Parking System, Function - GF54.65-D-0006TSA

Model 907

with code JB6 (Parking package with 360-degree camera)

Model 907

with code JB7 (Parking Package with reversing camera)

Block diagram

Function requirements, general

Circuit 15 ON
Engine running or drive train operational.
Vehicle speed < 10 km/h

The electronic ignition lock (EZS) control unit transmits the terminal status of terminal 15 via the suspension FlexRay to the parking system control unit.

The CDI control unit or the ME-SFI control unit sends the "engine running" signal or the "drivetrain operational" signal via the drive train CAN, powertrain control unit and chassis FlexRay to the parking system control unit.

The vehicle speed is calculated on the basis of the wheel speeds. The ESP® control unit sends the vehicle speed via the suspension FlexRay to the parking system control unit so that the deactivation behavior can be calculated.

Parking system, general

The parking system uses 12 PARKTRONIC sensors and the reversing camera (with code JB7 (Parking Package with reversing camera)) or the 360° camera system (with code JB6 (Parking Package with 360° camera)). The parking system assists the driver by:

Visual and/or acoustic warnings of objects in front of and behind the vehicle as well as at the sides of the vehicle
Speed limitation when driving off if obstacles are detected in the direction of travel (start-off assist).
Automatic braking to avoid collisions with traffic crossing the vehicle's path (vehicles, bikes and pedestrians with a minimum speed of 4 km/h) when reversing (with code JA7 (Blind Spot Assist))

The parking system is operated via the head unit.

The Audio/COMAND display shows the distances between the vehicle and the obstacle. Warning tones can also be issued.

Illustration of the principle (with code JB7 (Parking Package with reversing camera))

The Parking Package with reversing camera encompasses the following functions:

Backup camera
Park Assist

The reversing camera is an optical parking aid. Its tasks include the recording of images of the area to the rear of the vehicle, the generation of dynamic and static guide lines and the transmission of the picture data to the head unit. The area behind the vehicle is displayed on the head unit. Dynamic guide lines are displayed when reverse gear is engaged and according to the current steering wheel angle. The reversing camera only switches on within a defined vehicle speed range (maneuvering speed) and only if the function has not been deactivated via the head unit.

Illustration of the principle (with code JB6 (Parking Package with 360° camera))

The Parking Package with 360° camera comprises the following functions:

360° camera system
Park Assist

The 360° camera system consists of 4 digital cameras. There is one camera in the radiator grille, one in each of the outside mirror housings, and one above the rear-end doors. The calculated distances to obstacles are indicated by means of static guide lines.

The parking system uses the picture data to generate various views of the vehicle's surroundings. The driver is shown these views in real time in the Audio/COMAND display. The views can be generated either from the picture of one camera or from the pictures of the four cameras, e.g. for the bird's-eye view of the vehicle. Depending on the view, guide lines are displayed to assist the driver.

The 360° camera system only switches on at a speed ≤ 30 km/h.

Park Assist

The Parking Assist is an electronic parking assistance system with ultrasound and uses 6 PARKTRONIC sensors in each of the front and rear bumpers to monitor the vehicle's surroundings. The Parking Assist indicates the distance between the vehicle and an obstacle visually and acoustically.

The Parking Assist is based on ultrasound measurement. The parking system control unit actuates the PARKTRONIC sensors directly.

These then emit ultrasonic waves. The ultrasonic waves reflected by an obstacle are received again by the PARKTRONIC sensors. The parking system control unit reads in the signals of the PARKTRONIC sensors directly and evaluates them.

In principle a distinction is made between two measurements. On the one hand the direct measurement resulting from a direct echo and on the other hand the indirect distance measurement which is achieved by means of a cross echo (see illustration of the principle of the measuring procedure).

Echoes can usually also be received from adjacent PARKTRONIC sensors due to the large detection angles of the PARKTRONIC sensors; these are known as cross echoes. These occur at the obstacle due to scattered reflection.

With the help of the triangulation method, the distance from the vehicle to an obstacle can be calculated from two echo signals. The propagation times of the signals from the direct measurement and from the cross measurement are required for this method. A long signal propagation time therefore corresponds to a large distance, and a short signal propagation time corresponds to a short distance to the obstacle.

Illustration of the principle for measuring procedure

The Parking Assist cannot work correctly in certain cases due to the function principle (transmitting and receiving sound waves). So, for example, when approaching a highly sound-absorbent obstacle (e.g. a vehicle covered in snow), it is possible that false data may be displayed.

