Passive Integrated Navigation Based On Improved DTW Geomagnetic Matching Algorithm

The geomagnetic field itself exists on the earth,and it has characteristic information to identify the location.Therefore,geomagnetic navigation does not need to rely on other navigation information,and the value of the geomagnetic field is relatively stable and will not accumulate errors over time.Indoor navigation and positioning are not easily affected by emergencies,but in a complex outdoor environment,there may be other magnetic fields outside,resulting in large positioning results.Therefore,it is usually combined with other navigation systems.Geomagnetic matching is a very important link in geomagnetic navigation and positioning.The performance of the geomagnetic matching method will directly affect the positioning effect of the system.Therefore,this paper focuses on the geomagnetic matching algorithm.The work done is as follows:Firstly,the positioning principle and specific implementation process of the inertial navigation system are introduced.The geomagnetic navigation is analyzed,the positioning principle of the geomagnetic navigation is explored,and the origin of the geomagnetic field,the composition of the geomagnetic field,and the geomagnetic field model are described.The matching principle and matching process of various geomagnetic navigation matching methods were compared and analyzed.The classification,positioning principle and specific realization process of integrated navigation are introduced.Then,the traditional DTW matching algorithm is not efficient and requires a long calculation time.A geomagnetic matching integrated navigation algorithm that improves the efficiency of DTW operation is proposed.The DTW matching algorithm is improved as follows: the square of the Euclidean distance is used to compare the distance during the matching process,and the Itakura window is used as a constraint to restrict the search range and reduce The computational complexity is reduced.The results show that this method guarantees the positioning accuracy and the positioning efficiency is increased by 43.37%.Finally,in view of the possible "singularity" of the DTW matching algorithm,a geomagnetic/INS integrated navigation method based on an improved derivative dynamic time warping matching algorithm is proposed.The DDTW matching algorithm matches the geomagnetic sequence by comparing the first derivative of the sequence,and uses the Itakura window as a constraint to restrict the search range.The results show that the DDTW matching algorithm effectively alleviates the "singularity" problem.Under the premise of ensuring the positioning efficiency,the average positioning accuracy can reach 1.37 m.Through the above research,the positioning efficiency and positioning accuracy in geomagnetic matching have been improved respectively,and verified by measured data.