Recent Development in Astronomic Position Determinations.
DEFENSE MAPPING AGENCY HYDROGRAPHIC/ TOPOGRAPHIC CENTER WASHINGTON DC
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An advanced engineering model of an electro-optical star sensor system designed by Ball Aerospace Systems Division, incorporates a charge injection device CID detector having a 256 x 256 pixel array. The system is integrated with a Wild T-4 astronomic theodolite in the focal plane to replace the human eye. A star image is acquired and tracked across detector pixels to determine a time versus meridian angle intercept that is synchronized with a very accurate time. Zenith angle intercepts are also measured. Track position, interpolation, and data reduction algorithms are derived and incorporated into the system software to provide astronomic latitude and longitude to about or - 0.1 arc second 1 sigma. This system is being built for the Defense Mapping Agency under an on-going technical development program to improve the accuracy of astronomic position determinations. The need for accuracy improvements, the limitations of conventional instruments, an analysis of major error sources, the results of previous developmental efforts, and the design and use of advanced production instruments are also presented. Author