Acura RL. Manual - part 639

SYSTEM DESCRIPTION

OVERVIEW

The navigation system is a highly-sophisticated, hybrid locating system that uses satellites and a map
database to show where the vehicle is to help guide you to a desired destination.

The navigation system receives signals from the global positioning system (GPS), a network of 24 satellites
in orbit around the earth. By receiving signals from several of these satellites, the navigation system can
determine the latitude, longitude, and elevation of the vehicle. In addition, signals from the system's yaw
rate sensor and the PCM (vehicle speed pulse) enable the system to keep track of the vehicle's direction and
speed of travel.

This hybrid system has advantages over a system that is either entirely self-contained or one that relies
totally on the GPS. For example, the self-contained portion of the system can keep track of vehicle position
even when satellite signals cannot be received. When the navigation system is on, the GPS can keep track of
the vehicle position even when the vehicle is transported by ferry.

The navigation system applies all location, direction, and speed information to maps and calculates a route
to the destination entered. As you drive to that destination, the system provides both visual and audio
guidance.

This navigation system also has voice recognition that allows voice control of most of the navigation
functions. The Navigation TALK and BACK buttons on the steering wheel activate the voice control. The
voice control also allows control of the audio and climate functions.

The illumination signal (headlights ON) is used by the navigation unit to automatically switch the display
between "Night" and "Day" brightness modes when display is set to Auto. When the instrument panel is set
to night and the brightness control is set to full brightness (hold both "+" and "-" key at the same time), the
navigation system stays in the day mode, even with the headlights on.

The GA-NET II bus passes information back and forth between the display panel control unit, the
navigation unit and the audio system, The information passed on this bus are audio and climate control
settings directed by the navigation unit.

The "Comm. Bus" connects the HFL, XM (AcuraLink), and navigation units. This bus supports these
functions:



The navigation control unit receives traffic and message information from the AcuraLink Control unit.



The navigation control unit sends a POI phone number ("Calculate route to" screen) to the HFL for
dialing.



If vehicle problems are detected, and the client's cellular contract includes data service, then the HFL
can send vehicle data to the HFL unit for transmitting back to the AcuraLink servers.



The AcuraLink server can pass additional problem details back through the HFL, to the AcuraLink
Control unit, and finally to the navigation unit for display.

Navigation does not
call using the HFL

NAVIGATION DOES NOT CALL
USING THE HFL )

The wrong colored DVD or
version is installed

2007 Acura RL

2005-08 ACCESSORIES AND EQUIPMENT Navigation System - RL

Friday, June 05, 2009 3:28:15 PM

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System Diagram

Fig. 4: Navigation System - System Diagram
Courtesy of AMERICAN HONDA MOTOR CO., INC.

NAVIGATION FUNCTION

The navigation system is composed of the navigation unit, the PCM (vehicle speed signal), the GPS
antenna, the microphone, the voice control switch, the audio unit, the display unit, and the interface dial.

Function Diagram

2007 Acura RL

2005-08 ACCESSORIES AND EQUIPMENT Navigation System - RL

Friday, June 05, 2009 3:28:15 PM

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Fig. 5: Navigation System - Function Diagram
Courtesy of AMERICAN HONDA MOTOR CO., INC.

GA-Net Bus Configuration

The GA-Net bus passes audio and navigation commands throughout the navigation and audio components.
These commands include navigation audio/XM selections by voice, and XM station and music title names.
Because the entire bus is interconnected between components, an open or short in the GA-Net bus harness
may cause any or all of these functions to become inoperative.

Fig. 6: GA-Net Bus Configuration Diagram
Courtesy of AMERICAN HONDA MOTOR CO., INC.

Vehicle Speed Pulse

The vehicle speed pulse is sent by the PCM. The PCM receives a signal from the countershaft speed sensor,
then processes the signal and transmits it to the speedometer and other systems.

2007 Acura RL

2005-08 ACCESSORIES AND EQUIPMENT Navigation System - RL

Friday, June 05, 2009 3:28:15 PM

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Fig. 7: Vehicle Speed Pulse Diagram
Courtesy of AMERICAN HONDA MOTOR CO., INC.

Charge Signal, Navigation Unit Cooling Fan Operation and Trip Computer

The PCM sends a charge signal to the navigation unit via F-CAN. A thermister inside the navigation unit
monitors the units internal temperature. This information combined with a charge signal determines the
control units internal cooling fan operation. The navigation system displays trip computer information that is
calculated by the gauge assembly.

Fig. 8: Charge Signal, Navigation Unit Cooling Fan Operation And Trip Computer Diagram
Courtesy of AMERICAN HONDA MOTOR CO., INC.

Yaw Rate-Lateral Acceleration Sensor

The yaw rate-lateral acceleration sensor (located in the navigation unit) detects the direction change (angular
speed) of the vehicle. The sensor is an oscillation gyro built into the navigation unit.

Sensor Element Structure

The sensor element is shaped like a tuning fork, and it consists of the piezoelectric parts, the metal block,
and the support pin. There are four piezoelectric parts: one to drive the oscillators, one to monitor and
maintain the oscillation at a regular frequency, and two to detect angular velocity. The two oscillators,
which have a 90-degree twist in the center, are connected at the bottom by the metal block and supported by
the support pin. A detection piezoelectric part is attached to the top of each oscillator. The driving
piezoelectric part is attached to the bottom of one oscillator, and the monitoring piezoelectric part is attached
to the bottom of the other oscillator.

Oscillation Gyro Principles

The piezoelectric parts have "electric/mechanical transfer characteristics. "They bend vertically when
voltage is applied to both sides of the parts, and voltage is generated between both sides of the piezoelectric
parts when they are bent by an external force. The oscillation gyro functions by utilizing this characteristic

2007 Acura RL

2005-08 ACCESSORIES AND EQUIPMENT Navigation System - RL

Friday, June 05, 2009 3:28:15 PM

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