Methods, systems, computer-readable media, and apparatuses for determining one or more attributes of at least one target based on eigenspace analysis of radar signals are presented. In some embodiments, a subset of eigenvectors to use for forming a signal or noise subspace is identified based on principal component analysis. In some embodiments, the subset of eigenvectors is identified based on estimating the total number of targets using a discrete Fourier transform (DFT) or other spectral analysis technique. In some embodiments, a DFT is used to identify areas of interest in which to perform eigenspace analysis. In some embodiments, a DFT is used to estimate one attribute of a target, and eigenspace analysis is performed to estimate a different attribute of the target, with the results being combined to generate a multi-dimensional representation of a field of view.

A signal processing device includes: an acquisition unit configured to acquire phase information of a reception signal of each of plural virtual antennas generated based on a combination of plural transmission antennas and plural reception antennas; a first calculation unit configured to calculate, based on the phase information, at least one first phase difference between the plural transmission antennas in an outward path along which a transmission wave transmitted from the plural transmission antenna reaches a target; a second calculation unit configured to calculate, based on the phase information, at least one second phase difference between the plural reception antennas in a return path along which a reflected wave reflected by the target reaches the plural reception antennas; and a determination unit configured to determine, based on the first phase difference and the second phase difference, whether the outward path and the return path match each other.

A distributed radar system, apparatus, architecture, and method is provided for coherently combining physically distributed radars to jointly' produce target scene information in a coherent fashion without sharing a common local oscillator (LO) reference by configuring a first (slave) radar to apply fast and slow time processing steps to target returns generated from a second (master) radar, to compute an estimated frequency offset and an estimated phase offset between the first and second radars based on information derived from the fast and slow time processing steps, and to apply the estimated frequency offset and estimated phase offset to generate a bi-static virtual array aperture at the first radar that is coherent in frequency and phase with a mono-static virtual array aperture generated at the second radar, thereby achieving better sensitivity, finer angular resolution, and low false detection rate.

A radar processor for processing a frame of radar data received from one or more targets, the frame of radar data having a carrier frequency and comprising a sequence of codewords with a codeword repetition interval, wherein the carrier frequency and the codeword repetition interval define an unambiguous velocity range, the radar processor configured to: receive the frame of radar data; transform the frame to obtain a velocity data array; apply a correction algorithm to the velocity data array to correct a Doppler shift of the frame to obtain a corrected array, wherein the correction algorithm comprises a set of Doppler correction frequencies corresponding to a set of velocity gates and at least one of the set of Doppler correction frequencies corresponds to a velocity gate outside the unambiguous velocity range; and perform range processing on the corrected array to obtain a range-Doppler map.

A method of determining a distance between a radio frequency device and a target is disclosed in which the radio frequency device receives a radio frequency signal from the target. The method comprises determining a time domain channel response from the received radio frequency signal, determining an amplitude of a largest peak in the time domain channel response, determining an amplitude of a second, earlier, peak in the time domain channel response, comparing the second peak amplitude to a threshold based on the largest peak amplitude, identifying the largest peak as a shortest path peak if the second peak amplitude is less than the threshold, identifying the second peak as a shortest path peak if the second peak amplitude is greater than the threshold, and calculating the distance between the radio frequency device and the target based on a time corresponding to the shortest path peak.

A receiver includes a first discrete Fourier transform (DFT) block to perform a first single tone DFT on a positive tone associated with a sounding sequence. A second DFT block performs a second single tone DFT on a negative tone associated with the sounding sequence. A DFT coefficient generation block generates first DFT coefficients based on a nominal frequency of the positive tone and an estimated frequency offset between a transmitter frequency and a receiver frequency. The DFT coefficient generation block generates second DFT coefficients based on a nominal frequency of the negative tone and the estimated frequency offset. Multipliers in the DFT blocks multiply I and Q values of the sounding sequence with the coefficients. Accumulators in the DFT blocks accumulate multiplier outputs. An arctan function receives averaged accumulated values from the first and second DFT blocks and supplies first and second phase values used to calculate fractional timing.

A radar measuring device including at least: a circuit for generating a radar signal RF.sub.IN(t); an emitting antenna; an injection-locked oscillator; a first power divider comprising an input coupled to an output of the circuit for generating the radar signal RF.sub.IN(t), a first output coupled to the emitting antenna, and a second output to an input of the injection-locked oscillator which is configured to be locked over a portion of an effective band B of the radar signal RF.sub.IN(t); a receiving antenna intended to receive a reflected radar signal RF.sub.IN_REFL(t); a mixer comprising a first input coupled to the receiving antenna, a second input coupled to an output of the injection-locked oscillator, and an output coupled to an input to a signal processing circuit.

Methods, systems, computer-readable media, and apparatuses for determining one or more attributes of at least one target based on eigenspace analysis of radar signals are presented. In some embodiments, a subset of eigenvectors to use for forming a signal or noise subspace is identified based on principal component analysis. In some embodiments, the subset of eigenvectors is identified based on estimating the total number of targets using a discrete Fourier transform (DFT) or other spectral analysis technique. In some embodiments, a DFT is used to identify areas of interest in which to perform eigenspace analysis. In some embodiments, a DFT is used to estimate one attribute of a target, and eigenspace analysis is performed to estimate a different attribute of the target, with the results being combined to generate a multi-dimensional representation of a field of view.

In an embodiment, a method for tracking targets includes: receiving data from a radar sensor of a radar; processing the received data to detect targets; identifying a first geometric feature of a first detected target at a first time step, the first detected target being associated to a first track; identifying a second geometric feature of a second detected target at a second time step; determining an error value based on the first and second geometric features; and associating the second detected target to the first track based on the error value.

Health signal monitoring using continuous wave microwave signals is often affected by phase wrapping and null point detection issues. The disclosure herein generally relates to health monitoring, and, more particularly, to a method and a monitoring system for health monitoring using Amplitude Modulated Continuous Wave (AMCW) microwave signals. In this design of the monitoring system, the AMCW microwave signal comprises of a carrier signal and a modulating signal. The modulating signal is used for measuring heart rate and breathing rate of a subject, while the carrier signal is used to tune antenna size in the monitoring system. As the probing wavelength and the antenna size are independent of each other in this design of the monitoring system, the probing wavelength can be adjusted such that effect of the phase wrapping can be minimized. The system addresses the null point measurement problem by quadrature modulating the modulating signal.