Sub-millimeter Precision GPS Survey System at the Holloman High Speed Test Track

J.C. Hughes, J.A. Banks, A.J. Kerkhoff, B.W. Tolman, J.R. Wyant, R.E. Ellison

Abstract:	The National Geospatial-Intelligence Agency (NGA) provides high-accuracy survey support for the Air Force’s Holloman High Speed Test Track (HHSTT), a test facility that supports ground-level aerodynamic and impact testing at speeds in excess of Mach 8. Specifically, NGA provides three-axis positions of 1,018 survey benchmarks installed along the HHSTT. High performance traditional survey methods have been skillfully employed for many years and yield satisfactory measurement accuracy (approximately 1.0 mm in each axis), but these methods are manpowerintensive and slow. The high cost and high latency associated with these methods motivated NGA to task Applied Research Laboratories, The University of Texas at Austin (ARL:UT) to develop an alternative GPS-only survey method. In response, ARL:UT developed and deployed the Benchmark Survey System (BSS), a GPS system consisting of twenty-five portable devices that may be used to survey approximately forty-eight HHSTT baselines in a ten-hour work shift, to a precision of better than 1.0 mm in each axis. Relative to earlier methods, the BSS provides a substantial improvement in throughput, and the accuracy is at least comparable. This paper presents the Benchmark Survey System with a focus on the three key aspects of the system that are critical to the achievement of sub-millimeter baseline measurement performance. First, a method for precisely estimating GPS antenna phase center characteristics is presented. This method facilitates rapid and low cost characterization of antennas and has a proven repeatability of better than ±0.35 mm in each axis. Second, the mechanical design and requisite characterization methods necessary to ensure precise positioning of each GPS antenna relative to each survey benchmark is presented. This positioning process is faster than traditional methods, does not require bulky hardware, and is repeatable to better than ±0.05 mm in each axis. Third, an ARL:UT-developed GPS double-differenced carrier phase network positioning processor is presented. Testing of this processor has focused on the 30-meter baseline lengths representative of the benchmark spacing at the HHSTT, and baseline solution repeatability of better than ±0.32 mm in each axis has been consistently demonstrated using 3 hours of single frequency data. Finally, the paper presents results from the first full-system deployment test of the BSS at the HHSTT. BSS survey results will be compared with NGA-derived survey results obtained through the employment of traditional methods.
Published in:	Proceedings of the 19th International Technical Meeting of the Satellite Division of The Institute of Navigation (ION GNSS 2006) September 26 - 29, 2006 Fort Worth Convention Center Fort Worth, TX
Pages:	2743 - 2753
Cite this article:	Hughes, J.C., Banks, J.A., Kerkhoff, A.J., Tolman, B.W., Wyant, J.R., Ellison, R.E., "Sub-millimeter Precision GPS Survey System at the Holloman High Speed Test Track," Proceedings of the 19th International Technical Meeting of the Satellite Division of The Institute of Navigation (ION GNSS 2006), Fort Worth, TX, September 2006, pp. 2743-2753.
Full Paper:	ION Members/Non-Members: 1 Download Credit Sign In