Preliminary Orbit Determination of Artificial Earth Satellites from a Small Number of Angle-Only Observations
MASSACHUSETTS INST OF TECH LEXINGTON LINCOLN LAB
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The problem of determining the preliminary orbital elements of a previously unobserved earth satellite from a minimum number of angle-only observations has been investigated. The Planetary Ephemeris Program PEP was used to generate exact ephemerides of selected orbits which were then used as input to an angle-only tracking algorithm derived from the method of Gauss. This algorithm yields the approximate orbital elements under the assumption of Keplerian motion. Comparison of these elements with the ones assumed in PEP has indicated that the Keplerian approximation improves considerably as the unknown satellite altitude is increased from 14 to 3 times synchronous, and that such a tracking algorithm would be useful in many practical situations where one is constrained to a few angle-only observations. Estimates are given of the accuracy needed in the input data to insure reasonable success in this method of preliminary orbit determination.
- Spacecraft Trajectories and Reentry