Orbit Determination and Prediction Concept for NEMO, The Naval EarthMap Observer Program.

Patrick W. Binning, Alan S. Hope, Mark T. Soyka

Abstract:	The Naval EarthMap Observer Program (NEMO) is a joint development effort between the Navy and private industry. The primary payload for NEMO is a hyperspectral imaging camera which is to map various regions of the world. A Tensor GPS receiver will be used to aid in determining accurate position knowledge, which is required for image geolocation and onboard autonomous image planning and execu-tion. The following sections will focus on the opera-tions concept for the orbit determination measurement collection, the processing of the GPS measurements on the ground for the precision orbit required for geolo-cation and the use of this precise ephemeris to predict the onboard position through the use of an onboard propagator. Demonstration of the algorithm concept will be shown using data from the ORFEUS-SPAS Shuttle Free Flyer. The Tensor GPS receiver which NEMO will be flying is very similar to that which was flown on ORFEUS SPAS. A C/A-code phase ambiguity algo-rithm will be shown. The OCEAN Filter/Smoother results will be presented. The data will be corrected for the gross time tag errors and the OCEAN pre-processor will combine the ORFEUS SPAS data with data from 27 GPS ground stations to form the Space to Ground Differential observation. This will then be processed in the OCEAN WLS-OD and expected accu-racies will be shown. The final section will conclude with a wrap-up dis-cussion of the expected NEMO performance based on OCEAN runs with data from TOPEX/Poseidon. Results will also be shown comparing the predicted ephemeris against the estimated ephemeris.
Published in:	Proceedings of the 12th International Technical Meeting of the Satellite Division of The Institute of Navigation (ION GPS 1999) September 14 - 17, 1999 Nashville, TN
Pages:	837 - 848
Cite this article:	Binning, Patrick W., Hope, Alan S., Soyka, Mark T., "Orbit Determination and Prediction Concept for NEMO, The Naval EarthMap Observer Program.," Proceedings of the 12th International Technical Meeting of the Satellite Division of The Institute of Navigation (ION GPS 1999), Nashville, TN, September 1999, pp. 837-848.
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