The three options are:
1. Automatic (recommended)
This 'Accuracy' setting uses cellular tracking when the device is running on battery power, but switches over to GPS tracking when the device is plugged into an external power source like a laptop, wall charger, or cigarette lighter charger. Automatic is the default setting and is strongly recommended to optimize battery performance.
2. GPS Tracking
The second type of tracking (GPS) is far more accurate, right down to the location's street address. However, this draws much more power. If vWork is left running in GPS accuracy mode, you can expect battery life to only be a few hours. If you switch the accuracy setting from Automatic to GPS, ensure the device is plugged into a wall or car charger as much as possible. If not, you will end up with a flat battery within a few hours.
3. Cellular Tracking
The iOS vWork mobile app can track location in two different modes. The first is called Cellular Tracking and does not use GPS, it calculates location based on the device's proximity to cellular sites. This is not as accurate as GPS, but draws much less power. You can roughly expect to see what suburb the device is in when using cellular tracking.