Techniques and systems are described for Spatial-Block Code Division Multiplexing (CDM) for MIMO waveforms. A radar system includes multiple transmitters, receivers, and phase shifters. Electromagnetic (EM) signals are transmitted and received in a Spatial-Block CDM scheme. Each spatial block has multiple slots outnumbering the channels. In addition, each slot corresponds to a specific code of phase shifts applied across the channels by the phase shifters during that slot. Fast-Fourier Transformations are applied to reflections of the EM signals to generate complex observations at each of the channels during each slot. Based on the observations, whether a Doppler phase shift exists between two slots can be determined based in part on whether the phase shift has one or multiple possible values. The techniques allow velocities to be resolved, despite a mixed-Doppler interval detected. Analog beamforming is supported; slots can be directed at particular angles to change gain in a field of view.

A method of generating a reference signal for transmission over a wireless communication channel comprises generating a first signal of a first characteristic, generating a second signal with second characteristic, scaling the second signal at least in time and an amplitude to form a scaled signal and iteratively adding the scaled signal to the first signal to generate the reference signal. The iteratively adding comprises time indexing the first signal with plurality of time points, adding the scaled signal to first signal at each time point in the plurality of time points, computing a cost function to determine the cost of adding the scaled signal at each time point in the plurality of time points, selecting a set of time points that indicate reduction in the cost when the scaled signal is added and adjusting the amplitude of the scaled signal at each time point in the set of time points to reduce the cost.

Disclosed are devices, systems and methods for compensating radar measurements of a vehicle. One exemplary method includes generating a set of velocity hypotheses of a target object based on a first measurement data obtained from sensors mounted on the vehicle; generating cluster velocity estimates by applying a clustering algorithm to a second measurement data obtained from the sensors; and providing one or more selected velocity hypotheses from the set of velocity hypothesis as compensated radar measurements for the target object based on the cluster velocity estimates.

A method for confusing the electronic signature of a signal transmitted by a radar, includes the generation by the radar of at least one pulse, wherein the method comprises a step of modulation, in the pulse, of the polarization of the transmitted signal, according to two orthogonal or opposite polarizations, the modulation of the polarization being performed according to a predetermined modulation code.

This disclosure provides a signal processing method and apparatus. The method includes: obtaining Nr1×M1 signals, where the Nr1×M1 signals are echo signals of M1 signals that are sent by a radar to a target in a SIMO mode; obtaining Nt×Nr2×M2 signals, where the Nt×Nr2×M2 signals are echo signals of M2 signals that are sent by the radar to the target in a MIMO mode; performing first signal processing on the Nr1×M1 signals to obtain first processing data, where the first signal processing includes sequentially performing range FFT analysis, linear prediction, and Doppler FFT analysis; performing second signal processing on the Nt×Nr2×M2 signals to obtain second processing data, where the second signal processing includes range FFT analysis and Doppler FFT analysis; and performing velocity matching ambiguity resolution processing based on the first processing data and the second processing data.

Systems and methods are described to identify motion events on a sloped surface, such as a mountainside, using transmitted and received radio frequency (RF) chirps. A one-dimensional array of receive antennas can be digitally beamformed to determine azimuth information of received reflected chirps. Elevation information can be determined based on time-of-flight measurements of received reflected chirps and known distances to locations on the sloped surface. Motion events may be characterized by deviations in return power levels and/or return phase shifts. The systems and methods may, for example, be used to provide real-time detection of avalanches and/or landslides.

A synthetic aperture radar (SAR) generates concurrent first radar pulses in first frequency channels. The SAR transmits, and receives returns of, the concurrent first radar pulses by first antenna feeds that form first beams in the first frequency channels and that are directed to respective first subswaths of a swath on the Earth separated by subswath gaps. The SAR generates concurrent second radar pulses in second frequency channels. The SAR transmits, and receives returns of, the concurrent second radar pulses by second antenna feeds configured to form second beams in the second frequency channels and that are directed to respective second subswaths of the swath on the Earth and that coincide with the subswath gaps. The SAR processes the returns of the first radar pulses from the first subswaths and the returns of the second radar pulses from the second subswaths to form a SAR image contiguous across the swath.

A method for operating a stepped frequency radar system is disclosed. The method involves performing stepped frequency scanning across a first frequency range using frequency steps of a first step size, the stepped frequency scanning performed using at least one transmit antenna and a two-dimensional array of receive antennas, changing from the first step size to a second step size, wherein the second step size is different from the first step size, and performing stepped frequency scanning across a second frequency range using the at least one transmit antenna and the two-dimensional array of receive antennas and using frequency steps of the second step size.

A method for operating a stepped frequency radar system is disclosed. The method involves performing stepped frequency scanning across a first frequency range using frequency steps of a first step size, the stepped frequency scanning performed using at least one transmit antenna and a two-dimensional array of receive antennas, changing from the first step size to a second step size, wherein the second step size is different from the first step size, and performing stepped frequency scanning across a second frequency range using the at least one transmit antenna and the two-dimensional array of receive antennas and using frequency steps of the second step size.

In an embodiment, a method for authenticating a user of a car includes: transmitting a plurality of radiation pulses through a predetermined portion of a surface of the car towards a portion of a hand of the user using a millimeter-wave radar; receiving a reflected signal from the portion of the hand using the millimeter-wave radar; generating a fingerprint signature based on the reflected signal; comparing the fingerprint signature to a database of authorized fingerprint signatures; and authorizing the user based on whether the fingerprint signature matches an authorized fingerprint signature of the database of authorized fingerprint signatures.