Two-line element generation method based on model error compensation

Abstract

The invention discloses a two-line element generation method based on model error compensation. According to the method, first, observed position and speed vectors are converted to a true equator mean equinox coordinate system through a geocentric equatorial inertial coordinate system, then corresponding instant orbital elements are computed and are used as the initial estimated values of two-line element iterative computation; the position and speed vectors at the corresponding sampling instant are respectively predicted according to the initial estimated values, the difference values between the position and speed vectors and the position and speed vectors at the practical observing sampling instant are computed, whether a termination condition is met is judged; through a numerical differentiation method, a partial derivative matrix about the two-line elements of a simplified pervasive perturbation orbit prediction function at the sampling instant is computed; by solving a compensation least square problem, the correction of the two-line elements is obtained; new two-line elements are computed, and repeated iterative operation is carried out until the accuracy requirement is met. According to the method, the situations of single-point fitting and sampling fitting can be processed, and average errors are small when the two-line elements obtained by fitting are used for orbit prediction.

Description

technical field [0001] The invention belongs to space object trajectory calculation technology, in particular to a method for generating two-line radicals based on model error compensation. Background technique [0002] The two-line orbit element (TLE) is the format adopted by the U.S. Strategic Command to release space object catalog data. It is an average orbit element based on the Kepler element and has been widely used to describe space objects (including small satellites and space debris, etc.) trajectory. For the two-line elements, it is the average orbit element with the periodic disturbance item removed by a specific method. It must be used together with a specific orbit prediction model to predict the position and velocity of a space target at a certain moment. For near-Earth targets The forecast model is the SGP4 model provided by the North American Aerospace Defense Command (NORAD). As the most widely used analytical model at present, it considers the perturbati...

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Problems solved by technology

Lee (3.Byoung S L.NORAD TLE conversion from osculating orbital elements[J].Journal of Astronomy and Space Sciences,2002,19(4):395-402) proposed to use the instantaneous close orbital data of space targets to fit the The TLE of the target, but only studied the single-point fitting method, and did not consider the influence of the atmospheric drag factor; Dwight (4.Dwight E A.Computing NORAD mean orbital elements from a state vector[D].Ohio:Air Force Institute of Technology, Wright-Patterson Air Force Base, 1994) considered the problem of generating two-line radicals from position and velocity vectors, and proposed two methods, Newton's method and direct iteration, but this method did not solve the problem of eccentricity and orbital inclination The problem of inability to converge due to a singularity at a very small age; Liu Guangming et al. (5):1104-1107) proposed a space target TLE generation algorithm based on non-singular transformation, and introduced non-singular orbital elements instead of Kepler elements to solve the problem of possible singularities in the TLE sampling and fitting process, and gave An approximate analytical expression for the target state vector with respect to the matrix of partial derivatives of the two-row radicals, but the fitted target function only considers the position vector

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