Research On Pedestrian 3D Positioning Based On Smartphone Sensor

In recent years,with the development of the information society,location-based services(LBS)have become commonplace in daily life.Typical LBS applications such as navigation,content sharing,and instant messaging provide great convenience for people.With the increasing demand for positioning accuracy,pedestrian-based positioning technology has become a hot topic for scholars.Due to the attenuation of the signal in indoor and complex environments,the positioning accuracy is significantly reduced.At present,most of the research based on pedestrian track estimation is based on the normal forward movement of two-dimensional pedestrians.It is difficult to meet the user's needs and the pedestrian's abnormal walking pattern during exercise will cause errors.Based on the theoretical research,this paper uses the smart phone as a research platform to conduct in-depth research on the pedestrian track calculation technology in the three-dimensional space,and uses the built-in acceleration sensor of the mobile phone to achieve height measurement in the indoor environment,integrating step frequency,step size and Heading to achieve three-dimensional positioning.The main work is as follows:1.For the current pedestrian track estimation algorithm,there is a limitation to the manner in which the measurement unit is worn in a fixed posture,and the built-in sensor of the smart phone is used to dynamically update the posture of the mobile phone during exercise.2.Design a hierarchical recognition algorithm based on decision tree.Pedestrians' walking patterns are generally normal forward walking,and the current study also defaults to this walking pattern.However,the walking patterns of pedestrians are complex and diverse.A single walking pattern has great limitations and is not practical.According to the six different walking patterns in the process of pedestrians' movements,the actions of standing,normal forward walking,retreating,running,and going up and down the stairs are identified and judged to reduce the error of the extrapolation process.3.The mobile phone built-in accelerometer is used to measure the height of the room,and the method of barometer height measurement that is easily affected by environmental factors is eliminated.The zero-speed update algorithm is used to achieve pedestrian positioning in three-dimensional space.