In a method for calculating a location of a traffic incident a processor receives a first alarm message. The alarm message has a device identification, an event time stamp indicating detection of an incident, and a first distance vector. The processor calculates first isodistance information from the first distance vector and receives a second alarm message that has the device identification, the event time stamp, and a second distance vector. The processor calculates a second isodistance information for the second alarm message, and calculates a location of the incident based on the first isodistance information and the second isodistance information.

A method for estimating the location of a target user equipment (UE) using a positioning system comprising a set of N positioning reference nodes (PRNs). The method includes determining, from the set of N PRNs, a particular subset of PRNs that minimizes or maximizes an objective function, wherein the objective function is a function that is adapted to map information about a given subset of the N PRNs to an error value indicating a positioning error of the target UE. The method also includes using the determined particular subset of PRNs to estimate the location of the target UE.

A method of localizing a near vertical incidence skywave emitter. At a first site a first elevation angle of an incoming signal issued by the near vertical incidence skywave emitter is measured. At a second site a second elevation angle of an incoming signal issued by the near vertical incidence skywave emitter is measured, wherein the second site is different to the first site. The first elevation angle measured and the second elevation angle measured are converted into a first length and a second length respectively, which represent the distance between the respective site and the estimated location of the near vertical incidence skywave emitter. The respective length is processed, thereby generating an estimated area of the near vertical incidence skywave emitter for each of the different sites such that at least two different estimated areas are generated. The estimated areas for each site are superimposed, thereby obtaining an area of interest encompassing the estimated location of the near vertical incidence skywave emitter. Further, a direction finding system is described.

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 method, performed by a first electronic device, of performing ultra-wideband (UWB)-based communication with one or more electronic devices, is provided. The method includes determining first location information associated with a target point, based on an optical sensor and gradient information of the first electronic device, determining second location information associated with a second electronic device, based on the determined first location information and a UWB signal, determining third location information indicating a location of the target point relative to the second electronic device, based on the determined first location information and the determined second location information, and transmitting the determined third location information to the second electronic device so that the second electronic device performs an operation associated with the target point.

In the present invention, to make it possible to enhance the accuracy of positioning in an area not reached by a GNSS signal: a first position of a host device is estimated; the error of the first position is estimated; from a second device, other device information is received that includes a second position of the second device and a second error of the second position that have been estimated by the second device; and if the second error is smaller than the first error, the first position and first error are corrected on the basis of the other device information.

An interference source hunting method of hunting for an interference source of electromagnetic waves while moving between multiple measurement points, includes the steps of acquiring strength information of electromagnetic waves, estimating a distance from the measurement point to the location of the interference source, based on the strength information, calculating a first presence probability that the interference source is present at each position, based on whether a distance from the measurement point to the position is within the distance, updating second presence probabilities acquired in hunting in the past, based on the first presence probabilities, determining a position obtained by moving, by a predetermined distance, the measurement point toward a position with the second presence probability higher than the second presence probability at the measurement point, as a new measurement point, and determining, in a case where a size of an area in which each of the second presence probabilities is greater than or equal to a predetermined value is less than a predetermined value, that the location of the interference source is within the area.

Disclosed is a technique that can provide one or more countermeasures against spoofers. A beamformer can control an antenna pattern of a CRPA to generate a survey beam. The survey beam is swept across space to determine a characteristic signature based on carrier-to-noise ratios (C/No) for particular space vehicle signals. Matching C/No signatures can be used to identify the existence of spoofers and invoke a countermeasure, such as nulling.

Techniques are disclosed for determining a true bearing angle from an airborne platform to a source of a radar signal. In an embodiment, a grid is generated based on a coarse range to, and angle-of-arrival of, an electromagnetic signal. The grid represents a geographic area thought to contain the emission source. A measured spatial angle is computed for each pulse of the signal received during a data collection interval. Hypothesized spatial angles are computed for a point in each grid box in the grid. A score is generated for each grid point based on the computed hypothesized spatial angles for the grid point and the measured spatial angles. The grid point having the lowest score is identified as a seed location and is used to launch a Nelder-Mead algorithm that converges on a point in the grid. A true bearing angle to the source of a radar angle is computed to the point provided by the Nelder-Mead algorithm.

A system for determining a direction of arrival of a radio signal being emitted by a radio emitter, the system including: a single antenna configured to be moved through multiple spatial positions and configured to receive the radio signal at two or more of the multiple spatial positions; and a controller configured to determine one or more directions of arrival of the radio signal based on: a radio signal frequency; at least one residual phase difference value between at least two of two or more residual phase values each obtained based on the radio signal received by the single antenna at one of the two or more multiple spatial positions; and at least a portion of a motion data indicative of the movement of the single antenna.