Automotive radar device

Abstract

An automotive radar using combinations of the techniques of alternating transmit-receive bursts of digitally frequency modulated millimeter wave carriers; sparse MIMO antenna arrays with sidelobe-suppressive coarse and fine beamforming; frequency hopping; range-walking-compensated Doppler analysis and successive, and subtractive target detection in signal strength order.

The embodiments of the invention in which an exclusive property or privilege is claimed are defined as follows: 
     
         1 . An radar sensing system comprising:
 a transmitter configured to transmit radio signals;   a dual-polarized receiver configured to receive radio signals of two polarizations that include (i) the transmitted radio signals transmitted by the transmitter and reflected from objects in an environment, and (ii) other radio signals that include radio signals transmitted by at least one other radar sensing system;   wherein the dual-polarized receiver is configured to process the received radio signals of both polarizations and to segregate wanted targets from interference by using polarization differences.   
     
     
         2 . The radar sensing system of  claim 1 , wherein the dual-polarized receiver is configured to segregate received signals by direction of arrival and adapted to perform said segregation by polarization differences separately for each direction of arrival. 
     
     
         3 . The radar sensing system of  claim 1  further comprising a receive antenna array communicatively coupled to coarse beamforming to perform the segregation by direction of arrival. 
     
     
         4 . The radar sensing system of  claim 1 , wherein the dual-polarized receiver is configured to separate received signals into spectral components, and further configured to perform the segregation by polarization differences separately for each spectral component. 
     
     
         5 . The radar sensing system of  claim 1 , wherein the dual-polarized receiver is configured to separate receive signals into spectral components and further into directions of arrival for each spectral component and configured to apply the segregation by polarization differences separately for each combination of a spectral component and a direction of arrival. 
     
     
         6 . The radar sensing system of  claim 1 , wherein the transmitter is configured for installation and use on a vehicle, and wherein the dual-polarized receiver is configured for installation and use on the vehicle. 
     
     
         7 . A radar sensing system comprising:
 a transmitter configured to transmit radio signals;   a receiver configured to receive radio signals that include (i) the transmitted radio signals transmitted by the transmitter and reflected from objects in an environment;   wherein the receiver is configured to reduce interference to wanted signals by separating received signals by any combination of the domains of polarization, direction of arrival and frequency components using reversible transforms, further configured to null or deemphasize separated components deemed to contain interference and then to recombine the remaining separated components using reverse transforms for further processing to detect radar targets.   
     
     
         8 . The radar sensing system of  claim 7 , wherein the transmitter and receiver are configured to transmit and receive alternately in bursts, wherein the separation of received signals in multiple domains with interference reduction per separated component being adapted on a per burst basis. 
     
     
         9 . The radar sensing system of  claim 7  comprising a plurality of transmitters and a plurality of receivers, wherein the plurality of receivers are configured to reduce interference to other non-collaborating radars of the same or different design, wherein each transmitter of the plurality of transmitters is configured to transmit the combination of a coded transmitter signal unique to each transmitter and a nulling signal. 
     
     
         10 . The radar sensing system of  claim 9  further comprising a first calculating unit configured to estimate composite interference from the transmitters that would be received at a number of desired null positions, and a second calculating unit configured to calculate, based the estimated interference signals, the nulling signals to be combined with each transmitter's uniquely coded signal so that the composite interference received in each of the null directions is nominally zero. 
     
     
         11 . The radar sensing system of  claim 9  comprising a receive antenna array communicatively coupled to each receiver of the plurality of receivers, wherein the plurality of receivers are each configured to process the received signals to combine the received signals from the antenna array to produce receive nulls in specific directions from which interference may be received. 
     
     
         12 . The radar sensing system of  claim 11 , wherein each of the plurality of receivers is configured to downconvert the received radio signals. 
     
     
         13 . The radar sensing system of  claim 7 , wherein the transmitter is configured for installation and use on a vehicle, and wherein the receiver is configured for installation and use on the vehicle. 
     
     
         14 . An automotive radar device adapted to operate in a MIMO mode, comprising:
 a plurality of transmitters communicatively coupled to associated transmit antennas and configured to transmit a sequence of I,Q samples generated by a transmit modulation generator, the sequence of I,Q samples for each transmitter having one or more different distinguishing features;   a plurality of receivers communicatively coupled to associated receive antennas and configured to receive radio signals that include transmitted radio signals transmitted by the transmitters and reflected from objects in an environment;   a virtual receiver (VRX) processing module configured to correlate each of the receive signals with each of the transmitter I,Q sequences to produce a plurality of VRX signals for each of a number of delays between the transmitter IQ signals and the receive signals; each VRX signal having apparently been received from a virtual antenna having coordinates equal to the sum of the underlying transmit antenna coordinates and the underlying receive antenna coordinates, the virtual antennas forming a virtual antenna array (VRX array);   a Doppler processing module configured to process each of the VRX signals as it changes from time to time to determine for each of the VRXs and each delay a number of Doppler frequency amplitudes; and   a digital beamforming module configured to jointly process the VRX signals corresponding to the same Doppler frequency and delay to further segregate signals by angle of arrival, wherein digital beamforming module is configured to reduce the sidelobes of the VRX array when the VRX array is a sparse array.   
     
     
         15 . The automotive radar of  claim 14  in which the sequences of IQ samples transmitted by the transmitters represent a signal modulated with a digital code, wherein the code bits are different for each transmitter. 
     
     
         16 . The automotive radar of  claim 14  in which the sequences of IQ samples transmitted by the transmitters represent a signal offset in frequency by a frequency hopping offset valid for a burst time period and varying between different burst time periods. 
     
     
         17 . The automotive radar of  claim 14 , wherein the transmitters are configured for installation and use on a vehicle, and wherein the receivers are configured for installation and use on the vehicle.