Michael E Allison

US Patent:

6507738, Jan 14, 2003

Filed:

Dec 31, 1999

Appl. No.:

09/477045

Inventors:

Michael Timo Allison - Santa Clara CA
Ann Ciganer - San Mateo CA

Assignee:

Trimble Navigation, Ltd. - Sunnyvale CA

International Classification:

H04Q 720

US Classification:

455427, 701207, 701300, 455456

Abstract:

The system and method for long baseline RTK survey are disclosed. The system includes a primary base station (PBS), a secondary base station (SBS), a primary data link between the PBS and the SBS, and a secondary data link between the SBS and a rover. The PBS, the SBS, and the rover are equipped with satellite antennas for satellite navigational purposes, and with the wireless Internet data accesses devices (WIDAD). The long baseline vector between the PBS and the rover is established by combining the primary baseline vector between the SBS and the PBS and the secondary baseline vector between the SBS and the rover. The PBS is placed in a position with a known location. The PBS wirelessly downloads its logged set of data into the Internet server using the (PBS-WIDAD). The SBS determines its precise position coordinates by accessing wirelessly the PBS logged data on the Internet server using the (SBS-WIDAD). The rover determine its position coordinates in real time by accessing SBS directly using the (Rover-WIDAD), or determines its coordinates using the batch delayed delivery method by wirelessly accessing the SBS position coordinates published on the Internet server.

US Patent:

D493345, Jul 27, 2004

Filed:

Apr 28, 2003

Appl. No.:

29/180625

Inventors:

Michael P. Allison - Salinas CA 93906

International Classification:

0804

US Classification:

D 8 87, D8 82

US Patent:

51481790, Sep 15, 1992

Filed:

Jun 27, 1991

Appl. No.:

7/722512

Inventors:

Michael T. Allison - Santa Clara CA

Assignee:

Trimble Navigation - Sunnyvale CA

International Classification:

H04B 7185
G01S 502

US Classification:

342357

Abstract:

A method for accurately determining the position of a roving signal receiver positioned on or above the Earth's surface, relative to the position of a reference receiver whose position is known with sufficient accuracy, using ranging information, transmitted at a pair of predetermined carrier signal frequencies and received from each of n satellites (n. gtoreq. 4). Pseudorange double differences are formed, between each of the two receivers and each of a first satellite and the other three satellites, using pseudorange information obtained from either one of the two signal frequencies. Phase correction information, in the form of estimates of integer lane wavelength ambiguities, is then obtained from the pseudorange double differences and from certain measurable phase differences. This products n-1 simultaneous equations that can be solved for the roving receiver position cordinates. The method can be adapted to provide roving receiver position when signals carried by both of the two carrier frequencies are encrypted, where a separate non-encrypted signal is available on one of the two carrier frequencies.

US Patent:

53593324, Oct 25, 1994

Filed:

Dec 31, 1992

Appl. No.:

7/999099

Inventors:

Michael T. Allison - Santa Clara CA
Phillip Deaver - Cupertino CA
Scott Dreier - San Francisco CA

Assignee:

Trimble Navigation Limited - Sunnyvale CA

International Classification:

G01S 502
G01S 302

US Classification:

342357

Abstract:

A method for accurately determining the position of a roving receiver positioned on or above the Earth's surface, relative to the position of a reference receiver whose position is known with sufficient accuracy, using measurements of signal phase transmitted at one or more carrier frequencies and received from each of four or more satellites in a Satellite Positioning System (SPS). Phase double differences are formed, using the reference and roving receivers and any two satellites drawn from four or more satellites, using phase information obtained from either or both of the two carrier signal frequencies. Phase correction information, in the form of estimates of integer wavelength ambiguities, is then obtained from two sets of ambiguity estimates computed with the roving receiver antenna in each of two specified positions, with the reference receiver antenna lying between and being collinear with the two roving receiver-antenna positions. If the distance between the reference receiver antenna position and the two roving receiver antenna positions is sufficiently small, a set of estimates at only one of the roving receiver positions may suffice. If an azimuth angle measuring device is incorporated in the apparatus, a set of estimates at only one roving receiver position may again suffice.

