Global Positioning System (GPS) Limitations The GPS cannot detect the vehicle's position during the following instances: For the first 5 to 10 minutes after reconnecting the battery (This can take as long as 45 minutes). When the satellite signals are blocked by tall buildings, mountains, tunnels, large trees, inside parking structures or large trucks. When the GPS antenna is blocked by metallic window tinting or by an object placed above it in the vehicle. The GPS antenna requires a clear unobstructed view of the sky. When there is no satellite signal output (Signal output is sometimes stopped for satellite servicing). When the satellite signals are blocked by the operation of some electronic aftermarket accessories including, but not limited to non-OEM in-dash entertainment units (radio, CD players/changers, radar detectors and theft recovery systems), and cellphones placed near the navigation system. The accuracy of GPS is reduced during these instances: Metallic window tinting above the GPS antenna. When only two satellite signals can be received (Three satellite signals are required for accurate positioning). When the satellite control centers are experiencing problems. When driving near high tension power lines. When the satellite signals are blocked by the operation of some electronic aftermarket accessories including, but not limited to non-OEM in-dash entertainment units (radio, CD players/changers, radar detectors and theft recovery systems), and cellphones placed near the navigation system. |