Object Detection Description and Operation Except Holden
Parking Assist System (PAS) is an electronic system designed to provide an acoustic tone informing the driver of obstacles at or near the rear of the vehicle during low speed manoeuvres such as parking. The PAS consists of 3 ultrasonic object sensor assemblies mounted to the rear bumper fascia, an electronic control module and alarm assembly mounted to the driver side of IP tie bar. Sonar is used to detect the presence of obstacles within a defined area by measuring the time between the transmission and reception of sound waves.
When reverse gear is selected, the sensors transmit short ultrasonic pulses and then listen for an echo reflected from an object within range. The electronic control module uses echo data from one or more sensors to calculate the distance to the obstacle. The PAS only signifies the closest detected object.
When the ignition is on and reverse gear is selected, a tone will sound from the alarm (1 time for 0.05 second). The control module provides a voltage to each sensor sequentially which is converted into an ultrasonic pulse. Where an object is within the detection range, the ultrasonic pulse is reflected (echoed) and received by the same and/or adjacent sensors. The echoes are amplified, processed and returned to the control module as a digital signal. The control module processes this information and informs the driver of the object by activating an intermittent acoustic tone through the alarm. The sensors are mounted onto the rear bumper fascia in an arrangement that provides a slight overlap of the polar patterns. This provides the best coverage of the detection area. The maximum detection distance is 120 cm.
Object Detection Description and Operation Holden Genuine Accessory
The ultrasonic rear parking assist system is designed to identify and notify the driver of an object in the vehicle's path when reversing. The distance and location of the object is determined by object alarm sensors located in the rear bumper.
When the object detection system detects an object, the driver is notified through a series of buzzer sound from the object alarm indicators.
The rear object detection system is made up of the following components:
| • | Object alarm module |
| • | Object alarm sensors |
| • | Object alarm indicator |
Object Alarm Module
The object alarm module provides an 8-volt reference and a low reference to the object alarm sensors. The object alarm module receives individual signals from each of the object alarm sensors and determines the location and distance of an object based on these inputs. When an object is detected, the object alarm module activates the object alarm indicator.
Object Alarm Sensor
The parking assist sensors are located the in rear bumper of the vehicle. The sensors are used to determine the distance between an object and the rear bumpers. Each sensor emits an ultrasonic frequency which is reflected off object located behind the vehicle. These reflections are received by the sensors. The time difference between when the frequency was emitted and when the reflection is received, known as sensor ring time, is used to determine the distance to the object. The sensors report this information to the object alarm module.
Object Alarm Indicator
The object alarm module controls the buzzer sound produced by the object alarm indicator to indicate how close the vehicle rear bumper is to an object.
The object alarm indicator can be switched to the following settings:
| • | HIGH |
| • | LOW |
| • | OFF |
Rear Object Detection Distance and Buzzer Sounds
Distance M | Duration ON (MS) | Duration OFF(MS) |
|---|---|---|
Less than 0.45 | Continuous | -- |
0.45-0.90 | 75 | 75 |
0.90-1.50 | 75 | 150 |
Rear Object Detection Activation
To activate the object detection system the following criteria must be met:
| • | Ignition is ON. |
| • | Reverse gear is selected. |
To confirm the activation of the object detection system, two short buzzer sounds will be heard from the object alarm indicator.
Rear Object Detection System Deactivation
Automatic Deactivation
If the vehicle is fitted with a genuine Holden trailer harness, the rear object detection system is automatically disabled when the electrical connector of the trailer is connected to the vehicle.
Manual Deactivation
When towing trailers or caravans using non-compatible wiring harness; or when bike racks are fitted, the Rear Object Detection System can be manually deactivated by turning OFF the object alarm indicator switch.
