In a method for integrity monitoring in position determination by means of the Global Positioning System (GPS), especially by means of differential GPS (DGPS) or multi-station DGPS, wherein there is employed a monitor station (M) with a first GPS receiver, provided at a location with a known geographical position, GPS-based position measurement results are transferred on a communication line from the monitor station (M) to a user location (F) the integrity of whose geographical position has to b...

A method for determining an improved position fix by performing postprocessing on a realtime differentially corrected GPS position. A remote rover unit containing a GPS receiver is used to determine a differentially corrected position according to measured pseudoranges and realtime pseudorange correction vectors is broadcast by a base station. The rover unit applies realtime corrections to measurements to determine a more accurate realtime differential position. It then stores the realtime diffe...

A method and system for local computation of information to improve accuracy in a differential Global Navigation Satellite Systems (GNSS). The method comprising: determining a current location of a reference receiver; comparing the current location with at least one stored location; if a resultant of the comparing is less than a selected threshold, identifying as a reference location the at least one stored location, which is closest to the current location; otherwise establishing the current lo...

Differential data signal transmission technique, providing a differential data signal transmission technique inclusive of the correcting factor that requires no transmitter/receiver other than the GPS receiver, comprises the use of a differential ranging system where spread spectrum signals (SS signal) are multiplied at the same frequency, transmission rate, and modulation method used by the GPS satellites, but with different codes from those used by the GPS satellites, the SS signals used to tr...

A position determining system using a first communication network, a second communication network, and a positioning system. The system may include at least one reference station that has known position coordinates and that is operable to receive first position signals from the positioning system. The reference station further may transmit position data via the first communication network in response to the first position signals and the known position coordinates. A remote central host communic...

A differential global positioning system (DGPS) using coarse data for the locations-in-space of GPS satellites for ranging to the GPS satellites and then determining a precise differentially corrected GPS location of a GPS user receiver. The coarse GPS data can be GPS almanac data or non-current GPS ephemeris data as long as the same data is used by both a GPS reference receiver and the GPS user receiver.

Multiple geographically fixed reference stations, with precisely known locations, that each receive GPS signals send information to a central processing facility that generates a three dimension topographical gradient map or model of the differences between the known locations and the locations as calculated from the received GPS signals. GPS signals received by mobile users are communicated to the central processing facility whereupon the central processing facility, using the model, generates ...

A method for enhancing the accuracy of location coordinates and/or clock bias computed for a mobile user station that is part of a Satellite Positioning System (SATPS), such as GPS or GLONASS. A data processing station is provided with pseudorange corrections PRC(t;j;ref) for an SATPS reference station for each of M SATPS satellites (j=1, . . . , M; M.gtoreq.3) and with uncorrected location fix coordinates x'(t.sub.f), y'(t.sub.f)', z'(t.sub.f)' and/or b'(t.sub.f) for the mobile station for a se...

A 1-sigma pseudorange ground monitor (sigma monitor) is described. The sigma monitor calculates a weighted sum of squared deviations referred to as the discriminator for one or several reference receiver for a specific time period. The sigma monitor also calculates an alert threshold based on the chi-square or near chi-square probability distributions for one or several reference receivers and for the specific time period. The sigma monitor then compares the discriminator with the alert or alarm...

A method of generating differentially-corrected smoothed pseudorange data in a differential global positioning system (DGPS) includes generating, at a base station, non-mode specific pseudorange and carrier phase correction data. The non-mode specific pseudorange and carrier phase correction data is then provided to a remote receiver. At the remote receiver, one of a plurality of specific smoothing modes of operation is selected for use in generating differentially-corrected smoothed pseudorange...