Finding GPS signal strength

Question

Is there any way to get an iPhone's GPS signal strength? I'd like to make some kind of display like this:

• If GPS = 0 or No Signal: color = red / Poor or No Signal
• If GPS = <140 m Signal: Color Orange /Fair Signal
• If GPS = >140 m Signal: Color = Green / Good or Excellent Signal

Answer 1

No public API exists for checking GPS signal strength but it doesn't sound like that is what you are really looking for anyway. You absolutely can check the accuracy of the locations returned by CoreLocation.

Look at CLLocation, it has horizontalAccuracy and verticalAccuracy properties which indicate how accurate the device believes that location fix to be.

Answer 2

You should concentrate mainly on the CLLocation attribute horizontalAccuracy. This value represents the estimated accuracy related to the current latitude, longitude coordinate. verticalAccuracy represents the accuracy in altitude / height. Generally, GPS devices are not well suitable for accurate height measurement, so concentrate on the horizontal attributes.