Using GPS to Determine an Astronomic-Geodetic Transformation for a Precise Azimuth Reference (PAR).
NAVAL SURFACE WARFARE CENTER DAHLGREN DIV VA
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A technique is presented to generate a transformation between the astronomic and geodetic reference frames. The transformation is based on knowing the orientation of a plane in both reference frames. The planes astronomic orientation is assumed to be known. The geodetic orientation is determined using Global Positioning System GPS kinematic relative positioning. For the problem addressed in the report, the plane is a window used to make astronomic observations at Holloman Air Force Base, New Mexico. A precise azimuth reference at an accuracy approaching 0.1 arcsec is derived using observations of the star Polaris. Because the window is inaccessible and cannot be instrumented with GPS antennas, an indirect measurement technique is explored. UPS multipath signals reflected off the window are evaluated as a means whereby the orientation of the window may be determined. The viability of this method is untested. Results from a static positioning test are presented to demonstrate the technique of determining the planes geodetic orientation. Orientation consistency on the order of 1 arcsec is obtained. MM
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