GPS is a system to estimate location on Earth by using signals from a set of orbiting satellites. The GPS system includes the chip in your iOS device as well as the satellites above the Earth.
Examples of GPS Issues
- GPS drift: The GPS track deviates from the road. You may see that the route generally follows the shape of the road but with much less precision. Bad GPS data like this could cause your activity to report less distance than you actually traveled, or to not match segments that would have otherwise matched.
- Lost GPS signal: If the GPS signal is lost and sometime later re-acquired the pre- and post-signal-loss points will be treated just as any other two points (although more time has elapsed between them) and connect them with a straight line. Cases of signal loss like this can cause your activity to report less distance than you actually traveled, or to not match segments that you would have otherwise matched.
- GPS bounce: A 'jumpy' GPS track can cause your activity to report more distance than you actually traveled since each 'zig' and 'zag' of your GPS track has to be accounted for with a straight line connecting them. It can, in turn, cause you to receive inaccurate achievements on your activity, or miss segments you would have otherwise matched.
If you experience any of the above, unfortunately, it will not be possible for us to "fill in" the missing data. Thankfully, there is more that can be done to prevent bad GPS data from being recorded than there is to repair it. Please refer to the troubleshooting steps listed in this article to prevent similar issues in the future.
Tips: Achieving good initial GPS lock
To achieve fast startup and high-accuracy position estimates, you should provide:
- Clear view of a large portion of the sky
- Time to tune in to the signals from the satellites
The keys to a GPS lock are clear access to the sky and patience. Any obstructions between the phone and the sky can adversely affect signal strength. A big tree is an obvious obstacle, but even a jersey or a backpack can cause problems for the very low-strength signals.
To improve signal acquisition time, keep the device in one place and make sure the device's data communications are enabled. This allows the phone's GPS to get hints about its approximate location. Even with a perfectly clear sky, it can take a few minutes before a lock can be established in some situations. Most iPhones made in the last few years have had fairly solid GPS sensors. That being said, not all GPS sensors are created equal.
The GPS system includes the chip in your device as well as the satellites above the Earth. So even if your device is in the same place and the same setting as before, it may behave differently from one day to the next. Typically, the device needs to receive signals from about 5 satellites to get an accurate estimate of its position. With the changing position of the satellites, changing weather patterns, and the changing nature of the Earth's outer atmosphere, there are enough parts of the GPS system outside of your direct control and observation that it is difficult to make conclusions about what specifically is causing inconsistent performance. We recommend you try repeatedly before making a judgment about the best ways to work with your device's GPS in your setting.
Tips: Improving phone GPS performance
- Turn phone off/on
- Turn location services off/on
- Perform a GPS reset:
1. Double tap the home button. This will bring up tile sized images of all currently running apps. Swipe the screens of all apps upwards to close them.
2. Then go into settings and turn on airplane mode.
3. When you've done that go to settings, general, reset and choose reset network settings (you will need to re-enter your wifi passwords!)
4. Once your phone has reset go to settings, location services, turn it off then on again.
5. Then go settings > privacy > location services > system services, setting time zone OFF.
Steps to take when investigating GPS Issues
Try using the Strava app to record for 10 minutes, letting it search for signals with a wide open view of the sky, and keeping it completely immobile. If this does not produce useful location estimates, here are the steps we recommend to take next:
Determine if GPS works in other apps
If you are willing to get your hands a little dirty, try running one of the free apps that presents detailed GPS operating information. “GPS Status” is a free app that can reset your GPS and download fresh A-GPS data. You should see it eventually reporting 5 or more satellites acquired, and an overall accuracy range of fewer than 30 meters if everything is working properly.
Check for resource management apps
Some devices may have apps installed that disable GPS services or terminate backgrounded apps in an attempt to reduce battery usage and improve system performance. Examples of apps in this category include "Advanced Task Killer" and "Juice Defender." Please disable or adjust the settings of these apps to allow Strava to receive GPS information during long periods of background operation.
What to do when GPS just doesn't work
Contact our support team with a description of the device, iOS version, and version of Strava - as well as a full description of the problem. When sending a message to us from within the Strava app's support menu, all of this information gets included in the message automatically.