A method and a system for determining an in vivo transit distance and a corresponding transit time for an arterial pulse. An example system comprises a radar receiver connected to a processor to perform time-resolved measurements of reflections of wave pulses and to spectrally filter the reflections to select spectral components associated with the arterial pulse. The resulting signal samples are then organized into groups corresponding to different wave pulses, and the groups are processed to identify samples corresponding to a first arterial pulse point and a second arterial pulse point on the body of a subject, and the identified samples are further processed to determine the in vivo transit distance and the corresponding transit time for the arterial pulse. In some embodiments, a collection of arterial pulse points detected by the measurements may be mapped onto a reference constellation for a more-accurate determination of the in vivo transit distance.

A distributed radar includes a control unit, a receive antenna, and N transmit antennas. The N transmit antennas include a first transmit antenna, a second transmit antenna, and a third transmit antenna. There is a first distance (Δx1) between the first transmit antenna and the second transmit antenna, there is a second distance (Δx2) between the first transmit antenna (201) and the third transmit antenna (203), and Δx1 is less than Δx2. The second transmit antenna is connected to the control unit by using a first cable (L1), the third transmit antenna is connected to the control unit by using a second cable (L2), a ratio of Δx1 to Δx2 is a first ratio, a ratio of a length of L1 to a length of L2 is a second ratio, and the second ratio is greater than the first ratio.

A radar system for tracking UAVs and other low flying objects utilizing wireless networking equipment is provided. The system is implemented as a distributed low altitude radar system where transmitting antennas are coupled with the wireless networking equipment to radiate signals in a skyward direction. A receiving antenna or array receives signals radiated from the transmitting antenna, and in particular, signals or echoes reflected from the object in the skyward detection region. One or more processing components is electronically coupled with the wireless networking equipment and receiving antenna to receive and manipulate signal information to provide recognition of and track low flying objects and their movement within the coverage region. The system may provide detection of objects throughout a plurality of regions by networking regional nodes, and aggregating the information to detect and track UAVs and other low flying objects as they move within the detection regions.

Systems and methods for detecting the presence of a body (typically a human) in a network without fiducial elements while additionally using fiducial elements to assist the system and possibly reduce the computational loading on the system. The fiducial element may be used in many ways including, without limitation, assisting in ignoring some bodies present in the detection area and training the system using additional data.

An imaging apparatus includes: a reflector which covers an imaging space on a pathway that a human passes through, from at least one of both sides of the pathway, and diffusely reflects a sub-terahertz wave; a first light source which emits a sub-terahertz wave onto the reflector; and a first detector which receives a reflected wave of the sub-terahertz wave emitted from the first light source, diffusely reflected by the reflector, and reflected by the human, and generates an image based on the reflected wave received. The first light source and the first detector are located at a first direction side relative to a center of the imaging space in a direction in which the pathway extends.

Aspects of the present disclosure are directed to radar apparatuses and related methods. As may be implemented in connection with one or more embodiments, frequency-based representations of reflected radar signals received by different radar receivers are processed utilizing superposition of and combining of respective ones of the frequency-based representations. In response to said processing, phase noise in the frequency-based representations of reflected radar signals is corrected.

This application relates to a passive coherent location (PCL) system. In one aspect, the PCL system includes a signal measurement device configured to receive a plurality of signals from a plurality of illuminators and generate an In-phase signal and a Quadrature signal corresponding to each illuminator using the received signals. The PCL system also includes a signal processing device configured to detect a first target using the In-phase and Quadrature signals and measure a bistatic range of the first target and a bistatic velocity of the first target to generate a plurality of pieces of line track information corresponding to the first target. The PCL system further includes a locating device configured to generate target track information of the first target using the line track information and predict a position vector and a velocity vector of the first target using the target track information.

In one embodiment, a service receives signal data indicative of phases and gains associated with wireless signals received by one or more antennas located in a particular area. The service determines, from the received signal data, changes in the phases and gains associated with the wireless signals. The service estimates a direction of motion of one or more objects located in the particular area, based on the determined changes in the gains associated with the wireless signals. The service estimates a total mass of the one or more objects located in the particular area based on a ratio of the determined changes in the gains associated with the wireless signals over the determined changes in the phases associated with the wireless signals.

Apparatus and associated methods relate to a method of non-contact motion detection. A one-dimensional optical sensor detects motion of a target or objects on a conveyor belt through a continuous measurement of targets or objects and a real-time comparison of the pixel images captured by the one-dimensional optical sensor. In an illustrative embodiment, a one-dimensional sensor may be configured to determine motion of objects based on changes to the captured intensities of pixel images over time. The sensor may continually capture photoelectric pixel images and compare a current pixel image with a previous pixel image to determine a frame differential image value. The frame differential image value is evaluated against a predetermined threshold over a predetermined time period. Based on the evaluation, a signal is output indicating whether the objects on the conveyor belt are moving or jammed.

A method and system improve on the accuracy of and power consumption of occupancy detection systems. Embodiments may provide a dual mode system that includes a passive infrared sensor with low power consumption and a RADAR-based sensor with higher power consumption that is only powered when the system determines a room is occupied with the passive sensor and no new movement is detected after a threshold duration.