




More information about the time-nuts mailing list