Random noise automotive radar system

Abstract

An automotive radar system for use with an automotive control system such as a collision avoidance or smart cruise control system, for example. A wide-bandwidth, random noise signal generated at an RF frequency that is transmitted by a transmitter and reflected from targets in the vicinity of the system. The random noise modulation is sampled prior to transmission in a noise source sampler and this sampled image of the transmitted noise is stored and passed through a series of delay stages that are formed in a correlator. The noise signal reflected from objects is processed by a homodyne receiver and also sampled in a receiver sampler. The noise samples from the signal return are passed to the correlator where they are cross correlated with the delayed images of the transmit noise. The output from the correlator for each unit of delay (range gate) is processed in a digital signal processor to find the range and closing velocity (Doppler frequency) of objects in the field of view. The output (range gate) of the correlator where the delay of the sampled transmit modulation equals the transmit delay of the signal transmitted from the radar system to the object and back, contains the range and closing velocity of the objects. At delays (ranges) where there are no objects to reflect the signal, the outputs of the correlator contain noise. Output signals from the digital signal processor are coupled to the automotive control system which processes the output signals to control the vehicle to avoid collision with the detected targets.