Method and system for utilizing spherical cap harmonic model to determine disturbing gravity along orbit

Abstract

Disclosed is a method and system for utilizing a spherical cap harmonic model to determine disturbing gravity along an orbit. Before an aircraft is launched, with a first launching area as a sphericalcap area to be approached, the radius of a spherical cap is determined, and a spherical cap coordinate system is established; under the condition that an origin of coordinates is unchanged, the radius of the spherical cap is mapped to a hemisphere, and a new coordinate system is established; under the new coordinate system, a non-integral numerical value of a spherical cap harmonic expression iscalculated; on the basis of the non-integral numerical value, the spherical cap harmonic model is utilized to calculate the disturbing gravity under the new coordinate system; the disturbing gravity is converted into the original coordinate system, and the disturbing gravity of the aircraft along the orbit is obtained. By means of the method and system, the practical application effects of the spherical cap harmonic analysis model in studies of partial gravity fields are improved, under the condition of meeting the same accuracy, the speed of assigning the disturbing gravity of the spacecraftalong the orbit is increased, fewer memories are required, and mobile and quick launching is facilitated.

Description

technical field [0001] The invention provides a method and system for determining the gravitational disturbance along the track by using the spherical crown harmonic model, which can increase the value assignment speed of the gravitational disturbance along the track of the spacecraft, and is mainly used in the fast maneuvering launch of the aircraft. Background technique [0002] The aircraft flies in the outer space of the earth and is affected by the gravitational force of the earth. If the gravitational force of any point in the outer space of the earth is known, including the magnitude and direction, the force model of the entire operation stage of the aircraft can be refined to improve its guidance accuracy. In order to simply describe the gravitational force outside the earth, a rotating plastid with a regular shape is artificially selected as an approximation of the actual earth, and the gravitational force outside the plastid is as close as possible to the gravitati...

AI Technical Summary

Problems solved by technology

This method is widely used in the calculation of aircraft orbital motion, but this method also has the following problems: (1) The spherical harmonic function reflects more of the low-frequency part of the earth's gravitational field, which is suitable for global gravitational field assignment, but not suitable for local Low-altitude gravitational field assignment

For long-range aircraft, the calculation of the active segment is not applicable

(2) Due to the need for recursive calculations, the amount of calculation is large when the order is high, which cannot meet the requirements of fast assignment

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