Bright Ideas: Adaptive Cruise Control

It’s a smooth ride behind the wheel of the upmarket VW Phaeton, but then add the optional adaptive cruise control (ACC) system from TRW and you’ve got yourself a bonafied dream cruise.

Developed by Autocruise, originally a joint venture between TRW Automotive and the Thales Group and now under the sole ownership of TRW, the first generation ACC debuted on the 2002 Phaeton and the option is selected in better than 20 percent of the Phaetons sold.

The system effectively identifies and tracks the nearest vehicle up to 150 meters ahead, adaptively accelerating or decelerating to maintain a safe stopping distance. The driver selects the desired cruise control speed as with any system and the ACC system takes it from there making adjustments continuously in imperceptible increments.

This is a true radar system, not infrared, so it has all weather functionality.

A Transmit Receive Module (TRM) and Monolithic Microwave Integrated Circuitry (MMIC), are at the heart of the ACC. MMIC chips were initially developed for defense and telecommunications.

The first generation AC 10 will soon be replaced by the second generation AC 20 system which is smaller, lower cost and also has greater functionality. The AC 20 has “follow to stop” capability, meaning the system will brake the vehicle to a complete stop without driver intervention.

The new low power AC 20 system, less than 10 mW, operates at a frequency of 76-77 GHz with a ranging precision of 5 percent, relative speed measurement from 0-180 km/h, speed measurement precision of 0.2 km/h, with a search area of 12 degrees.