Trimble Navigation Limited

Paul N Skoog

Michael Timo Allison

Geoffrey R Kirk

Ian Timothy Viney

A centimeter level survey system includes reference base station and rover GPS units connected by a radio data link. Each includes recorders for the storage of raw measurement information including range, phase, cycle counts and time information. The rover unit is typically moved to points of interest during a survey while the base remains over a fixed, and known location. Generally, the base antenna is located to optimize a clear view of the sky. The rover is subject to interruption of the radio data link from the primary reference station. During periods that the rover is initialized and in contact with the primary reference station base station over the radio data link, the rover provides real time centimeter level position solutions to a survey user, otherwise, the rover records its raw measurements in a file that begins with the last valid initialization information and that ends with any newly reestablished initialization information. A post-processor is initialized by transferring the position filter states and covariance matrix of the real-time processor in the rover directly to the position filter of the post-processor, provided that continuous satellite tracking and no carrier cycle slips have occurred.

Automatic transference between real-time operation and post-processing

A GPS antenna comprises an antenna body that can rotate between horizontal and vertical positions between the handle horns on the top of an optical total station. A GPS receiver embodiment comprises an integrated body and antenna that can similarly be rotated between horizontal and vertical positions between the handle horns on the top of an optical total station to avoid interference with the total station optics.

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Fremont, CA, United States of America

Paul N Skoog