Reference18Driving with Dead Reckoning (2650 Only)The StreetPilot 2650 comes with dead reckoning capabilities, which means that you continue to getnavigation guidance even if you lose GPS reception, such as when you are travelling in dense urbanenvironments with tall buildings and tunnels.To achieve dead reckoning, the 2650 utilizes an internal angular rate sensor, an external speed sensorinput, and an external reverse light sensor input. A special dead reckoning cable is connected to yourvehicle’s speedometer and backup lights (it must be professionally installed by an authorized Garmininstaller). Thus, when you lose GPS reception, your StreetPilot can acknowledge your turns as well as yourdistance travelled while you are driving. In this way, it can continue to accurately give navigation guidanceuntil your GPS reception returns. Driving with dead reckoning capabilities is so seamless, you will noteven know that you do not have GPS reception.You can simply unplug the dead reckoning cable from the vehicle adapter if you want to use the StreetPilot2650 in another vehicle. It will navigate the same way as the StreetPilot 2610.Driving with Dead ReckoningThe only way you can tell that your StreetPilot is usingDead Reckoning is to view the GPS Information page.See page 56 for more information on GPS.
