A chip-implementation of a millimeter wave MIMO radar comprises transmitters for transmitting short bursts of digitally modulated radar carrier signals and receivers for receiving delayed echoes of those signals. Various signal formats defined by the number of bits per transmit burst, the transmit burst duration, the receive period duration, the bitrate, the number of range bins, and the number of bursts per scan, facilitate the choice of modulating bit patterns such that when correlating for target echoes over an entire scan, the correlation codes for different ranges and different transmitters are mutually orthogonal or nearly so. In the event of imperfect orthogonality, simple orthogonalization schemes are revealed, such as subtraction of strong already-detected target signals for better detecting weaker signals or moving targets that are rendered non-orthogonal by their Doppler shift.

False alarms in RADAR processing are reduced. One or more transforms may be performed to generate an array of spectrum values for a first domain spanning at least one of a range axis, a direction of arrival (DoA) axis, or a velocity axis. One or more spectrum values may be obtained from the array of spectrum values, wherein for each of the one or more spectrum values, (1) the spectrum value is associated with a range estimate, and (2) the spectrum value exceeds a range-dependent maximum threshold established based on a quartic function of the range estimate. The one or more spectrum values identified as exceeding the range-dependent maximum threshold may be excluded, or one or more reduced-magnitude values obtained, to generate an array of modified spectrum values for the first domain, used to generate a range estimate, a DoA estimate, or a velocity estimate, or any combination thereof.

False alarms in RADAR processing are reduced. One or more transforms may be performed to generate an array of spectrum values for a first domain spanning at least one of a range axis, a direction of arrival (DoA) axis, or a velocity axis. One or more spectrum values may be obtained from the array of spectrum values, wherein for each of the one or more spectrum values, (1) the spectrum value is associated with a range estimate, and (2) the spectrum value exceeds a range-dependent maximum threshold established based on a quartic function of the range estimate. The one or more spectrum values identified as exceeding the range-dependent maximum threshold may be excluded, or one or more reduced-magnitude values obtained, to generate an array of modified spectrum values for the first domain, used to generate a range estimate, a DoA estimate, or a velocity estimate, or any combination thereof.

An RF imaging receiver using photonic spatial beam processing is provided with an optical beam steerer that directs the modulated optical signals to steer the composite optical signal and move the location of the spot on the optical detector array. The optical beam steerer may be implemented with one or more phase-dependent steering units in which each unit includes a waveplate and polarization grating to steer the modulated optical signals. The optical beam steerer may be configured to act on the individual modulated optical signals to induce individual phase delays that produce a phase delay with a linear term, and possibly spherical or aspherical terms, to steer the composite optical signal in which case the optical beam steerer may be implemented, for example, with an optical phase modulator and optical antenna in each optical channel which together form an OPA, a Risley prism or a liquid crystal or MEMs spatial light modulator.

Provided is a system for range detection including at least one beam source arrangement configured to provide illumination of certain coherence length, an optical arrangement, and a detection arrangement including at least one detector unit.

Aspects of the present disclosure are directed to radar apparatuses and related methods. As may be implemented in connection with one or more embodiments, frequency-based representations of reflected radar signals received by different radar receivers are processed utilizing superposition of and combining of respective ones of the frequency-based representations. In response to said processing, phase noise in the frequency-based representations of reflected radar signals is corrected.

An RF imaging receiver using photonic spatial beam processing is provided with an optical beam steerer that directs the modulated optical signals to steer the composite optical signal and move the location of the spot on the optical detector array. The optical beam steerer may be implemented with one or more phase-dependent steering units in which each unit includes a waveplate and polarization grating to steer the modulated optical signals. The optical beam steerer may be configured to act on the individual modulated optical signals to induce individual phase delays that produce a phase delay with a linear term, and possibly spherical or aspherical terms, to steer the composite optical signal in which case the optical beam steerer may be implemented, for example, with an optical phase modulator and optical antenna in each optical channel which together form an OPA, a Risley prism or a liquid crystal or MEMs spatial light modulator.

The present disclosure provides a system for processing radar data. The system may comprise a frequency generator configured to generate a reference frequency signal; a timing module configured to generate a shared clock signal or a plurality of timing signals; and a plurality of radar modules in communication with the frequency generator and timing module. The radar modules may be configured to: (i) receive the reference frequency signal and at least one of a shared clock signal and a timing signal, (ii) transmit a first set of radar signals based in part on the reference frequency signal and at least one of the shared clock signal and the timing signal, and (iii) receive a second set of radar signals reflected from a surrounding environment. The system may comprise a processor configured to process radar signals received by each radar module, by coherently combining radar signals using phase and timestamp information.

The present disclosure provides a system for processing radar data. The system may comprise a frequency generator configured to generate a reference frequency signal; a timing module configured to generate a shared clock signal or a plurality of timing signals; and a plurality of radar modules in communication with the frequency generator and timing module. The radar modules may be configured to: (i) receive the reference frequency signal and at least one of a shared clock signal and a timing signal, (ii) transmit a first set of radar signals based in part on the reference frequency signal and at least one of the shared clock signal and the timing signal, and (iii) receive a second set of radar signals reflected from a surrounding environment. The system may comprise a processor configured to process radar signals received by each radar module, by coherently combining radar signals using phase and timestamp information.

Aspects of the present disclosure are directed to radar communications with disparate pulse repetition intervals, as may be implemented with radar transmission, receiver and processing circuitry. As may be utilized in accordance with one or more embodiments herein, time division multiplexing (TDM) multi-input multi-output (MIMO) radar signals are transmitted by transmitting sets of successive radar signals, each set having a pulse repetition interval (PRI) that is different than the PRI of sets of radar signals transmitted in another one of the sets. Positional characteristics of a target may be ascertained based on the PRI used in each of the sets and on phase characteristics of ones of the radar signals reflected from the target.