Indoor positioning method for smartphone user based on terrestrial magnetism-corrected inertial navigation

Abstract

The invention relates to an indoor positioning method for a smartphone user based on terrestrial magnetism-corrected inertial navigation. The method comprises the following steps: dividing a to-be-positioned area into small grids according to a plane map of a building; allowing the smartphone user to acquire the intensity data of terrestrial magnetism at the center of each grid for a period of time by using a smartphone with a built-in magnetometer; averaging the intensity data of terrestrial magnetism acquired in each grid and constructing and storing an off-line terrestrial magnetism fingerprint database; allowing the user to start to walk with the smartphone, detecting steps and estimating step length by processing the data of an accelerometer of the smartphone, and acquiring an included angle between a movement direction and a true north direction and current intensity of terrestrial magnetism by processing the data of a gyroscope; acquiring a predicted value of a current state; calculating a covariance matrix and Kalman gain in a prediction phase; calculating observation and measurement results; and updating a state. The method provided by the invention can realize high indoor positioning precision only by using the smartphone.

Description

Technical field [0001] The invention belongs to the field of mobile terminal applications, and uses a smart phone to obtain multiple sensor data that is built-in to perform indoor positioning of a user. Background technique [0002] The Global Positioning System (GPS) can provide high-precision outdoor location services, but due to the occlusion of buildings, the GPS signal is very weak or even invisible indoors, so the GPS positioning system cannot be used for indoor positioning. Nowadays, more and more people's activities are carried out indoors, and location-based services are getting more and more attention. With the rapid development of radio technology and the increasing popularity of mobile intelligent terminals, indoor positioning and navigation technology has developed rapidly as a complementary technology to GPS. Because mobile intelligent terminal equipment (smartphone) has become a daily necessity for people, it has the characteristics of fast calculation speed,...

AI Technical Summary

Problems solved by technology

This method can achieve high positioning accuracy, but this method is only suitable for positioning in narrow and long areas such as corridors

[0005] Although the geomagnetic field has been widely used in indoor positioning, there are still problems that have not been dealt with well. First, the geomagnetic field strength is very weak (only about tens of uT). Secondly, for the fingerprint method, a single geomagnetic field strength is used as a fingerprint to The resolution to distinguish between different positions is too low

Although the three-axis magnetometer can obtain three-dimensional geomagnetic field data, it is natural to think of using all three-axis geomagnetic field strengths to improve the resolution of geomagnetic fingerprints, but in fact, the three data collected by the magnetometer will follow the sensor coordinate system. changes, therefore, only the total magnetic field strength can be used indoors

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