If the Parking Assist is not switched on and an obstacle is detected in the vehicle's path, a window appears in the Audio/COMAND display at speeds ≤ 10 km/h.

Input factors

The parking system control unit evaluates among others the following input factors:

Tml. 15 status (function requirement)
"Engine running" or "drivetrain operational" signal (function requirements).
Vehicle speed/acceleration/direction of travel (function requirement)
Reverse gear engaged (with manual transmission) or drive range engaged (with automatic transmission) (function requirement)
Status of parking brake, brake and ESP®
Status of trailer operation (with code E40 (Trailer socket, 7-pin) or with code E43 (Trailer socket, 13-pin))
Status of Blind Spot Assist (with code JA7 (Blind Spot Assist))
Blind Spot Assist warning (with code JA7 (Blind Spot Assist))
Blind Spot Assist braking request (with code JA7 (Blind Spot Assist))
Steering wheel angle and steering wheel velocity
Accelerator pedal position
Status of the front doors

Tml 15 status:

The EZS control unit sends the terminal status of terminal 15 via the suspension FlexRay to the parking system control unit.

Signal "Engine running" or "Drive train operational"

Vehicle speed/acceleration/direction of travel:

The vehicle speed and deceleration are calculated from the wheel speeds. The direction of travel is defined using the wheel rotation direction. The ESP® control unit sends corresponding information via the suspension FlexRay to the parking system control unit.

Reverse gear engaged (with manual transmission) or drive range engaged (with automatic transmission):

Manual transmission:

Engaging of the reverse gear is detected by the backup lamp switch. The powertrain control unit reads in the signal from the reversing lamp switch directly, uses it to generate the "Reverse gear engaged" signal and sends this via the suspension FlexRay to the EZS control unit.

Automatic transmission:

The fully integrated transmission control (VGS) electric controller unit (model 907) sends information about the engaged drive range via the powertrain CAN, the powertrain control unit and the suspension FlexRay to the parking system control unit.

Status of electric power steering, front wheel angle:

The electric power steering (ES) control unit sends the status of the electric power steering via the suspension FlexRay to the parking system control unit.

Status of parking brake brake and ESP®

The ESP® control unit sends the relevant status via the suspension FlexRay to the parking system control unit.

Trailer recognition (with code E40 (Trailer socket, 7-pin) or with code E43 (Trailer socket, 13-pin)):

When a trailer is detected, the trailer recognition control unit sends the "Trailer detected" status via the interior CAN, the EZS control unit and the suspension FlexRay to the parking system control unit.

Status of Blind Spot Assist (with code JA7 (Blind Spot Assist)):

The head unit sends the status of the Blind Spot Assist via the user interface CAN, the EZS control unit and the suspension FlexRay to the parking system control unit.

Blind Spot Assist warning (with code JA7 (Blind Spot Assist)):

The request to issue a warning is sent by the outer left front PARKTRONIC sensor or the outer right front PARKTRONIC sensor via a direct line to the parking system control unit.

Steering wheel angle and steering wheel velocity:

The steering wheel angle and the steering wheel velocity are detected by the steering wheel angle sensor. The steering column tube module (MRM) control unit reads in the signals from the integrated steering wheel angle sensor directly and sends the information about the steering wheel angle and steering wheel velocity via the suspension FlexRay to the parking system control unit.

Accelerator pedal position:

The powertrain control unit receives information about the accelerator pedal position from the accelerator pedal module (A68) and sends this via the suspension FlexRay to the parking system control unit.

Status of the front doors:

The driver door control unit and the front passenger door control unit send the status of the relevant door (open or closed) via the interior CAN, the EZS control unit and the suspension FlexRay to the parking system control unit.

Output factors

The parking system control unit outputs the following output factors:

Parking system status
Increase/reduce braking torque.
Request for control mode (limit vehicle speed)
Information on distance to obstacle (remaining distance to obstacle)
Request for braking mode
Request for surround lighting (with code JB6 (Parking Package with 360° camera))
Parking system indicator in the Audio/COMAND display
Output of system and warning messages.

Parking system status:

The parking system control unit sends the status of the parking system via the suspension FlexRay to the ESP® control unit and to the electric power steering (ES) control unit and additionally via the suspension FlexRay, the powertrain control unit and the powertrain CAN to the CDI control unit or the ME-SFI control unit.

