PRECISE TERRESTRIAL TIME-A MEANS FOR IMPROVED BALLISTIC MISSILE GUIDANCE ANALYSIS

Eldon E. Ehrsam, Stephen A. Cresswell, George R. McKelvey, Frank L. Matthews

Abstract:	Significant improvements in ballistic missile guidance performance has necessitated the guidance systems analysis community to adopt more precise timing standards for the evaluation of test data. To date, data timing is achieved at the ground instrumentation sites since the missile dynamics are too demanding for currently available high precision missile borne timing sources. In the past five years as noted in the 1973 PTTI paper, "Precise Timing Correlation in Telemetry Recording and Processing Systems", accuracy improvements in evaluation of guidance systems were expected to exceed the IRIG timing techniques used in time tagging guidance telemetry data. An approach developed by Space and Missile Test Center (SAMTEC) to improve the ground instrumentation time tagging accuracy has been adapted to support the Minuteman ICBM program and has been designated the Timing insertion Unit (TIV). The TIU technique produces a telemetry data time tagging resolution of one tenth of a microsecond, with a relative intersite accuracy after corrections to better than 0.5 microsecond. Metric tracking position and velocity data (range, azimuth, elevation and range rate) also used in missile guidance system analysis can be correlated to within ten microseconds of the telemetry guidance x, y, z and X, ý, z data. This requires precise timing synchronization between the metric and telemetry instrumentation sites. The timing synchronization can be achieved by using the radar automatic phasing system time correlation methods. Other time correlation techniques such as Television (TV) Line-10 and the Geostationary Operational Environmental Satellites (GOES) terrestrial timing receivers are being considered. With the continuing improvement of ballistic missile guidance performance, on-board clocking stability of one part in 10 may be required. This increased on-board stability will influence improvements in terrestrial time precision and accuracy.
Published in:	Proceedings of the 10th Annual Precise Time and Time Interval Systems and Applications Meeting November 28 - 30, 1978 Goddard Space Flight Center Greenbelt, Maryland
Pages:	85 - 100
Cite this article:	Ehrsam, Eldon E., Cresswell, Stephen A., McKelvey, George R., Matthews, Frank L., "PRECISE TERRESTRIAL TIME-A MEANS FOR IMPROVED BALLISTIC MISSILE GUIDANCE ANALYSIS," Proceedings of the 10th Annual Precise Time and Time Interval Systems and Applications Meeting, Greenbelt, Maryland, November 1978, pp. 85-100.
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