Method and apparatus for orbit determination
First Claim
1. A method of estimating in real-time an orbit of a satellite using a recursive filter and wherein the recursive filter first receives an a priori state estimate and an a priori state error covariance matrix for the satellite, and wherein the method comprises:
- inputting tracking measurements for the satellite received in real-time from tracking stations to the recursive filter at filter time update “
T”
;
inputting filter tracking station platform data to the recursive at filter time update “
T”
;
computing recursively the current state estimate, the current error covariance and the current filter measurement update of the satellite at filter time update “
T”
;
moving the state estimate and error covariance from filter time update “
T”
to filter time update “
T+1”
;
incorporating into the filter measurement update the information provided by the tracking data measurement at filter time update T; and
determining a current estimate of the orbit of the satellite.
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Abstract
A method and apparatus for estimating the orbits of spacecraft or other objects relative to primary celestial bodies, given applicable measurements The present invention uses the variation of parameters in universal variables for spacecraft trajectory propagation during operation of its optimal sequential orbit estimation. This method provides a universal capability for all three conics: elliptic, parabolic, and hyperbolic, forward-time and backward-time numerical integration for filtering and smoothing, respectively. A method for determining local and global estimates of atmospheric density is also provided. A method for realistic orbit simulation provides a means for validating an orbit estimate.
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Citations
11 Claims
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1. A method of estimating in real-time an orbit of a satellite using a recursive filter and wherein the recursive filter first receives an a priori state estimate and an a priori state error covariance matrix for the satellite, and wherein the method comprises:
-
inputting tracking measurements for the satellite received in real-time from tracking stations to the recursive filter at filter time update “
T”
;
inputting filter tracking station platform data to the recursive at filter time update “
T”
;
computing recursively the current state estimate, the current error covariance and the current filter measurement update of the satellite at filter time update “
T”
;
moving the state estimate and error covariance from filter time update “
T”
to filter time update “
T+1”
;
incorporating into the filter measurement update the information provided by the tracking data measurement at filter time update T; and
determining a current estimate of the orbit of the satellite. - View Dependent Claims (2, 3, 4, 5, 6, 7, 8, 9, 10, 11)
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Specification