Trimble Navigation Limited

Zoltan Biacs

Dominic G Farmer

John F Rogers

Jinye Li

A method and system for rapidly initializing a rover unit in a networked system. In one embodiment, the present invention acquires rover unit initialization data at a reference station. In one embodiment, the rover unit initialization data is selected from the group consisting of: ephemeris data, almanac data, satellite health data, ionospheric data, UTC and GPS time and approximate rover position information. In the present embodiment, the present invention then communicatively couples the reference station to a server station having memory for storing the rover unit initialization data. After communicatively coupling the reference station to the server station, the present embodiment transfers the rover unit initialization data from the reference station to the server station. The present embodiment then communicatively couples the rover unit to the server station. Next, the present embodiment supplies the rover unit initialization data from the server station to the rover unit. As a result, in the present embodiment, the rover unit is able to be initialized and obtain a first position fix without requiring the rover unit to acquire the initialization data directly from at least one satellite. In another embodiment, the present invention provides a method and system for providing differentially corrected position information to a rover unit in a networked system. In still another embodiment, the present invention provides a method and system for providing both initialization data and differentially corrected position information to a rover unit in a networked system.

Near-real time DGPS network and server system

A method for determining an improved position fix by performing postprocessing on a realtime differentially corrected GPS position. A remote rover unit containing a GPS receiver is used to determine a differentially corrected position according to measured pseudoranges and realtime pseudorange correction vectors is broadcast by a base station. The rover unit applies realtime corrections to measurements to determine a more accurate realtime differential position. It then stores the realtime differential position and the realtime pseudorange correction vector. Subsequently, postprocessing is performed to determine a postprocessed pseudorange correction vector. A difference vector representing the difference between the realtime pseudorange correction vector and the postprocessed pseudorange correction vector is then determined. This difference vector is applied to the realtime differential position to calculate a more accurate, improved position fix. This same process can be applied to determine velocities as well.

Growing community of inventors

San Francisco, CA, United States of America

Zoltan Biacs