Abstract: A method and a safety system for localizing at least two objects has a control and evaluation unit, and at least one radio location system. The radio location system has at least three arranged radio stations, wherein at least two respective radio transponders are arranged at the objects. The two radio transponders are arranged spaced apart from one another. Position data of the radio transponders and thus position data of the objects can be determined by means of the radio location system, and the position data can be transmitted from the radio station of the radio location system to the control and evaluation unit and/or the position data can be transmitted from the radio transponder to the control and evaluation unit. The control and evaluation unit is configured to cyclically detect and compare the position data of the radio transponders.

Abstract: A radio detection and ranging (radar) signal processing device obtains radar data by compensating for a change in a carrier frequency of a sensed radar signal, and outputs a radar image map based on the obtained radar data. The radar signal processing method includes obtaining a beat frequency signal based on a radar transmission signal generated based on a frequency modulation model and a radar reflection signal obtained from the radar transmission signal being reflected from an object, and generating radar data by compensating the beat frequency signal for a carrier frequency change by the frequency modulation model.

Abstract: An apparatus is disclosed for proximity detection using multiple power levels. In an example aspect, the apparatus includes a first antenna, a second antenna, and a wireless transceiver coupled to the first antenna and the second antenna. The wireless transceiver is configured to transmit multiple transmit signals at multiple power levels via the first antenna. The wireless transceiver is also configured to receive multiple receive signals via the second antenna. At least one receive signal of the multiple receive signals includes a portion of at least one transmit signal of the multiple transmit signals that is reflected by an object. The wireless transceiver is additionally configured to adjust a transmission parameter based on the at least one receive signal. The transmission parameter varies according to a range to the object.

Abstract: An antenna displacement correction method for an OAM multiplexing communication system includes: a step of estimating a displacement amount by evaluating an evaluation function defined such that a theoretical channel response between a transmitting antenna and a receiving antenna matches a measured channel response estimated in a receiving station by using a known signal transmitted from a transmitting station, wherein the theoretical channel response has, as a parameter, the displacement amount indicating an amount of displacement of a reference axis predefined for each of the transmitting antenna and the receiving antenna from a predetermined position with respect to a desired relative positional relationship between the transmitting antenna and the receiving antenna; and a step of correcting a displacement of each of the transmitting antenna and the receiving antenna according to the estimated displacement amount.

Abstract: Based on a ratio between Doppler frequencies calculated from a plurality of reception signals outputted by a receiver, a position detector calculates a relative position of a plurality of antennas in a mobile wireless apparatus to a stationary wireless apparatus. A train position detector calculates a position of a train from the calculated relative position, a placement position of the stationary wireless apparatus and placement positions in the train of the plurality of antennas.

Abstract: Disclosed are a variable antenna and an apparatus for detecting a radio signal. The variable antenna includes: a first receiving unit including at least one liquid metal antenna element; a second receiving unit including at least one liquid metal antenna element having a length different from a length of the first receiving unit; and a gain control unit configured to electrically adjust lengths of the liquid metal antenna elements for one of the first receiving unit and the second receiving unit according to the frequency of a received signal, wherein each antenna array realized by the liquid metal antenna elements of the first receiving unit and the second receiving unit is arranged in a single bay.

Abstract: A subsea measurement system (400) comprises a first reference beacon (110) disposed at a first known location, a second reference beacon (112) disposed at a second known location, and an acoustic communications module (302) for coupling to a subsea element to be monitored. The acoustic communications module (302) is capable of moving, when in use, relative to the first reference beacon (110) and the second reference beacon (112). The acoustic communications module (302) also comprises a processing resource and is arranged to determine first range-related data to the first reference beacon (110) in response to receipt of a first signal by the acoustic communications module (302) from the first reference beacon (110) and second range-related data to the second reference beacon (112) in response to receipt by the acoustic communication module (302) of a second signal from the second reference beacon (112).

