Research On Floor Discrimination Method Based On Barometric Altimetry

With the rapid development of smartphones and mobile internet,the demand for location-based services is growing.In indoor positioning,the two-dimensional positioning service is limited,and it is difficult to meet people's needs.The acquisition of elevation information has become an important dimension of location information,such as shopping positioning service in commercial buildings,fire emergency response and indoor emergency rescue service.However,the technology of elevation positioning is not mature.The main reasons are low positioning accuracy and high cost of equipment investment.Many smart phones have built-in air pressure sensors,which provide conditions for differential barometric height aided floor discrimination.In this paper,the advantages and disadvantages of the traditional differential barometric height aided floor identification method are analyzed,and a dynamic differential barometric height aided floor identification method is proposed.The principle of this method is to use the built-in air pressure sensor of smart phone to get the air pressure data,and then use the air pressure-elevation model to calculate the height difference,and to determine the floor after obtaining the height difference.The main contents of this paper are as follows:(1)The relationship between air pressure and altitude difference is discussed,and the air pressure data collected by the built-in air pressure sensor of smart phone is analyzed.The influence of various interference factors(temperature,humidity and wind speed,etc.)on air pressure altimetry is verified by experiments.(2)On the basis of analyzing the characteristics of air pressure,the suitable method of air pressure data filtering is selected.The experimental analysis shows that the traditional differential barometric altimetry method is feasible for floor positioning,but it is vulnerable to environmental factors,and the positioning accuracy is low,only75%.(3)The regularity and characteristics of barometric height measurement are systematically analyzed,and an auxiliary floor determination method for barometric height measurement is proposed,that is,the dynamic differential barometric height determination auxiliary floor identification method.The experimental results show that this method not only overcomes the errors caused by atmospheric drift,but also avoids the interference of heterogeneity and environmental factors of mobile phones.D-DPF algorithm can accurately identify the moving upstairs and downstairs,and theaccuracy of floor identification is greatly improved.(4)Floor discrimination experiments were carried out in complex environments(a high-rise residential building in Xuzhou,Suning Building,Nandu International and Jindi Shangdu Commercial Building).This experiment fully considers the real life situations and is closer to life.It provides a reliable basis for assistant floor determination of dynamic differential barometric height measurement.The accuracy of dynamic differential barometric altimetry is better than 1 m.The probability of accurately identifying floors within 20 floors(80 m)by one-time transformation is100%.This proves the validity of D-DPF algorithm.