Your Opel Mobile device will try to use it GPS hardware to obtain the location from the satellites. If it is not available, then it will use Wi-Fi signal to obtain the approximate location. But if both are not available, then it will use cellular network towers to calculate its location. While the accuracy of GPS hardware is generally between 10m-100m, so it is normal for a device to jump around on the map with up to 100m when stationary. The discrepancy may be even larger when it is only using cellular network towers to obtain its location by calculation. GPS reception also can be interfered when the device is indoors, surrounded by tall buildings, or even during bad weather time. These limitations occur on all types of GPS devices and apps, even Uber experiences this. Although we do have algorithms to help to fix the bad location data, but unfortunately it is not possible to fix all scenarios.