Abstract: The present invention discloses a method for scheduling user equipment on a full-duplex cellular network, including: determining a pairing set for each piece of user equipment in a cell, where a pairing parameter of the piece of user equipment and any piece of user equipment that is in the pairing set of the piece of user equipment meets a preset threshold; and selecting, when a piece of user equipment is scheduled to perform data transmission, another piece of user equipment from a pairing set of the piece of user equipment to perform data transmission in an opposite direction. Embodiments of the present invention further provide a corresponding apparatus. According to the technical solution of the present invention, existing spectrum resources can be utilized more thoroughly and spectrum utilization efficiency of wireless access can be improved.

Abstract: A phase-locked loop (PLL) filter of a read channel includes a filter portion having an input coupled to delay circuitry having an output. The input of the filter portion is configured to receive a phase error signal. A look-up table is coupled to the filter portion. The look-up table comprises phase coefficients and frequency coefficients associated with a plurality of phase error magnitudes. The look-up table is configured to provide one or both of a selected phase coefficient and a selected frequency coefficient based on a magnitude of the phase error signal. The PLL filter is configured to adjust a bandwidth of the filter portion using one or both of the selected phase coefficient and the selected frequency coefficient. A phase signal indicative of estimated phase disturbance is produced at the output of the delay circuitry.

Abstract: A system, method, and apparatus for a significant random number generator are disclosed. The method involves sensing, with a sensor on a spacecraft, a physical phenomenon. In one or more embodiments, the system utilizes a Lower Earth Orbiting (LEO) Iridium satellite for the spacecraft. The method further involves outputting, from the sensor, a value for the physical phenomenon. Also, the method involves inputting the value of the physical phenomenon into a pseudo-random number generator (PRNG). In addition, the method involves generating, with the PRNG, a sequence of random numbers using the value of the physical phenomenon as a seed for the PRNG. In some embodiments, the disclosed significant random number generator is employed by a spot beam based authentication system that is used to authenticate a claimant. In other embodiments, the disclosed significant random number generator is used for cryptology, routing network traffic, anti-jamming, certified time stamping, and secure identification applications.

Abstract: The present application discloses a personal navigation system for providing route guidance and description information to visually impaired users. The system includes a terminal located near an entrance of an area to be traversed. The terminal stores data related to the physical layout of the area. A plurality of location transmitters are distributed about the area and broadcast a signal. A portable electronic device is configured to receive data from the terminal upon entry and determine the location of the user by processing the broadcasted signal of the transmitters. Route guidance is provided to the user via audible or sensory methods. Information may also be provided to the user describing the surrounding area.

Abstract: In general, the subject matter described in this specification can be embodied in methods, systems, and program products for identifying a location of a mobile computing device. A first location estimate of a mobile computing device and an accuracy of the first location estimate is determined at a mobile computing device based on wireless signals received from one or more beacons. A time period based on the accuracy of the first location estimate is determined. One or more subsequent location estimates of the mobile computing device and respective accuracies are determined. The determination of the subsequent location estimates is stopped at an end of the time period. A preferred location estimate from the determined location estimates is determined at the mobile computing device.

Abstract: In general, the subject matter described in this specification can be embodied in methods, systems, and program products for identifying a location of a mobile computing device. A first location estimate of a mobile computing device and an accuracy of the first location estimate is determined at a mobile computing device based on wireless signals received from one or more beacons. A time period based on the accuracy of the first location estimate is determined. One or more subsequent location estimates of the mobile computing device and respective accuracies are determined. The determination of the subsequent location estimates is stopped at an end of the time period. A preferred location estimate from the determined location estimates is determined at the mobile computing device.

Abstract: An apparatus includes a transmitter and a receiver device, which includes a receiver section and a processing module. The transmitter transmits a high carrier frequency signal. The receiver section includes first and second antennas that have an antenna radiation relationship for receiving the high carrier frequency signal. A receiver module of the receiver section determines first and second signal properties of the received high carrier frequency signal. The processing module determines a position of the receiver device with respect to the transmitter based on the first and second signal properties and maps the position to a coordinate system.

