A method for improving target location accuracy in direction finding systems is disclosed. A target search region is identified based on a set of received signals, and the target search region is projected onto the earth's surface. An initial search grid, which is smaller than the target search region, is placed within the target search region. Next, the initial search grid is expanded to a full search grid by using an optimum number of virtual grid points in order to cover the entire target search region. The correlation coefficients at the virtual grid points between the estimated phases of emitted signals and the estimated phases of the received signals are then calculated. A target is designated as being at a location associated with the highest correlation coefficient. At this point, a new travel path can be initiated to engage or avoid the target.

A method for improving direction finding and geolocation error estimation in direction finding and geolocation systems is disclosed. The corresponding phases of the received signals are determined. After an initial target estimation point of the received signals has been identified, the initial target estimation point is projected onto the earth's surface. A search grid having multiple grid points is then overlaid on the projected initial target estimation point, surrounding the projected initial target estimation point. The phase of signals emitting from a theoretical emitter located at each of the grid points of the search grid is estimated. Correlation coefficients between the estimated phases of the emitting signals and the determined phases of the received signals are determined. An error ellipse can be generated around one of the grid points having the highest correlation coefficient, and a source emitter is likely to be located within the error ellipse.

Method for estimating the position of a portable device which includes: a first estimation step (11), in which is estimated the position and the extension of a first spatial region (100) where the portable device is located and; a second estimation step (12), in which is estimated the position of the portable device by the selection of the position where the portable device is located among the positions included in the first spatial region (100).

Described herein are techniques for determining motion characteristics of trains traveling along a train track. In some embodiments, a processor may determine an estimated position of a train using an observed position obtained using one or more UWB antennas and an observed position obtained using one or more GNSS receivers. In some embodiments, a processor may access information specifying a geometry of a train track and determining the position of a train along the train track using an observed position determined using one or more UWB antennas and/or GNSS receiver(s) and the information specifying the geometry of the train track. In some embodiments, a processor may determine estimated positions of a train using the geometry of the train track and at least one observation of the train obtained using one or more positioning devices and select the position of the train from among the estimated positions.

A method for improving direction finding and geolocation error estimation in direction finding and geolocation systems is disclosed. The corresponding phases of the received signals are determined. After an initial target estimation point of the received signals has been identified, the initial target estimation point is projected onto the earth's surface. A search grid having multiple grid points is then overlaid on the projected initial target estimation point, surrounding the projected initial target estimation point. The phase of signals emitting from a theoretical emitter located at each of the grid points of the search grid is estimated. Correlation coefficients between the estimated phases of the emitting signals and the determined phases of the received signals are determined. An error ellipse can be generated around one of the grid points having the highest correlation coefficient, and a source emitter is likely to be located within the error ellipse.

Disclosed are a tunnel positioning method, apparatus and system and a storage medium. The method includes: acquiring first delay information corresponding to the first radio remote unit and second delay information corresponding to the second radio remote unit when a target device moves between a first radio remote unit and a second radio remote unit, the first radio remote unit and the second radio remote unit are any two adjacent radio remote units in a tunnel; and determining a position of the target device in the tunnel according to the first delay information, the second delay information, and a distance and a frame header delay difference between the first radio remote unit and the second radio remote unit acquired in advance.

A method for determining geo-position of a target by an aircraft includes: receiving navigation data related to the aircraft including aircraft attitude information; receiving multilateration information related to the target including an angle to the target; calculating an axis for a cone fixed to the aircraft, based on the received aircraft attitude information; calculating a central angle for the cone from the received angle to the target; generating two vectors orthogonal to the cone axis; calculating a cone model from the axis, the central angle and the two vectors; and intersecting the cone model with an earth model to obtain a LEP curve, wherein the LEP curve is used to determine the geo position of the target.

Method for estimating the position of a portable device (A), which comprises: a first estimation step (11), in which is estimated the position and the extension of a first spatial region (100) where is located said portable device (A); a second estimation step (12), in which is estimated the position of said portable device (A) by the selection of said position among the positions included in said first spatial region (100).

Techniques relating to ultra-wideband (UWB) wireless communications include identifying a plurality of clusters for UWB time difference of arrival (TDOA) ranging, where each cluster includes an initiating anchor to transmit a plurality of UWB messages to wireless devices for TDOA ranging. These techniques further include forming a first supercluster including a first two or more clusters, and a second supercluster including a second two or more clusters, based on determining that a respective initiating anchor associated with each of the two or more clusters in the first supercluster is radio frequency (RF) isolated from respective recipient anchors associated with each of the two or more clusters in the second supercluster. The techniques further include conducting TDOA ranging using the plurality of clusters, based on scheduling transmission of UWB messages in parallel from initiating anchors in both the first and second superclusters.

Disclosed are techniques for wireless communication. In an aspect, a positioning entity receives motion state information associated with a user equipment (UE), the motion state information indicating constraints on a location of the UE relative to a moveable object with which the UE is associated, and estimates the location of the UE based on at least the motion state information.