DMAHTC (Defense Mapping Agency Hydrographic/Topographic Center) GPS Point Positioning Software: Initial Results

摘要

Absolute positioning software written at the Defense Mapping Agency Hydrographic/Topographic Center (DMAHTC) was designed to process Texas Instruments 4100 (TI 4100) geodetic receiver phase and range observations. This paper describes absolute positioning solutions obtained by processing data collected during the Spring 1985 High Precision Baseline Test. The positioning software can accept phase or range observations and treat them as either pseudoranges or range differences, thus allowing four different processing modes. The software estimates receiver position, scaling for the tropospheric correction, clock bias, drift, and aging parameters, and biases to the scaled phase measurement. Data from the Spring Baseline Test have been reduced and position offsets relative to given reference positions have been tabulated. Comparisons have been made between solutions computed using different ephemerides, processing methods, observation types, clock treatments, and initial station offsets. Means and standard deviations of the differences between the position solutions and the reference positions are presented. Results show that the positioning software is computationally stable but that significant day to day variations of the solution are present due to the data. (Author)