ADAS Calibration

Vehicle crashes are measured in inches and not with the plus or minus tolerances of the vehicle specifications. For an ADAS system to operate at its full potential, it must be calibrated with the highest possible accuracy. If the sensors are misaligned, the further the vehicle is looking at the road, the greater the inaccuracy. This can affect all ADAS functions, such as AEB, Lane Keeping and Blind Spot Monitoring.

For example, most long-range radar sensors can see the street over two and a half football fields. So if the radar sensor is rotated even slightly by a bumper impact or misaligned thrust angle, it will look to the side of the road, not the center. Of course, medium-range radars can detect and classify obstacles or vehicles when they are within 65 feet. However, at this point, the radar has only one second to correct if the vehicle is traveling at 50 mph. This is why accuracy is important for more sophisticated ADAS systems.

What is the calibration procedure?

There are two types of calibration procedures, static and dynamic. Static calibration is performed with the vehicle parked in the shop. Dynamic calibration is performed with the vehicle in motion.

During static calibration, the procedure involves using targets of a certain pattern, shape or even thickness. The target is set at a certain distance, angle and orientation from the measured point on the vehicle. The vehicle knows what the target or equipment should look or sound like because it is programmed into the system at the factory. The scan tool activates this memory, so it can compare and adjust.

The dynamic calibration procedure involves driving the vehicle in a learning mode which is initiated by a scan tool. While the vehicle is being driven, sensors analyze input from various sensors for calibration. This involves the ADAS control module cross-reference radar, camera and vehicle dynamic inputs.

Proven Accuracy

With some ADAS equipped vehicles it is easy to find the ADAS calibration procedure in the service information. As long as your scan tool has the software and basic tools such as a plum bob, string, and tape measure, you should probably be able to calibrate the ADAS sensor. You may also need a decent printer to make targets.

The problem with this calibration procedure is that it was made for low mileage vehicles. Many of the measuring points used to match a vehicle to a target are emblems, license plates and bumper mounts. If you’re dealing with an older vehicle, these points may not be in optimal condition. In addition, some tools such as strings, plum bobs, or print targets are not precision tools. Getting to a ±3-5mm tolerance is difficult, to say the least.

Your next option is to use an ADAS kit. These tools are usually square vehicles using wheels. The wheel target resembles the camera target used for alignment. Using the wheels, alignment of the vehicle is much more accurate than points on the body.

Some systems can even use targets on all four wheels to verify alignment angles such as toe and thrust. In addition, some systems can look for problems with ride height using targets.

Once the equipment is adapted to the vehicle, technicians can set targets at the correct distance from cameras, radar or lidar sensors. The target and setting must be very precise.

As previously discussed, buried deep within the ADAS system software is what the optimal settings for camera or sound look like in the case of radar. The “perfect” results are then used to calibrate the sensor using internal electronic adjustments or external mechanical adjustments. If the target is misaligned or misaligned with the vehicle, the procedure may be aborted or the sensor may not calibrate accurately. This can lead to disabled ADAS features or false activation of the ADAS system.

Most kits are designed to work with proprietary scan tools. Unlike some OEM procedures, the software can guide technicians through the setup process and ensure targets are correctly set up for the vehicle before calibration begins.

However, ADAS calibration scanning tools and equipment do not get you past a basic vehicle inspection. Before starting, check sensors and other vehicle systems.

I’m not just talking about alignment angles, sensor mounts and ride height. Special attention needs to be paid to the other modules in the vehicle to ensure that each system is active and communicating. This is why scanning of all modules is so important for fast and accurate calibration. If the module has a communication code or low voltage, it needs to be resolved before calibration.

The most frequently overlooked item by technicians is the battery. If the battery is unable to maintain 12 volts or more during the calibration procedure, it will stop when the voltage drops. Some OEMs may recommend that a power supply be used during calibration.