We have updated the Time Trial GPS lap timing app.
Basic functionality is the same but we had added a calibration function for the GPS accuracy. Click the “CAL” button at the top of the app screen to see your current selection or to use a different setting.
If you find the GPS on your phone is missing the coordinates you have entered for your route/lap you can adjust the accuracy/threshold of the coordinates.
The default accuracy is “4”. If you find your device’s GPS sensor is missing your start/finish/split points increase the number to “8” and see if this solves your problem. We would expect most devices to work with 8, there should be no need for 12 and 16.
Choosing split points
Typical GPS refresh rates on Android devices is 1hz ie 1 time per second. If you are travelling at high speed through the split point or the start finish point the vehicle can cover a lot of distance in one second. Possibly enough distance for the GPS sensor to miss the location of your chosen split/start/finish line.
By increasing the CAL number in the app, the app has a greater tolerance for the location of the vehicle.
The problem with reducing accuracy/increasing tolerance
By increasing the CAL number we are increasing the GPS area that the app will recognise as the start line/finish line/split point. This will have an effect on recorded times because there is a greater range of locations that can trigger recording in the app. You should aim to use the lowest CAL number your device/location will allow.
Choosing Start/Finish/Split Points
We recommend you choose your split points at the slowest parts of your route/lap. This gives the GPS sensor in the device the greatest opportunity to log your position.
If you are using the app in an area where GPS reception is less than ideal, you may have no choice but to increase the CAL number above 4.
You should also choose points which are as far as possible from the other points on your lap. This will reduce the chance that the GPS sensor confuses split points/start/finish line.
If your device has zero issues logging your position, you can reduce the CAL number to get more accurate times.
Increasing GPS Accuracy
Apps which use GPS may reduce the accuracy of your GPS sensor. Not a problem if you are using GPS for navigation but for lap timing we need the fastest update speed possible. Close any app which may be using your GPS sensor, Google Maps for example may stop the GPS from working at all with other apps.
Mount the device where it has the clearest, least obstructed view of the sky. The more satellites it can see the more accurate the GPS sensor can be.
TimeTrial2 can be purchased and downloaded from the shop now.