The automotive navigation system is gaining momentum. Collision avoidance systems have been used at 70 GHz to detect objects in front of vehicles. The proposed concept is to use a similar principle for tracking and following moving vehicles. One application would be to lock on the vehicle ahead and maintain a safe distance without the driver control. Another application would be to use the tracking system as a means to tow a driverless vehicle or convoy of vehicles behind a leading truck.
Tracking systems have been used in radar and satellite application using Pseudo Mono-pulse Timed Multiplexed scanning antenna sensors. The proposed approach will use ultrasonic wave and array of sound transducers to measure the relative azimuth and elevation angles using a beacon sound signal from the leading vehicle. Only the relative azimuth angle and the time of flight between the two vehicles will be used to determine the feedback error signals.
Figure 1 is a block diagram of the proposed ultrasound system operating at frequencies from 20 KHz to 4 MHz. The two receivers are mounted at a slightly slanted angle to improve the gain of one transduce over the other. Both transducer signals are equal at the symmetrical plane. The starting prototype will use the TI EVM (Evaluation Module) and Renesas micro controller to read, scale, and display the horizontal gain of each transducer. The angle data can be extracted from the known transducer gain patterns. The angular signals will be processed and sent to the tracking vehicle’s attitude and speed control modules. In phase 2 of the prototype, 4 transducer will be used to improve the angular accuracy (not shown).
The application is unique and has not been implemented in automotive consumer products. The potential application for towing unmanned vehicle could be realized in shipyards, warehouses, and cargo industry as well as interstate highway systems.