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 vehicle radar system (3) and method including a first and second radar sensor arrangement (4a, 4b). Each radar sensor arrangement (4a, 4b) includes at least two transmitter antenna devices (10a1, 10a2) and at least two receiver antenna devices (13a1, 13a2, 13a3, 13a4), where each receiver antenna device (13a1, 13a2, 13a3, 13a4) has a corresponding boresight extension (46a, 46b) that is perpendicular to an antenna plane (57). Each receiver antenna device (13a1, 13a2, 13a3, 13a4) has a corresponding antenna radiation pattern (47a, 47b) that has a lower gain (48a, 48b) in its boresight extension (46a, 46b) than at a certain corresponding first maximum gain azimuth angle (φ.sub.1a, φ.sub.1b) where there is a first maximum gain (49a, 49b). Each radar sensor arrangement (4a, 4b) is mounted such that each first maximum gain (49a, 49b) is directed along a corresponding first maximum gain extension (51a, 51b), such that an overlap part (56) of the antenna radiation patterns (47a, 47b) is formed.

Angle-resolving radar sensor for motor vehicles, including: an antenna array including multiple antennas, configured for receiving, situated in various positions in one direction in which the radar sensor is angle-resolving, and a control and evaluation unit configured for an operating mode in which at least one antenna of the radar sensor configured for transmitting transmits a signal received by multiple of the antennas of the radar sensor configured for receiving, and the angle of a radar target is estimated based on amplitude and/or phase relationships between signals of respective evaluation channels, which correspond to different configurations of transmitting and receiving antennas, an evaluation of the signals of the evaluation channels for a respective distance for a respective evaluation channel taking place for an individual estimation of an angle of a radar target, different distances being selected for respective evaluation channels as a function of an angle or angle range hypothesis.

A frequency conversion beam squint correction method of an active phase array antenna system including a plurality (m) of beamforming units configured of an antenna, a first amplifier, a phase shifter, a variable attenuator, and a second amplifier, the method includes the steps of: adjusting a delay time of an applied RF signal by arranging m/2 true time delays (TTDs) for every two adjacent beamforming units; and converting the frequency of the RF signal by mixing the RF signal transferred to each of the m/2 true time delays and a local oscillation signal using a mixer.

In imaging radar, examples are directed to uses of multiple sets of transmit antenna included with transceiver circuitry, for transmitting in a plurality of modes. Transmissions may involve having at least one transmit antenna, from each of at least two of the multiple sets, to transmit continuous-wave energy concurrently (simultaneously) in one or more of the plurality of different modes. Transceiver circuitry may include multiple receive antennas which may be receiving reflections of the continuous-wave energy from various targets. Signals from the multiple receive antennas may route to signal processing circuitry. The signal processing circuitry may respond to the received reflections of the continuous-wave energy by assessing differences in antenna gain and/or phase due to transmit antenna position associated with the received reflections. This signal processing assessment may mitigate or resolve at least one spatial ambiguity in at least one direction of arrival dimension associated with the received reflections.

Angle-resolving radar sensor for motor vehicles, including: an antenna array including multiple antennas, configured for receiving, situated in various positions in one direction in which the radar sensor is angle-resolving, and a control and evaluation unit configured for an operating mode in which at least one antenna of the radar sensor configured for transmitting transmits a signal received by multiple of the antennas of the radar sensor configured for receiving, and the angle of a radar target is estimated based on amplitude and/or phase relationships between signals of respective evaluation channels, which correspond to different configurations of transmitting and receiving antennas, an evaluation of the signals of the evaluation channels for a respective distance for a respective evaluation channel taking place for an individual estimation of an angle of a radar target, different distances being selected for respective evaluation channels as a function of an angle or angle range hypothesis.

The present system and method allow for accurate estimation of angle and angle rate for a target using a slewing antenna. These issues are accounted for by using a special form of non-coherent integration. An extension of the non-coherent integration may be used to estimate the target's angle rates. This technique can also be expanded to determine whether a target is in the main lobe or in a side lobe in one or two directions.

A radar system, comprising: a receive antenna configured to receive a receive signal reflected from a bullet, the receive signal exhibiting a Doppler shift according to the motion of the bullet; and a detector implementing a set of matched filters each configured to determine a measure of correlation between the Doppler shift of the receive signal and one of a set of pre-stored Doppler shifts, wherein each of the pre-stored Doppler shifts respectively represents the Doppler shift of a bullet passing the antenna at a different speed or a distance of a point of closest approach.

In imaging radar, examples are directed to uses of multiple sets of transmit antenna included with transceiver circuitry, for transmitting in a plurality of modes. Transmissions may involve having at least one transmit antenna, from each of at least two of the multiple sets, to transmit continuous-wave energy concurrently (simultaneously) in one or more of the plurality of different modes. Transceiver circuitry may include multiple receive antennas which may be receiving reflections of the continuous-wave energy from various targets. Signals from the multiple receive antennas may route to signal processing circuitry. The signal processing circuitry may respond to the received reflections of the continuous-wave energy by assessing differences in antenna gain and/or phase due to transmit antenna position associated with the received reflections. This signal processing assessment may mitigate or resolve at least one spatial ambiguity in at least one direction of arrival dimension associated with the received reflections.

An angle measuring device includes: a signal extracting unit for extracting a signal that includes a first reflection wave and does not include a second reflection wave as a first demodulated signal and a signal that includes the second reflection wave and does not include the first reflection wave as a second demodulated signal from reception signals output from one or more reception antennas among a plurality of reception antennas; an elevation calculating unit for calculating an elevation of a target by performing monopulse angle measurement using a sum signal of the first demodulated signal and the second demodulated signal and a difference signal between the first demodulated signal and the second demodulated signal; and an azimuth calculating unit for calculating an azimuth of the target using reception signals output from the plurality of reception antennas.