Techniques that facilitate reconfigurable transmission of a radar frequency signal are provided. In one example, a system includes a signal generator and a power modulator. The signal generator provides a radar waveform signal from a set of radar waveform signals. The power modulator divides a local oscillator signal associated with a first frequency and a first amplitude into a first local oscillator signal and a second local oscillator signal. The power modulator also generates a radio frequency signal associated with a second frequency and a second amplitude based on the radar waveform signal, the first local oscillator signal and the second local oscillator signal.

Apparatus and methods are presented for characterising the environment of a user platform. In certain embodiments RF signals are transmitted and received through an antenna array having a plurality of elements activated in a predetermined sequence, and received signals are manipulated with round-trip path corrections to enhance the gain of the array in one or more directions. Objects in those directions are detected from the receipt of returns of transmitted signals, and the manipulated received signals processed to estimate range to those objects. In other embodiments RF signals transmitted by one or more external transmitters are received and manipulated to enhance the gain of a local antenna array or antenna arrays associated with the one or more transmitters to enhance the gain of the arrays in one or more directions. Objects in those directions are detected from the receipt of reflected signals from the transmitters, and the manipulated received signals processed to estimate range to those objects.

A system and method to generate a family of orthogonal signals for a code division multiple access (CDMA) radar system involve selecting a first signal of the family of orthogonal signals for transmission by one of a plurality of transmitters of the radar system. The method includes using an algorithm to determine a second signal of the family of orthogonal signals. The algorithm uses cross-correlation values between candidate signals for consideration as the second signal of the family of orthogonal signals and the first signal. The method also includes transmitting the first signal of the family of orthogonal signals and the second signal of the family of orthogonal signals simultaneously from two different transmitters, and obtaining and processing reflections resulting from transmission of the first signal of the family of orthogonal signals and the second signal of the family of orthogonal signals.

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.

A synthetic aperture radar (SAR) is operable in an interrogation mode and in an imaging mode, the imaging mode entered in response to determining a response to interrogation pulses have been received from a ground terminal and position information specifying a ground location has been received from the ground terminal. A ground terminal is operable to receive interrogation pulses transmitted by a SAR, transmit responses, and transmit position information to cause the SAR to enter a imaging mode. The ground terminal receives first and subsequent pulses from the SAR where subsequent pulses include backscatter and are encoded. The ground terminal generates a range line by range compression. If the SAR is a multi-band SAR the transmitted pulses can be in two or more frequency bands, and subsequent pulses in one frequency band can include encoded returns from pulses transmitted in a different frequency band.

A radar apparatus includes a plurality of transmission antennae and a radar transmitter that transmits transmission signals by using the plurality of transmission antennae. In a virtual reception array including a plurality of virtual antennae formed of a plurality of reception antennae and the plurality of transmission antennae, disposition positions of at least two of the virtual antennae are the same as each other, and, transmission intervals of the transmission signals that are sequentially transmitted from transmission antennae corresponding to the at least two virtual antennae among the plurality of transmission antennae are an equal interval.

Radar receiver calculates a first reception power in each of a predetermined number of beam directions by using a reflected wave signal in a first cell among a plurality of cells into which a region represented by at least one of a distance component and a Doppler frequency component is divided, calculates a second reception power on the basis of reception powers of reception array antennae by using the reflected wave signal in a peripheral cell of the first cell among the plurality of cells, and determines whether or not a target is present in the first cell on the basis of a comparison result between the first reception power and a first threshold value that is a value obtained by multiplying the second reception power by a first coefficient.

A system comprises a multifunction radar receiver that in turn comprises processing circuitry and front-end circuitry. The front-end circuitry is operable to receive a millimeter wave burst via a plurality of antennas to generate a plurality received signals. The processing circuitry is operable to receive a first scene representation that is an aggregate of scene representations generated by one or more other radar receivers. The processing circuitry is operable to process the received signals to generate a second scene representation. The processing circuitry is operable to compare the first scene representation and the second scene representation and generate a difference scene based on the comparison. The processing circuitry is operable to generate a control signal based on the difference scene.

A radar device is mounted on a vehicle, which is a moving object, and includes a doppler correction phase-rotation controller and a phase rotator. Based on the speed of the vehicle, the doppler correction phase-rotation controller calculates a Doppler correction phase-rotation amount for correcting a Doppler frequency due to movement of the vehicle. By using the Doppler correction phase-rotation amount, the phase rotator pre-corrects Doppler frequency components with respect to a radar transmission signal in each transmission interval of the radar transmission signal.

A radar transmitter transmits a radar signal through a transmitting array antenna at a predetermined transmission period, and a radar receiver receives a reflected wave signal which is the radar signal reflected by a target through a receiving array antenna. A transmitting array antenna and a receiving array antenna each include multiple subarray elements, the subarray elements in the transmitting array antenna and the receiving array antenna are linearly arranged in a first direction, each subarray element includes multiple antenna elements, the subarray element has a dimension larger than a predetermined antenna element spacing in the first direction, and an absolute value of a difference between a subarray element spacing of the transmitting array antenna and a subarray element spacing of the receiving array antenna is equal to the predetermined antenna element spacing.