초록 ▼

A method and apparatus for rapidly and accurately determining the position coordinates of a remote, movable receiver relative to a fixed reference receiver. The technique utilizes successive code measurements and carrier phase measurements of both the L1 and L2 carrier signals broadcast from four or

A method and apparatus for rapidly and accurately determining the position coordinates of a remote, movable receiver relative to a fixed reference receiver. The technique utilizes successive code measurements and carrier phase measurements of both the L1 and L2 carrier signals broadcast from four or more orbiting GPS satellites. Code measurements based on a weighted average of the individual L1 and L2 code measurements in each satellite/receiver link are adjusted in accordance with the corresponding carrier phase measurement for an L1-L2 carrier difference signal and are further smoothed over time. This yields a rapid determination of the remote receiver\s position coordinates, with progressively increasing accuracy. After merely about two to three minutes of processing, a wide laning carrier phase procedure can be implemented to yield a position determination that is accurate to within about one centimeter.

대표청구항 ▼

A method for determining the coordinates of a remote receiver relative to a reference receiver having known coordinates, the method using the modulated L1 and L2 carrier signals broadcast from four or more GPS satellites, the method comprising steps of: measuring the range to each of the four or mor

A method for determining the coordinates of a remote receiver relative to a reference receiver having known coordinates, the method using the modulated L1 and L2 carrier signals broadcast from four or more GPS satellites, the method comprising steps of: measuring the range to each of the four or more satellites from both the reference receiver and the remote receiver, at each of a succession of time points, the step of measuring including steps of detecting the L1 and L2 codes, to produce a code measurement for each satellite/receiver pair, at each time point, the code measurement being based on a predetermined linear combination of the detected L1 and L2 codes, and detecting the L1 and L2 carrier phases, to produce a carrier phase measurement for each satellite/receiver pair, at each time point, the carrier phase measurement being based on a predetermined linear combination of the detected L1 and L2 carrier phases, wherein the predetermined linear combinations of the detected L1 and L2 codes and carrier phases are selected such that the ionosphere affects the resulting code and carrier phase measurements substantially equally; smoothing the successive code measurements for each satellite/receiver pair in accordance with the corresponding carrier phase measurements for the same time point and in accordance with the code measurements and carrier phase measurements for previous time points, to produce a smoothed code measurement for each satellite/receiver pair, at each time point; comparing the successive smoothed code measurements for the reference receiver with theoretical range values based on the known coordinates of the reference receiver and known orbits of the four or more satellites, to produce an error value for each smoothed code measurement for the reference receiver; determining the errors in the internal clocks of each of the four or more satellites, based on the error values produced in the preceding step of comparing; adjusting the successive smoothed code measurements for the remote receiver, to eliminate the effects of the satellite clock errors determined in the preceding step of determining and thereby produce a succession of corrected range measurements for each satellite; and determining the particular coordinates of the remote receiver that minimize errors in the successive corrected range measurements.