Apparatus being a first or second apparatus comprising a transceiver and configured to communicate to a second apparatus; wherein the first apparatus is configured to transmit first and second reference signal also referred to as double burst forward link to the second apparatus so that the second apparatus receives the first and the second reference signal in order to calculate a first phase difference d.sub.?1 (d.sub.?1=angle(RS.sub.22,RX)?angle(RS.sub.21,RX)) between the first and the second reference signal and/or to report the first phase difference d.sub.?1; wherein the first apparatus is configured to receive from the second apparatus third and fourth reference signal also referred to as to double burst return link in response to the first and second reference signal in order to calculate a second phase difference d.sub.?2 (d.sub.?2=angle(RS.sub.12,RX)?angle(RS.sub.11,RX)) between the third and the fourth reference signal, and/or to report second phase difference d.sub.?2; wherein a distance and/or a distance change and/or a relative speed (v) of the first and the second apparatus is calculable based on d.sub.?1 and d.sub.?2 or based on the formula d.sub.?Movement=(d.sub.?1+d.sub.?2)/2.

In some implementations, a method may comprise obtaining channel state information (CSI) data corresponding to a set of RF signals received by one or more receiving devices, wherein: the set RF signals comprises two or more reflected RF signals successively received by the one or more receiving devices after being reflected from a person, and the two or more reflected RF signals are received by the one or more receiving devices over a period of time. The method may further comprise determining an identity of the person based at least in part on an observed gait of the person and an observed shape of the person, wherein the observed gait of the person and the observed shape of the person are determined based at least in part on the CSI data. The method may further comprise outputting an indication of the determined identity of the person.

Methods and apparatus to reduce communications for position, navigation and timing (PNT) determinations are disclosed. A disclosed example apparatus to enable PNT determination for a mobile station includes at least one memory, machine readable instructions, and processor circuitry to at least one of instantiate or execute the machine readable instructions to identify features of signals of opportunity (SOOP) measured at a reference station, generate a model based on the identified features of the SOOP in conjunction with a position and a timing of the reference station, and provide at least one of the model or parameters associated with the model to the mobile station for the PNT determination.

An electronic device may include wireless circuitry that detects the location of external objects. A signal generator may concurrently transmit different radio-frequency ranging signals over two or more transmit antennas. The ranging signals may include waveforms with time-varying frequencies, where each waveform includes frequencies that are non-overlapping with the frequencies of each of the other waveforms at any given time. Antennas may receive reflected versions of the ranging signals and a processor may process the reflected versions of the ranging signals to identify the location of the external objects. This may prevent interference between the ranging signals and may significantly reduce the latency of location detection relative to examples where the ranging signals are transmitted by different transmit antennas in series.

First information corresponding to a radio signal received at a first sensing device from a candidate location is obtained. Second information corresponding to a radio signal received at a second sensing device from the candidate location is obtained. A first relationship between the first sensing device and the candidate location and a second relationship between the second sensing device and the candidate location are determined. A first inverse and a second inverse of respectively the first and second relationships are obtained. A first estimate of the radio signal at the first sensing device is determined from the first information and the first inverse. A second estimate of the radio signal at the second sensing device is determined from the second information and the second inverse. Energy emitted from the candidate location is measured based on the first estimate and the second estimate.

A system for multi-ship geolocation of a signal emitter of interest uses differential GPS (DGPS) to determine the relative positions of two or more receivers in order to determine baseline vectors between them. The geolocation of the signal emitter is then determined as a function of the baseline vectors. The use of DGPS allows for more efficient and useful geometries between the receivers as two receivers can both be in a mainlobe of an emitted signal and still provide increased geolocation accuracy.

A method for a first wireless device receiving a reference signal for measuring a distance in a wireless communication system, according to one embodiment of the present invention, may comprise the steps of: receiving, from a second wireless device, a first reference signal comprising a first sinusoidal signal having a first angular frequency and a first initial phase value, and a second sinusoidal signal having a second angular frequency and a second initial phase value; acquiring the phase difference between the first sinusoidal signal and the second sinusoidal signal on the basis of a fast Fourier transform (FFT) performed on the first reference signal; correcting the phase difference on the basis of the first initial phase value and the second initial phase value; and transmitting, to the second wireless device, a second reference signal for measuring a distance, and a third reference signal representing information on the corrected phase difference.

Embodiments provided describe detections of RF leakage test signal emanating from cable plant. In one embodiment a single mobile receive antenna, connected to a complex demodulator mobile receiver, receives a stabilized test signal radiating from the cable plant. The test signal may be a known continuous wave (CW) carrier or other deterministic signal. The received test signal varies in phase as a function of a position of the mobile receive antenna relative to the location of a leakage antenna. The phase variance forms a Doppler shift as the test antenna moves relative to the leakage antenna. The receiver generates multiple in-phase (I) and quadrature (Q) test signal samples over a SPA (synthetic phased array) distance as the test antenna's travels, and the samples are inserted into a Fourier transform. The result of the transform is instantaneous Doppler frequency shift, from which a bearing angle can be computed.

Systems, methods, and apparatus are provided for automated identification of open space in a wireless communications spectrum, by identifying sources of signal emission in the spectrum by automatically detecting signals, analyzing signals, comparing signal data to historical and reference data, creating corresponding signal profiles, and determining information about the open space based upon the measured and analyzed data in near real-time.

A system is disclosed for Doppler nulling configured for security. The system may include a receiver or transmitter node. The receiver or transmitter node may include a communications interface with an antenna element and a controller. The controller may include one or more processors and have information of own node velocity and own node orientation relative to a common reference frame. The receiver or transmitter node may be time synchronized to apply Doppler corrections to signals, the Doppler corrections associated with the receiver or transmitter node's own motions relative to the common reference frame, the Doppler corrections applied using Doppler null steering along Null directions based on a protocol. The protocol may include a protocol modulation, such as a modulation of the signals for security purposes.