Increase/reduce braking torgue:

The parking system control unit sends the request "Increase braking torque" or "Reduce braking torque" via the suspension FlexRay to the ESP® control unit. The ESP® control unit then directly actuates the traction system hydraulic unit, which increases or decreases the braking torque in accordance with the actuation.

Request for control mode (limit vehicle speed):

The parking system control unit sends the request "Limit vehicle speed" via the suspension FlexRay to the ESP® control unit.

Information on distance to obstacle (remaining distance to obstacle):

The parking system control unit sends information about the distance to the obstacle via the suspension FlexRay to the ESP® control unit.

Reguest for braking mode:

The parking system control unit sends the request "Braking mode" via the suspension FlexRay to the ESP® control unit.

Request for surround lighting (with code JB6 (Parking Package with 360° camera)):

The parking system control unit sends the request "Switch on surround lighting" via the suspension FlexRay, the EZS control unit and the interior CAN to the SAM control unit. The SAM control unit as the exterior lights master control unit then evaluates the ambient brightness. When it is dark, the SAM control unit sends a corresponding request via the interior CAN to the driver door control unit and the front passenger door control unit. They activate the ambient illumination in the outside mirror housings.

Parking system indicator in the Audio/COMAND display:

For a better representation of the camera pictures, the parking system control unit performs electronic distortion correction.

Output of system and warning messages:

The parking system control unit sends the requests to output system and warning messages via the suspension FlexRay, the EZS control unit and the user interface CAN to the head unit, which then outputs the corresponding system and warning messages via the Audio/COMAND display. In addition, the parking system sends the requests via the suspension FlexRay, the EZS control unit and the user interface CAN to the instrument cluster.

The description of the parking system is given in the following order as an example:

Activate and deactivate parking system.
Adjust warning tones.
Picture capture, picture output
Monitoring with reverse travel
Monitoring with forward travel
Start-off assist
"Rear Cross Traffic Alert" (with code JA7 (Blind Spot Assist))

Activate and deactivate parking system

The parking system is activated automatically when reverse gear is engaged (with manual transmission) or when drive range "R" is engaged (with automatic transmission).

Automatic activation/deactivation of the parking system must have been enabled at the corresponding operating level of the head unit. The head unit sends this status via the user interface CAN, the EZS control unit and the suspension FlexRay to the parking system control unit.

When shifting to the neutral position in vehicles with manual transmission, the previously shown picture continues to be shown on the Audio/COMAND display.

In vehicles with automatic transmission, the parking system is automatically deactivated when gear range "P" is engaged.

During initial startup and after replacement of the parking system control unit, a camera, an outside mirror or the radiator grille, the corresponding cameras must be recalibrated. After replacement of a camera, the parking system control unit has to be coded again.

The following situations lead to deactivation of the parking system:

Vehicle speed > 10 km/h
Engagement of drive range "P" (with automatic transmission)
Circuit 15 OFF

Adjust warning tones

The acoustic warnings can be set via the corresponding operating level of the head unit:

Volume of warning tones.
Determine when acoustic warnings are output:
It is possible to define whether the warning tones of the parking system are to be output at a relatively long distance from the obstacle.
Switch audio lowering on or off:
It is possible to define whether the volume of audio playback should be reduced during a parking system warning tone.

The head unit sends the status of the settings via the user interface CAN, the EZS control unit and the suspension FlexRay to the parking system control unit.

Picture capture, picture output

Vehicles with code JB7 (Parking Package with reversing camera):

The reversing camera (RFK) control unit sends the request to display the picture data via the user interface CAN to the head unit. The reversing camera (RFK) control unit also processes the recorded picture data and transmits them to the head unit. The head unit activates the Audio/COMAND display control unit via the telematics CAN and transmits the picture data via HSVL to the Audio/COMAND display control unit. The picture data is then shown on the Audio/COMAND display.

The reversing camera (RFK) control unit uses the steering wheel angle and stored vehicle parameters (lane and exterior contour of the vehicle) to calculate guide lines which are superimposed on the display.

The steering wheel angle is registered by the steering wheel angle sensor, which is integrated in the steering column tube module (MRM) control unit. The steering column tube module (MRM) control unit sends information about the steering wheel angle via the suspension FlexRay, the EZS control unit and the user interface CAN to the reversing camera (RFK) control unit.

Vehicles with code JB6 (Parking Package with 360° camera):

The pictures captured by the 360° cameras are read in by the parking system control unit via HSVL lines and processed. The parking system control unit calculates guide lines to be shown on the Audio/COMAND display taking into account the steering wheel angle and stored vehicle parameters. Additionally, the parking system control unit evaluates information from the 12 PARKTRONIC sensors, for example to mark the areas of the vehicle that are at risk during maneuvering.

