Error analysis in gravity aided navigation

Wei Hongwei,Wang Shenquan,Tie Junbo,Wu Meiping,X Lei,S.P Kozaitis,C.-C Ku

doi:10.1051/matecconf/201816007006

Abstract

For underwater vehicles, because GPS signals are not always available, it is necessary to use inertial navigation system (INS) for navigation. In order to improve the navigation performance, the gravity value calculated by the gravity field model is introduced into the navigation system to reduce the influence of gravity on the navigation accuracy. However, due to the difference between the actual gravity field and the gravity field model, the navigation error caused by gravity field still exists. In this paper, this error is studied based on the theoretical analysis and simulation. The results show that the accuracy of gravity-aided navigation will decrease sharply when the position error of the underwater vehicles reach 9.6 n miles, because at this moment, the calculation error of vertical deflection is the largest. In the simulation experiment, the position error of the gravity-aided navigation system reach 9.6 n miles in 44 hours. Therefore, for the underwater vehicles navigation system, it is recommended that the vehicles should be corrected once every 44 hours.

Highlights

As a basic physical field, gravity field restricts all physical events of the earth itself and its adjacent space [1]
The inertial navigation system is affected by the earth gravity field, and the navigation accuracy of inertial navigation system is closely related to the value of gravity
The compensation method that using vertical deflection, which is achieved from the horizontal gravity disturbance that calculated using EGM2008, to assist inertial navigation can effectively reduce the error of the navigation system and improve the navigation accuracy

Summary

Introduction

As a basic physical field, gravity field restricts all physical events of the earth itself and its adjacent space [1]. The compensation method that using vertical deflection, which is achieved from the horizontal gravity disturbance that calculated using EGM2008, to assist inertial navigation can effectively reduce the error of the navigation system and improve the navigation accuracy. Horizontal gravity disturbances can be calculated, using EGM2008 as follows: The perturbed potential of gravity is denoted by T , since it is a harmonic function. It can be expressed by the following equation: this compensation method does not eliminate the errors caused by we will study the error in this cgoramvpiteyn fsiaetlido.nImn eththisodp,apaenrd, T. The horizontal gravity disturbance can be calculated by equation(7)

Analysis of vertical deflection

Simulation

Conclusion