Continued use of GPS running in the background can dramatically decrease battery life. Portman GPS App is a real time GPS/GSM/GPRS tracking Application . User must choose any of the advanced Portman Tracking devices to be installed in the vehicle, then you can use your Portman GPS App to monitor it. iOS 4.0 or above is necessary in order to use Push notification service. Up to 10 tracking devices can be monitored at the same time.