Vehicular radar system with self-interference cancellation
First Claim
1. A radar system for a vehicle, the radar system comprising:
- a plurality of transmitters configured for installation and use on a vehicle, wherein the transmitters are configured to transmit digitally modulated radio signals;
a plurality of receivers configured for installation and use on the vehicle;
wherein the transmitters and the receivers are configured to operate simultaneously in a same frequency spectrum during an operational period;
wherein a first receiver of the plurality of receivers receives at least one interfering signal due to local signal coupling from at least one transmitter of the plurality of transmitters, and wherein the local signal coupling comprises at least one interfering path or mechanism;
a spillover cancellation unit comprising a digital modulator configured to output a delayed, amplitude weighted, and phase changed replica of each of the at least one interfering signal transmitted by respective ones of the at least one transmitter of the plurality of transmitters as received through respective ones of the at least one interfering path or mechanism;
a combiner configured to combine into a signal path of the first receiver the delayed, amplitude weighted, and phase changed replica of each of the at least one interfering signal transmitted by respective ones of the at least one transmitter of the plurality of transmitters from which interference is to be suppressed to subtract the at least one interfering signal from the first receiver'"'"'s signal path; and
wherein the first receiver receives the transmitted digitally modulated radio signal reflected from objects in the environment without saturating the signal path of the first receiver due to the subtraction of the at least one interfering signal from the first receiver'"'"'s signal path.
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Accused Products
Abstract
A digital FMCW radar is described that simultaneously transmits and receives digitally frequency modulated signals using multiple transmitters and multiple receivers and associated antennas. Several sources of nearby spillover from transmitters to receivers that would otherwise degrade receiver performance are subtracted by a cancellation system in the analog radio frequency domain that adaptively synthesizes an analog subtraction signal based on residual spillover measured by a correlator operating in the receivers'"'"' digital signal processing domains and based on knowledge of the transmitted waveforms. The first adaptive cancellation system achieves a sufficient reduction of transmit-receive spillover to avoid receiver saturation or other non-linear effects, but is then added back in to the signal path in the digital domain after analog-to-digital conversion so that spillover cancellation can also operate in the digital signal processing domain to remove deleterious spillover components.
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Citations
20 Claims
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1. A radar system for a vehicle, the radar system comprising:
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a plurality of transmitters configured for installation and use on a vehicle, wherein the transmitters are configured to transmit digitally modulated radio signals; a plurality of receivers configured for installation and use on the vehicle; wherein the transmitters and the receivers are configured to operate simultaneously in a same frequency spectrum during an operational period; wherein a first receiver of the plurality of receivers receives at least one interfering signal due to local signal coupling from at least one transmitter of the plurality of transmitters, and wherein the local signal coupling comprises at least one interfering path or mechanism; a spillover cancellation unit comprising a digital modulator configured to output a delayed, amplitude weighted, and phase changed replica of each of the at least one interfering signal transmitted by respective ones of the at least one transmitter of the plurality of transmitters as received through respective ones of the at least one interfering path or mechanism; a combiner configured to combine into a signal path of the first receiver the delayed, amplitude weighted, and phase changed replica of each of the at least one interfering signal transmitted by respective ones of the at least one transmitter of the plurality of transmitters from which interference is to be suppressed to subtract the at least one interfering signal from the first receiver'"'"'s signal path; and wherein the first receiver receives the transmitted digitally modulated radio signal reflected from objects in the environment without saturating the signal path of the first receiver due to the subtraction of the at least one interfering signal from the first receiver'"'"'s signal path. - View Dependent Claims (2, 3, 4, 5, 6, 7, 8)
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9. A continuous wave, multiple-input, multiple-output (MIMO) radar system for use on vehicle, the MIMO radar system comprising:
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a plurality of receivers coupled to associated receive antennas; a plurality of co-located transmitters coupled to associated transmit antennas, and configured to transmit radio signals on a programmable radio carrier frequency modulated with digital symbol sequences; a spillover cancellation unit and associated first combiners configured to cancel interference from a signal path of each of the plurality of receivers due to local spillover from the plurality of transmitters; wherein for each of the plurality of receivers, the spillover cancellation unit comprises a signal generator configured to produce a cancellation signal for each respective receiver of the plurality of receivers as defined in part by the digital symbol sequences; and wherein the first combiners are configured to combine each spillover cancellation signal into the received signal path of each intended receiver, wherein the interference from the plurality of transmitters due to the local spillover is removed by subtraction, and wherein combining a spillover cancellation signal into a received signal path subtracts transmitter interference from the signal path. - View Dependent Claims (10, 11, 12)
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13. A method for preventing receivers of a continuous wave multiple-input, multiple-output (MIMO) radar system from being saturated by local spillover from transmitters of the MIMO radar system, the method comprising:
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operating a plurality of receivers of the MIMO radar system during a system calibration phase with only one of a plurality of transmitters of the MIMO radar system operating at a time; via monitoring an output signal of each receiver of the plurality of receivers, determining a recipe for each receiver for forming a cancellation signal based on knowledge of a modulation of the only one operating transmitter which, when the cancellation signal is combined with the received signal in the receive path, minimizes a determined output due to the only one operating transmitter; via continued monitoring of the output signal of each receiver of the plurality of receivers, determining individual outputs due to each transmitter of the plurality of transmitters as each transmitter is operated in turn as the only operating transmitter to obtain recipes for forming a cancellation signal for each combination of a receiver and a transmitter; and combining the recipes for all transmitters for a given receiver to form a cancellation signal generation recipe for the given receiver that will cancel the local spillover due to all transmitters at the given receiver when all transmitters are operated at once, and repeating for all receivers to determine a cancellation signal generation recipe for each receiver. - View Dependent Claims (14, 15, 16, 17, 18, 19, 20)
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Specification