Navigation System: Description and Operation
NAVIGATION SYSTEMThe navigation system is integral to the audio unit. The audio unit controls the operation of the navigation system, the audio system and the 6 compact disc (CD) changer. A map CD stored in the audio unit visually guides the user with the maneuvers required to arrive at the destination entered. The 6 CD changer provides audio CD capability while the navigation CD in the audio control unit provides navigation.
In order to calculate initial vehicle position, a global positioning system (GPS) antenna is used to track several available satellites simultaneously. The GPS antenna only receives data and does not communicate with the satellites. A hardwired reverse input from the smart junction box (SJB) and a hardwired vehicle speed input from the anti-lock brake system (ABS) module are also used to improve the accuracy of the navigation system.
The navigation system also displays separate user selected screens for high voltage power flow and fuel economy. The data is supplied from the controller area network (CAN) and then translated from CAN messages into audio control protocol (ACP) messages by the ACP module. These ACP messages are used by the audio unit to calculate the high voltage power flow and fuel economy screens.