The Study Of Gravity Disturbance Compensation Method Of High-accuracy Long-time INS

In low-precision inertial navigation systems(INS), the low precision of inertialcomponents is the major source of navigation error. By contrast, the error caused by thegravity disturbance is so small as to be ignored. However, with the increasing precisionof inertial components, the gravity disturbance has become the main cause of thenavigation error in high-precision long-time navigation systems. Thus, it should becompensated instead of being ignored. By discussing the influence of the gravitydisturbance on the high-precision long-time INS error and its compensation methods, thisthesis analyzes the mathematical mechanism of the gravity disturbance’s influence oninertial navigation error, and proposes new compensation methods based on the existingresults. The content of this thesis covers:The influence of gravity disturbance on INS error is studied. On the basis of basicINS mechanical arrange, this thesis deduces the mathematics principle of how gravitydisturbance influences the INS error. After that, this thesis conduct an INS position errorsimulation based on gravity disturbance simple model, and analyzes different influencesof different gravity disturbance model on INS position error. The conclusion is thatgravity disturbance has a great influence on INS position error and must be compensated.Gravity disturbance compensation methods are studied. This thesis introducesseveral ways of accessing gravity disturbance and compares the strengths and weaknessesof the existing compensation methods. On this basis, this thesis proposes the gravitydisturbance compensation method based upon partly fitting low order model of gravitydisturbance and conducts comparison simulation experiment. The simulation resultindicates that the method proposed in this thesis effectively reduces the position errorcaused by gravity disturbance, which does better than the existing ones.This thesis proposes the concept of gravity disturbance residual error, and analyzes itin theory. And a method to compensate the gravity disturbance residual error based onKalman filter estimation is proposed, we propose the method of compensating the INSerror caused by the remaining gravity disturbance after the gravity disturbancecompensation.