Methods, apparatus and systems for outdoor target tracking are described. In one example, a described system comprises: a transmitter, a receiver, and a processor. The transmitter is configured for transmitting a first wireless signal through a wireless multipath channel. The receiver is configured for receiving a second wireless signal through the wireless multipath channel. One of the transmitter and the receiver is a located device at a known location. The other of the transmitter and the receiver is a moving device. The second wireless signal differs from the first wireless signal due to the wireless multipath channel which is impacted by a movement of the moving device. The processor is configured for: obtaining a plurality of time series of channel information of the wireless multipath channel based on the second wireless signal, computing a spatial-temporal information (STI), and tracking the moving device based on the STI.

The invention is directed to a receiver (100) for an RF presence-sensing arrangement (150). The receiver is configured to receive a first intra-network RF sensing signal (102) from a first transmitter (104), both pertaining to a first local-area RF communication network (106) spanning a first presence-sensing volume (114) and to additionally receive an inter-network RF sensing signal (108) from a second transmitter (110) pertaining to a second local-area RF communication network (112), thus spanning a third presence-sensing volume (120) and to provide a first and an inter-network signal-strength signal (S.sub.1, S.sub.3) indicative of a respective received-signal strength. In the RF presence-sensing arrangement, a presence detection unit (122) is configured to provide, based on the signal-strength signals, a presence detection signal (S.sub.DET) indicative of a change in presence of a subject or object in the first or in the third presence-sensing volume, thus increasing the accuracy of the presence determination.

In a general aspect, a system is disclosed for sensing radio frequency (RF) electromagnetic radiation. The system includes a receiver formed of dielectric material. The receiver includes a photonic crystal structure having an elongated slot disposed therein. The receiver also includes an antenna structure extending from the photonic crystal structure and configured to couple to a target RF electromagnetic radiation having a frequency in a range from 100 MHz-1 THz. A vapor or source of the vapor in the elongated slot. The system also includes a laser system configured to provide input optical signals to the elongated slot that interact with one or more electronic transitions of the vapor. The system additionally includes an optical detection system configured to detect the target RF electromagnetic radiation based on output optical signals from the elongated slot.

Computerized method and system for estimating a rain attribute on microwave communications, the estimation being carried out by: obtaining quantized minimum and maximum levels of received signals and transmitted signals over a microwave link during a period; subtracting the quantized maximum level of received signals from the quantized minimum level of transmitted signals to provide a minimal attenuation value; subtracting the quantized minimal level of received signals from the quantized maximal level of transmitted signals to provide a maximal attenuation value; calculating an attenuation difference related to the period by subtracting the minimal attenuation value from the maximal attenuation value; calculating a bias compensated attenuation difference based on the attenuation difference, and bias value related to the microwave link; and calculating the rain attribute, including the average rain during the period, based on the bias compensated attenuation difference.

Bi-static radio-based object location detection can include determining, by a wireless device, a location of a remote wireless device; obtaining a ToF and an angle of arrival (AoA) of a reflected WWAN reference signal reflected by a remote object; and determining a location of the remote object based on the location of the remote wireless device, the ToF, and the AoA. In another example, a wireless device includes a wireless transceiver; a non-transitory computer-readable medium; and a processor communicatively coupled to the wireless transceiver and non-transitory computer-readable medium, the processor configured to determine a location of a remote wireless device; obtain a ToF and an angle of arrival (AoA) of a reflected WWAN reference signal reflected by a remote object; and determine a location of the remote object based on the location of the remote wireless device, the ToF, and the AoA.

A multistatic array topology and image reconstruction process for fast 3D near field microwave imaging are presented. Together, the techniques allow for hardware efficient realization of an electrically large aperture and video-rate image reconstruction. The array topology samples the scene on a regular grid of phase centers, using a tiling of multistatic arrays. Following a multistatic-to-monostatic correction, the sampled data can then be processed with the well-known and highly efficient monostatic Fast Fourier Transform (FFT) imaging algorithm. In this work, the approach is described and validated experimentally with the formation of high quality microwave images. The scheme is more than two orders of magnitude more computationally efficient than the backprojection method. In fact, it is so efficient that a cluster of four commercial off-the-shelf (COTS) graphical processing units (GPUs) can render a 3D image of a human-sized scene in 0.048-0.101 seconds.

A Doppler motion sensor device is used for detecting a motion of an object. The Doppler motion sensor device includes a first antenna and a second antenna. The first antenna is used to transmit or receive a first wireless signal. The second antenna is used to transmit or receive a second wireless signal. A first straight line passing through a first feed-in point and a first middle point of the first antenna is orthogonal to a second straight line passing through a second feed-in point and a second middle point of the second antenna. One of the first wireless signal and the second wireless signal is a transmission signal. The transmission signal is reflected by the object to form the other one of the first wireless signal and the second wireless signal.

Systems, methods, and devices are provided for detecting the presence of an object near an electronic device. A radio frequency (RF) system of an electronic device may include a first circuit that includes one or more transmission paths for transmitting a reference signal external to the electronic device. The RF system may include a second circuit that includes one or more receiving paths for receiving a reflection signal based on the reference signal. The RF system may also include a processor that may instruct the RF system to perform a comparison between the reference signal and the reflection signal, determine whether the object is in proximity based at least in part on whether comparison results exceed a comparison threshold, and decrease power output by the RF system below the comparison threshold.

A system for generating a three dimension (3D) imaging of an object, the system comprising: an electromagnetic transducer array such as an RF (radio- frequency) antenna array surrounding the object said array comprising: a plurality of electromagnetic transducers; a transmitter unit for applying RF signals to said electromagnetic transducer array; and a receiver unit for receiving a plurality of RF signals affected by said object from said electromagnetic transducers array; a Radio Frequency Signals Measurement Unit (RFSMU) configured to receive and measure said plurality of plurality of affected RF signals and provide RF data of the object; and at least one processing unit, configured to process said RF data to identify the dielectric properties of said object and construct a 3D image of said object.

This disclosure provides systems, methods and apparatus, including computer programs encoded on computer storage media, for multistatic radar communications. In one aspect, a wireless communication device may determine a distance and direction of one or more receiving devices. The wireless communication device may transmit, to the one or more receiving devices, timing information indicating a timing relationship between a codeword sequence and one or more pulses. The wireless communication device may transmit a respective codeword of the codeword sequence in the direction of each of the one or more receiving devices. The wireless communication device may further transmit the one or more pulses in a plurality of directions. The wireless communication device may receive feedback from at least one of the one or more receiving devices and determine ranging information about an object based on the feedback and the distance or direction of at least one receiving device.