GPS accuracy and reliability comparison

[+TravelingViking]

In various forums one discussion point that keeps popping back up is the accuracy and reliabilty of various GPS devices. Out of curiosity I would like to collect more "hard data" on that topic and am asking for your participation.

 

A quite simple test that can probably be done with "almost any device" is a continous track recording - of a device laying still in one spot for an hour or so. Then visualize the track to see if and what kind of jumps are in there - a good receiver should have all measurements close to each other.

 

I set three Garmin devices - Venture HC, GPSMAP 60CSx and Colorado 300 to continous track recording, every 4 seconds, and made two measurement runs, one with free horizons, and one under more "Geocacher like conditions" - in thewoods, leaf covered trees all around.

 

To my own surprize the Venture HC showed the best performance - I guess I'll carry that around again more often now...

 

You can see the visualizations of hese tests at GeoDrift.com.

 

I would be very interested in seeing how other GPS devices perform for this test - so please go ahead, make recordings and publish your findings.

 

Thanks,

 

Olaf

[Kyle_freemason]

Hi Olaf,

 

I would be very interested in testing my gpsr's to determine their accuracy. I went to the Geodrift website, but I am not sure how to run the test or upload the findings. From what I gather, you set the gpsr to track mode, then let it sit an hour in the same position. From that point I am not sure where to go to upload the data or how to upload the data. I have the Garmin Etrex Legend Hcx. Hopefully, you can help me and I can get the data for two gpsr's that I have. Thanks for the interesting data!

 

Kyle

[zulutime]

Thanks, Olaf, for creating your website, the stations, and your insightful measurements. A few questions:

 

Were your tracks made with EGNOS/WAAS enabled in the Garmins?

 

Approximately how old is your Venture? Can you tell us which chipset and firmware it has?

 

Many thanks.

[+TravelingViking]

I would be very interested in testing my gpsr's to determine their accuracy. I went to the Geodrift website, but I am not sure how to run the test or upload the findings. From what I gather, you set the gpsr to track mode, then let it sit an hour in the same position. From that point I am not sure where to go to upload the data or how to upload the data. I have the Garmin Etrex Legend Hcx. Hopefully, you can help me and I can get the data for two gpsr's that I have. Thanks for the interesting data!

 

The latest measurements have not much to do with the Geodrift web site other than I found it the right platform to host such data.

 

To run your own test: make the the track recording - make sure to set record mode to a fixed time, like every 4s. Record at least 1h, don't move the GPS in that time. Save the track as GPX file.

 

Upload the GPX file to www.gpsvisualizer.com and as output format choose PNG graphic.

 

If you have no place to host the graphic file, just send it to me, if there is enough interest I'll add it to the Geodrift web pages.

 

Olaf

[+TravelingViking]

Were your tracks made with EGNOS/WAAS enabled in the Garmins?

 

Approximately how old is your Venture? Can you tell us which chipset and firmware it has?

 

I had EGNOS/WAAS disabled, if I do a test run with it it would probably only make sense under a free horizon as the correctionsignal seems to be easy to loose.

 

The Venture HC was bought beginning this year - how do I know which chipset it has without opening it? I ran web updater about 2 weeks ago, so assume its the current firmware.

 

Olaf

[zulutime]

...

 

The Venture HC was bought beginning this year - how do I know which chipset it has without opening it? I ran web updater about 2 weeks ago, so assume its the current firmware.

 

Olaf

 

I'm not sure how to tell about the chipset. There is at least one thread here discussing Mediatech versus Garmin(?) chipsets in the etrex H line. Maybe it is indicated in the startup screen or in firmware copyright ststements.

 

Thanks.

[+Leaky Spoon]

To check the version of firmware, go into System Setup and hit the options button. There's a selection for "software version" and will tell you the version of firmware and the unit ID. I'm going to check mine; I've been having accuracy issues the past couple of weeks - think we fixed it somehow, but it would be good to check.

[+TravelingViking]

...Venture? Can you tell us which firmware it has?

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