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 transmitter of a radar system repeatedly transmits a first OFDM symbol into a scene to be characterized during a first time interval, and repeatedly transmits, during a second time interval that occurs after the first time interval, a second OFDM symbol into the scene. A receiver of the radar system generates a first channel response estimate for a first section of the scene based on: received reflections of the first symbol, at least one of which was received during transmission of the second OFDM symbol in the second time interval, and a first channel response estimate for a second section of the scene based on the first channel response estimate for the first section of the scene, received reflections of the first symbol, and received reflections of the second symbol. The receiver detects objects present in the scene based on the first channel response estimate for the first section of the scene and the first channel response estimate for the second section of the scene.

A platform operates in an environment with other platforms using active sensing. The platform includes an active sensing system configured to provide a point cloud associated with the environment. The point cloud is used to navigate the platform. The active sensing system includes a transmitter configured to provide pulses of electromagnetic energy in a light band or a radar band or sonic energy and a receiver configured to receive returns associated with the pulses striking one or more targets in the environment. The transmitter is configured to impose a code onto the pulses, and the receiver is configured to detect the code to determine when the pulses of light where transmitted or to determine a source of the pulses.

A method of environmental sensing through pilot signals in a spread spectrum wireless communication system is provided with a plurality of wireless terminals. The plurality of wireless terminals includes a plurality of multi-input multi-output (MIMO) radars and at least one base station. The plurality of terminals broadcasts a beacon pilot signals containing a terminal-specific information and encoded with a corresponding identifier. Using the corresponding identifier, an arbitrary radar from the plurality of MIMO radars separates the beacon pilot signal from an ambient signal. More specifically, the arbitrary radar compares the ambient signal to the corresponding identifier of each wireless terminal to identify at least one origin terminal. Subsequently, the arbitrary radar extracts the terminal-specific information from the beacon pilot signal of the origin terminal. The terminal-specific information is used to exchange data between the plurality of wireless terminals for autonomous driving.

A high-throughput communications channel is encoded using transmit waveforms which satisfy a variety of technical constraints deemed desirable for effective radar operations and signal processing. This enables new cooperative spectrum sharing modalities for radar and communications systems.

Methods and devices for estimating an angle between a transmitter and a receiver for beamforming are provided. A method includes, with an antenna element in a first device, transmitting an omnidirectional pulse and detecting an echo of the pulse reflected from a second device. An angle between the first device and the second device is estimated based at least on a characteristic of the echo. The method includes transmitting the angle to the second device for use in beamforming between the first device and the second device.

A radar apparatus is provided which includes a counter which counts a transmission count of pulse codes from start of measurement, a pulse code generator which selects a complementary group from among a plurality of complementary groups obtained by grouping a plurality of pulse codes generated by at least one code coupling process on at least one basic code pair as complementary codes every time the transmission count is an integral multiple of a code count in the plurality of complementary groups, and a transmitter which transmits the pulse codes belonging to the selected complementary group.

A vehicle radar system, such as a multiple input multiple output (MIMO) radar system, for estimating a Doppler frequency shift and a method of using the same. In one example, a modulated signal is mixed with an orthogonal code sequence and is transmitted by a transmit antenna array with a plurality of transmitting antennas. The signals reflect off of a target object and are received by a receive antenna array with a plurality of receiving antennas. Each of the received signals, which likely includes a Doppler frequency shift, is processed and mixed with a number of frequency shift hypotheses that are intended to offset the Doppler frequency shift and result in a series of correlation values. The frequency shift hypothesis with the highest correlation value is selected and used to correct for the Doppler frequency shift so that more accurate target object parameters, such as velocity, can be obtained.

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.

An estimating method includes: measuring and receiving reception signals including a reflected signal reflected by a moving body, for a first period equivalent to a cycle of movement of the moving body; calculating first complex transfer functions indicating propagation characteristics, from the reception signals measured in the first period; calculating second complex transfer functions having reduced components corresponding to fluctuations, from the first complex transfer functions; extracting moving body information corresponding to a component related to the moving body by extracting moving body information corresponding to a predetermined frequency range of the second complex transfer functions calculated; and estimating a direction in which the moving body is present using the moving body information.