GPS-Based Launch Vehicle Tracking Using a Common Multi-Patch Antenna Configuration

M. Santina, J. Leung, G. Smit, J. Tekawy, G. T. Seng, J. McKay and S. Bandel

Abstract:	A GPS-based launch vehicle tracking architecture is under serious consideration by the Air Force to replace or augment the current radar-based tracking system. Due to the unique launch vehicle configuration, demanding operational environments, and stringent timing and reliability requirements, the application of GPS to launch vehicles presents special implementation and integration challenges different from both earth-surface and satellite navigation. Standardization of GPS antenna configuration and implementation for different launch vehicles is a critical element in AF’s acquisition strategy. Finding such a standardized configuration is the objective of this paper. The paper presents a brief review of the antenna configuration trades including the trade between ring and patch antennas and the trade study on patch size and number. A l/4-wave patch, which is commercially available, has a broad beam width but is more sensitive to edge diffraction effects caused by the neighboring structural elements. Aerospace has developed a prototype l/2-wave patch, which can reduce the edge diffraction effects with a reduced beam width. Results of the trade studies indicate that either three l/4-wave patches or four l/2-wave patches should provide adequate GPS satellites coverage. A four l/2-wave patch configuration, which is less sensitive to peculiar neighboring structural elements of different vehicles, is a better choice for standardization. The first phase of development of a modularized simulation program is completed and has been used to evaluate the system tracking performance. The simulation includes the following key modules: vehicle trajectory and attitude motion, experimentally verified patch antenna models (with user’s choice of patch number, size, location on vehicle, and signal combining scheme), GPS constellation and visibility, antenna switching logic, and an integrated receiver/IMU. Using the actual flight trajectory and geometry of several vehicles, the same four l/2-wave patch antenna configuration was simulated. The results confmed the preliminary finding of the trade studies that the four patch configuration can satisfy the stringent launch vehicle requirements. Therefore, a common patch antenna configuration is feasible for standardized applications.
Published in:	Proceedings of the 8th International Technical Meeting of the Satellite Division of The Institute of Navigation (ION GPS 1995) September 12 - 15, 1995 Palm Springs, CA
Pages:	1885 - 1893
Cite this article:	Santina, M., Leung, J., Smit, G., Tekawy, J., Seng, G. T., McKay, J., Bandel, S., "GPS-Based Launch Vehicle Tracking Using a Common Multi-Patch Antenna Configuration," Proceedings of the 8th International Technical Meeting of the Satellite Division of The Institute of Navigation (ION GPS 1995), Palm Springs, CA, September 1995, pp. 1885-1893.
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