Why isn’t my GPS working?

A recent spate of white label projects, some general technical support queries and a real-word tradeshow flaming incident have brought the issue of generic SmartPhone and tablet GPS locational accuracy to the fore over the last couple of months, so we thought that we should share some of what we have learnt.

Before we hit the geeky bits in our second GPS based posting here are some of the more common reasons why your position might not be accurate (i.e. consistently out by 50 to a 100 metres or more from where you actually are) on your smartphone and how you might resolve them.

  1. Can your smartphone see the sky? (if it is in a bag, inside a building, in a train, a tunnel, under a bridge or on a balcony facing north then this might effect the device’s ability to calculate its location. Fix this by going outside and holding your device away from your body and facing away from North – if in northern hemisphere –or away from South if you are in the Southern Hemisphere. Give it a couple of minutes to fix its location.
  2. Are you under trees with leaves? Not only do trees provide shade, if the sap is high then they will provide your smartphone GPS with an effective barrier to accurate location fixes. Get out from under the trees, or at least find a clearing.

    Gps under dense tree cover is not going to be that effective.[/caption]

  3. Are you in a city or town with tall buildings? Yes, we are saying it again! less sky visibility, less location accuracy
  4. Are you moving? If you are continually moving i.e. in a vehicle then it is more difficult for your device to accurately calculate its position.
  5. Are you in a car with a heated windscreen/windshield. Most modern vehicles have heating elements in the windscreen, these filaments will act as a filter for the GPS signal and can cause issues
  6. Has your phone been off or asleep for a while? Have you just got out of a plane or train after a long journey? Give the phone a few minutes of clear sky to reacquaint itself with those satellites in the sky.
  7. Is your battery low? GPS uses a fair bit of that precious phone juice so if your phone is running low on power the operating system could be doing its best to save what’s left for “perhaps” phone calls?
  8. What is the weather like? If there is thick cloud cover (something we have a globally recognised expertise of in the mountains of Eryri/Snowdonia) then this tropospheric anomaly can again cause issues.
  9. Have you done a hard reset? Is it a new smartphone. It could take some time for the phone to acquire its first location fix.
  10. Do you have data? Do you have a phone signal at all ?A-GPS (assisted GPS) which the vast majority of smartphones use requires access to a signal from mobile cell towers in order to operate, so if you have no data or voice connectivity on your phone it may not be able to access this additional locational data. This also applies if you have activated Flight mode!
  11. Finally, do you have more than one app that uses location i.e. a mapping app and a satnav app? If so, check if both apps are experiencing the same issue. If only one app is providing you with less than adequate location accuracy then perhaps the app might be an issue. Try upgrading to latest version, check forums, send them an e-mail.

If none of the above situations are relevant and the suggested fixes work and you are continuing to experience accuracy issues you could have a smartphone with a faulty GPS or A-GPS.

If there is something that we have not covered then please let us know!