A ground map monitor method comprises obtaining positions of communication nodes in a communications network, selecting transmission and reception nodes from the communication nodes, and measuring bistatic signals between the transmission and reception nodes to determine nominal signal performance characteristics for the bistatic signals, including reflected signal time delays, frequency shifts, and power levels. The method further comprises monitoring the bistatic signals for changes to nominal signal performance characteristics. The method uses discriminators between the nominal signal performance characteristics and a current performance level of the bistatic signals, and compares the discriminators against performance thresholds, to determine whether current signal performance characteristics have varied from their nominal levels. An alert signal is broadcast that a section of a navigation map is not useable for navigation of a vehicle if changes in the current performance level of the bistatic signals exceeds the performance thresholds.

Disclosed are systems and techniques for wireless communications. For example, a process can include determining a subset of radio frequency (RF) sensing devices from a plurality of available RF sensing devices for performing an RF sensing technique for a target object. The subset of RF sensing devices may be determined based on a plurality of factors associated with the plurality of available RF sensing devices. The process can include transmitting, to at least one RF sensing device of the subset of RF sensing devices, at least one message instructing the subset of RF sensing devices to perform the RF sensing technique for the target object to obtain one or more characteristics of the target object.

A micro impulse radar (MIR) system includes an MIR transceiver circuit configured to transmit, towards a subject, at least one transmitted radar signal, and receive at least one radar return signal. The system includes a control circuit configured to generate a control signal defining a radar signal parameter of the at least one transmitted radar signal, provide the control signal to the MIR transceiver circuit to cause the MIR transceiver circuit to transmit the at least one transmitted signal based on the radar signal parameter, and determine, based on the at least one radar return signal, a physiological parameter of the subject.

This disclosure provides systems, methods and apparatus, including computer programs encoded on computer storage media, for multistatic radar communications. In some implementations, a transmitting device may transmit, to a receiving device, a radar alert frame followed by a codeword and one or more radar pulses. The radar pulses are transmitted, using beamforming, in a number of directions. The timing information indicates a timing offset or delay between one or more codewords of the codeword sequence and the beginning of the radar pulses. The receiving device may detect one or more codewords of the codeword sequence and an echo of at least one of the radar pulses, and determine the time at which the corresponding pulse was transmitted by the transmitting device. The receiving device may compare the timing of the echo with the timing of the transmitted pulse to determine a relative distance of an object that produced the echo.

A system identifies and localizes an object. The system contains a bistatic FMCW radar sensor system having two FMCW radar sensors and is configured to operate coherently or quasi-coherently and to emit a series of repeating ramp signals. An active RFID transponder is disposed on an object to be identified and to be localized and is configured to produce a modulated bistatic backscatter signal. A ramp signal sent out by the radar sensors at a ramp repetition frequency is modulated with an amplitude modulation signal, the modulation frequency is less than half the ramp repetition frequency. An evaluation unit establishes an association between a beat frequency and the modulation frequency of the active RFID transponder, which modulation frequency is already known, on the basis of the modulated bistatic backscatter signal by two Fourier transforms of the modulated backscatter signal according to the frequency and to the amplitude.

A radar system for air volume surveillance, the radar having a transmitter and receiver with separate antennas. The receiver aperture being relatively large compared with the transmitter aperture such that the receiving beam is narrower than the transmitting beam, which itself is relatively small compared with the volume to be surveyed. Multiple receiving beams can be configured so that collectively they substantially match the angular volume of the transmitting beam; and in which the transmitter is arranged, when operating, to transmit a signal with a duty cycle greater than fifty percent.

A surface-based transmitter system for assisting determination of vehicle location is presented. The system comprises a set of radio frequency (RF) transmitter nodes that, when deployed at different respective locations, are configured to output a sequence of respective RF pulses with a predefined inter-pulse delay between each pair of consecutive RF pulses in the sequence, wherein the pre-defined inter-pulse delay is longer than one microsecond. The set of RF transmitter nodes include at least a first RF transmitter node, a second RF transmitter node, a third RF transmitter node, and a fourth RF transmitter node, which are configured to output a first RF pulse, a second RF pulse, a third RF pulse, and a fourth RF pulse, respectively, of the sequence of RF pulses.

A transmitting STA can transmit a sensing initiation frame to a first receiving STA in a wireless local area network (wireless LAN) system. The sensing initiation frame can include information related to an STA for transmitting a sounding frame and a session identifier (ID) related to an STA group that is to perform sensing. The transmitting STA can transmit the sounding frame to the first receiving STA. The transmitting STA can receive a first feedback frame for the sounding frame from the first receiving STA. The sounding frame can be a frame transmitted to identify a target. The first feedback frame can include information about a channel changed by means of the target. The sounding frame can include a null data packet announcement (NDPA) frame and a null data packet (NDP) frame.

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.

A cellular network system and method provided herein are directed to generating an area topographic map of a surrounding area of the cellular network system. The cellular network system comprises a transmitter, a receiver, memory, and one or more processors (processors) communicatively coupled to the transmitter, the receiver, and the memory. The memory stores computer-executable instructions that, when executed by the processors, perform certain operations. The transmitter transmits in a target direction a first signal, which is a communication signal intended for a user equipment (UE) and the receiver receives a second signal. The processors determine whether the second signal is a reflected signal associated with the first signal, determine topographic data associated with the surrounding area of the cellular network system in the target direction based at least in part on the second signal, and generate the area topographic map of the surrounding area based on the topographic data.