Abstract:
The invention relates to a method for improving positioning accuracy in the across track axis for a road navigation application using a Global Navigation Satellite System - GNSS, comprising - receiving signals from n satellite of the GNSS in view (S10), - processing a n-dimensional vector y (S12), which represents the difference between the ranges observed from the n satellite of the GNSS in view, and the theoretical range from an arbitrary chosen linearization space/time point and the n satellite in view, - estimating a vector x (S 14) representing the user space/time position respective to the linearization space/time point by using the processed vector y, a satellite geometric matrix G, and a weighting matrix W equal to the invert of the variance of user ranging errors, - measuring the accuracy of positioning (S16) along a direction D perpendicular to a vehicle motion by the variance of the expression (Dt x), and - finding for the direction D the weighting matrix W(D) (S18) that minimizes the variance of the expression (Dt x).
Abstract:
In a mobile-unit positioning device, phases of pseudo noise codes carried on satellite s.ignals from satellites are observed at a mobile unit to measure a position of the mobile unit. A pseudo distance between one of the satellites and the mobile unit is measured for every satellite during a stop of the mobile unit using an observed value of the phase acquired during a stop of the mobile unit. An error index value indicating an error of the measured pseudo distance is computed based on the pseudo distances measured at points in time during a stop of the mobile unit. A weighting factor is determined based on the index value computed for every satellite. A weighted positioning computation using the determined weighting factor is performed to determine a position of the mobile unit during movement using an observed value of the phase acquired during movement. A further device is proposed wherein the position is measured using a similar method, however, in this case, the error "index is based on an error of a computed mobile unit speed, rather than on the pseudo distance.
Abstract:
A method and apparatus for constructive use of a multipath signal in GPS signal processing is provided. In one embodiment, the method includes: a) receiving a GPS signal at a mobile object from a satellite vehicle, b) determining a distance characteristic relating a reflecting object to the mobile object, c) determining at least one inertial characteristic associated with the mobile object, d) predicting at least one multipath signal characteristic associated with reflection of the GPS signal by the reflecting object toward the mobile object, and e) determining the GPS signal received in a) includes a multipath signal associated with reflection of the GPS signal by the reflecting object toward the mobile object. In one embodiment, the apparatus includes: a GPS receiver, a storage device, an inertial measurement device, and a controller. In another embodiment, the apparatus also includes a distance measurement device.
Abstract:
A method and apparatus for providing assistance data for satellite positioning system receivers utilizing a secure user plane location (SUPL) service. In one embodiment, the assistance data is supplied by a global secure user plane location center that contains global assistance data.
Abstract:
A module (software or ASIC) for use in a serving mobile Location Centre (SMLC) or a mobile station having a GPS receiver (or an A-GPS receiver) for determining an ITOW for a CNAV-1 signal. Also provided is a module for a mobile with GPS (or A-GPS receiver) so that the mobile can use the ITOW (either the ITOW provided with the CNAV-2, or that calculated for the CNAV-1) to uniquely identify ephemeris information in a request for assistance message. Also provided is a module for a SMLC by which the SMLC can use the IOD fields in the assistance data messages in a way that uniquely identifies the associated ephemeris information.
Abstract:
A method and location determination module is provided for determining a location of one of a plurality of units (16A, 16B, 16C, 12, 14) using neighbor lists (212). Each unit is communicatively coupled to at least some of the other plurality of units (16A, 16B, 16C, 12, 14), where at least some of the plurality of units (16A, 16B, 16C, 12, 14) are reference units, whose locations are known. The units communicate with other (16A, 16B, 16C, 12, 14) nearby units within communication range, to establish neighbor lists (212). A unit to be located then identifies an aggregate value corresponding to the number of occurrences of the reference units in the neighbor list (212) of the unit to be located and the neighbor lists (212) of each of a group of associated units. The location of the unit to be located is then determined, based upon the known locations of the reference units and the number of identified occurrences of the reference units in the corresponding neighbor lists (212).
Abstract:
Method and apparatus for validating an initial position in a satellite positioning system using range-rate measurements is described. In one example, range-rate measurements are obtained at the remote receiver with respect to a plurality of satellites. Expected range-rates are computed with respect to the plurality of satellites using the initial position. Single differences are computed using the range-rate measurements. Expected single differences are computed using the expected range-rates. Single difference residuals are computed between the single differences and the expected single differences. The single difference residuals are compared to a threshold. The initial position may be deemed valid if the absolute value of each of the single difference residuals is less than or equal to the threshold. A valid initial position may be used to fix the pseudorange integers.
Abstract:
In accordance with preferred embodiments of the invention, a method and corresponding apparatus is provided for deducing the location (342, 344) of one or more items or objects (326) to be monitored. In exemplary embodiments, the method and corresponding apparatus is implemented in RFID (radio frequency identification) applications (e.g. reading RFID tags at 13.56 MHz and approximately 900 MHz) by deducing the location of an item associated with a unique RFID tag (118) in one or more areas of detection (314, 324) covered by multiple RFID reader antennae (110, 120).
Abstract:
A user equipment related multicast/broadcast multimedia service information present in a serving radio network controller can be coupled with the multicast/broadcast multimedia service controlling radio network controller service context in the corresponding controlling radio network controller over the interface between the radio network controller entities.
Abstract:
A GPS-based underwater cable positioning system for use in determining the shape and position of hydrophone streamers towed underwater behind survey vessels involved in marine seismic prospecting. The system includes a plurality of surface units towed behind the vessel. Each surface unit includes a GPS receiver to receive radio frequency GPS signals and to determine its positions. Each surface unit also has an acoustic transmitter to transmit an acoustic message signal representing its position and an optional time stamp into the water. Acoustic receiver units, attached spaced apart locations along one or more streamer cables, each include an acoustic receiver to receive the acoustic message signals from the surface units and to determine its position from the message signals. To augment the message signals from the surface units at locations distant from the surface units, acoustic transceiver units may be used. The acoustic transceiver units are attached to the streamer cables at ranges between the surface units and distant acoustic receiver units. The acoustic transceiver units each include an acoustic receiver that performs as the receivers in the acoustic receiver units and an acoustic transmitter to transmit acoustic message signals representing its position and an optional time stamp into the water to be received by the acoustic receiver units. In this way, the positions and shapes of towed streamer cables can be determined.