Abstract: There is provided a communication device including: a receiving unit that receives radio signals transmitted from another communication device using a plurality of transmitting antennas by a plurality of receiving antennas; an estimation unit that estimates a range of a position where said another communication device possibly exists based on a phase of each radio signal received by the receiving unit and antenna spacing between the transmitting antennas; and a position determination unit that determines an existing position of said another communication device within the range estimated by the estimation unit.

Abstract: Synthetic aperture antenna device for receiving signals of a system comprising a carrier and means for determining its trajectory, comprising, for each signal respectively associated with a spatial direction, processing means adapted for generating a signal with stationary phase over a time window corresponding to the distance traversed by the device during the duration of coherent integration, after demodulation of the said signal received, the said processing means comprising correction means adapted for correcting the carrier phase of the said signal.

Abstract: An apparatus includes a transmitter and a receiver device, which includes a receiver section and a processing module. The transmitter transmits a high carrier frequency signal. The receiver section includes first and second antennas that have an antenna radiation relationship for receiving the high carrier frequency signal. A receiver module of the receiver section determines first and second signal properties of the received high carrier frequency signal. The processing module determines a position of the receiver device with respect to the transmitter based on the first and second signal properties and maps the position to a coordinate system.

Abstract: Example methods, apparatuses, and articles of manufacture are disclosed herein that may be utilized to facilitate or otherwise support RF ranging-assisted local motion sensing based, at least in part, on measuring one or more characteristics of a range between communicating devices in one or more established RF links.

Abstract: Methods and systems for determining the distance between two objects and optionally activating an alarm when the distance exceeds a predetermined threshold. The detection system includes a base unit and a remote unit. The base unit includes a first transmitter for transmitting at least one locator pulse; a first receiver for receiving at least one return pulse, the first receiver including a pulse detector for detecting the leading edge of the at least one return pulse; and a distance measurement unit. The remote unit includes a second receiver for receiving the at least one locator pulse; and a second transmitter for transmitting the at least one return pulse in response to the at least one locator pulse. The distance measurement unit is adapted for determining the distance between the base unit and the remote unit based on the leading edge of the at least one return pulse.

Abstract: A distance separation tracking process is provided that includes the transmission of a periodic radio frequency original signal from a beacon transceiver. The original periodic signal from the beacon transceiver is received at a remote target transceiver as a target received periodic signal. The target retransmits the received periodic signal to the beacon transceiver as a return periodic signal. Data points of the return periodic signal are sampled and used to calculate a phase differential between the original periodic signal and the return periodic signal that correlates to the distance separation range between the beacon transceiver and the target transceiver.

Abstract: Methods and systems to determine at multi-dimensional coordinates of an object based on propagation delay differences of multiple signals received from the object by each of a plurality of sensors. The signals may include optical signals in a human visible spectrum, which may be amplitude modulated with corresponding frequency tones. An envelope may be detected with respect to each of the sensors, and signals within each envelope may be separated. A phase difference of arrival may be determined for each of the signals, based on a difference in propagation delay times of the signal with respect to multiple sensors. The phase differences of arrival may be converted to corresponding distance differences between a corresponding transmitter and the corresponding sensors. A linear distance and a perpendicular offset distance may be determined from a combination the distance differences, a distance between the corresponding transmitters, and a distance between the corresponding sensors.

Abstract: A method and apparatus are disclosed for determining the position, or change in the position, of a mobile terminal. The terminal has a receiver for receiving the signals from one or more transmission sources at unknown positions and an independent positioning device able to find, when operative, the position of the mobile terminal. The method uses the independent positioning device to measure the position of the mobile terminal at one or more first locations. A respective first set of time or phase offset values of signals received from the transmission sources relative to each other or to a reference in the mobile terminal is measured in the mobile terminal, at each first location.

