Circuit Description
Navigation SystemHow the Circuit Works
Power Supply
Battery voltage is supplied at all times through fuse 5 (in the driver's under-dash fuse/relay box) to the navigation unit.
Battery voltage is supplied at all times through fuse 7 (in the driver's under-dash fuse/relay box) to the display panel control unit.
Battery voltage is supplied with the ignition switch in the ACC (I) or ON (II) position through fuse 32 (in the driver's under-dash fuse/relay box) to the navigation unit and to the display panel control unit.
System Description
The navigation unit, display panel control unit, and the interface dial are the main components of the navigation system. The display panel control unit does not have a touch panel. Instead, an interface dial and surrounding buttons allows control of the navigation system. The navigation unit, and display panel control unit communicate with each other through the GA-Net II communication bus. The navigation unit generates the screen graphics, and then passes them to the display panel control unit as Red, Green, and Blue (RGB) color signals, and a composite sync signal.
Voice Control System (Talk/Back buttons)
The voice control system is the primary method for the driver to communicate with the navigation system. The system consists of a Talk and Back button located on the left steering wheel spoke. The audio speakers are used to verbally confirm commands, and to prompt the driver for additional inputs. The HandsFreeLink (HFL) has it's own Talk and Back switches (also on the steering wheel) that operate in a manner similar to the navi switches.
Audio-HVAC-Subdisplay-Clock (Upper display)
The audio unit controls the audio, climate, and time data displayed on this device. The time is updated by the navigation unit, and can be adjusted in the navigation "setup" menu.
Navigation Function
The navigation system utilizes the GPS signals obtained by the GPS antenna, the vehicle speed signal from the ECM/PCM, and the yaw rate sensor contained in the navigation unit to get a user from a starting position to a desired destination. The GPS signals, the vehicle speed signal and the yaw rate sensor (in the navi control unit) determine the position of the vehicle icon on the map. The navigation system relies on the DVD ROM for maps and points of interest (P01) in order to provide the user with the optimum route between starting and destination positions.
Route Guidance
When en route to a destination, the navigation system provides turn-by-turn map and voice guidance. The audio system outputs the navigation voice guidance prompts to the front speakers.
GPS Signal Reception
The GPS signals obtained by the GPS antenna are provided by up to 24 different satellites. The navigation unit supplies the GPS antenna with 5V through a coax cable to power the antenna's amplifier. The GPS receiver in the navigation unit receives the amplified GPS signals back through the same coax cable. The GPS receiver identifies the satellites and processes the different GPS signals. These signals are then converted to actual locations by the navigation unit in order to determine the position of the vehicle.
Other Navigation Inputs
The navigation unit uses the vehicle speed signal from the PCM, a yaw rate sensor (in the navigation unit), and the reverse signal to display the vehicle's direction and speed of travel on the map. The sunlight sensor senses the ambient light and is used to determine whether to switch the display between the day or night display modes.
GA-NET
The GA-Net bus is basically an audio bus. The GA-Net bus connects the navigation control unit, display panel control unit, audio unit, XM unit, and HFL unit. Data passed on this bus includes manual audio control functions, like XM station selection, audio voice commands from the driver, and the muting signal from the navigation unit.
COMM - BUS (XM/HIP, and HFL)
The navigation system is fully integrated with the HandsFreelink (HFL) and with the XM (AcuraLink receiver). This high-speed bus communicates with the navigation control unit, XM unit, and the HFL. Data sent by the XM/HIP unit to the navigation unit include traffic information and AcuraLink messages. The HFL utilizes the bus to transmit whether a bluetooth cell phone is currently paired, a navi P01 phone number to be dialed by the HFL, and vehicle data to be transmitted up to the Acura servers.
F-CAN Communications
Fast Controller Area Network (F-CAN) multiplex network information is transmitted across the communication lines for "real time" functions such as vehicle speed, fuel, emissions, and traction control data.
B-CAN communications
B-CAN passes low speed vehicle functions between components. Typically these include door lock/unlock commands that can be activated by OnStar. See the same section of the Service Manual as in F-CAN above for troubleshooting information.
Climate Bus
The climate bus connects the navigation unit with the climate control unit. Data on this line consists of manual selections of mode, or fan speed, and voice control commands issued by the driver.
Muting
The audio unit orchestrates all muting logic. All voice commands are broadcast over the front audio speakers. Because the OnStar system provides emergency assistance, it has the highest priority for audio output. The priority of the other audio inputs are as follows: The HFL, XM-AcuraLink messages, Navi voice, and the audio unit CD/DVD or AM-FM-XM music channels.
On Star Integration
The OnStar system is a self-contained unit that interfaces with the audio unit by a mute and voice signal. It utilizes it's own cellular antenna, GPS antenna, and a keypad (located in the roof console).
System Diagram