Radar system with enhanced processing for increased contrast ratio, improved angular separability and accuracy, and elimination of ghost targets in a single-snapshot
A radar system with enhanced processing for increased contrast ratio, improved angular separability and accuracy, and elimination of ghost targets. The radar system is equipped with transmitters, receivers, pluralities of transmit antennas, and pluralities of receive antennas. The enhanced processing chain on-board the radar system iteratively detects target(s) by first finding the strongest target, subtracting the estimated received signal from the detected target, and repeating the process for subsequent targets until a predefined number of iterations is completed or an exit condition is tripped. The enhanced processing chain's subtraction increases the contrast ratio of detectable targets. The detection is thus refined by determining optimal azimuth, elevation, gain, and phase of each detection through a joint optimization of all detections. The subtraction and refinement aid in eliminating ghost targets by removing sidelobe signals and residual errors that cause ghost targets to appear.
1 . A radar system comprising:
a transmitter configured to transmit radio signals;
a receiver configured to receive radio signals that include the transmitted radio signals transmitted by the transmitter and reflected from objects in an environment;
wherein the receiver is configured to receive radio signals transmitted by other radar systems; and
wherein the receiver is configured to utilize an iterative target detection process operable to perform a target detection and parameter estimation process that iteratively detects targets in the received radio signals by detecting a target that is a strongest target, subtracting an estimated received signal from the detected target signal to calculate a residual error, and repeatedly detecting a next target that is a strongest target and subtracting the estimated received signal from the next detected target signal until at least one of a plurality of exit conditions is reached, wherein a first exit condition of the plurality of exit conditions comprises a completion of a selected quantity of iterations, such that targets in the received radio signals are detectable with signal strengths below a given sidelobe signal level.
2 . The radar system of claim 1 , wherein the receiver is configured to calculate radar data comprising increasingly smaller residual errors between an expected response of estimated detections and actual measured responses.
3 . The radar system of claim 1 , wherein the receiver is operable to perform the iterative target detection process to first perform conventional beamforming to find approximate parameters of a target and to then perform a joint estimation of target parameters for all targets for each new detection added to a detection list.
4 . The radar system of claim 3 , wherein the approximate parameters comprise azimuth/elevation angles, magnitudes, and phase of the target.
5 . The radar system of claim 3 , wherein the receiver is operable to take a ratio of the maximum conventional beamforming output to the mean conventional beamforming output and compare this ratio to a predetermined threshold and use the result as another exit condition of the plurality of exit conditions of the target detection process.
6 . The radar system of claim 3 , wherein the receiver is operable to compare a change in a residual norm between the current and prior iteration to a predefined threshold and to use the result as another exit condition of the plurality of exit conditions of the target detection process.
7 . The radar system of claim 3 , wherein the receiver is operable to compare the change in a residual norm between the current and prior iteration to a predefined threshold and the result is used as another exit condition of the plurality of exit conditions of the target detection process and to end the joint estimation.
8 . The radar system of claim 1 , wherein the receiver is operable to execute the entirety of an enhanced detection algorithm on the data collected within a single snapshot, and wherein the single snapshot is a single time-instance of radar data collection.
9 . The radar system of claim 1 , wherein the transmitter and the receiver are configured for use in a robot and/or a vehicle.
10 . The radar system of claim 1 , wherein the other radar systems comprise a known radar system.
11 . A radar system comprising:
a plurality of transmitters configured to transmit radio signals;
a plurality of receivers configured to receive radio signals that include the transmitted radio signals transmitted by the transmitters and reflected from objects in an environment;
wherein the receivers are configured to utilize an enhanced processing procedure to increase accuracy and reduce the presence of ghost targets;
wherein the receivers are configured to detect targets, and wherein the receivers are operable to detect a first target and to subtract a signal contribution from the first target from a measured antenna response, and to then iteratively detect one or more additional targets that are farther away than the first target which was previously undetectable before signal subtraction and subtract corresponding signal contributions from the one or more additional targets from the measured antenna response until at least one of a plurality of exit conditions is reached, and wherein a first exit condition of the plurality of exit conditions comprises a completion of a selected quantity of iterations; and
wherein the receivers are operable to jointly optimize estimated parameters of all previous detections before each subtraction, and wherein the receivers are configured to use the joint estimation to reduce residual errors which prevent ghost targets from being detected by the receivers.
12 . The radar system of claim 11 , wherein the estimated parameters comprise target azimuth, elevation, magnitude, and phase.
13 . The radar system of claim 11 , wherein the subtraction of the signal contribution increases a contrast ratio of detectable targets.
14 . The radar system of claim 11 , wherein the receivers are configured to jointly optimize the estimated parameters through a joint optimization of all target detections, thereby increasing the accuracy of the radar system.
15 . The radar system of claim 14 , wherein the target subtraction and refinement both aid in eliminating ghost targets by removing sidelobe signals and residual errors which cause ghost targets to appear.
16 . The radar system of claim 11 , wherein the transmitters and receivers are each configured for use in a robot and/or a vehicle.
17 . The radar system of claim 11 , wherein the receivers are configured to receive radio signals transmitted by other radar system comprising at least one known radar system.