US Patent:

57576467, May 26, 1998

Filed:

Nov 7, 1996

Appl. No.:

8/745579

Inventors:

Nicholas Charles Talbot - Cupertino CA
Michael Timo Allison - Santa Clara CA
Mark Edward Nichols - Sunnyvale CA

Assignee:

Trimble Navigation Limited - Sunnyvale CA

International Classification:

G01S 302
G01S 502
G06F16500

US Classification:

3644499

Abstract:

A system embodiment of the present invention comprises a fixed and a roving pair of four-observable GPS receivers and a communication link between them for double differencing code and carrier measurements. Carrier phase integer ambiguities are resolved efficiently by searching the simultaneous narrow-lane intersections of both the L1 and L2 wave fronts propagated by the GPS satellites being tracked. External constraint information, such as elevation, is additionally used to speed up integer ambiguity resolution. Data between the reference station and the rover is communicated in compressed form at a regular interval, e. g. , once a second at each epoch, and demi-measurements of carrier phase are obtained more frequently, e. g. , ten times a second, and used to propagate solutions between epochs.

US Patent:

56106149, Mar 11, 1997

Filed:

Sep 13, 1995

Appl. No.:

8/528506

Inventors:

Nicholas C. Talbot - Cupertino CA
Michael T. Allison - Santa Clara CA
Peter Griffioen - Clayton, AU

Assignee:

Trimble Navigation Limited - Sunnyvale CA

International Classification:

H04B 7185
G01S 502
G01C 2100
H04B 1700

US Classification:

342352

Abstract:

A real-time kinematic system includes base and rover GPS units connected by a data link. The rover unit is typically moved to points of interest during a survey while the base remains over a fixed, and known location. An initialization testing program of the present invention is mounted on a personal computer platform that forces in the rover a loss of signal tracking, thus simulating losses in signal reception caused by obstructions of the satellite signals. A complete initialization is forced to occur. The test program uninitializes the RTK solution by causing a loss of integer ambiguities resolution by forcing a loss of lock on one or more satellites. The test program then monitors the subsequent initialization process, e. g. , the time needed to search for phase ambiguity candidates, discovering the prevalent satellite geometry, determination of whether the correct ambiguity candidate was found, finding the ratio of the second best to best solution variances of the ambiguity candidates in the list throughout the candidate propagation process or similar statistical test, computing the RMS error of the solution at the time that initialization was declared and after initialization, and calculating the baseline vector between the rover and base at the time of initialization and after initialization. All such statistical parameters are logged and used in post and real-time analyses of the initialization algorithm.

US Patent:

58900918, Mar 30, 1999

Filed:

Feb 19, 1998

Appl. No.:

/027827

Inventors:

Nicholas Charles Talbot - Cupertino CA
Michael Timo Allison - Santa Clara CA
Mark Edward Nichols - Sunnyvale CA

Assignee:

Trimble Navigation Ltd. - Sunnyvale CA

International Classification:

G01S 302
G01S 502
G06F16500

US Classification:

701215

Abstract:

A system embodiment of the present invention comprises a fixed and a roving pair of four-observable GPS receivers and a communication link between them for double differencing code and carrier measurements. Carrier phase integer ambiguities are resolved efficiently by searching the simultaneous narrow-lane intersections of both the L1 and L2 wave fronts propagated by the GPS satellites being tracked. External constraint information, such as elevation, is additionally used to speed up integer ambiguity resolution. Data between the reference station and the rover is communicated in compressed form at a regular interval, e. g. , once a second at each epoch, and demi-measurements of carrier phase are obtained more frequently, e. g. , ten times a second, and used to propagate solutions between epochs.

US Patent:

55196209, May 21, 1996

Filed:

Feb 18, 1994

Appl. No.:

8/199387

Inventors:

Nicholas C. Talbot - Cupertino CA
Michael T. Allison - Santa Clara CA
Mark E. Nichols - Sunnyvale CA

Assignee:

Trimble Navigation Limited - Sunnyvale CA

International Classification:

G01S 302
G01S 502
G06F16500

US Classification:

364449

Abstract:

A system embodiment of the present invention comprises a fixed and a roving pair of four-observable GPS receivers and a communication link between them for double differencing code and carrier measurements. Carrier phase integer ambiguities are resolved efficiently by searching the simultaneous narrow-lane intersections of both the L1 and L2 wave fronts propagated by the GPS satellites being tracked. External constraint information, such as elevation, is additionally used to speed up integer ambiguity resolution. Data between the reference station and the rover is communicated in compressed form at a regular interval, e. g. , once a second at each epoch, and demi-measurements of carrier phase are obtained more frequently, e. g. , ten times a second, and used to propagate solutions between epochs.