Hitachi Zosen Corporation

The University of Tokyo

Institute of National Colleges of Technology, Japan

Teruyuki Kato

Yukihiro Terada

Masao Kinoshita

Hiroshi Isshiki

Atsushi Tsuchiya

Hideshi Kakimoto

Haruhiko Yoshida

Toshihide Miyake

A method for measuring sea waves includes: transmitting ultrasonic waves from an ultrasonic transmitterprovided on a buoyinto the sea, and receiving the ultrasonic waves from three transponderson the seabed together with the time signals; detecting distances between the transpondersand the ultrasonic transmitterbased on the propagation time of the ultrasonic waves; high-pass filtering the distance data to extract a short-term fluctuation component; preparing and solving linear equations to determine the displacement in the height direction of the short-term fluctuation component and obtain a wave height.

Method for measuring sea waves by means of ultrasonic waves, as well as sea wave measuring system

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.

Method and apparatus for measuring displacement of object using GPS

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.

Growing community of inventors

Fujisawa, Japan

Teruyuki Kato