The sat nav aerial enables your car's sat nav unit to communicate with GPS (Global Positioning Satellites) which means it can receive the signal it needs to carry out its job.
The sat nav unit's job is to calculate your car's exact location whilst providing you with the most direct route to your chosen destination. Without the sat nav aerial, the sat nat won't pick up the vital signal it needs to do this job.
Sat nav aerials can be fixed on to the dashboard of the car using a suction cup mount. The best place to fix it is close to the windshield base, providing clear access to the sky and therefore a clear line of sight between the sat nav aerial and the satellites it is communicating with. This enables it to pick up a clear signal and provide accurate data. You can also mount it to the windscreen itself with strong tape. If you are fixing the sat nav aerial to the dashboard or windscreen of the car, it is linked to the GPS with the aerial cable provided with the sat nav aerial. The sat nav aerial can also be mounted to the roof of the car with a magnetic mounting bracket. The sat nav aerial may also need to be secured with screws. A sat nav aerial that is fixed outside on the roof of the car will also have an aerial cable which is fed through the window into the car and connects to the GPS unit.
The sat nav aerial is designed to be durable and to hold its own against adverse weather conditions but general wear and tear will naturally take its toll and you will eventually need to replace your sat nav aerial. If you are experiencing a loss of signal and inaccuracy with the sat nav it is worth looking into whether you need to buy a new sat nav aerial.