Abstract: Embodiments of the present invention include a method of determining a location of a mobile device. The method comprises transmitting a signal between a plurality of known locations and receiving signal at device of unknown location such as a mobile device. The signal may include multiple tones having different frequencies and resulting in sets of residual phase differences. The location of the mobile device may be determined using the known locations and the frequency and phase differences between the transmitted tones. In one embodiment, OFDM signals may be used between an access point and mobile device, for example, to determine the location of the mobile device.

Abstract: The invention relates to a method for increasing the location accuracy for unsynchronized radio subscribers, in which phase evaluation is used to ascertain the position of a transmitter which is to be located. The transmitter to be located and a further transmitter, whose location is known, respectively send a sequence of N signals to at least two receivers, wherein the transmission channel to be used for transmitting a signal is varied, in line with the invention, on the basis of a prescribed, symmetrical hopping scheme. The advantageous characteristics of the hopping scheme and the additional application of the TDOA (time difference of arrival) principle mean that highly accurate location is possible.

Abstract: Embodiments of a circuit are described. In this circuit, a transmit circuit provides signals to antenna elements during an acquisition mode, where a given signal to a given antenna element includes at least two frequency components having associated phases, and where the phase of a given frequency component in the given signal is different from phases of the given frequency component for the other antenna elements. Moreover, an output node couples the transmit circuit to the antenna elements that transmit the signals. Note that these signals establish an angle of a communication path between the circuit and another circuit.

Abstract: There is provided a communication device including: a receiving unit that receives radio signals transmitted from another communication device using a plurality of transmitting antennas by a plurality of receiving antennas; an estimation unit that estimates a range of a position where said another communication device possibly exists based on a phase of each radio signal received by the receiving unit and antenna spacing between the transmitting antennas; and a position determination unit that determines an existing position of said another communication device within the range estimated by the estimation unit.

Abstract: There is provided a method and system for positioning a transponder, the system comprising an antenna array of at least two spaced-apart antennas coupled to a common generating and switching unit. The generating and switching unit is configured for generating a periodic signal and switching the signal between said at least two antennas, constituting a positioning signal transmitted to the transponder. The system comprises a receiver for receiving a returned signal and a phase difference estimator coupled to the receiver and operable to measure phase differences between portions of the returned signal. The system further comprises a positioning utility coupled to said phase difference estimator and configured to determine the position of the transponder relative to the positioning system.

Abstract: A method and system for locating and positioning using broadcast frequency modulation (FM) signals, is provided. One implementation involves receiving FM stereo signals from three FM stations at one or more receivers, each stereo signal including a modulated 19 KHz FM pilot tone; and determining a geographical position at each receiver based on the phase difference of the demodulated pilot tones in the received FM signals.

Abstract: The present disclosure provides an RTD that is released from a single primary platform to collect signals from a target emitter and relay data back to a single primary platform, enabling the precise geo-location of the target emitter to be determined in a minimal amount of time. The RTD is released from a single platform and quickly creates a long signal collection baseline between the released RTD and the single platform. Various techniques for determining geo-location may be used with the present disclosure, such as angle of arrival (AOA), time difference of arrival (TDOA), and frequency difference of arrival (FDOA) methods.

Abstract: An Automatic Location Identification (ALI) system for cellular telephone networks, along with a pseudo Automatic Number Identification (ANI) typically representing a particular face of a cell tower receiving an emergency call, compares the electromagnetic footprint of the call to stored field strength data to ascertain the coordinates of a small polygon subsuming the location of the caller. Along with connecting the emergency call to the emergency (i.e., “911”) dispatch center, the system also transmits the caller's Directory Number (DN), the cell tower location, and the coordinates of the location polygon. This approach gives the emergency dispatch center a more definite location than prior art approaches which only provide a large triangular area based on a cell tower face as the location region of the caller. It can also serve as a back-up to more sophisticated resource-intensive approaches using signal time differentials and the like.

