Geomagnetic signal extreme value detecting and feature matching based positioning method

Abstract

The invention discloses a geomagnetic signal extreme value detecting and feature matching based positioning method. The geomagnetic signal extreme value detecting and feature matching based positioning method is characterized by comprising the following steps: 1) obtaining geomagnetic signal strength of a to-be-detected position according to certain time period; 2) performing smooth filtering on the geomagnetic signal strength; 3) performing extreme value point detection on the filtered geomagnetic signal strength, constructing a to-be-matched geomagnetic feature vector if the extreme value point is detected, otherwise, not outputting positioning results at the current moment; and 4) performing similarity matching on the to-be-matched geomagnetic feature vector and a geomagnetic feature vector in a constructed database, outputting coordinates of the position of a matched point as positioning results of the current moment if the matching is successful, otherwise, not outputting the positioning results at the current moment. The method can effectively avoid the proportioning problem of a signal sequence during continuous positioning, has the advantages of being high in positioning precision, strong in robustness, small in calculating amount and the like, can be independently used, also can be fused with other methods, and is widely applied to various indoor and outdoor scenes.

Description

technical field [0001] The present invention belongs to the field of positioning. Background technique [0002] With the promotion of the concept of smart cities and the rapid development of related technologies, the importance of location information is self-evident, which has greatly promoted the rapid development of positioning technology, and derived a variety of positioning technologies based on different signal sources. [0003] Positioning technology based on geomagnetic signals is currently in its infancy. According to the theory of the geomagnetic field, the geomagnetic field is the basic physical field of the earth. Any point in the earth's near-earth space has a magnetic field strength, and its strength and direction will vary with different longitudes, latitudes and altitudes. At the same time, according to the magnetic field theory, magnetic substances will have an effect on the magnetic field. Most modern buildings are reinforced concrete or steel structures,...

AI Technical Summary

Problems solved by technology

[0004] Most of the common geomagnetic positioning methods are based on the matching method. The corresponding location information is obtained by matching the real-time sampled geomagnetic data with the geomagnetic features of the known positions in the database. However, there are still some problems to be solved in practical applications: (1) geomagnetic The strength is not unique, and there are multiple physical locations corresponding to the same geomagnetic signal strength. Therefore, the method based on single-point matching often needs to be combined with other positioning methods for positioning, and cannot exist independently

(2) The continuous positioning method based on line matching mostly uses the minimum mean square error as the objective function to find the optimal solution, but the obtained trajectory may not be the real trajectory, and this type of method often has a large amount of calculation

(3) Due to the different moving speeds of the target to be positioned, the geomagnetic signal sequence collected during real-time positioning and the geomagnetic signal sequence in the database often have a scaling problem in terms of time length, which brings certain difficulties to the positioning method based on line matching

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