GF82.61-P-2010LEJ Position Finding and Destination-Oriented Navigation, Function

GF82.61-P-2010LEJ Position Finding And Destination-oriented Navigation, Function
- with CODE (529) HIGH Class Japan


Function requirements
^ Status of "Circuit 30 ON" for Global Positioning System (GPS) position finding
^ Status "Circuit 15R ON", for basic position finding
^ COMAND control unit (A40/3) activated via the "ON" button (A40/9s6) on the front central operating unit (A40/9)
^ "Navi" menu selected
^ Destination has been entered
^ No error in GPS antenna system

General position finding
GPS is available worldwide. The GPS satellites permanently transmit time and position data (longitude and latitude). GPS position finding is irretrievable after vehicle transport (e.g. by train or ferry or after towing).
Basic position finding runs parallel to GPS position finding. The position finding function consists of the following subfunctions:
^ Function sequence for GPS position finding
^ Basic position finding function sequence
^ Destination-oriented navigation function sequence

Function sequence for GPS position finding
The global positioning system receiver is integrated into the COMAND controller unit. It receives the GPS signals from the GPS antenna (A2/49a2) over the following path:
- Direct line
- COMAND controller unit

The GPS signals are used by the COMAND controller unit to calculate the current vehicle position (receiver). In addition, the vehicle's direction of travel is determined with the aid of the sequence of the locations calculated with GPS.

Possible problems in GPS signal reception
Since GPS operates in the gigahertz (GHz) range (microwaves) and the signals are weak, reception interference can occur as a result of the following events:
- Atmospheric interference, e.g. inclement weather, water vapor, fog, snow
- Multiple path reception due to reflection of the signals
- Signal blocking, e.g. in built-over areas and in tunnels, through high-rise buildings, trees

Basic position finding function sequence
For basic position finding the COMAND controller unit requires the following information:
- Wheel speed signals
- Vehicle orientation (change in angle)
- Direction of travel data (forwards or backwards)
- Last position

The wheel speed signals are recorded by the following rpm sensors:
- Left front rpm sensor (L6/1)
- Right front rpm sensor (L6/2)
- Left rear rpm sensor (L6/3)
- Right rear rpm sensor (L6/4)

The wheel speed signals are received by the COMAND controller unit from the rpm sensors in the following way:
- Direct line
- ESP control unit (N47-5)
- Chassis CAN
- Central gateway control unit (N93)
- Central CAN

The travel distance data is also determined from the wheel speeds.
The vehicle alignment data (change in angle) is processed internally by the COMAND controller unit's integrated turn rate sensor (gyro sensor).

The data on the direction of travel (forward or back) is received by the COMAND controller unit from the central gateway control unit via the central CAN. The COMAND controller unit uses the travel distance covered to calculate the coupled position, taking the vehicle alignment into consideration as well as the direction of travel.
This coupled position is compared with the GPS data (longitude, latitude, direction). This position data is then compared with the map data (map matching).
Special features here are the "Two Layer Logic" and the "Parking Logic". The "Two Layer Logic" enables position finding in the case of overlapping roads (elevated road). The vertical angle (from 3D gyro) and the data of the Electronic Toll Collection System (ETC) gates and the Vehicle Information and Communication System (VICS) distance signals are also considered (dealer option). The "Parking Logic" (multi-level car park detection) enables fast position finding when leaving multi-level car parks.

Error during position finding
Basic position finding is falsified when a vehicle rolls backwards with "circuit 15 OFF" (ignition switched off) or if it is transported somewhere. In both instances the deviation is automatically corrected by the COMAND controller unit's integrated navigation processor upon reception of GPS data.

Destination-oriented navigation function sequence
The navigation is comprised of the following subfunctions:
^ Destination-oriented navigation function sequence through voice output
^ Destination-oriented navigation function sequence through visual display
^ VICS function sequence over FM multiplexer
^ Dynamic route guidance function sequence, VICS (dealer option)

Destination-oriented navigation function sequence through voice output
The integrated navigation processor continuously compares the route calculation data with the position finding data and uses the data to deduce measures for further destination-oriented navigation.

The navigation voice output is sent by the COMAND control unit via the MOST to the audio tuner control unit (N93/1) and from there - on model 221 - via direct lines to the following speakers:
- Left front door speaker group (H4/1), except code (810) Sound system
- Right front door speaker group (H4/2), except code (810) Sound system
- Left rear door speaker group (H4/3)
- Right rear door speaker group (H4/4)
- Bass box speaker (H4/17)
- Center cockpit speaker (centerfill) (H4/27)
- Left rear surround speaker (H4/54), with code (810) Sound system
- Right rear surround speaker (H4/57), with code (810) Sound system
- Left front door sound tweeter (H4/68), with code (810) Sound system
- Right front door sound tweeter (H4/69), with code (810) Sound system
- Left front door sound woofer and midrange speaker group (H4/72), with code (810) Sound system
- Right front door sound woofer and midrange speaker group (H4/73), with code (810) Sound system

The audio signals are emitted on model 216 by the audio tuner control unit via direct lines to the following speakers:
- Left door rear speaker (H4/3)
- Right door rear speaker (H4/4)
- Bass box speaker
- Center cockpit speaker (centerfill)
- Left rear surround speaker
- Right rear surround speaker
- Left door sound tweeter (H4/68)
- Right door sound tweeter (H4/69)
- Left door sound woofer and midrange speaker group (H4/72)
- Right door sound woofer and midrange speaker group (H4/73)

Destination-oriented navigation function sequence through visual display
The signals for visual display of the navigation (map navigation) are generated by the COMAND control unit and shown on the COMAND display (A40/8).

VICS function sequence over FM multiplexer
The driver is provided with vital information by the VICS on the current traffic situation. Traffic impairments and traffic jams are shown on the map, however they are not incorporated into the dynamic route guidance. The radio antenna signal path is as follows:
- Rear window antenna amplifier module (A2/12)
- Direct line
- Audio tuner control unit
- MOST
- COMAND controller unit

The VICS information is processed in the FM multiplexer integrated into the COMAND controller unit. Next, the information is shown on the COMAND display. In addition, the FM multiplexer can also receive additional information, e.g. on the weather or earthquakes.

Dynamic route guidance function sequence, VICS (dealer option)
The VICS control unit (A2/37) is required for "dynamic destination-oriented navigation", which is installed in the dashboard. The VICS function is integrated into the COMAND controller unit. The VICS antenna communicates in the microwave range (2.5 GHz) with the VICS beacons installed along the road (transmission antennas). Received signals are sent directly to the COMAND controller unit where they are decoded. The traffic messages are stored and provided to the integrated navigation processor. The navigation processor makes the decision whether the route should be changed. If necessary, a message that the route was changed is output via the vehicle speaker. The VICS signals are routed as follows:
- VICS antenna
- VICS control unit
- Direct line
- COMAND controller unit