Centimeter accurate global positioning system receiver for on-the-fly real-time kinematic measurement and control

Patent 5890091 Issued on March 30, 1999. Estimated Expiration Date:

February 19, 2018. Estimated Expiration Date is calculated based on simple USPTO term provisions. It does not account for terminal disclaimers, term adjustments, failure to pay maintenance fees, or other factors which might affect the term of a patent.

Abstract Claims Description Full Text

Patent References

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Inventors

Assignee

Trimble Navigation Limited

Application

No. 027827 filed on 02/19/1998

US Classes:

701/215, Having multiple GPS antennas or receivers (e.g., differential GPS)342/357.12, GPS receiver signal processing342/457Land vehicle location (e.g., bus, police car

Examiners

Primary: Zanelli, Michael J.

Attorney, Agent or Firm

Blakely Sokoloff Taylor & Zafman, LLP

International Classes

G01S 003/02
G01S 005/02
G06F 165/00

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.