The Principle And Simulation Of Underwater Geomagnetic Aided Inertial Navigation Based On SITAN Algorithm

Inertial navigation system with the advantages such as independent,good hiding ability,work around the clock,it can provides continuous and real-time navigation parameters to the carrier,and has high navigation accuracy in a short time.how ever,the errors of the inertial navigation systerm will be accumulated with time,and the performance of systerm gets worse in a long time.Therefore,we need an algorithm to correct the error which causeed by inertial navigation.Geomagnetic field is a natural physical fields of the Earth,which is superimposed by a variety of different origins and different variation magnetic field.At the same time due to the time changing of the geomagnetic field is global nature,and the spatial variation of the geomagnetic field has minimal dependence on time,So we can say that the geomagnetic field is a function of space over a period of time,That is,any point on earth and space will have a unique magnetic vector value.Due to the magnetic field has such a characteristic,so we use it to aid inertial navigation system is a theoretical and meaningful.In this paper,we analyze the principle of the SITAN algorithm.we proposed the SIMAN solution to use of geomagnetic value aided inertial navigation solution,because of the magnetic contour map has high similarity with the terrain elevation map.Through simulation experiments of navigation on the magnetic map of school playground and Songhua lake,we verify the feasibility of the algorithm.In this paper,we launched a geomagnetic aided navigation experiment by use optically pumped magnetometer as a magnetic survey tool.Optically pumped magnetometer is based on the Zeeman splitting effect of atomic level and uses of the principle of optical pumping and optical magnetic resonance to measure magnetic field strength.Optical pumping magnetometer has advantages such as: it has no zero offset,continuous measurement,high accuracy and low noise as well as large measurement range.In this paper,the value of geomagnetic was measured by use of CS-L-type optically pumped in this experiments.The main work of this paper include the following:First,this paper introduces the key technologies of geomagnetic aided navigation system,includs measuring geomagnetic values,ploting high-precision geomagnetic graphs and selecting geomagnetic aided navigation algorithm.In this paper,the widely used matching algorithm has been introduced,such as TERCOM algorithm and ICCP algorithm.Secondly,we introduced the basic principles of SITAN system and the valuation principles of inertial navigation systems.we got the detailed mathematical model of state equation and measurement equation through analysis the principle of SITAN system.This paper detailed analysis the core technology of SITAN system,including terrain stochastic linearization technique and Kalman filtering techniques.We detailed analysis four principles of terrain stochastic linearization and the workflow of Kalman filtering technique.Finally,based on the basic principles of SITAN algorithm,we proposed the SIMAN system solutions which uses the geomagnetic field to aid inertial navigation.Proved the validity of Kriging in the drawing of local area geomagnetic map by plotting the playground geomagnetic map.And the feasibility of the SIMAN system have been verified by used of this geomagnetic map.At last we take simulation experiment by use of the geomagnetic map of SongHua lake,and the experimental results show that: SIMAN system uses the geomagnetic field to aid inertial navigation is feasible and has a good effect in some areas.This scheme has certain significance to the late geomagnetic navigation research.