Navigation Function
The navigation system is composed of the navigation unit, the ECM/PCM (vehicle speed signal), the GPS antenna, microphone, voice control switch, audio unit, climate control unit, and the display unit.
Function Diagram
Vehicle Speed Pulse
The vehicle speed pulse is sent by the ECM/PCM. The ECM/PCM receives a signal from the countershaft speed sensor, then it processes the signal and transmits it to the speedometer and other systems.
Charge Signal
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 charge signal determines the control units internal cooling fan operation.
Fuel Use Level Data
The navigation unit monitors the ECM/PCM fuel usage and tank level data via the F-CAN bus. The navigation system combines this information, the vehicle speed signal, GPS, and the map data for trip computer calculations.
Yaw Rate Sensor
The yaw rate 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 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.
Operation

1. The driving piezoelectric part oscillates the oscillator by repeatedly bending and returning when an AC voltage of 6 kHz is applied to the part, The monitoring-side oscillator resonates because it is connected to the driving-side oscillator by the metal block.

1. The monitoring piezoelectric part bends in proportion to the oscillation and outputs voltage (the monitor signal). The navigation unit control circuit controls the drive signal to stabilize the monitor signal.

1. When the vehicle is stopped, the detecting piezoelectric parts oscillate right and left with the oscillators, but no signal is output because the parts are not bent (no angular force).

1. When the vehicle turns to the right, the sensor element moves in a circular motion with the right oscillator bending forward and the left oscillator bending rearward. The amount of forward/rearward bend varies according to the angular velocity of the vehicle.

1. The detecting piezoelectric parts output voltage (the yaw rate signal) according to the amount of bend. The amount of vehicle direction change is determined by measuring this voltage.

Global Positioning System (GPS)
The global positioning system (GPS) enables the navigation system to determine the current position of the vehicle by utilizing 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 three or more satellites simultaneously, it calculates the current position of the vehicle based on the distance to each satellite and the satellite is 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 precision is indicated by the color of the GPS icon shown on the display.

GPS ICON | NUMBER OF SATELLITES | CONDITION | DESCRIPTION
--- | --- | --- | ---
No GPS icon shown | 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.
Square GPS icon shown with white ‘‘GPS'' | 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)
Cube GPS icon shown with green ‘‘GPS'' | 4 or more | Vehicle position detectable in 3 dimensions | 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
The GPS receiver is built in the navigation unit. It calculates the vehicle position by receiving the signal from the GPS antenna. The vehicle position and signal reception condition is transmitted from the GPS receiver to the navigation control unit to adjust vehicle position.
Navigation Unit
The 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 DVD-ROM drive, and interprets voice commands. With control of all these items, the navigation unit makes the navigation picture signal, then it transmits the signal to the display unit and audio driving instructions to the audio unit.
Calculation of Vehicle Position
The 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 the PCMs vehicle speed pulse (VSP) signal.
Map Matching Tuning
The map matching tuning is accomplished by indicating the vehicle position on the roads on the map. The map data transmitted from the DVD-ROM is checked against the vehicle position data, and the vehicle position is indicated on the nearest road. Map matching tuning does not occur when the vehicle travels on a road not shown on the map, or when the vehicle position is far away from a road on the map.
GPS Tuning
The GPS tuning is accomplished by indicating the vehicle position as the GPS's vehicle position. The navigation unit compares its calculated vehicle position data with the GPS vehicle position data. If there is large difference between the two, the indicated vehicle position is adjusted to the GPS vehicle position.
Distance Tuning
The distance tuning reduces the difference between the travel distance signal from the VSP and the distance data on the map. The navigation unit compares its calculated vehicle position data with the GPS vehicle position data. The navigation unit then decreases the tuning value when the vehicle position is always ahead of the GPS vehicle position, and it increases the tuning value when the vehicle position is always behind the GPS vehicle position.
Route Guidance
The navigation unit can calculate different routes to a selected destination. You have five options:

- Direct Route − Calculate a route that is the most direct.
- Easy Route − Calculate a route that minimizes the number of turns needed.
- Minimize Freeways − Calculate a route that avoids freeway travel. If that is not possible, keep the amount of freeway travel to a minimum.
- Minimize Toll Roads − Calculate a route that avoids, or minimizes travel on toll roads.
- Maximize Freeways − Calculate a route that uses freeways as much as possible.

