Yoaz Eliezer Bar-Sever

US Patent:

8120529, Feb 21, 2012

Filed:

Sep 11, 2008

Appl. No.:

12/208525

Inventors:

Yoaz E. Bar-Sever - Altadena CA, US
William I. Bertiger - Altadena CA, US

Assignee:

California Institute of Technology - Pasadena CA

International Classification:

G01S 19/27

US Classification:

34235766

Abstract:

Methods and apparatus for autonomous in-receiver prediction of orbit and clock states of Global Navigation Satellite Systems (GNSS) are described. Only the GNSS broadcast message is used, without need for periodic externally-communicated information. Earth orientation information is extracted from the GNSS broadcast ephemeris. With the accurate estimation of the Earth orientation parameters it is possible to propagate the best-fit GNSS orbits forward in time in an inertial reference frame. Using the estimated Earth orientation parameters, the predicted orbits are then transformed into Earth-Centered-Earth-Fixed (ECEF) coordinates to be used to assist the GNSS receiver in the acquision of the signals. GNSS satellite clock states are also extracted from the broadcast ephemeris and a parameterized model of clock behavior is fit to that data. The estimated modeled clocks are then propagated forward in time to enable, together with the predicted orbits, quicker GNSS signal acquision.

US Patent:

59631678, Oct 5, 1999

Filed:

Mar 13, 1997

Appl. No.:

8/816260

Inventors:

Stephen M. Lichten - Pasadena CA
Kenneth Hurst - Lebec CA
Geoff Blewitt - Durham, GB
Thomas Yunck - Pasadena CA
Yoaz Bar-Sever - Altadena CA
James Zumberge - San Martin CA
William I. Bertiger - Altadena CA
Ronald J. Muellerschoen - Pasadena CA
Catherine Thornton - Arcadia CA
Michael Heflin - La Crescenta CA

Assignee:

California Institute of Technology - Pasadena CA

International Classification:

G01S 502

US Classification:

34235706

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.

US Patent:

62950215, Sep 25, 2001

Filed:

Aug 18, 1999

Appl. No.:

9/377308

Inventors:

Stephen M. Lichten - Pasadena CA
Yoaz Bar-Sever - Altadena CA
James Zumberge - San Marino CA
William I. Bertiger - Altadena CA
Ronald J. Muellerschoen - Pasadena CA
Kenneth Hurst - Lebec CA
Geoff Blewitt - Durham, GB
Thomas Yunck - Pasadena CA
Catherine Thornton - Arcadia CA
Michael Heflin - La Cresenta CA

Assignee:

California Institute of Technology - Pasadena CA

International Classification:

H04B 7185
B64G 136

US Classification:

342355

Abstract:

Techniques for monitoring and controlling yawing of a GPS satellite in an orbit that has an eclipsing portion out of the sunlight based on the orbital conditions of the GPS satellite. In one embodiment, a constant yaw bias is generated in the attitude control system of the GPS satellite to control the yawing of the GPS satellite when it is in the shadow of the earth.