Time-to-Contact control for safety and reliability of self-driving cars

For safety and reliability of self-driving cars, their control system must use the relative velocity of vehicles. The relative velocity can be estimated by differentiating the measured distance between cars with respect to time. However, inevitable measurement noise in the distance measurements will be amplified by the derivative operation. In this paper, we provide, as an alternative, a time-to-contact based approach to estimating the relative velocity, which can also be fused with measurements from other sensors, if desired. The system is implemented on Android smart phones running in real-time.