Effects Of The Disturbing Gravity On The Fall-point Of Trajectory Missile

In all the factors which affect the fall-point of the ballistic missile,disturbing gravity is the one that must be considered.The analysis on the effects of disturbing gravity could be found in lots of literatures,but most of them were qualitative analysis.This dissertation focuses on the quantitative analysis of the missile fall-point deviation due to the disturbing gravity.The main works and contributions are summarized as follows:1.The boost phase missile trajectory is simulated according to the position and velocity of the ballistic missile in the turn-off-point at the boost phase.Based on the gravity anomaly data of the physical geodesy test field,the disturbing gravity of the boost phase missile trajectory is calculated by the method of degree-degree residuals of gravity anomalies.Then,the effects of the disturbing gravity on the boost phase missile are analyzed.2.The magnitude and spectrum sensitivity of disturbing gravity at different altitude and different spectrum bands are derived by Tscherning-Rapp model,and hereby the propagation features of disturbing gravity are investigated.The impacts of the grid gravity anomalies at resolution of 1'×1',5'×5' and 20'×20' in the physic geodesy test field at different altitudes on the fall-point are estimated,and then the maximum valid altitudes of the different grid gravity anomalies are presented.The correlated fall-point deviation caused by disturbing gravity with different integration radius is calculated and then the best integration radius of 1'×1',5'×5' and 20'×20' grid gravity anomaly are presented.3.The influence of the passive phase disturbing gravity on missile fall-point is analyzed by using gravity field model with different orders,and the best truncated order for calculating the passive phase disturbing gravity is presented.The passive phase disturbing gravity is calculated and the impacts on fall-point are also analyzed,on the assumption that the missile's range is 12000km and missile is respectively launched from 40 points,which equally located over our country with 5°differences on both latitude and longitude.The results indicated that the fall-point deviation caused by disturbing gravity is maximal when the launch point is located in the west area of our country.4.The influence of the possible errors in the calculation of disturbing gravity on missile fall-point is presented.The results show that the system error of disturbing gravity has the greatest impacts on fall-point deviation;the affect on boost phase could reach to 100m and 700m on passive phase by 5mGal system error.Thus,it is very important to improve the model accuracy in order to improve the hit precision.