Richard W Sharpe

US Patent:

6753810, Jun 22, 2004

Filed:

Jan 7, 2003

Appl. No.:

10/338264

Inventors:

Yunchun Yang - Harbor City CA
Ronald R. Hatch - Wilmington CA
Richard T. Sharpe - Torrance CA

Assignee:

NavCom Technology, Inc. - Torrance CA

International Classification:

H04B 7185

US Classification:

34235714, 34235706

Abstract:

A method of fast GPS carrier phase integer ambiguity resolution is based on properties of a Residual Sensitivity Matrix (S matrix), which directly relates a set of integer ambiguities to carrier phase residuals. In one embodiment, the method uses the singular value decomposition of the S Matrix to split the integer ambiguity set into two integer ambiguity subsets and to derive a relationship between the two integer ambiguity subsets. Thus, searching for the integer ambiguity set is reduced to searching for one of the two integer ambiguity subsets, resulting in greatly reduced search space. In an alternative embodiment, a portion of the rows of the S matrix that are linearly independent rows are selected and the S matrix is rearranged according to the selection. The rearranged S matrix is then split into four sub-matrices, which are used to relate the two integer ambiguity subsets.

US Patent:

6864836, Mar 8, 2005

Filed:

Sep 5, 2003

Appl. No.:

10/656956

Inventors:

Ronald R. Hatch - Wilmington CA, US
Richard T. Sharpe - Torrance CA, US
Yunchun Yang - Harbor City CA, US

Assignee:

Navcom Technology, Inc. - Torrance CA

International Classification:

G01S005/02
H04B007/185

US Classification:

34235715, 34235706

Abstract:

A method for detecting and identifying a faulty measurement among a plurality of GPS measurements, obtained by a GPS receiver with respect to a plurality of satellites in view of the GPS receiver, determines whether the plurality of GPS measurements include a faulty measurement. In response to a determination that the plurality of GPS measurements include a faulty measurement, the method identifies a satellite contributing the faulty measurement by computing a correlation value associated with each of the plurality of satellites, and selecting a satellite associated with a highest correlation value as the satellite contributing the faulty measurement.

US Patent:

7071870, Jul 4, 2006

Filed:

Jul 13, 2005

Appl. No.:

11/181410

Inventors:

Richard T. Sharpe - Torrance CA, US
Frederick W. Nelson - Waukee IA, US
Terence D. Pickett - Waukee IA, US
Ronald R. Hatch - Wilmington CA, US
Yunchun Yang - Harbor City CA, US

Assignee:

Navcom Technology, Inc. - Torrance CA

International Classification:

H04B 7/185
G01S 5/14

US Classification:

34235704, 34235703

Abstract:

The present invention includes a method for a combined use of a local RTK system and a regional, wide-area, or global differential carrier-phase positioning system (WADGPS) in which disadvantages associated with the RTK and the WADGPS navigation techniques when used separately are avoided. The method includes determining a floating ambiguity value and a first position of an object using WADGPS in a first mode of operation, and determining a second position of the object using the local RTK system in a second mode of operation.

US Patent:

7117417, Oct 3, 2006

Filed:

Jul 30, 2003

Appl. No.:

10/630302

Inventors:

Richard T. Sharpe - Torrance CA, US
Ronald R. Hatch - Wilmington CA, US
Frederick W. Nelson - Waukee IA, US

Assignee:

Navcom Technology, Inc. - Torrance CA

International Classification:

G06F 11/00
G01S 1/00
G01C 21/26

US Classification:

714746, 34235702, 34235712, 701214

Abstract:

A method for generating satellite clock corrections for a WADGPS network computers satellite clock corrections after removing other substantial error components. Errors caused by the ionosphere refraction effects are removed from GPS measurements taken at reference stations using dual-frequency GPS measurements. The multipath noise are removed by smoothing of GPS pseudorange code measurements with carrier-phase measurements. The tropospheric refraction effect can be largely removed by modeling, and if desired, can be improved by the use of small stochastic adjustments included in the computation of the clock correction. After removing the above error factors, satellite clock corrections are computed for individual reference stations, and an average clock correction is formed for each of a plurality of satellites by taking an average or weighted average of the satellite clock corrections over reference stations to which the satellite is visible.

