Navigation System Description and Operation
Navigation System Description and Operation
Each item in the list below represents topics covered in detail below.
* Audio System Description
* Navigation System Components
* Navigation Radio
* Global Positioning System (GPS) Antenna
* Route Guidance
* Voice Recognition
* Points of Interest
* Traffic Information
* Weather Information
Audio System Description
The Navigation radio operates similar to a traditional radio. For information on the audio description and operation, see Radio/Audio System Description and Operation (Radio/Audio System Description and Operation).
Navigation System Components
The navigation system contains the following components:
* Navigation radio
* Info display module
* Radio/HVAC controls
* Global positioning system (GPS) antenna
* Auxiliary audio jacks (If equipped)
Navigation Radio
This component acts as the operator interface for the navigation system, provides the data input from the operator to the navigation system and provides navigation information to the operator via the display screen. The navigation radio is located in the center of the instrument panel. The navigation radio provides the following:
* The hard disk drive provides map data for navigation and map route guidance.
* The navigation system map with routing information displayed on the info display module screen.
* Provides verbal guidance to the operator.
* Connection to the global positioning system (GPS) antenna, which provides the vehicle position information.
Navigation Radio Communications Diagram
1 - Radio/HVAC Controls
2 - Info Display Module
3 - Radio
4 - HVAC Control Module
5 - Data Link Connector
a - GMLAN
b - Local Interconnect Network
c - CAN Graphical Interface
d - Digital Video
e - Touch Screen Serial Data
Info Display Module
The info display module has continuous power and ground. When the navigation radio is on, a discrete 12 V signal is supplied on the remote enable circuit to the color display module. This signal is used to control the power state of the module, which is active when the signal is high and inactive when the signal is low.
The info display module receives digital video data from the radio for on-screen display information through the navigation video signal circuits. With touch-screen capable displays, the radio communicates with the info display module over the serial data circuits for touch screen inputs.
Backlighting dimming level is also communicated to the info display through the touch screen serial data circuits. For non-touch screen displays, a pulse width modulated dimming circuit from the radio controls the display backlighting.
Radio/HVAC Controls
When equipped with the navigation radio, the radio/HVAC controls communicate radio control inputs directly to the navigation radio with the CAN Graphical Interface (CGI) data circuits. When the operator rotates a radio control knob to change radio stations or increase the volume a message is sent to the radio over CGI serial data. After receiving the message the radio will make the adjustment. Messages communicated between the radio and the radio/HVAC controls include the following:
* Button presses/knob rotations
* Commands for the state of indicators
* Radio control back-lighting
HVAC data for controls and status indicators is communicated between the radio/HVAC controls and the HVAC control module with a separate LIN serial data circuit. HVAC status screen information from the HVAC control module is transmitted to the radio on the GMLAN serial data circuit. The radio then displays the desired screen information on the info display using the video data circuits.
Global Positioning System (GPS) Antenna
The global positioning system (GPS) antenna is located in the upper center of the I/P. The GPS antenna is powered through the same coaxial cable used to send the signals to the NAV radio. Interference to the system may occur if any of the following exist:
* Signals are obstructed by objects such as, tall buildings or trees.
* Metallic objects located on the dashboard.
* Aftermarket glass tinting has been applied to the vehicles windshield.
Route Guidance
The map will display the route to the selected destination. Voice prompts alert the operator of upcoming events (turns) and arrivals at the destination. The navigation system will automatically recalculate if the route is not followed. The navigation radio uses data received from the global positioning system (GPS) satellites as well as the vehicle speed signal to accurately display the current position of the vehicle. The map DVD must be in the NAV radio for route guidance.
Voice Recognition
The Navigation System's voice recognition allows for hands-free operation of navigation and audio system features. The voice recognition can be used when the ignition is in accessory or ON, or when retained accessory power is active. This feature only works if the map DVD is inserted and the AGREE button has been pressed. For a complete list of available commands, refer to the Owners Manual Navigation Supplement and/or Personalization in the Owners manual.
Points of Interest
Points of interests are locations that are frequently visited. Points of interest can be can be displayed on the map or set as a destination. The following are some of the available Points of interests:
* Gas Station
* Restaurant
* College
* Police Station
Traffic Information
XM NavTraffic(TM) is a subscription based service that enhances the navigation system with live traffic information. The service provides information on traffic conditions such as traffic speed, accidents, disabled vehicles, construction and road closings.
The integrated XM satellite radio receives the information. When Traffic Information is turned ON in the configuration menu, the available information will be displayed on the map screen.
The traffic information can vary based upon coverage in the area, and coverage is not available in all areas. No information will be displayed if coverage is not available, if there is no traffic information for the area, or if there is no subscription to receive the information.
A subscription fee is required in order to receive the XM NavTraffic(TM) service. No traffic data will be displayed without a current subscription.
Weather Information
XM NavWeather(TM) is a subscription based service that transmits weather information to the integrated XM satellite radio. Real time information such as current and future weather and road conditions, atmospheric conditions, and National Weather Service warnings is provided, as well as 3 day forecasts for some cities. Received information is available to be displayed on the Weather Info screen.
A subscription fee is required in order to receive the XM NavWeather(TM) service. No weather data will be displayed without a current subscription.