Navigation System Description - Overview (2014 2015 2016 2017)
Basic Configuration
The navigation system is a highly-sophisticated, hybrid locating system that uses satellites and a map database to show you where you are and to help guide you to a desired destination.
The navigation system receives signals from the global positioning system (GPS), a network of 24 or more 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.
Control Interface
Center Display Unit
The center display unit uses a liquid crystal display (LCD). The LCD is an 8 inch diagonal wide-VGA, thin film transistor (TFT), strip type with 384, 000 picture elements. The LED back light is laid out on the back of the liquid crystal film.
The center display unit displays navigation map screen, trip information, audio information, and any customize screen via the audio-navigation unit. When the vehicle is in R position/mode, the display changes to the rearview information.
The center display uses a color dot matrix screen to display variety of information from the audio-navigation unit. To provide information, the audio-navigation unit connects to several data lines on the vehicle. Then send to the center display via the digital video data line (GVIF).
The display dimmer signal is sent from the gauge to the audio-navigation unit via the B-CAN, then send the signal to the center display via the GA-NET. The audio-navigation unit also sends the contrast and black level information via the GA-NET.
Fail-Safe Function
When the center display temperature is 167 deg.F (75 deg.C) or higher, the display sends the information to the audio-navigation unit via the GA-NET. The audio-navigation unit outputs the warning screen for about 30 seconds and then the display back light turns off until the temperature cools down.
Self-Diagnostic Function
The System Diagnostic Mode can check GA-NET data connections between the center display unit. The System Diagnostic Mode also includes several screens designed to check the dot matrix screen performance.
Center Switch Panel
- The hard buttons and the interface dial are used to input audio/navigation/HFL commands.
- The display mode button switches the display between Day mode, Night mode, and off.
NOTE: When you activate this button, the display auto dimming is turned off.
- The AUDIO button is used to display the audio system information to the center display.
Interface Dial
The center switch panel is directly connected to the interface dial. The signal input by the center switch panel button is sent to the audio-navigation unit via the interface dial.
| Switch Code | Button Name |
|---|---|
| SW-A | NAV |
| SW-B | PHONE |
| SW-C | INFO |
| SW-D | AUDIO |
| SW-E | BACK |
| SW-F | MENU |
| SW-G | |
| SW-H | SETTINGS |
| SW-I | Not used |
Steering Commander Switch
The audio remote switch and the HFL-navigation voice control switch are integrated to the left steering commander switch that uses the digital communication.
- TALK Button: Activates the voice control system in the audio-navigation unit to accept voice commands.
- HANG-UP/BACK Button: Returns the display to the previous screen (similar function as the CANCEL button), or is used to end a call.
- PICK-UP Button: This button is used to answer incoming calls or to make outgoing calls. You can also go directly to the Cellular Phone screen by pressing this button.
Front Microphone
Receives voice commands and transmits them to the audio-navigation unit or the telematics (HandsFreeLink) control unit. The microphone unit consists of two microphones. One microphone is combined with the ANC/active sound control microphone. The microphones detect the driver's voice and the passenger's voice separately.
The microphone switches the directivity by changing the voltage on the HFT MUTE line.
| HFT MUTE Signal | |
|---|---|
| NAVI recognition mode | 0 - 1.5 V |
| HFL telephone mode | 3 - 5 V |
| HFL recognition mode | 7 - 9.5 V |
HDD Navigation System
The Acura RLX uses a hard disc drive (HDD). The HDD system improves route calculation and POI searching time. There are two software programs that run on the audio-navigation system:
- Navigation system software - This software comes pre-loaded on the HDD and runs the navigation system. It can be updated with the update disc.
- Map software - This is commonly referred to as update navigation DVD that clients can order to update their map info, POI DB, and CDDB information. This also comes pre-loaded on the HDD, but the client can choose to update it yearly.
When you order a reman HDD, the latest navigation system software is loaded on the HDD, along with the latest map software that the client had installed on their HDD.
Fail-Safe Function
The HDD shuts down to protect itself from damage:
- If the audio-navigation unit internal temperature is 158 deg.F (70 deg.C) or higher.
- If the atmospheric pressure below about 62.1 kPa (0.633 kgf/cm 2, 9.00 psi). The atmospheric pressure signal from the PCM via the F-CAN.
Navigation Function
The basic navigation system is composed of the audio-navigation unit, the vehicle signal (vehicle speed pulse, reverse signal), the GPS antenna, and the center display unit.
The audio-navigation unit calculates the vehicle position and guides you to the destination. The unit performs map matching correction, GPS correction, and distance tuning. It also controls the menu functions and the HDD, and interprets voice commands. With control of all these items, the audio-navigation unit makes the navigation picture signal, then it transmits the signal to the center display unit.
Function Diagram
Calculation of Vehicle Position
The audio-navigation unit calculates the vehicle position (the driving direction and the current position) by receiving the directional change signals from the yaw rate sensor and the travel distance signals from vehicle speed pulse (VSP) of the PCM and the BACK-LT (reverse) signal.