US Patent:

7119741, Oct 10, 2006

Filed:

Jan 13, 2004

Appl. No.:

10/757340

Inventors:

Richard T. Sharpe - Torrance CA, US
Frederick W. Nelson - Waukee IA, US
Terence D. Pickett - Urbandale IA, US
Ronald R. Hatch - Wilmington CA, US
Yunchun Yang - Harbor City CA, US

Assignee:

Navcom Technology, Inc. - Torrance CA

International Classification:

H04B 7/185
G01S 5/14

US Classification:

34235704, 34235703

Abstract:

The present invention includes a method for a combined use of a local RTK system and a regional, wide-area, or global differential carrier-phase positioning system (WADGPS) in which disadvantages associated with the RTK and the WADGPS navigation techniques when used separately are avoided. The method includes using a known position of a user receiver that has been stationary or using an RTK system to initialize the floating ambiguity values in the WADGPS system when the user receiver is moving. Thereafter, the refraction-corrected carrier-phase measurements obtained at the user GPS receiver are adjusted by including the corresponding initial floating ambiguity values and the floating ambiguity values are treated as well known (small variance) in subsequent processes to position the user receiver in the WADGPS system.

US Patent:

7212155, May 1, 2007

Filed:

May 7, 2004

Appl. No.:

10/841689

Inventors:

Ronald R. Hatch - Wilmington CA, US
Richard T. Sharpe - Torrance CA, US
Yunchun Yang - Harbor City CA, US

Assignee:

Navcom Technology, Inc. - Torrance CA

International Classification:

G01S 5/14

US Classification:

34235712, 34235701

Abstract:

The present invention includes a process for navigating an object according to signals from satellites by propagating the position of the object forward in time using successive changes in the carrier-phase measurements. The process computes at a low rate matrices required for solving for the position of the objects, and repeatedly uses the most recently computed matrices to compute position updates at a high rate until the next low-rate computation is completed.

US Patent:

7248211, Jul 24, 2007

Filed:

Jul 26, 2004

Appl. No.:

10/899570

Inventors:

Ronald R. Hatch - Wilmington CA, US
Richard T. Sharpe - Torrance CA, US

Assignee:

Navcom Technology Inc. - Torrance CA

International Classification:

G01S 5/04

US Classification:

34235703, 34235708, 34235709

Abstract:

A method and system are provided to determine a relative position vector between primary receiver associated with a reference station and secondary receiver associated with a user. The method and system determine a position of the reference station at the reference station according to signals received thereat from a plurality of satellites, determine a position of the user receiver at the user based on measurements obtained thereat and on error corrections computed at the reference station, and compute the relative position vector by differencing the position of the reference station and the position of the user.

US Patent:

7427950, Sep 23, 2008

Filed:

Jul 14, 2006

Appl. No.:

11/457745

Inventors:

Daniel J. Eslinger - Redondo Beach CA, US
Jing Sun - Torrance CA, US
Richard T. Sharpe - Torrance CA, US
Frederick W. Nelson - Waukee IA, US
Terence D. Pickett - Urbandale IA, US
Ronald R. Hatch - Wilmington CA, US

Assignee:

Navcom Technology, Inc. - Torrance CA

International Classification:

G01S 5/14

US Classification:

34235703, 34235704

Abstract:

The present invention includes a method for a combined use of a local positioning system, a local RTK system and a regional, wide-area, or global differential carrier-phase positioning system (WADGPS) in which disadvantages associated with the local positioning system, the RTK and the WADGPS navigation techniques when used separately are avoided. The method includes determining a first position of the object based on information from the WADGPS, and determining a second position of the object based on position information from a local positioning/RTK positioning system. Thereafter, position determined by the WADGPS and the position determined by the local positioning/RTK positioning system are compared. The WADGPS position is used for navigating the object when the WADGPS position and local positioning/position differ by more than a predefined threshold, and using the local positioning/RTK position for navigating the object when the WADGPS position and local positioning/RTK position differ by less than the predefined threshold.