C 350 (204.056) V6-3.5L (272.961) (2008)
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after vehicle transport (e.g. by train or ferry or after towing).
Relocating with GPS (after interruption of satellite reception) may require several minutes (up to 20 min when emergency call system control unit is
commissioned).
Basic position finding runs parallel to GPS position finding.
The following points are vehicle tracking objectives:
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Retrieval of stolen or misappropriated vehicles
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Fast assistance in event of a "car jacking"
The position finding function consists of the following subfunctions:
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GPS position finding function sequence
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Basic position finding function sequence
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Vehicle tracking function sequence
GPS position finding function sequence
The GPS receiver integrated into the emergency call system control unit receives the GPS signals from the multifunction antenna (A28/11) in the
following way:
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Discrete line
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Global positioning system antenna splitter (A2/5), with code (512) COMAND APS with DVD changer
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Discrete line
The GPS signals are used by the emergency call control 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.
Basic position finding function sequence
For basic position finding, the emergency call control unit requires the following information:
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Wheel speed signals
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Distance traveled data
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Vehicle alignment (cardinal points)
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Direction of travel data (forwards or backwards)
The wheel speed signals are recorded by the following rpm sensors:
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Left front axle rpm sensor (L6/1)
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Right front axle rpm sensor (L6/2)
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Left rear axle rpm sensor (L6/3)
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Right rear axle rpm sensor (L6/4)
The wheel speed signals from the rpm sensors are received by the emergency call system control unit in the following way:
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Discrete line
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ESP control unit
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Chassis CAN
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Front SAM control unit with fuse and relay module (N10/1)
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Diagnostic CAN
The distance traveled data from the instrument cluster (A1) is received by the emergency call system control unit in the following way:
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Interior CAN
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"Master control unit"
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Interior CAN
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Front SAM control unit with fuse and relay module
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Diagnostic CAN
The vehicle alignment data (cardinal points) is internally processed by the emergency call system control unit's integrated turn rate sensor (gyro sensor).
The direction of travel data (forwards or backwards) is received by the emergency call system control unit via the diagnosis CAN from the front SAM
control unit with fuse and relay module.
After this the emergency call system control unit uses the distance traveled, the vehicle alignment and the direction of travel to calculate the vehicle
position (degree of longitude and degree of latitude) at any given time.
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 navigation processor integrated into the emergency call system control unit when it receives
GPS data.
