A GPR system the implements a modified multistatic mode of operation is provided. The GPR is suitable for mounting on an unmanned aerial vehicle. The GPR system has radar transceivers. The GPR system transmits transmit signal serially via the transceivers. For each transceiver that transmits a transmit signal, the GPR system receives a return signal acquired by each transceiver except for a return signal for the transceiver that transmits the transmit signal. The GPR system outputs of matrix of return signals that includes a null value for the return signals of the transceivers that transmit.

Disclosed are an indoor non-contact human activity recognition method and system. The method comprises: collecting an indoor reflected signal by using an antenna array; filtering the reflected signal to obtain a noise-removed reflection signal; and inputting the noise-removed reflected signal to a pre-trained human activity recognition model, and determining a human activity category, the human activity recognition model being a pre-trained CNN network model based on a transfer learning algorithm. The recognition method and system have the advantages that: the antenna array is configured for collecting human actions to carry out activity recognition indoors, which can be applied to home-based care scenes; original data is denoised, so that most of high-frequency noises can be removed, and a phase change of the signal is reserved; a CNN structure is adopted for training so as to reduce a complexity of the system location-free sensing.

An apparatus for radar synchronization may include a local radar device configured to transmit and receive radar signals; a wireless device configured to wirelessly transmit and receive data; at least one processor operably coupled to the wireless device and the radar device, and the at least one processor configured to perform a method including obtaining local radar information regarding one or more radar pulses sent and/or received by the local radar device; and obtaining neighboring radar information associated with radar pulses sent and/or received from one or more neighboring radar devices; and updating a radar data structure using the obtained local and neighboring radar information, wherein the radar data structure comprises radar information for each of a plurality of radar pulses transmitted by the local radar device and/or the one or more neighboring radar devices.

A sensor signal processing unit (100) arranged to detect a configuration of parking slots (1a,1b,1c,1d) based on radar detections received from a radar-based sensor system (120). The unit includes a histogram unit arranged to generate a representation of a spatial distribution of a set of radar detection coordinates, and a detection unit arranged to detect the configuration of parking slots. The detection unit is arranged to detect the configuration of parking slots based on a Fourier transform of the representation of spatial distribution.

A system for virtual aperture array radar tracking includes a transmitter that transmits first and second probe signals; a receiver array including a first plurality of radar elements positioned along a first radar axis; and a signal processor that calculates a target range from first and second reflected probe signals, corresponds signal instances of the first reflected probe signal to physical receiver elements of the radar array, corresponds signal instances of the second reflected probe signal to virtual elements of the radar array, calculates a first target angle between a first reference vector and a first projected target vector from the first reflected probe signal, and calculates a position of the tracking target relative to the radar array from the target range and first target angle.

A system comprises a first phased array radar assembly configured to be attached to a vehicle. The first phased array radar assembly includes a first plurality of antennas arranged in an array and attached to a circuit board. The system also includes one or more circuits attached to the circuit board. Each of the one or more circuits includes transmitter circuitry communicatively coupled to a subset of the first plurality of antennas and receiver circuitry communicatively coupled to the subset of the first plurality of antennas.

The disclosed system and method for smart detection of an armament projectile can mitigate the detection of its radar by counter-radar systems. Particularly, the system may include an array of acoustic sensors for sensing one or more volleys associated with an armament projectile. An intelligent filtering module, coupled to the array of acoustic sensors, may select a volley based upon a learning algorithm, which can be applied to a target profile of historical system data logs. Based upon sensed parameters of the volley, the intelligent filtering module can calculate a radiation duration and a search fan width for radar transmission. Specifically, a controller, within the intelligent filtering module, may couple to actuate the radar at the calculated search fan width for the calculated radiation duration. In some embodiments, the intelligent filtering module can selectively actuate one radar based upon highest expanded detection probability relative to location and status.

A radar device includes a transmission module and a reception module disposed separately from the transmission module. The transmission module includes: a transmission circuit unit mounted on the first surface of a circuit board; an antenna substrate provided on the second surface side of the circuit board; and a transmission antenna mounted on the second surface of the antenna substrate and not provided in a range on the back surface side of the antenna substrate corresponding to the range in which the circuit board is disposed. The reception module includes: a reception circuit unit mounted on the third surface of a circuit board; an antenna substrate provided on the fourth surface side of the circuit board; and a reception antenna mounted on the fourth surface of the antenna substrate and not provided in a range on the back surface side of the antenna substrate corresponding to the range in which the circuit board is disposed.

Methods, apparatus and systems for wirelessly tracking keystrokes on a surface are described. In one example, a described system comprises: a transmitter configured for transmitting, using a transmit antenna, a first wireless signal through a wireless channel of a venue including the surface; a receiver configured for receiving, using a plurality of receive antennas, a second wireless signal through the wireless channel, wherein the second wireless signal comprises a reflection of the first wireless signal by at least one moving object in the venue; and a processor. The processor is configured for: obtaining, regarding each receive antenna, a time series of channel information (CI) of the wireless channel based on the second wireless signal, detecting at least one keystroke on the surface based on the time series of CI (TSCI) obtained regarding each receive antenna, determining at least one location of the at least one keystroke on the surface, and determining at least one key associated with the at least one keystroke based on the at least one location.

Methods, apparatus and systems for wireless proximity sensing are described. In one example, a described system comprises: a transmitter configured for transmitting a first wireless signal through a wireless multipath channel of a venue; a receiver configured for receiving a second wireless signal through the wireless multipath channel; and a processor. The second wireless signal differs from the first wireless signal due to the wireless multipath channel that is impacted by a movement of an object in the venue. The processor is configured for: obtaining a time series of channel information (TSCI) of the wireless multipath channel based on the second wireless signal, wherein each channel information (CI) of the TSCI comprises a plurality of CI components, each of which is associated with an index; computing an inter-component statistics based on the plurality of CI components; computing, based on the inter-component statistics, a proximity information of the object with respect to a reference location in the venue; and performing a task based on the proximity information of the object.