Techniques are provided for geolocation of a radar emitting source. A methodology implementing the techniques according to an embodiment includes calculating time difference of arrival (TDOAs) of ground emitter radar pulses, within a dwell period, between two long baseline interferometer (LBI) antennas. The TDOA calculations are based on a precision estimate of the time of arrival of the radar pulses. The method further includes calculating an LBI phase wrap disambiguation factor based on (1) the TDOAs, (2) an average of frequencies of the radar pulses within the dwell period, and (3) an average of phase shifts of the radar pulses between the LBI antennas within the dwell period. The method further includes mapping a curve of points onto the surface of the earth based on an LBI cone angle calculation employing the LBI phase wrap disambiguation factor. The curve of points is associated with a geolocation of the ground emitter.

Methods, program products, and systems for using multiple sensors to determine a location fingerprint are described. A sampling device can measure RF signals detected at a train station of a transit system or a route of the transit system. The sampling device, or a location server receiving the measurements, can filter RF signal measurements using one or more readings from sensors coupled to the sampling device and that are different from RF receivers. The readings can be taken concurrently with the RF signal measurements. These readings, designated as motion cues, can include motion sensor readings, barometer readings, or magnetometer readings. Using the motion cues, the sampling device or location server can distinguish different platforms of a station of the transit system and different levels of the station, or filter out RF signal measurements that may have been inaccurate, e.g., as caused by disturbances from a train entering or leaving a station.

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.

In a method of determining the location of a locomotive when GPS signals are not available, triangulation between one or two radio transmitters and, respectively, two or one radio receivers mounted on the train can be used. In the method, the distance between each radio transmitter and each radio receiver can be determined according a number of cycles of the radio signal generated by the radio transmitter that are received/counted by the radio receiver. The radio signal can also have modulated thereon the geographical location of the radio transmitter, which location can be demodulated by the radio receiver. Utilizing the demodulated geographical location of each radio transmitter and the distance between the radio transmitter and each radio receiver, triangulation can be used to determine the geographical location of the train.

An apparatus comprising a processor and a transceiver. The processor may (i) receive messages from a plurality of vehicles and (ii) determine relative coordinates of the vehicles based on the messages. The transceiver may (i) communicate the messages using a first channel in a first range and (ii) communicate short messages using a second channel in a second range. Communicating using the second channel may consume more power than communicating using the first channel. The messages may be sent from the transceiver to a cluster head within the first range. The short messages may communicate less data than the messages. The short messages may be sent directly to a target vehicle outside of the first range to determine an associated cluster head for the target vehicle. The messages may be sent to the target vehicle from the associated cluster head via the cluster head within the first range.

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.

An interactive mobile robot system and a method for creating an invisible track for a mobile robot. The system and method allow the creation of invisible tracks by guiding objects. They also allow the use of such invisible tracks for the semi-autonomous or autonomous control of toys, including model cars and model trains, or of mobile robots to move them along a real-world path. The system includes a mobile robot, receiver circuitry to receive one or more position signals, and processing circuitry. The processing circuitry is configured to determine position information associated with the mobile robot based on the one or more position signals. The processing circuitry is further configured to create an invisible track based on the position information, to determine a current position of the mobile robot, and to generate control signals based on the current position of the mobile robot and the invisible track.

An apparatus comprising a transceiver, a processor and a memory. The transceiver may be configured to send/receive data messages to/from a plurality of vehicles. The processor may be configured to execute instructions. The memory may be configured to store instructions that, when executed, perform the steps of (A) generating signal distance calculations between the apparatus and at least three of the vehicles using the data messages, (B) calculating a plurality of potential positions of the vehicles using the signal distance calculations, (C) performing a scaling operation on the plurality potential positions of the vehicles to determine relative positions of the vehicles on a coordinate system, (D) implementing a procrusting procedure on the coordinate system to generate a corrected coordinate system and (F) determining changes of the relative positions using the corrected coordinate system.

A position estimation unit (2) comprising a first transceiver device (3) and a processing unit (10) that is arranged to repeatedly calculate time-of-flight (TOF) for radio signals (x.sub.1, x.sub.2, x.sub.3, x.sub.4, x.sub.5, x.sub.6) sent pair-wise between two transceivers among the first transceiver device (3) and at least two other transceiver devices (7, 8, 9); calculate possible positions for the transceiver devices (3, 7, 8, 9), which results in possible positions for each transceiver device (3, 7, 8, 9); and perform Multidimensional scaling (MDS) calculation in order to obtain relative positions of the transceiver devices (3, 7, 8, 9) in a present coordinate system. After two initial MDS calculations, between every two consecutive MDS calculations, the processing unit (10) is arranged to repeatedly perform a processing procedure comprising translation, scaling and rotation of present coordinate system such that a corrected present coordinate system is acquired. The processing procedure is arranged to determine the corrected present coordinate system such that a smallest change for the relative positions of the transceiver devices (3, 7, 8, 9) between the consecutive MDS calculations is obtained.

An apparatus comprising a transceiver, an antenna and a processor. The transceiver may be configured to send/receive data messages to/from a plurality of vehicles. The antenna may be configured to receive signals from GNSS satellites. The processor may be configured to (i) determine a first region based on relative coordinates calculated using the data messages, (ii) determine a second region calculated using the signals received from the GNSS satellites, (iii) determine whether a pre-determined amount of the first region to the second region overlap and (iv) increase a confidence level of a positional accuracy of the plurality of vehicles if the pre-determined amount of the first region and the second region overlap. One of the vehicles implements one or more automatic responses based on the confidence level of the positional accuracy.