The proposed investigation will perform an elaborate error analysis and will develop appropriate force and measurement models to precisely determine the vandenberg-kwajalein ballistic missile trajectory. Among the error sources considered will include (1) station coordinate errors for the three tracking stations located at vandenberg, hawaii and kwajalein; (2) gravity anomaly model errors at launch site, in mid-trajectory, and at impact areas; (3) atmo- spheric and aerodynamic model errors during launch and during reentry; and (4) measurement model errors associated with radar instruments, including altair, tradex, alcor and mmw; and on-board sensors, sich as rate gyro and accelerometer. This investigation will dealt primarily with the gravity anomaly model errors and the measurement model errors affecting the ballistic trajectory. The software tools to be used include the trajectory analysis program (trap) which was developed at the university of texas at austin and is also operational at sandia national laboratory. However, trap has limitations in some of modelings needed to perform the proposed investigation. If necessary, the university of texas orbit processor (utopia) will also be used in providing trajectory analysis to identify some of the error sources. State-of-the-art gravity models, including the university of texas geopotential (teg-2), wgs-84 and the ohio state university field osu89b will be used to choose the best model for the problem. Tracking station coordinates will be estimated relative to the terrestrial reference system determined by satellite laser ranging to lageos (accurate to within 5 cm) to assess its effect on the ballistic trajectory. It in envisioned that phase I work will produce a detailed error analysis and phase II and phase iii tasks will perform the appropriate modeling and software development. The eventual objective is provide software tools and analytical means to precisely determine ballistic trajectories to within several meters of accuracy (root-mean- squared).
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