Abstract: A glide path transmitter for an instrument landing system. The transmitter includes several antenna radiators by way of which high frequency signals containing various low frequency modulated carrier and side band components are radiated. The components overlap each other in the far field where they form a guide signal which can be evaluated by aircraft. Phases of the carrier oscillations of the radiated high frequency signals form the guide signal having a set relationship with each other. A separate digitally controlled modulator is provided for each high frequency signal fed to an antenna radiator. The modulator modulates the phase and amplitude of a high frequency oscillation fed thereto according to a given model and inputs the modulated high frequency signal into the antenna radiator allocated thereto, thus reducing the supply network expenditure.

Abstract: A method and system for determining the geolocation--i.e., the latitude, longitude, and altitude--of a stationary RF signal emitter from two or more moving observer aircraft. The observers receive signals from the emitter and the system measures the phase difference between the signals. The observers then perform pulse time of arrival (TOA) measurements over a predetermined clock interval, and calculate the time difference of arrival (TDOA) of corresponding, same-pulse, emitter signals. Based on geometric relationships, the system creates a series of circular lines of position (LOPs) for each observer, and computes hyperbolic LOPs based on the TDOA calculations. The system determines emitter location from the intersection of the hyperbolic LOPs and the circular LOPs.

Abstract: A positioning system uses a multiplicity of commercial broadcast stereo FM radio signal transmitters, at known fixed locations, each of which transmits a beacon signal having a phase that is un-synchronized with the phases of the beacon signals of the other transmitters. All the beacon signals have a frequency approximately equal to a 19 KHz. A fixed position observer unit, positioned at a known location, receives the beacon signals from all the transmitters in the vicinity, determines their relative phases, and broadcasts data representing these relative phases. Mobile units, at unknown locations, receive these broadcast values, as well as beacon signals from at least three radio transmitters. Each mobile unit includes phase detection circuitry that detects the phases of the beacon signals at the mobile receiver's current position. This is accomplished using a single radio signal receiver.

Abstract: A positioning system uses a multiplicity of commercial broadcast stereo FM radio signal transmitters, at known fixed locations, each of which transmits a beacon signal having a phase that is un-synchronized with the phases of the beacon signals of the other transmitters. All the beacon signals have a frequency approximately equal to a 19 KHz. A fixed position observer unit, positioned at a known location, receives the beacon signals from all the transmitters in the vicinity, determines their relative phases, and broadcasts data representing these relative phases. Mobile units, at unknown locations, receive these broadcast values, as well as beacon signals from at least three radio transmitters. Each mobile unit includes phase detection circuitry that detects the phases of the beacon signals at the mobile receiver's current position. This is accomplished using a single radio signal receiver.

Abstract: In a method of locating and orienting a first direction linked to the position and to the orientation of an autonomous first mobile object (M), such as a ship towing a marine geophysical prospecting cable, and a second direction formed by a non-autonomous second mobile object (Bj), such as a buoy at the trailing end of the towed cable, and at least one reference point on the first mobile object relative to a fixed reference radionavigation system comprising at least two reference beacons (Si, Si+1) the first mobile object (M) and the second mobile object (Bj) are respectively provided with a first communication device (MI) providing communications between the first mobile object (M) and the reference beacons (Si, Si+1) and a second communication device (MJ) providing communications between the first mobile object (M) and the second mobile object (Bj). They are further provided with a communication device (BIJ) providing communications between each reference beacon (Si, Si+1) and the second mobile object (Bj).

Abstract: A method and a system for radio direction-finding by measuring the Time of Arrival (ToA) of the leading edge of signals from a distant source at two relatively closely spaced receiving elements. In order to give a good degree of immunity to multipath, the times at which the instantaneous detected amplitudes of the received signals first exceed a minimal threshold value such that received signals can be satisfactorily distinguished from noise is measured in such a manner that the measured time is not affected by multipath which involves more than a few meters additional path length for the indirect, delayed signal. A suitable timing circuit is disclosed.By making ToA measurements on three coplanar, non-collinear receivers, directions of incidence in three dimensions can be determined.A method and a system using both ToA and phase-difference measurements can provide the accuracy of interferometry but be simpler and cheaper.

