Research On Calibration Technology Of Indoor Electromagnetic Positioning System

Since the new century,China's informationization and army building have entered a new era.In order to cope with modern warfare,soldiers need to have a higher quality.This not only imposes strict standards on individuals,but also puts high demands on daily training.Targeting training is an indispensable link.The core of aiming training is positioning technology,and the positioning accuracy often determines the quality of the training effect.Electromagnetic positioning system is widely used in virtual reality and medical operation navigation.The electromagnetic positioning system has the advantages of relatively cheap price,large working range and no visual line occlusion.The receiving sensor of the electromagnetic positioning system is fixed on the aiming device.When training,the sensor and the aiming device move together with the training personnel,and the sensor can track the pointing and position of the aiming device in real time.However,due to its own characteristics,the electromagnetic positioning system is easily interfered by external metal conductors and other electromagnetic environments,resulting in large positioning errors.The subject requires a position coordinate accuracy of 0.5 cm and a direction angle accuracy of 0.5° in the range of 1.8 m.In order to adapt to the positioning accuracy requirements of the aiming training system,the error calibration plays a decisive role in ensuring the accuracy.In order to achieve the calibration of the electromagnetic positioning system to meet the accuracy requirements of the aiming training system,the specific work of this paper is as follows:Construct an experimental environment and conduct experimental design and analysis.Firstly,the law of direction angle error variation is demonstrated to determine the calibration method of direction angle error.Secondly,data acquisition is performed,the distribution of current electromagnetic positioning system error is analyzed,and the calibration database of position and direction angle is established.Finally,data collection is performed and statistically found.The accuracy of 40% X coordinate,13% Y coordinate and 4% Z coordinate reaches the target index,and the accuracy of 0% azimuth and 12% pitch angle reaches the target index,so calibration is very necessary.The traditional polynomial fitting method is used to directly fit the data in the sampling space.The shortcomings of the error model trend and some local area errors after calibration are not considered.The error model is segmented and fitted to the error.calibration.Through simulation,it is found that the traditional second,third and fourth order polynomial fittings are compared and analyzed to improve the positioning accuracy.And with the aim of this project aiming at the simulation training accuracy requirements,it is found that 91% of the position coordinates meet the index requirements,and 95% of the direction angles meet the index requirements.In order to further improve the accuracy,after the calibration of the first method proposed in this paper,there are still some problems that some local regions cannot meet the requirements of the index at a long distance.The traditional neighbor interpolation algorithm is improved,and one has been applied to the geographical and atmospheric fields.Kriging interpolation algorithm.First,the Delaunay is divided into the sampling points;then the interpolation points are searched to determine the tetrahedron where it is located;finally,the error is calibrated.By comparing with the traditional inverse distance interpolation method and the gravity center coordinate interpolation method,the Kriging interpolation has higher calibration accuracy,which verifies the effectiveness of the algorithm.At the same time,the sampling interval was quantified.The simulation found that when the sampling interval is 5cm,99% of the position coordinates and direction angles meet the index requirements.