A linear-depolarization ratio calculator (12) is configured so as to determine a radar reflectivity factor Z.sub.hh in transmission of a horizontally polarized wave and reception of a horizontally polarized wave, the radar reflectivity factor being a reflected wave intensity after integration of a reflected wave intensity V.sub.hh(n) calculated by a reflected-wave intensity calculator (11), and a radar reflectivity factor Z.sub.vh in transmission of a horizontally polarized wave and reception of a vertically polarized wave, the radar reflectivity factor being a reflected wave intensity after integration of a reflected wave intensity V.sub.vh(n+2) and calculate a linear depolarization ratio LDR.sub.vh which is the ratio between the radar reflectivity factor Z.sub.hh and the radar reflectivity factor Z.sub.vh. As a result, even when three types of polarized-wave transmission/reception processing elements are repeatedly performed, the linear depolarization ratio LDR.sub.vh can be calculated.

A linear-depolarization ratio calculator (12) is configured so as to determine a radar reflectivity factor Z.sub.hh in transmission of a horizontally polarized wave and reception of a horizontally polarized wave, the radar reflectivity factor being a reflected wave intensity after integration of a reflected wave intensity V.sub.hh(n) calculated by a reflected-wave intensity calculator (11), and a radar reflectivity factor Z.sub.vh in transmission of a horizontally polarized wave and reception of a vertically polarized wave, the radar reflectivity factor being a reflected wave intensity after integration of a reflected wave intensity V.sub.vh(n+2) and calculate a linear depolarization ratio LDR.sub.vh which is the ratio between the radar reflectivity factor Z.sub.hh and the radar reflectivity factor Z.sub.vh. As a result, even when three types of polarized-wave transmission/reception processing elements are repeatedly performed, the linear depolarization ratio LDR.sub.vh can be calculated.

A reconfigurable radar unit is described that includes: a millimetre wave (mmW) transceiver (Tx/Rx) circuit; a mixed analog and baseband integrated circuit; and a signal processor circuit. The mmW Tx/Rx circuit and mixed analog and baseband integrated circuit and signal processor circuit are configured to support a plurality of radar operational modes. a radar sensitivity monitor and architecture reconfiguration control unit (260) is coupled to the signal processor circuit and is configured to monitor a radar performance and, in response thereto, initiate a change in the radar operational mode. In this manner, a large number of radar operational modes is supported and can be dynamically adopted by the reconfigurable radar unit dependent upon any prevailing radar performance condition.

A reconfigurable radar unit is described that includes: a millimetre wave (mmW) transceiver (Tx/Rx) circuit; a mixed analog and baseband integrated circuit; and a signal processor circuit. The mmW Tx/Rx circuit and mixed analog and baseband integrated circuit and signal processor circuit are configured to support a plurality of radar operational modes. a radar sensitivity monitor and architecture reconfiguration control unit (260) is coupled to the signal processor circuit and is configured to monitor a radar performance and, in response thereto, initiate a change in the radar operational mode. In this manner, a large number of radar operational modes is supported and can be dynamically adopted by the reconfigurable radar unit dependent upon any prevailing radar performance condition.

A distributed radar system, apparatus, architecture, and method is provided for coherently combining physically distributed radars to jointly produce target scene information in a coherent fashion without sharing a common local oscillator (LO) reference by configuring a first (slave) radar to apply fast and slow time processing steps to target returns generated from a second (master) radar, to compute an estimated frequency offset and an estimated phase offset between the first and second radars based on information derived from the fast and slow time processing steps, and to apply the estimated frequency offset and estimated phase offset to generate a bi-static virtual array aperture at the first radar that is coherent in frequency and phase with a mono-static virtual array aperture generated at the second radar, thereby achieving better sensitivity, finer angular resolution, and low false detection rate.

A method for measuring an elevation angle and/or azimuth angle with an antenna array. Identical transmitted signals that are formed of successive linear-frequency-modulated ramps are transmitted through the transmitting antennas of the antenna array using time division multiplexing, wherein the time division multiplexing is achieved through alternating attenuation of the signals transmitted by the transmitting antennas. Echoes of the transmitted signals are received by the receiving antennas and are down-converted to a baseband and sampled. The down-converted and sampled echoes are transformed by an FFT into a 2D image domain. Phase differences are determined from the image data, and, in order to compensate for a systematic error present because of the lack of separation of the two transmitted signals, an error-compensated elevation angle and/or an error-compensated azimuth angle is determined by means of a compensation.

There is provided a mmWave RTLS (Real-Time Location Sensing) system for detecting the presence of one or more objects. The system includes multiple anchors. Each anchor includes a mmWave radar subsystem that uses radar algorithms to detect one or more objects and determine the one or more location-based objects characteristics. The location-based object characteristics include one or more of the following: range, direction-of-arrival, velocity, absolute position, or logical position, each determined relative to one or more anchors.

A method for determining an arrival-time of a rotor blade that includes attaching an RF reader to a stationary surface and an RF tag to the rotor blade. Time-of-flight data points are collected via an RF monitoring process that includes: emitting an RF signal from the RF reader and recording a first time; receiving the RF signal at the RF tag and emitting a return RF signal by the RF tag in response thereto; receiving the return RF signal at the RF reader and recording a second time; and determining the time-of-flight data point as being the duration occurring between the first time and the second time. The RF monitoring process is repeated until multiple time-of-flight data points are collected. A minimum time-of-flight is determined from the multiple time-of-flight data points, and the arrival-time for the rotor blade is determined as being a time that corresponds to the minimum time-of-flight.

A method for determining an arrival-time of a rotor blade that includes attaching an RF reader to a stationary surface and an RF tag to the rotor blade. Time-of-flight data points are collected via an RF monitoring process that includes: emitting an RF signal from the RF reader and recording a first time; receiving the RF signal at the RF tag and emitting a return RF signal by the RF tag in response thereto; receiving the return RF signal at the RF reader and recording a second time; and determining the time-of-flight data point as being the duration occurring between the first time and the second time. The RF monitoring process is repeated until multiple time-of-flight data points are collected. A minimum time-of-flight is determined from the multiple time-of-flight data points, and the arrival-time for the rotor blade is determined as being a time that corresponds to the minimum time-of-flight.

A system is provided with a ranging transmitter and receiver pair or a transceiver pair. The system classifies a group of radio frequency (RF) channels between ranging transmitter and receiver pairs. In a first scenario, a ranging transmitter transmits at least three channels to an active reflecting receiver. A ranging receiver then receives reflected instances of the at least three transmitted channels from the active reflecting receiver. A processor of the system then determines a ranging measurement between the ranging transmitter and the active reflecting receiver based on measured phase changes and received signal strength and assigns a classification to the determined ranging measurement indicating a relative level of accuracy for the determined ranging measurement. The classification may be a general classification, a linearity classification, a multipath classification, or a combination classification that is based on both a linearity classification and a multipath classification.