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

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 analys