Map Matching Tuning
Map match tuning means that the vehicle's position is properly indicated on mapped roads. The map data transmitted from the HDD is checked against the current vehicle position data and the vehicle's position is indicated on the nearest road. Map matching tuning cannot be done when the vehicle is on an unmapped road, or if the vehicle is far away from a mapped road.
GPS Tuning
GPS tuning improves the accuracy of the vehicle's actual position in relation to the GPS vehicle position. The audio-navigation unit compares its calculated vehicle position with the GPS position. If there is a large difference between the two positions, the GPS tuning adjusts the calculated vehicle position to the GPS position.
Distance Tuning
The audio-navigation unit compares the vehicles calculated distance using the VSP and the vehicle's actual position based on GPS data. If the values are different, the audio-navigation unit decreases or increases the tuning value depending if the vehicle's calculated position is always ahead or behind the GPS position.
Vehicle Speed Pulse
The vehicle speed pulse is sent by the PCM. The PCM receives a signal from the output shaft speed sensor, then processes the signal and transmits it to the speedometer and other systems.
Yaw Rate Sensor
The yaw rate sensor (located in the audio-navigation unit) detects the direction change (angular speed) of the vehicle. The sensor is an oscillation gyro built into the audio-navigation unit.
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 of the piezoelectric parts and Coriolis force. (Coriolis force deflects moving objects as a result of the earth's rotation.) In the oscillation gyro, this force moves the sensor element when angular velocity is applied.
Global Positioning System (GPS)
The global positioning system (GPS) enables the navigation system to determine the current position of the vehicle by using the signals transmitted from the satellites in orbit around the earth. The satellites transmit the satellite identification signal, orbit information, transmission time signal, and other information. When the GPS receiver receives a signal from four or more satellites simultaneously, it calculates the current position of the vehicle based on the distance to each satellite and the satellite's position in its respective orbit.
Position Detection Image with GPS Satellite
Precision of GPS
The precision of the GPS varies according to the number of satellites from which signals are received and the view of the sky. The accuracy is indicated by the color of the GPS icon shown on the display.
| GPS Icon Color | Number of Satellites | Condition | Description |
|---|---|---|---|
| No GPS icon shown | None | Faulty reception | GPS cannot be utilized due to a faulty GPS receiver, GPS antenna, or other fault or interference. |
| 2 or less | Impossible to detect vehicle position | GPS function is normal. The satellite signals received by the GPS are too few to detect the vehicle position. | |
| White GPS icon shown | 3 | Vehicle position detectable in 2 dimensions | The longitude and latitude of the vehicle position can be detected (less precise than detection in three dimensions). |
| Green GPS icon shown | 4 or more | Vehicle position detectable in 3 dimensions (elevation displayed) | The longitude, latitude and the altitude of the vehicle position can be detected (more precise than detection in two dimensions). |
GPS Antenna
The GPS antenna amplifies and transmits the signals received from the satellites to the GPS receiver.
GPS Receiver and Clock
The GPS receiver is built into the audio-navigation unit. It calculates the vehicle position by receiving the signal from the GPS antenna. The current time, vehicle position and signal reception condition is transmitted from the GPS receiver to the audio-navigation unit to adjust vehicle position and the clock in the center display and the clock subdisplay.
Audio Guidance
The audio-navigation unit transmits audio driving instructions before entering an intersection or passing a junction. The audio instructions come through the stereo amplifier to the center speaker.
Voice Control Function
This navigation system also has voice recognition that allows voice control of most of the navigation functions. The TALK and BACK buttons on the steering wheel activate the voice control. The voice control also allows control of the audio and the climate functions.
If the driver is using voice recognition, the audio-navigation unit sends the fan mute signal to the climate control unit via the B-CAN bus. The blower fan operating voltage may be reduced depending on the current fan speed.
Solar Angle
The climate control unit uses the sun's angle from the GPS, along with the sunlight sensor to control the driver/passenger A/C air flow.
Turn-by-Turn Directions
The audio-navigation unit outputs the route guidance (direction) information to the multi-information display via the B-CAN. In the case of route guidance, the multi-information display shows the simple routing guidance using arrow. When other than route guidance mode, the multi-information display shows the azimuth (direction) information in 16-directions.
Flying Start
To shorten the start-up time of the navigation system, the audio-navigation unit has a flying start circuit. If the driver's door is opened, the audio-navigation unit is powered on in the background. When the vehicle is turned to the ON mode, the disclaimer screen turns on quickly. When the vehicle turned to the OFF (LOCK) mode, the audio-navigation unit keeps the last mode for about 2 minutes.
Multi-View Rear Camera System
The multi-view rear camera system allows the driver to see what is behind the vehicle by displaying the image on the audio-navigation unit. There are three different selectable views. Refer to the audio system Overview.