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Can I extract the Dilution of Precision (DOP) Values from a Garmin Etrex
nise1409
Hello,

Could anyone please advise me if it is possible to extract the Dilution of Precision (DOP) Values from a Garmin Etrex.

Thank you.

Ken in Regina
If you know which NMEA sentence(s) contains that information, yes, you can.

Your eTrex can output it's GPS data through the USB port to a connected PC. You will need a program on the PC that can capture that data. Then you can view it. A good place to start would be Franson's GPSGate. It has a 14-day free trial and if you like it you can get the Express version which will serve your purpose. It's cheap like dirt.

When you run GPSGate, you will not see a window on the screen. It simply puts an icon in the system tray (over at the end of your task bar by the clock). You open it from that icon. Once GPSGate is running, connect your eTrex to a USB port on your PC and turn it on. Then you can go into the setup wizard in GPSGate and tell it to find your GPS receiver. Once it has done that you can set it up to capture the incoming data to a log file. Or you can allow it to set up virtual COM ports that will output the data and you can use some other program - either an existing utility (there are loads of them on the internet) or one you write yourself - to capture that data.

...ken...
nise1409
Thank you for this Ken
Ken in Regina
Glad to help. Let us know how it works. Or holler if you have trouble.

...ken...
MrUmbra
If you can use a terminal program such as HyperTerm (included with Windows XP) to observe the NMEA data stream look for:

$GPGSA - GPS DOP and Active Satellites.

Example: $GPGSA,A,3,04,05,,09,12,,,24,,,,,2.5,1.3,2.1*hh

(hh is two hex characters the check sum)

When the fix is valid, the three comma delimited fields before the * character are:

PDOP = 2.5
HDOP = 1.3
VDOP = 2.1


--- CHAS
samsonizzle
There's another way to achieve this without hooking your unit up to a computer.

Follow directions here: http://www.gpsinformation.org/dale/secret.htm to reach the diagnostic mode, this will enable you to view your current HDOP, unfortunately it doesn't display your PDOP or VDOP.
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