Circuit Description
Navigation SystemHow the Circuit Works (RTL, EX-L)
Diagram 156-5:
The navigation unit, navigation display, CD changer and audio unit are the main components of the navigation system. These 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.
Power Supply
Fuse 7 (in the under-dash fuse/relay box) 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 (in the under-dash fuse/relay box) to the navigation unit and to the navigation display.
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. 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 (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. 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 24 or more satellites supported by the U.S. Department Of Defense. 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.
NOTE: Window tinting, electronic accessories or loose items sitting on the dashboard can block the GPS signal reception entirely. The longitude, latitude and elevation may not always agree with other GPS based navigation systems.
GA-NET BUS
The GA-Net II communication bus is used by the navigation unit to communicate with the audio unit, CD Changer and XM receiver (if equipped). Any open or short in this bus will disable some, or all, of the components in the Navigation, audio or entertainment systems.
Display-Clock (in Audio unit)
The time is updated by the navigation unit, and is accurate to within 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 consist of manual selections of temperature, mode, or fan speed, and voice control commands issued by the driver. The "night mode" illumination signal is passed by B-Can to the HVAC unit, and then sent to the navigation control unit on the UART bus.
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. "Night" mode illumination can be overridden (canceled) by setting the dash illumination to the maximum brightness level. This signal is passed by B-Can to the HVAC unit, and then sent to the navigation control unit on the UART bus.
Rearview Camera (optional)
The optional 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 be used to adjust the brightness.
Navigation DVD (White labeled disc)
Only the white-labeled Navigation DVDs are designed to work in this navigation system. The navigation system DVD player cannot play or utilize black or orange labeled Honda/Acura DVDs other PC based navigation DVDs, mapping programs, Music CDs, or DVD movies. 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. If the DVD door is open or ajar, a "door open" error message is displayed.