US 5,963,167 AGranted

Analyzing system for global positioning system and general satellite tracking

AssigneeCalifornia Institute of Technology

InventorsStephen M. Lichten, Sien-Chong Wu, Kenneth Hurst, Geoff Blewitt, Thomas Yunck, Yoaz Bar-Sever, James Zumberge, William I. Bertiger, Ronald J. Muellerschoen, Catherine Thornton, Michael Heflin

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Abstract

An improved analyzing system based on GIPSY-OASIS II software package developed at the Jet Propulsion Laboratory for Global Positioning System, general satellite tracking, orbit determination and trajectory studies. New features and functions include yaw compensation, precise satellite positioning by high-rate GPS clocks, enhanced data filtering and smoothing, a new user interface for controlling orientation of a satellite and its components, and no-fiducial approach to global geodesy. The present invention allows a fully automatic operation and delivery of validated daily solutions for orbits, clocks, station locations and others with no human intervention. A 3D GPS orbit accuracy of 15 cm and the daily repeatability of the 3D global geocentric station location in better than 1 cm have been achieved.

Claims28

Dependent claims

A method for GPS positioning, comprising:

collecting broadcast signals of a plurality of earth-orbiting satellites with a plurality of earth-fixed receivers, said broadcast signals being indicative of timing and positioning of said satellites;
converting said broadcast signals into raw data in digital form;
editing said raw data to remove an amount of data points based on a data selection criterion and to detect carrier phase breaks therein based on a phase criterion, thus producing refined data indicative of pseudoranges of said satellites;
computing a plurality of forces acting on said satellites;
estimating effects of earth geometric factors and a plurality of transmitting delays of said broadcast signals;
performing a yaw compensation on yawing of said satellites according to orbital positions of said satellites;
computing orbiting trajectories of said satellites by using a priori model and said refined data with information indicative of said forces, said effects of earth geometric factors, said transmitting delays, and said yawing;
processing said refined data by Kalman-type filtering according to said orbiting trajectories of said satellites so as to produce updated data having information indicative of said timing and said positioning of satellites;
predicting orbits of said satellites with said updated data and information from said yaw compensation to produce updated orbits of said satellites;
and
verifying said updated orbits of said satellites.

8 more elements

A global positioning system for locating a target, comprising:

a plurality of satellites, orbiting around the earth, each of said satellites operating to broadcast radio wave signals having information indicative of timing and positioning of said satellites relative to a preselected reference;
a GPS receiver at said target to receive said radio wave signals broadcasted from said satellites;
an attitude control module in each of said satellites for determining yawing of each of said satellites, having a pair of solar sensors arranged relative to each other on surfaces of solar panels in said attitude control module, operating to induce a fixed biasing in an output of said pair of solar sensors, thereby yielding a biasing yawing in said yawing of said satellites;
and
a control module, configured to communicate with said satellites and said GPS receiver and a digital computer with input and output devices, said computer having a readable storage medium that is configured with a computer program and operating to control said satellites and said attitude control module, said control module processing said information indicative of said timing and said positioning from said satellites by predicting trajectories of said satellites with previously existing information indicative of said orbiting of said satellites, with yawing status from said control module, and with external force information indicative of an effect selected from a group consisting of gravitational effects, solar pressure, atmospheric drag, thermal radiation, and gas leaks,
whereby said positioning system determines three-dimensional position parameters of said GPS receiver relative to said preselected reference.

3 more elements

Dependencies are inferred from the claim text.