Research On Key Technology Of Floor Switch And Satellite Positioning Based On Differential Pressure Altimetry

In recent years,with the rapid development of information technology and the improvement of people’s quality of life,indoor and outdoor location services has become an indispensable part of people’s life.Precise indoor positioning requires accurate identification of crowded spaces inside the building and accurate switching of the floors where the users are located.In the outdoor environment,only three satellites can be received in some locations.In this case,the traditional satellite positioning method is difficult to obtain more accurate positioning results.In view of the above issues,this dissertation studies the key technologies of floor switching and satellite positioning based on differential pressure altimetry:(1)In the existing floor switching technologies,the technology based on WiFi fingerprint positioning needs to deploy a large number of AP nodes with higher cost.And the floor switching technology based on differential pressure altimetry is greatly affected by indoor and outdoor environments and has low recognition accuracy.Based on the above research,this dissertation proposes a floor switching technology based on the results of differential pressure altimetry,pedestrian movement recognition and map accurate matching.The test results show that the proposed technology has a floor recognition rate of about 98.2%,which is slightly improved than that of the WiFi-based floor recognition technology without deploying the APs.Compared with the floor switching technology based on differential pressure altimetry,the accuracy of the proposed algorithm is improved by 1.4%.(2)Aiming at the issue of the poor positioning accuracy of existing satellite positioning with less satellites,this dissertation proposes a auxiliary satellite positioning technology based on differential pressure altimetry.The technology needs to use the coordinate of the previous positioning result as the reference point coordinate to establish virtual satellite pseudo-range observation equations.Newton iterative method is used to get the result of single-point positioning result.The Kalman filter is used to fuse the inertial sensor information and single-point positioning results to get more accurate positioning results.The experimental verification shows that the proposed technology can also locate in the visible three-satellite case with the accuracy of 1.82 meters(1σ),which is 27.63%more accurate than the existing three-satellite positioning technology based on terrestrial mobile communication base stations.When four satellite signals are received,the proposed technology has a positioning accuracy of about 1.44 meters(1σ),which is 32.08%more accurate than the test of same environment with only four satellites for positioning.