The parking system control unit sends the request for picture output via the suspension FlexRay, the EZS control unit and the user interface CAN to the head unit. This then activates the Audio/COMAND display control unit via the telematics CAN. The parking system control unit then transmits the processed picture data via HSVL to the head unit. The head unit then transmits the data via HSVL to the Audio/COMAND display control unit. There the processed camera pictures including the guide lines are displayed.

For a better representation of the camera pictures, the parking system control unit performs electronic distortion correction.

Parking Assist:

Parking Assist can be operated in the following modes which can be selected by the driver:

Maneuvering mode
Trailer mode (with code E40 (Trailer socket, 7-pin) or with code E43 (Trailer socket, 13-pin))
Wde-angle mode

The corresponding selection is made via the operating menu of the head unit.

If the reversing camera was previously operated in maneuvering mode, the maneuvering mode is activated again when reverse gear or the "R" gear range is engaged. This function does not apply if the reversing camera was previously operated in trailer mode.

Object detection is active in the view "Full screen rearward field of view". Objects and pedestrians are marked by object detection lines (visual warning).

Maneuvering mode:

The maneuvering mode assists the driver when reversing while parking. To do so, dynamic guide lines are shown in the display in addition to the pictures recorded by the reversing camera.

To ensure that the surrounding area can also be recorded in the dark, the ambient illumination in each of the outside mirror housings is activated, irrespective of the ambient brightness.

Display of dynamic and static guide lines (with steered wheels)

Virtual steering angle (yellow lane):

As soon as the driver engages reverse gear or drive range "R", the virtual steering angle (21) is shown. It indicates to the driver the path that the vehicle would follow with the current steering wheel angle (current steering angle). This curve is automatically adapted as the steering wheel angle changes. The distance between the virtual steering angle (yellow lane) corresponds to slightly more than the width of the vehicle.

Trailer mode (with code F40 (Trailer socket 7-pin) or with code F43 (Trailer socket 13-pin)):

The trailer mode shows the ball head of trailer hitch. To do so, special guide lines are shown in the display in addition to the pictures recorded by the reversing camera.

Display of distance lines in trailer mode (with code E40 (Trailer socket, 7-pin) or with code E43 (Trailer socket, 13-pin))

Virtual steering angle (yellow guide line):

The virtual steering angle (yellow guide line) and the distance line (red guide line) are shown as soon as the driver engages reverse gear or the gear range "R". The virtual steering angle indicate to the driver the path which the vehicle would follow with the current steering wheel angle. This curve is automatically adapted to the situation as the steering angle changes. The length of the guide line corresponds to approx. 1 m.

Distance line around the ball head (red guide line):

The distance line (red guide line) is shown with a radius of 0.3 m around the ball head.

All the guide lines are hidden for an attempted correction (forward travel) and shown again when the reverse gear or gear range "R" is engaged again taking the following parameters into consideration:

Time period ≤ 255 s
Vehicle speed ≤ 10 km/h
Driving distance during forward travel ≤ 10m

The picture displayed disappears when these parameters are exceeded. The reversing camera then remains in standby mode.

The direction of travel is defined using the wheel rotation direction.

The vehicle speed is calculated from the wheel speed.

The ESP® control unit sends the corresponding information via the suspension FlexRay to the parking system control unit.

Wide-angle mode:

The wide-angle mode supports the driver when reversing in unclear traffic areas. The reversing area is shown in the Audio/COMAND display as a three-part view with an angle of α > 180°. This gives the driver a clear view of crossing roads in good time, e.g. when reversing out of narrow streets.

View of the area to the rear of the vehicle in wide-angle mode

360° views (with code JB6 (Parking Package with 360° camera)):

When the outside mirror housings are folded in, the areas on the side of the vehicle can no longer be recorded. The corresponding areas are also hidden in the Audio/COMAND display in this case.

The views shown on the Audio/COMAND display can be switched over both automatically and manually. Depending on the engaged gear or the engaged gear range, the display switches automatically between the frontward view and rearward view. In addition to automatic selection, the driver can also switch manually between the various detailed views via the head unit.

The "Vehicle from above" view also shows, for example, open doors. The picture data from the camera on the open front door are not shown.

