Achieving High Navigation Accuracy for Spacecraft Using High-Order Representation Model of Disturbing Gravity

Aiming at the low precision of gravity model in the Inertial Navigation System (INS) of the vertical launch vehicle, a disturbing gravity representation model which covers the launch area was presented in this paper. Even trading accuracy against speed, the results achieved by this method have sufficient precision for navigation calculation. By this means, the disturbing gravity is assigned to the navigation computation loop within a very short time and with an extraordinary accuracy. Several numerical simulations have shown that the average approximation error of disturbing gravity is less than 2 mGal at any height level and the relative approximation error is less 2%.