[time-nuts] Distance between GPS Antennae

k4cle at aol.com k4cle at aol.com
Sun Dec 18 17:50:29 EST 2011

Some GPS receivers automatically go into "position hold" mode if less than 1  
mph is detected for several seconds.  However, they usually have a command  
to disable that feature if you search the manual for the command.

Connected by DROID on Verizon Wireless

-----Original message-----
From: Tom Van Baak <tvb at LeapSecond.com>
To: Discussion of precise time and frequency measurement  
<time-nuts at febo.com>
Sent: Sun, Dec 18, 2011 22:35:42 GMT+00:00
Subject: Re: [time-nuts] Distance between GPS Antennae

From: "Brent Gordon" <time-nuts at adobe-labs.com>
>   The best answer is try it it and see what happens.  In my case two
>   systems with patch antennas ten inches apart interfere significantly.
>   Here are plots (using VisualGPS) of my position over a day or two.
>   This is using a GPS from Sure Electronics.  Note that the standard
>   deviation is 0 for over 100,000 samples.  As a side note, it must have
>   some kind of heavy filtering going on to not show any position
>   variation.  This kind of result is repeatable with this unit.


That's really interesting. It looks like one receiver is in GPS
hold mode (so you would expect the position to remain fixed)
and the other is in a normal 2D or 3D mode. Can you look at
the NMEA logs and tell which is which? Is this the same GPS
receiver I played with (leapsecond.com/pages/MG1613S)?


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