Views in Audio/COMAND display

Vehicle top view and forward field of view

Vehicle top view and field of view of front wheels on both sides

Vehicle top view and rearward field of view

Vehicle top view and field of view for trailer coupling (with code E40 (Trailer socket, 7-pin) or with code E43 (Trailer socket, 13-pin))

System limits:

The functions and displays of the parking system are limited. Distortion and "blind spots" can occur.

In the "Vehicle from above" view, objects outside road level (e.g. vehicles) are displayed with distortion.

Objects in the "Full screen forward/rearward field of view" view (front camera and reversing camera active) are also shown with distortion. The assignment of objects in the picture to how they appear in real-life can therefore be unusual.

There are different Models of "blind spots" depending on the system and model in question. One reason is the camera position over the front bumper: Here, the camera loses the field of view immediately in front of the vehicle. On the other hand, they are system-related, particularly in the four overlapping areas of the fields of view of the cameras, when calculating a "Vehicle from above" view.

Furthermore, due to the low installation height of the cameras, there are areas where only objects close to the ground can be seen. This means, for example, that people are shown only to about knee height in the "Vehicle from above" view. In both cases, however, support is provided by the parking system.

Monitoring with reverse travel

During reverse travel the areas in front of and behind the vehicle are monitored. When the speed drops below the lower limit speed of 10 km/h, the parking system changes to measuring mode. When objects in front of or behind the vehicle are detected, the driver is warned visually by the lighting of the warning segments in the Audio/COMAND display and acoustically via the warning buzzer (for front) or the parking assistance system warning buzzer (for rear).

When the upper limit speed of 12 km/h is exceeded, the parking system changes back to standby mode.

The parking system control unit sends the request to show the parking system display in the Audio/COMAND display via the suspension FlexRay, the EZS control unit and the user interface CAN to the head unit. The parking system control unit actuates the parking assistance system warning buzzer directly (for rear) or sends the request to output a warning via the suspension FlexRay, the EZS control unit and the user interface CAN to the instrument cluster. The instrument cluster then actuates the warning buzzer directly (for front).

Monitoring with forward travel

When the upper limit speed of 10 km/h is exceeded, the parking system changes back to standby mode.

The parking system control unit sends the request to show the parking system display in the Audio/COMAND display via the suspension FlexRay, the EZS control unit and the user interface CAN to the head unit. The parking system control unit sends the request to output a warning via the suspension FlexRay, the EZS control unit and the user interface CAN to the instrument cluster. The instrument cluster then directly actuates the warning buzzer.

When driving forwards the area in front of the vehicle is monitored. When the speed drops below the lower limit speed of 10 km/h, the parking system changes to measuring mode. When obstacles are detected in front of the vehicle, the driver is warned visually by the lighting of the warning segments of the parking system indicator in the Audio/COMAND display and acoustically via the warning buzzer.

Additional function requirements for start-off assist (with automatic transmission)

Parking Assist switched on
Drive range change to R or D when stationary
Obstacle is less than 1 m away
No trailer operation

Start-off assist (with automatic transmission)

The start-off assist is intended to prevent a collision with a detected obstacle from occurring in the direction of travel when starting off as a result of the driver confusing the brake pedal with the accelerator pedal or engaging the wrong gear. If an obstacle is detected in the direction of travel while the vehicle is stationary, the speed during start-off is limited (speed limitation to 3 km/h for 1 m). This speed limit is performed via the speed interface in the ESP® control unit.

Additional function requirements for "Rear Cross Traffic Alert"

With CODE JA7 (Blind Spot Assist)
Vehicle speed < 10 km/h
Parking Assist switched on
"Blind Spot Assist" in "Assistance" menu activated
Reverse gear engaged

"Rear Cross Traffic Alert"

The "Rear Cross Traffic Alert" (with code JA7 (Blind Spot Assist)) issues a warning and applies the brakes if traffic crosses the vehicle's path and a hazardous situation arises. Crossing vehicles, motorcycles, bicycles and pedestrians with a minimum speed of 4 km/h are detected by the following PARKTRONIC sensors at the rear area of the vehicle:

Parktronic sensor, outer left rear
Parktronic sensor, outer right rear

The driver is warned of hazardous situations. If the driver does not react to this warning, the vehicle can be braked automatically.

Detection area of the radar sensor system

Electrical function schematic of parking system	Model 907 with code JB6 (Parking Package with 360° camera) or code JB7 (Parking Package with reversing camera	PE54.65-D-2055-97TSA
Overview of system components, parking system		GF54.65-D-9992TSA