Research On Heading Correction Algorithm Based On PDR Of Smartphone

GNSS positioning technology has gradually matured and can provide users with good location services outdoors.However,in an indoor or high-rise urban area,GNSS technology is difficult to use because its signals cannot penetrate buildings.The popularity of smart phones has risen rapidly and performance has gradually increased,making indoor positioning research based on smart phones a hot topic in indoor positioning technology research.Bluetooth,WiFi,cellular mobile,and other positioning technologies based on smart phones have emerged.From the perspectives of workload,external facilities,computing requirements,and cost,the advantages of PDR positioning technology based on the built-in sensors of mobile phones are prominent.However,heading accuracy is one of the difficulties in impeding the accuracy of PDR positioning algorithms.The improvement of heading accuracy is a critical issue in PDR algorithms.In this context,this paper studies the PDR algorithm based on the built-in sensor of smart phones,and explores ways to improve the heading accuracy.The main contents are as follows:1.Analyze and compare two methods for solving the quaternion in the PDR heading solution.Under the ideal condition,the fourth-order Runge-Kutta method has higher accuracy than the second-order Runge-Kutta method.The experimental results show that compared with the positioning algorithm of the second-order Runge-Kutta method and the fourth-order Runge-Kutta method when using the built-in sensor of the mobile phone as the research object,the positioning accuracy solved by the second-order Runge-Kutta method is more accurate.2.The Mahony filtering algorithm is studied.The error compensation of the gyro data by the accelerometer data reduces the random drift error of the gyro to a certain extent.The experimental results show that the Mahony filtering algorithm can significantly improve the accuracy of the roll angle and the pitch angle,but it has no obvious effect on the heading correction.Therefore,it does not improve the localization accuracy of the positioning algorithm,and it may even lead to a reduction in the final positioning accuracy.3.The HDE algorithm is studied.The algorithm is applied to the PDR based on the built-in sensor of the mobile phone and its stability is improved.The judgment condition of the algorithm is added.The step-size attenuation model is improved and the direct correction image of the HDE algorithm is changed.The experimental results show that the HDE algorithm can significantly improve the heading accuracy and improve the positioning accuracy to a certain extent:in the indoor environment of about 400m,the positioning accuracy can be maintained within 5m,and the positioning accuracy can be increased by more than 65%.