Circuit Description
Navigation SystemHow the Circuit Works
The navigation unit and the navigation display are the main components of the navigation system. These two components communicate with each other through the GA-Net communication bus. The navigation unit generates the screen graphics, and then passes them to the navigation display as Red, Green, and Blue (RGB) color signals, and a sync signal.
Diagram 156-7:
System Diagram
Power Supply
Fuse 7 is hot at all times and supplies battery voltage to the navigation unit and to the navigation display. With the ignition switch in ACC (I) or ON (II), battery voltage is applied through fuse 32 to the navigation unit and to the navigation display. Both fuses are located in the driver's under dash fuse box.
User Controls
The navigation system can be controlled in three ways; (1) voice commands, (2) hard button inputs, and (3) touch screen inputs. The hard button and touch screen input information is communicated to the navigation unit from the navigation via the GA-Net communication bus. The voice commands are communicated to the navigation unit by the microphone in the roof console when the TALK switch on the steering wheel is pressed. The navigation unit compares the microphone signal with a library of stored voice files in order to find a match. Most of the navigation, audio, and HVAC functions can be controlled with voice commands. When the voice control system is in use, all of the speakers are muted, except the Rear Entertainment System (RES (DVD)) headphones. Refer to the Navigation System Owner's Manual, or to the "Voice Command Help" Information screen for a list of valid voice commands.
Navigation Function
The navigation system utilizes the GPS signals obtained by the GPS antenna, the vehicle speed signal from the PCM, and the yaw rate sensor contained in the navigation unit to get a user from a starting position to a destination position. The position of the vehicle icon on the map is determined jointly by the GPS signals, the vehicle speed and reverse signals, and the yaw rate sensor. The navigation system relies on DVD maps and points of interest (POI) in order to provide the user with the optimum route between starting and destination positions.
Route Guidance
When in 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. During navigation voice guidance prompts, the normal audio signal to the front speakers is muted.
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 5 V 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. Note: Window tinting, electronic accessories or loose items sitting on the dashboard can block GPS signal reception entirely.
GA-NET BUS
The GA-Net II communication bus is used by the navigation unit to communicate with the audio unit, XM receiver, CD Changer, and Rear Entertainment System (if applicable). Naturally, any open or short in this bus will disable some or all of the components.
Display-Clock
The time is updated by the navigation unit, and is accurate to a second. The time is automatically adjusted for daylight saving, and when driving across time zone borders. If necessary, settings can be adjusted in the navigation "Setup" menu.
Climate Bus (UART)
The climate bus connects the navigation unit with the front/rear climate control units. Data on this bus consists of manual selections of temperature, mode, or fan speed, and voice control commands issued by the driver.
Display mode (Day-Night)
The display has two modes, "Day" and "Night". This mode is selectable in Setup, as "Day", "Night", or "Auto". When in the factory default mode "Auto", the navigation unit uses the illumination signal (Headlights on) to automatically set the display to the "Night" mode. This "night mode" can be overridden by setting the dash illumination to the maximum brightness.
Rear Camera
The rear camera is automatically activated when the navigation unit detects the "reverse" signal. While viewing the rear camera image, the "Zoom In/Out" buttons can adjust the brightness.
Navigation DVD (White labeled disc)
Only white-labeled Navigation DVDs are designed to work in this navigation system. The navigation system DVD player cannot utilize Black or Orange labeled Honda/Acura DVDs. Other PC based navigation DVDs, mapping programs, Music CDs, or DVD movies will not operate. For information on ordering a new or replacement DVD, see the Navigation Owner's Manual.
PC Slot
This slot (located behind the DVD door), is for factory use and has no features that can be utilized by the customer. Do not insert anything in this slot unless instructed to do so by the factory.