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 as compared to a random selection of codes. In the event of imperfect orthogonality, the subtraction of strong already-detected target signals allows for better detecting of weaker signals or moving targets that are rendered non-orthogonal by their Doppler shift.

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 as compared to a random selection of codes. In the event of imperfect orthogonality, the subtraction of strong already-detected target signals allows for better detecting of weaker signals or moving targets that are rendered non-orthogonal by their Doppler shift.

The disclosure relates in some aspects to providing miniature power-efficient agile photonic generators of microwave waveforms. Illustrative examples use chip lasers integrated in close thermal proximity with one another to provide a miniature microwave arbitrary waveform generator (AWG). Due to the small size of the lasers and the close integration, common ambient fluctuations from the environment or other sources can be efficiently reduced, yielding improved spectral purity of generated radio-frequency (RF) signals. Tight physical integration also permits a small device footprint with minimal acceleration sensitivity. The lasers may be locked to cavities or other resonators to allow efficient decoupling of the frequency and amplitude modulation of the lasers to provide flexibility to the waveform generator. Exemplary devices described herein can produce frequency chirped signals for radar applications. The frequency chirp may be linear and/or nonlinear. Tuning methods are also described herein.

A method for mitigating a leakage signal in an FMCW radar and a radar system thereof are disclosed. The method for mitigating the leakage signal in the radar system includes generating an in-phase signal and a quadrature signal for a beat signal, generating a complex signal using the in-phase signal and the quadrature signal, concentrating a phase noise of the leakage signal included in the complex signal on a stationary point, and mitigating the phase noise based on stationary point concentration (SPC) of the phase noise.

A method for mitigating a leakage signal in an FMCW radar and a radar system thereof are disclosed. The method for mitigating the leakage signal in the radar system includes generating an in-phase signal and a quadrature signal for a beat signal, generating a complex signal using the in-phase signal and the quadrature signal, concentrating a phase noise of the leakage signal included in the complex signal on a stationary point, and mitigating the phase noise based on stationary point concentration (SPC) of the phase noise.

The present application relates to radio detection and ranging (radar) systems and, in particular, to a radar system having a photonics-based signal generator. Such a radar system comprises a stepped-frequency optical signal generator, an optical-to-electrical converter, and a transmitter. The stepped-frequency optical signal generator is configured for converting an optical signal into a stepped-frequency optical signal. The optical-to-electrical converter for converting the stepped-frequency optical signal into a stepped-frequency electrical signal. The transmitter for transmitting a microwave signal based on the stepped-frequency electrical signal.

A method for operating a radar system for a vehicle in order to detect at least one target object in the surroundings of the vehicle, wherein the following steps are carried out: providing a first, a second, and at least one third transmit signal, transmitting the provided transmit signals, wherein the transmit signals are transmitted successively via a transmit antenna of the radar system, in each case with partial signals transmitted at time intervals, and the intervals of the partial signals differ for different transmit signals.

A method for operating a radar system for a vehicle in order to detect at least one target object in the surroundings of the vehicle, wherein the following steps are carried out: providing a first, a second, and at least one third transmit signal, transmitting the provided transmit signals, wherein the transmit signals are transmitted successively via a transmit antenna of the radar system, in each case with partial signals transmitted at time intervals, and the intervals of the partial signals differ for different transmit signals.

A radar system comprises a transmitter and a receiver. The radar system is operable to define a near range and a far range. The radar system is operable to, during each one of a plurality of time intervals, repeatedly transmit, via the transmitter, a plurality of OFDM symbols. The transmitter is operable to select a transmit power for the transmission during the one of the time intervals based on from which of the near range and the far range reflections of the OFDM symbols are to be received during the one of the time intervals. The receiver is operable to receive reflections of the OFDM symbols, and process, in the receiver, the reflections of the OFDM symbols to detect objects within the near range and the far range.

A radar system comprises a transmitter and a receiver. The radar system is operable to define a near range and a far range. The radar system is operable to, during each one of a plurality of time intervals, repeatedly transmit, via the transmitter, a plurality of OFDM symbols. The transmitter is operable to select a transmit power for the transmission during the one of the time intervals based on from which of the near range and the far range reflections of the OFDM symbols are to be received during the one of the time intervals. The receiver is operable to receive reflections of the OFDM symbols, and process, in the receiver, the reflections of the OFDM symbols to detect objects within the near range and the far range.