Description
Parking Aid
CONTROL DIAGRAM - PARKING AID
CONTROL DIAGRAM - PARKING AID CAMERA
PARKING AID
The parking aid module receives and ignition power mode 6 supply from the RJB (rear junction box).
The parking aid module is connected to the entertainment system control module by the medium speed CAN (controller area network) bus and the Media Orientated System Transport (MOST). The entertainment system is used by the parking aid system to provide the driver with an audible warning. If an obstacle is sensed by the rear parking aid sensors, the rear audio system speakers will sound. If an obstacle is sensed by the front parking aid sensors (if fitted), the front audio system speakers will sound.
The parking aid system operates using ultrasonic signals which are transmitted by the sensors. The reflected echo from this output is received by the sensors and used by the parking aid module to calculate the distance from an object.
When the parking aid module activates the system, the switch LED (light emitting diode) is illuminated to indicate that the system is operating. The parking aid module then processes signals received from the sensors to determine if there is an object with the detection range of the sensors. A parking aid screen is automatically displayed in the Touch Screen Display. If the vehicle has a parking aid camera fitted, the camera display is automatically displayed in the TSD in preference to the parking aid alert display. To view the parking aid sensor display, a single touch of the TSD screen will remove the camera image display and show the parking aid alert display.
Parking Aid Alert Display
In the combined mode, the sensors emit a series of ultrasonic impulses and then switch to receiver mode to receive the echo reflected by an obstacle within the detection range. The received echo signals are amplified and converted from an analogue signal to a digital signal by the sensor. The digital signal is passed to the parking aid module and compared with pre-programmed data stored in an EEPROM (electrically erasable programmable read only memory) within the module. The module receives this data via the signal line from the sensor and calculates the distance from the object using the elapsed time between the transmitted and received impulse. The duration of the impulse duration is determined by the module, with the sensor controlling the frequency of the impulse output.
In receiver mode, the sensor receives impulses that were emitted by adjacent sensors. The module uses this information to precisely determine the position and distance of the object.
If no objects are detected there are no further warning tones. If an object is detected, repeated audible tones are emitted from either the front or rear audio speakers as appropriate. The time delay between the tones decreases as the distance between the object and the vehicle decreases, until at approximately 250 mm (10 inches), the audible tone becomes continuous.
If, after the initial detection of an object, there is no decrease in distance between the object and the vehicle, the audible warning tones remain constant if the object is detected by a central sensor or stops after 3 seconds if the object is detected by a corner sensor.
The audible tones will stop if the vehicle is moved out of reverse gear. The module continues to monitor the distance and will resume the warning tones if a decrease in distance is detected.
The volume output of the parking aid audible tones can be adjusted by selecting the 'Vehicle Settings' menu and selecting 'Parking' from the menu on the TSD. The volume can be adjusted using the + or - selections on the TSD.
System operation is cancelled when the parking aid switch is pressed or the ignition is switched off. System operation is also cancelled if the vehicle travels more than 50 m (164 ft) or the vehicle forward speed exceeds 30 km/h (19 mph).
The system can detect when a trailer is connected to the vehicle by a message output on the medium speed CAN (controller area network) bus from the trailer module. When the parking aid module detects that a trailer is connected to the vehicle, the rear sensors are disabled to prevent constant warnings due to the close proximity of the trailer.
The parking aid module also incorporates software that compensates for the effects of frost, ice or rain on the sensors. Ice compensation occurs if the ambient temperature, received on a medium speed CAN (controller area network) bus message from the instrument cluster, is less than 6°C (43°F).
Distance Calculation
An intermittent warning tone is emitted once the object is within the detection range for the particular sensor. When the object is 250 mm (10 inches) from the sensor, the tone changes to a continuous tone.
The maximum detection range for the front sensors is 800 mm (31 inches) for the central sensors and 600 mm (23.5 inches) for the corner sensors.
The maximum detection range for the rear sensors is 1800 mm (70 inches) for the central sensors and 600 mm (23.5 inches) for the corner sensors.
PARKING AID CAMERA
The parking aid camera receives an ignition power mode 6 power supply from the RJB (rear junction box). It also has a LIN (local interconnect network) bus connection from the RJB (rear junction box) which is not used at the moment but installed for a later enhancement of the parking aid camera.
A shielded co-axial cable connection between the camera and the Touch Screen Display (TSD) is used for the video image transmission.
The camera receives power at all times when the ignition is in power mode 6. When reverse gear is selected, the RJB (rear junction box) transmits a reverse selected signal on the medium speed CAN (controller area network) bus message to the entertainment system control module. This message is transferred on the MOST to the TSD which displays the parking aid camera video input from the camera in preference to the parking aid alert screen.
If the driver does not require the camera image in the TSD, a single touch on the screen will revert the display to the parking aid alert screen. The camera view can be reselected by pressing the 'Rear Camera' softkey on the TSD.
