[time-nuts] How can I measure GPS Antenna quality?
holrum at hotmail.com
Sun Nov 20 22:41:05 EST 2016
When I was developing the precision survey code for Lady Heather, I used a lot of antennas. My definition of antenna quality boiled down to how well the results of a 48 hour survey compared to the cm level survey point that I had for my antenna position (from a Ashtech Z12 receiver / matched choke ring antenna).
One thing you can try is running Lady Heather with various antennas with the receiver in 3D positioning mode and enabling the lat/lon "scattergram" display (G I command in the next release). This will produce an X-Y plot of fixes from the point when the display was enabled. Better antennas will produce "tighter" scattergrams.
Another thing to try is running Lady Heather's precision survey command. This will display the scattergram and also write all the position fix data to the file "lla.lla" that you can process as you see fit.
Also, the next version of Lady Heather can write GPX, XML and KML format log files that have the lat/lon/alt info in them.
More information about the time-nuts