Abstract: Relative vector between an observation receiver located at an object and a reference receiver are divided into long period variation components not dependent on object displacements and short period variation components dependent on object displacements, and the short period variation component are represented by x, y and z axis components of unit vectors from the reference receiver toward the satellite. Then, carrier phases between at least three GPS satellites and the receivers are measured, and these measurement data are passed through a band pass filter to extract short period phase components corresponding to the short period variation components of the relative vectors. Next, at least three receiver to receiver single differences between the receivers and the GPS satellites are found for the short period phase components, and axial components of the short period variation components of the relative vectors are found by computation based on said at least three receiver to receiver single differences.

Abstract: The present invention is a method for measuring a distance between a GPS receiver installed in a floating body and a GPS satellite, subjecting this measured distance data to a moving averaging process, removing from the measured distance data, distance data corresponding to a distance to a satellite orbit to determine a variance of the GPS receiver, removing wind wave-induced noise from the data, then determining three linear equations that use three-dimensional coordinates of the GPS receiver as unknown numbers, based on variances relative to GPS satellites and an azimuth and an elevation of each GPS satellite, and then solving these simultaneous equations to determine displacement of the GPS receiver corresponding to its variation component quantities on three-dimensional coordinate axes.