When reverse gear is deselected, the camera image remains on the TSD for 10 seconds after the transmission has been put into drive 'D'. This is to prevent the TSD switching between screens if the vehicle is being manoeuvred into a parking space. If the vehicle forward speed exceeds 16 km/h (10 mph) within the 10 second period, the camera image is removed from the TSD.
If the TSD display is switched off, the camera image will be automatically displayed when reverse gear is selected. When reverse gear is deselected and the 10 second period has expired, the TSD will revert back to its switched off state.
PARKING AID
Two levels of parking aid system can be fitted; a rear only system or a front and rear system.
The parking aid system provides an audible warning to the driver when any obstacles are in the path of the vehicle during forward (if front sensors are fitted) or reverse parking maneuvers. The system consists of four ultrasonic sensors in each bumper, a parking aid module and a parking aid switch.
At low speeds, the parking aid module uses the ultrasonic sensors to monitor the area around the front and rear bumpers. If an object is detected within a monitored area, the module then outputs a warning using the audio system speakers. The sensors can detect solid objects such as posts, walls and other vehicles and can also detect less solid objects such as a wire mesh fence. Objects very close to the ground may not be detected, but because of their low height may not cause damage to the vehicle.
The parking aid system comprises the following components:
- Parking aid module
- Parking aid switch
- Eight parking aid sensors.
The parking aid module communicates via the medium speed CAN (controller area network) bus with the audio system via the integrated audio module. The audio system then outputs the applicable warning tones from the front or rear speakers when an object is detected. The medium speed CAN (controller area network) bus is also used to collect vehicle data from other vehicle systems.
Parking Aid Module
The parking aid module is located on the LH (left-hand) side of the luggage compartment.
The parking aid module has three connectors which provide for power, ground and CAN (controller area network) bus connections, front parking aid sensors and rear parking aid sensors. The medium speed CAN (controller area network) bus connections provide for the receipt of the following information from other systems:
- ABS (anti-lock brake system) module - Road speed signal
- TCM (transmission control module) - Reverse gear engaged signal
- Trailer module - Trailer attached to vehicle
- Instrument cluster - Ambient temperature signal.
The module also outputs messages on the medium speed CAN (controller area network) bus which are received by the integrated audio module. The integrated audio module processes these messages and converts them into Media Orientated System Transport (MOST) signals which are passed to the audio system power amplifier. These signals are then used by the power amplifier to emit the applicable warning tones from the front or rear audio speakers when an object is detected by the front or rear parking aid sensors. A warning tone can also be emitted to alert the driver to a fault in the parking aid system.
The parking aid module performs self check routines and when the system is active checks the sensor wiring for short or open circuits. If a fault is detected a code is stored in a memory in the module and if necessary either the front and/or rear sensors can be disabled. The driver is made aware of any fault condition by the parking aid switch LED (light emitting diode) flashing and a continuous warning tone being emitted for 3 seconds, in place of the normal short tones when the system is functioning normally. Fault codes can be read using an approved Jaguar diagnostic system via the diagnostic socket.
Parking Aid Sensors
Four ultrasonic sensors are located in the front and rear bumpers. Each sensor comprises a sensor and a bumper insert. The insert ensures that each sensor is correctly orientated in relation to its location in the bumper.
Each sensor has a three pin connector which mates with a bumper harness, which in turn is connected to the main body harness. Three pins provide for power supply, ground and signal lines to and from the parking aid module.
Each sensor comprises a plastic housing which contains a piezo electric disc. The disc resonates at a frequency of 34.8kHz, producing the ultrasonic output. The disc also receives the reflected echo signal from any objects within range.
The parking aid module controls the operation of each sensor using a digital output on the signal line. The module controls the sensor in one of two modes; combined transmitter and receiver mode or receiver mode only.
Parking Aid Switch
The parking aid switch is located in the instrument panel switch pack, above the touch screen. The switch is the LH (left-hand) switch with an integral LED (light emitting diode).
The switch is a non-latching push switch which allows the driver to select the parking aid system on or off. When pressed, the switch momentarily connects a ground to the parking aid module.
The LED (light emitting diode) indicates when the parking aid system is active. The LED (light emitting diode) is controlled by the parking aid module. The switch allows the driver to disable the parking aid system when reverse gear is selected or to activate the parking sensors when not in reverse gear.
If a fault exists in the parking aid system, the LED (light emitting diode) flashes continuously when reverse gear is selected or the driver selects the parking sensors on, using the switch.
PARKING AID CAMERA
The parking aid camera is located on a bracket which is attached to the luggage compartment lid finisher.
The camera is connected to the vehicle harness by one 3 pin connector for the power, ground and LIN (local interconnect network) bus and a second connector for the video co-axial cable.
the camera produces color images to an analogue NTSC format, with a resolution of 640 x 480 pixels and an aspect ratio of 4:3.
The image captured by the camera is mirrored to give the driver a true representation of the rear view on the TSD.