Research On Inertial/geomagnetic Integrated Navigation Matching Algorithm

The geomagnetic navigation system has good autonomy and excellent concealment,so it is researched by more and more scholars in recent decades.It can be used in any places of near earth space and applied in all weathers compared to other navigation techniques.The inertial/geomagnetic integrated navigation system can be acquired by inertial navigation system(INS)and geomagnetic navigation system,which makes up each other shortcomings by their advantages.It is foreseeable that the geomagnetic navigation technology will become the necessary navigation method of high-tech weapons in the future.This paper studied the inertial/geomagnetic integrated navigation system,including the Strap-down Inertial Navigation System(SINS),the geomagnetic reference field model,the Magnetic Contour Matching(MAGCOM)algorithm,the Iterative Closest Contour Point(ICCP)algorithm,the geomagnetic matching algorithm based on affine model and the anti-outlier geomagnetic matching algorithm.Firstly,the gyroscope and the accelerometer ideal outputs are acquired by mathematical method,and the error models of the inertial instruments are analysed.The SINS is simulated and the simulation result shows that the navigation error increases as time goes on.Secondly,the geomagnetic field theory and model are researched.The geomagnetic map is obtained by the International Geomagnetic Reference Field(IGRF)model.Next,MAGCOM algorithm and ICCP algorithm are researched and simulated.The simulation results show that MAGCOM algorithm can adjust the displacement error but it is helpless to the heading error.ICCP algorithm needs harsh conditions and it is easy to fall into local optimum.Considering the deficiencies of MAGCOM and ICCP,a novel geomagnetic matching algorithm based on affine model is proposed.The simulation results show that the proposed algorithm can adjust displacement,heading and zoom errors,and it has the higher precision than MAGCOM algorithm and ICCP algorithm.Therefore,it is worthy to research.Finally,the anti-outlier geomagnetic matching algorithm based on robust estimation theory is proposed to eliminate the influence of the outliers in the geomagnetic measured data.The mathematical principle of the proposed algorithm is introduced in detail.The simulation results indicate that the precision of the anti-outlier geomagnetic matching algorithm is far higher than that of the algorithm based on affine model when the outlier is small.Meanwhile,the algorithm based onaffine model mismatches when the outlier is large while the anti-outlier geomagnetic matching algorithm still has higher precision.Therefore,the anti-outlier geomagnetic matching algorithm has many advantages.