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I've been doing some tests with a self-written application that uses the GPS to report locations and plot them on a map. One of the things I've noticed is that the coordinates seem to be more accurate when the interval at which they are gathered is smaller. In general, when reporting every 10 or 15 seconds the coordinates seem to correlate more with the actual position at that time, whereas when reporting every 30 or 60 seconds they seem to be less accurate.

This is even true for a non-moving phone. If I put it down in my backyard and leave it to gather 10 coordinates, once every 10 seconds, I seem to get coordinates that are less spread out and actually are a pretty good indication of the actual location. When gathering 10 coordinates, once every minute, I get a lot less accurate measurements.

Is there any hard evidence to suggest that gathering coordinates at a small interval is more accurate? Or is what I am seeing just coincidence?

  • What's happening during these intervals? If you're in a car or something I would guess that the phone loses sight of more satellites the further you move. – Matthew Read Jun 10 '15 at 13:42
  • I've done some tests just walking around, moving about 20-30 meters. But also tried just putting the phone down somewhere and not touch it... – JDT Jun 10 '15 at 13:47
  • An easy explanation (no source, so not proven): The shorter the interval, the less the device could have moved. GPS accuracy is not "down to the millimeter", but with shorter intervals errors are easier to compensate. Think of adjusting your time via ntpdate, same principle there: even with a single server given, by default it asks 4 times and then builds the "average" out of the results – while for more accuracy you can have it ask more times before "correlating". However keep in mind: the shorter the interval, the more battery it eats (keyword: WAKE_LOCK). Find a balance. – Izzy Jun 10 '15 at 14:58
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Not really.

It's more accurate the more satellites it's receiving. On a shorter interval, it's most likely that more satellites are received, compared to just restarting every minute.

Also, it depends on your location. On a flat field, you will receive a lot of satellites fast, whereas close to buildings or houses, it will also take longer.

What I measured is that you could check the accuracy of the received location. If it's equal or less then 10m, the location could be used. If it's bigger, then wait until you receive a more accurate location.

  • The tracking is not 'restarted', I'm simply asking for updates from the LocationManager at bigger intervals. So you're saying that bigger intervals might cause the LocationManager to stop tracking satellites and I should actually 'warm up' by requesting, say, 5 location fixes so the device actually starts looking for more satellites again? – JDT Jun 11 '15 at 10:08
  • yes thats true, you could also use all providers, not only gps, inside a city wlan works also pretty good. this behavior you could also see in google maps, first your position circle is width, after some time it's get smaller and more precise – fmt.Println.MKO Jun 11 '15 at 10:11

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