[time-nuts] Precise positions for GPSDOs

[Gabs Ricalde]

On Thu, May 2, 2013 at 5:29 PM, Stewart Cobb <stewart.cobb at gmail.com> wrote:
> GPS surveying equipment can easily determine the position of your antenna
> to within a few centimeters (~20 ps). Unfortunately, such equipment is
> expensive and difficult to borrow.
>
> A high-end GPSDO designed today should have the ability to record phase
> data into RINEX files, which could be sent to a service like OPUS to find
> the antenna position.
>
> <http://www.ngs.noaa.gov/opus/>
>
> But few do, so far.
>

There are relatively cheap single frequency GPS receivers that output
raw (code and carrier phase) measurements. If you are near a base
station (e.g., [1]) that provides similar measurements, you can use
RTKLIB to post process both measurements and obtain a position within a
few cm.

A sample plot of the position of the patch antenna outside my window is
attached. The receiver is a u-blox LEA-6T, the RINEX of the base station
is from an IGS station 7.2 km away.

[1] http://igscb.jpl.nasa.gov/network/netindex.html
-------------- next part --------------
A non-text attachment was scrubbed...
Name: rtkplot.png
Type: image/png
Size: 10493 bytes
Desc: not available
URL: <http://febo.com/pipermail/time-nuts_lists.febo.com/attachments/20130502/69ca5a4c/attachment.png>