Smartphone GPS App Accuracy
I've seen a couple threads discussing the merits of various tracker apps and that got me thinking. I've been using Endomondo on my LG Revolution and it consistently reads about 5-10% short on distance. After seeing another thread about variation in smartphone GPS devices I'm wondering if there's a better combination of tracker app and phone that will give more accurate results. Has anyone done a side by side comparison with a dedicated GPS or bike computer and found a better tracker app or phone?
Friends of mine use Strava and we occasionally compare final distances, sometimes Strava seems more accurate and sometime it seems much worse than Endomondo so I'm hesitant to go for it. Anyone have any thoughts/insight?
too much inaccuracy in the cell phone GPS hardware itself to make a good comparison. some days, one app will be better, on others another will be better. You'd have to run many apps on the same phone hardware at the same time that are all using the same raw data to make much sense of the apps themselves.
and then there's the phone hardware variability. generally speaking, newer hardware is better, but there's an occasional lemon out there.
either way, it's better to remove the phone GPS hardware from the equation entirely and buy an external bluetooth GPS receiver if you absolutely have to use your phone. Lots of manufacturers and models. They're all better than the integrated hardware if you care about accuracy, but comparing between them, some are also better than others so you have to look at reviews for specific ones.
I also have to ask....your phone is 5-10% short on distance compared to what? not all measurements you will find posted anywhere will be accurate enough for that kind of comparison. they'll probably have at least that much error already. comparing to your friends' devices also doesn't tell us a whole lot because we don't know how far off from "true" those measurements are.
Anyone can quickly and easily test the accuracy of the GPS in their cell phone, iPad or other mobile device.
1. Start Gmap4: http://www.mappingsupport.com/p/gmap4.php
2. Click (or touch) Menu ==> Search
3. Enter your address at the top of the screen and then click Search
4. Click/touch Terrain and change the basemap to Satellite
5. Notice the cross hair at the center of the screen. Drag the screen so the crosshair is over some place outside that is recognizable and where you can go stand.
6. Zoom in all the way and do a careful job of positioning the map so the crosshair is in just the right spot. For example, the corner of a green lawn would do fine.
7. Gmap4 always displays the coordinates that Google supplies for the center of the map. These coords have nothing to do with the GPS in your mobile device. These coords are displayed either in the lower right or upper right corner of the screen. The datum is WGS84.
8. Now take your phone, iPad, etc and go stand at that spot.
9. Ask some app in your device to tell you the coords where you are standing and compare them to the coords supplied by Google.
If you are curious you can perform some different versions of this test. For example, you could try:
1. Wi-fi on and GPS off
2. Wi-Fi off and GPS on
3. Wi-fi on and GPS on
However, each test should be taken at a different location at least a block apart.
You could also look for a suitable test location under heavy tree cover and/or next to a building that would block some of the sky (and thus also block the signal from some of the GPS satellites).
Oh, yeah - The latest beta version of Gmap4 (see link below) includes a feature to make Gmap4 work more like a GPS. In addition to testing any native GPS apps you have you can also test the GPS accuracy of Gmap4 which is a browser app. Start the beta version in the browser of your mobile device and then touch Menu ==> My Location. Touch the symbol that appears to see the coords. These coords are where your browser thinks you are standing. Since Gmap4 is a browser app, you must be online. If you walk around, the location symbol on the screen should follow you. If you play with this Gmap4 beta feature I would love to hear the results.
To start the Gmap4 beta version:
Gmap4 homepage: Gmap4 = Free Online Topographic Maps + Google Maps + More
Joseph, the Gmap4 guy