Abstract: A distance-measuring receiver and system uses a transmitter which transmits only a single continuous-wave signal. The receiver produces a first component and a second component from the received signal. The first component is frequency doubled and used to produce a signal indicative of the beginning of a measurement window. The second component is used to produce a signal indicative of the end of the measurement window. The size of the measurement window can be used to produce a real time indication of the position of the receiver form the transmitter.

Abstract: A distance measuring receiver system and method for determining the distance of a receiving station from a transmitting station, which provides the distance information by the reception and processing of a pair of signals (preferably continuous wave carrier) transmitted by the transmitting station. The filter subsystem 106 supplies the upper signal to the first channel 501 and the lower signal to the second channel 502 of a lane expansion subsystem 108, which produces a plurality of difference frequency signals 113, 115, 117, 119 (of preselected multiples) in accordance with the upper and lower signals. A reference subsystem 112 in accordance with the oscillator signal 121 supplies a plurality of reference signals 127, 129, 131, 133 (having frequencies equal to the frequencies corresponding to difference frequency signals).

Abstract: A craft guidance system 200 has signal transmission stations AB, CD, AC operable to provide three intersecting hyperbolic lattices 21, 20, 120. One transmission station pair AB provides a moving lattice 21 which travels at the same speed and in the direction of the craft 22 using the system. The other station pairs CD, AC provide fixed lattices 20, 120. Equipment (FIG. 5) carried by the craft 22 operates whereby, when translated by reference to the phase difference between the transmissions of each pair AB, CD, AC, the lattices 21, 20, 120 provide hyperbolic lines of position continuously in time at infinitely variable positions. The moving lattice 21 is caused to travel at the intended speed and in the direction of the craft 22. The fixed lattice 20 provides craft track guidance; and both fixed lattices together provide craft position fixes. The fixed lattice 20 and the moving lattice 21 together provide craft moving position guidance; the moving lattice 21 provides craft speed guidance.

Abstract: A circuit is shown which utilizes signals transmitted from global positioning system satellites to create change in phase signals. The change in phase signals are measured over a predetermined time interval, one second, and stored. The stored signals are applied to a Kalman filter and back to the storage unit so that each one second time interval includes the information from all previous time intervals. This accumulated information is referred to as accumulated Delta-Range information which permits a more rapid determination of position by the circuit.

Abstract: A vehicle-mounted passive synthetic aperture system for locating sources of electromagnetic radiation having a given wavelength .lambda.. The system includes first and second receiving antennas, a phase sensitive receiver and a signal processor. The first and second antennas are mounted to a vehicle and spaced apart from each other in the principle direction of motion associated with the vehicle. The first and second antennas respectively provide first and second received signals in response to a wavefront of electromagnetic radiation having the given wavelength .lambda.. The phase sensitive receiver is coupled to the first and second antennas and responds to the first and second received signals by providing a phase difference signal that indicates a phase difference .phi. between the wavefronts of the radiation of the given wavelength received by the respective first and second antennas when the received radiation is radiated spherically from its source. The speed of the vehicle also is measured.

Abstract: Incoming radio frequency signals from one or more remote transmitters, that may be changing or "hopping" in frequency, are received at two closely spaced antennas. A pair of Chirp-Z transform processors are respectively coupled to said antennas. The transform processors are operated in synchronism and produce a pair of sampled comb filter output responses, each of which comprises a multiple of frequency "bins" distributed over a given spectrum. The bins are read out of the Chirp-Z processors in a synchronous sequential order, and each bin is represented by a pair of signals in phase quadrature. The phase quadrature signals of corresponding bins are multiplied in a predetermined manner and the products thereof are selectively added and subtracted to provide a predetermined function (tan .PHI.) of the phase difference (.PHI.) between the signals incident on the pair of antennas. This predetermined function is coupled to a processor that calculates a trigonometric function (sin.sup.