A wireless communication method in a network comprising a plurality of nodes including ranging masters, broadcasting a chirp-modulated ranging requests, and ranging slaves slave, replying with thereto with chirp-modulated ranging responses, whereby mobile nodes can locate themselves passively by listening to the request/reply exchanges, based on the respective time differences of arrival.

Systems (100) and methods (400) for providing Digital Selective Calling (DSC) based services. The methods involve: using Space-Born Maritime (SBM) receivers of satellites (104) deployed in space as a satellite constellation to collect and process DSC emergency messages transmitted from DSC transmitters of terrestrial radios; using the satellites to position validate the DSC emergency messages; determining first positions of the DSC transmitters in transit based on geolocation data and time location data respectively assigned by the satellites to the DSC emergency messages; and validating the first positions to more precise second positions based on results of cross-correlations of the geolocation data and time location data with Automatic Identification Systems (AIS) data obtained for the DSC transmitters.

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.

An apparatus having processing circuitry configured to estimate beyond line-of-sight emitter location may be configured to receive signal information indicative of TDOA and FDOA measurements at a first receiver and a second receiver. The signal information may be generated based on indirect wave signals received from the emitter at each of the first and second receivers. The processing circuitry may be further configured to employ a first analytical model of the ionosphere to generate coarse TDOA and FDOA contour maps, and generate a first geolocation estimate based on the coarse TDOA and FDOA contour maps.

Methods, systems, computer-readable media, and apparatuses for using a smart meter as a reliable crowd-sourcing agent are presented. In some embodiments, a smart meter installed at a location may observe one or more wireless signals at the location. Subsequently, the smart meter may provide, to at least one signal almanac server, information that identifies the location and describes one or more detected properties of the one or more observed wireless signals. In at least one arrangement, the information provided to the at least one signal almanac server may be configured to be used by the at least one signal almanac server in providing position assistance information to one or more mobile devices located in a vicinity of the location.

A method of geolocating comprises: receiving wirelessly, at an asset located on the Earth's surface and from at least two airborne aircraft, ADS-B signals, respectively; interpolating, using a Bayes filter, at least some state information of the at least two airborne aircraft based on the ADS-B signals, respectively; determining differences in received signal strength indicator (RSSI) values (RSSI-difference values) of successive aircraft-specific ADS-B signals, respectively; estimating, using a likelihood function, locations of the asset based on the RSSI-difference values, the ADS-B signals and the interpolated state information, respectively, thereby producing a set of estimated locations; and searching amongst the set to find one of the estimated locations that is regarded as being most likely to most accurately describe an actual position of the asset.

An Ultra Wide Band (UWB) ranging method, a UWB ranging device, and a non-transitory storage medium thereof are provided. The UWB ranging method includes: filtering, in response to determining a first time of flight for UWB ranging, the first time of flight based on a low-pass filter to obtain a filtered first time of flight; and performing the UWB ranging based on the filtered first time of flight.

The invention relates to a method for locating a transmitter, which is implemented in a processing unit of a processing station of a locating system.

Radio frequency (RF) sensing by a sensing entity with an oscillator that introduces frequency errors is supported using dual direction bistatic sensing. The sensing entity transmits a sensing signal that is reflected by an object and received by a second sensing entity, which measures a first frequency offset that includes an oscillator error from the transmission of the sensing signal and a Doppler shift from the object. The sensing entity also receives and measures a second frequency offset of a sensing signal transmitted by the second sensing entity and reflected by the object, which includes a second frequency offset that includes an oscillator error from the reception of the sensing signal and a Doppler shift from the target object. The velocity of the object may be estimated based on a combination of the first and second frequency offsets, which cancels the oscillator error caused by the sensing entity.

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.