Audio Guidance
The navigation unit transmits audio driving instructions before entering an intersection or passing a junction. The audio instructions come through the audio unit to the front speakers.
NOTE: The front speakers are muted whenever the navigation system is giving guidance commands, and all of the speakers when the voice control system is being used.
DVD-ROM
The map data (including all scale rates) is stored in the DVD-ROM. The map data includes:

- Road distances, road widths, speed limits, traffic regulations, passing time at junction, distances to junctions, and the driving instructions for audio guidance.
- Latitude and longitude GPS.

Audio Unit
The audio unit receives the audio driving instructions from the navigation unit and transmits the instructions through the front speakers even when the audio system is in use. The audio unit is also a termination point in the GA-Net bus.
Display Unit
The display unit uses liquid crystal display (LCD). The LCD is a 7-inch-diagonal, thin film transistor (TFT), stripe type with 330,960 picture elements, The color film and fluorescent light are laid out on the back of the liquid crystal film.
The touch sensor on the front of the LCD consists of a touch sensitive resistive membrane with an infinite number of possible touch locations. To maintain compatibility with earlier display units the sensing locations are confined to a grid of 20 vertical and 10 horizontal touch locations. This produces 200 total sensing zones. The display unit transmits the signal from each operation key and the touch switches to the navigation unit over the GA-Net bus.
Glossary
The following is a glossary of terms pertaining to the Voice Recognition Navigation System.

Item | Definition
--- | ---
Audio-HVAC subdisplay | The upper display that shows the time and current status of the audio and climate control systems.
Breadcrumbs | Off road tracking dots that can be followed on the map to retrace your route back to a mapped (digitized) road. This function can be turned on/off in Setup screen 1.
CAN | Controller Area Network. This communication network allows processors in the vehicle to send/receive information. The fuel pulses used by the trip computer are received from the PCM using the F-CAN (Fast Controller Area Network) bus.
B-CAN | Body CAN Bus (see CAN)
CPU | Central Processing Unit. The main device within the navigation unit that coordinates the rest of the electronic functions.
Database | This consists of the Map data, and the POI (Points Of Interest) data stored on the DVD
DBW | Drive By Wire. Allows electrical control of the throttle without the need of a mechanical linkage.
DCA | Detailed Coverage Area. Main metropolitan areas in the Lower 48 states, and Southern Canada are mapped to this level. See the Navigation Owner's manual for a list of these areas.
DTC | Diagnostic Trouble Codes. Use the HDS tablet to obtain, and troubleshoot the cause of these codes.
Dead Reckoning | The use of the speed signal, and yaw rate sensor to position the vehicle on the map even when the GPS signal is obscured by tall buildings, or while driving in a tunnel.
Digitized Road | A road that appears on the navigation screen. The road name will appear at the bottom of the navigation screen. If the user drives ‘‘off road'', the navigation system will display ‘‘Not on a digitized road'', and if 1/2 mile, then ‘‘breadcrumbs'' will appear.
Disclaimer Screen | Screen containing cautionary information. It is meant to be read carefully and acknowledged by the customer when using the navigation system.
DVD or DVD-ROM | Digital Versatile Disk. The navigation program and database resides on this disk. See the Navigation Owner's Manual for information on how to order a replacement or update DVD.
ECM | Engine Control Module. Typically referred to as the PCM.
E/T | Elapsed Time for the current trip as displayed by the trip computer screen.
FAQ | Frequently Asked Question. See the Navigation Owner's Manual for a list of the customer FAQs, and troubleshooting information.
F-CAN | Fast CAN Bus (see CAN)
FE | Fuel Economy value as displayed on the trip computer screen.
Fuel Pulses | This signal is transmitted on the CAN bus, and is used by the Trip Computer to calculate the fuel economy.
GA-Net bus | Units communication line.
GPS | Global Positioning System. A network of 24 satellites in orbit around the earth. The navigation system can simultaneously receive signals from up to 12 satellites to accurately position the vehicle on the map.
HDS | Honda Diagnostic System. A hand held tablet PC for use in diagnosing vehicle problems. This device can be used to obtain DTC codes for diagnosis of navigation system CAN related problems.
H/U | Head Unit. The navigation system display unit assembly in the dash.
Initialization | This refers to the period needed to re-acquire the GPS satellite orbital information whenever the navigation system power has been disconnected. This can take from 10 to 45 minutes.
LCD | Liquid Crystal Display (the navigation screen)

