Remote recovery of acoustic signals from passive sources is provided. Wideband radars, such as ultra-wideband (UWB) radars can detect minute surface displacements for vibrometry applications. Embodiments described herein remotely sense sound and recover acoustic signals from vibrating sources using radars. Early research in this domain only demonstrated single sound source recovery using narrowband millimeter wave radars in direct line-of-sight scenarios. Instead, by using wideband radars (e.g., X band UWB radars), multiple sources separated in ranges are observed and their signals isolated and recovered. Additionally, the see-through ability of microwave signals is leveraged to extend this technology to surveillance of targets obstructed by barriers. Blind surveillance is achieved by reconstructing audio from a passive object which is merely in proximity of the sound source using clever radar and audio processing techniques.

A multiple input multiple output (MIMO) radar system for detecting a moving object is based on an explicit signal model. The explicit signal model accounts for waveform separation residuals by relating measurements of the virtual array to an auto-term including a Kronecker product of object-receiver signatures and transmitter-object signatures; and a cross-term including a Kronecker product of object-receiver signatures and transmitter-object residual signatures. The radar system uses a spatial MIMO object detector that is based on the explicit signal model to detect the moving object.

A multiple input multiple output (MIMO) radar system for detecting a moving object is based on an explicit signal model. The explicit signal model accounts for waveform separation residuals by relating measurements of the virtual array to an auto-term including a Kronecker product of object-receiver signatures and transmitter-object signatures; and a cross-term including a Kronecker product of object-receiver signatures and transmitter-object residual signatures. The radar system uses a spatial MIMO object detector that is based on the explicit signal model to detect the moving object.

In an inductive charging system energy is transferred via a magnetic field. An object detection apparatus for an inductive charging system comprises: a transmitter configured to transmit a signal; a receiver having a field of view including a substantial portion of the magnetic field, the receiver configured to receive within the field of view a reflected signal of the signal; and a signal processor configured to examine characteristics of the received, reflected signal to identify a hazard condition in relation to the magnetic field. By converting the received signal into a frequency domain signal, hazard conditions may be identified depending on the form of the frequency domain signal. The object detection apparatus is suitable for use in a charging apparatus for an electric vehicle.

Radio frequency motion sensors may be configured for operation in a common vicinity so as to reduce interference. In some versions, interference may be reduced by timing and/or frequency synchronization. In some versions, a master radio frequency motion sensor may transmit a first radio frequency (RF) signal. A slave radio frequency motion sensor may determine a second radio frequency signal which minimizes interference with the first RF frequency. In some versions, interference may be reduced with additional transmission adjustments such as pulse width reduction or frequency and/or timing dithering differences. In some versions, apparatus may be configured with multiple sensors in a configuration to emit the radio frequency signals in different directions to mitigate interference between emitted pulses from the radio frequency motion sensors.

Radio frequency motion sensors may be configured for operation in a common vicinity so as to reduce interference. In some versions, interference may be reduced by timing and/or frequency synchronization. In some versions, a master radio frequency motion sensor may transmit a first radio frequency (RF) signal. A slave radio frequency motion sensor may determine a second radio frequency signal which minimizes interference with the first RF frequency. In some versions, interference may be reduced with additional transmission adjustments such as pulse width reduction or frequency and/or timing dithering differences. In some versions, apparatus may be configured with multiple sensors in a configuration to emit the radio frequency signals in different directions to mitigate interference between emitted pulses from the radio frequency motion sensors.

A SIL monopulse radar includes a self-injection-locking oscillator (SILO), a transmit antenna, two receive antennas, a hybrid coupler, a first demodulator, a second demodulator and a processor. The transmit antenna transmits the oscillation signal of the SILO to object. The two receive antennas receive a reflected signal from the object as a first echo signal and a second echo signal. The hybrid coupler outputs a difference signal and a sum signal. The difference signal is injected into the SILO. The first demodulator frequency-demodulates the oscillation signal to produce a first demodulated signal. The second demodulator phase-demodulates the sum signal by using the oscillation signal as a reference signal to produce a second demodulated signal. The processor processes the first and second demodulated signals to produce a monopulse ratio signal. The SIL monopulse radar can identify the posture and motion of a human body by analyzing the monopulse ratio signal.

A SIL monopulse radar includes a self-injection-locking oscillator (SILO), a transmit antenna, two receive antennas, a hybrid coupler, a first demodulator, a second demodulator and a processor. The transmit antenna transmits the oscillation signal of the SILO to object. The two receive antennas receive a reflected signal from the object as a first echo signal and a second echo signal. The hybrid coupler outputs a difference signal and a sum signal. The difference signal is injected into the SILO. The first demodulator frequency-demodulates the oscillation signal to produce a first demodulated signal. The second demodulator phase-demodulates the sum signal by using the oscillation signal as a reference signal to produce a second demodulated signal. The processor processes the first and second demodulated signals to produce a monopulse ratio signal. The SIL monopulse radar can identify the posture and motion of a human body by analyzing the monopulse ratio signal.

A system for providing contactless movement of a vehicle door relative to a vehicle body including an electric-motor movement device for moving the vehicle door, a radar sensor system for detecting, in the region of the vehicle door, a gesture to be performed by a user, and a control device for controlling the movement device according to a detection by the radar sensor system. The radar sensor system is configured to detect, in a first operating mode, a movement in a detection region in an environment of the vehicle door and to detect, in a second operating mode, a gesture for moving the vehicle door, the radar sensor system being configured to switch to the second operating mode when a movement is detected in the first operating mode.

Systems and methods for Wi-Fi sensing using UL-OFDMA are provided. Wi-Fi sensing systems include sensing devices and sensing transmitters configured to communicate through radio-frequency signals. Initially, first channel resources are allocated to first expected transmissions from the sensing transmitters and first sensing trigger message to trigger first series of sensing transmissions from the sensing transmitters is transmitted. Further, a first series of sensing transmissions is received, and the first series of sensing measurements are generated. Thereafter, identification of feature of interest is obtained and a selection of sensing transmitters is determined. Second channel resources are allocated to second expected transmissions from the selection of sensing transmitters. A second sensing trigger message to trigger a second series of sensing transmissions from the selection of the sensing transmitters is provided. A series of sensing transmissions is received, and a second series of sensing measurements is generated based on the second series of sensing transmissions.