Item | Definition
--- | ---
Map Matching | The received GPS information allows the navigation system to position the vehicle on the map. Map matching has occurred if the map screen is displaying the current street name in the bottom-shaded area.
Mic | Abbreviation for the microphone used for receiving voice commands. It is located near the map light in the ceiling.
Model (in the diagnosis Version screen) | A ‘‘model code'' stored on an internal ‘‘chip'' in the navigation unit. The model code tells the navigation unit what software to load. Every navigation unit ‘‘model'' has a unique part number for the navigation unit.
MW | Maneuver Window. While on-route to a destination, this window displays information about the next maneuver.
Navi | Abbreviation for the Navigation System
Off Route | This occurs when the user leaves mapped roads. Off road tracking dots (‘‘breadcrumbs'') are displayed if the option is enabled in Setup. The user can use them to return to a mapped road. The bottom of the navigation screen will say ‘‘Not on a digitized road''.
Outlying Areas | These are rural areas that typically have only their main roads mapped. All other roads are shown in light brown for reference only, since they have not been verified.
PC Card Slot | The PC Card (PCMCIA, type II) slot is for factory use only.
PCM | Powertrain Control Module. This unit supplies the navigation system speed signal, and sends fuel pulses for the trip computer function via the F-CAN network.
PCMCIA | A computer industry defined term referring to the PC Card slot standard.
PIN | Personal Identification Number. A random 4 digit number created by the customer to protect personal information.
POI | Point Of Interest. These are the businesses, schools etc. found under the ‘‘places'' option on the main menu.
Polygon | Colored areas on the map screen denoting parks, schools etc. See the Navigation Owner's Manual ‘‘Traveling to Your Destination'' for a list of the assigned colors.
QWERTY | Keyboard layout resembling the typewriter keys. The keyboard layout can be changed to an alphabetical layout in the Setup mode.
SCS connector | The 2-pin connector used to put the navigation system into the diagnostic mode.
Touch Switches or Touch Sensor | The navigation screen is covered by a clear film that has 1 vertical resistor and 1 horizontal resistor. When the user pushes on the screen, the voltage is read across the resistors and the desired function is selected.
Tuning | A continual update of internal navigation system scaling factors. See the individual sensor tuning discussions under either ‘‘System Description'', or ‘‘System Diagnosis Mode'' in this manual.
Unverified Streets | These streets have not been verified for turn restrictions, one-way, etc. They are shown in light brown on the map. You can enter address destinations in these areas, but voice guidance ends at the last verified street closest to your destination.

Item | Definition
--- | ---
Verified Streets | These streets consist of the detailed metropolitan coverage areas, and all other inter-town connection roads. These roads are shown in black on the map.
VP | Vehicle Position. When in map mode, this circular icon shows the vehicle position on the map. Touch this icon to show the latitude, longitude, and elevation of your current position.
VR | Voice Recognition. This allows voice control of many of the navigation functions. The hardware consists of the microphone, steering wheel (Talk/Back) buttons, and the front speakers. See the overview for more information.
VSP | Vehicle Speed Pulse. This pulse signal coming from the PCM is used to update the Vehicle position on the map, and to calculate the trip computer fuel economy. These pulses do not indicate direction (forward or backward). When in reverse, the navigation receives a signal from the MICU and directs the VP to move backwards on the map.
VSS | Vehicle Speed Sensor. This sensor reads the output shaft speed at the transmission and, provides a speed pulse to the PCM. The PCM sends this pulse to the navigation system and speedometer.
Yaw Sensor | This device is located in the navigation system control unit and senses the side-to-side twisting force generated when the vehicle turns.