Research On Indoor Floor Plan Establishment Method Based On Crowdsourcing IMU Data

Nowadays,with the rapid popularity of smart phones,indoor navigation and location service with high precision is playing an indispensable role in our daily life.People could use their smart phones to enjoy variety of indoor location-based services.Generally,no matter which techniques,like WiFi,Bluetooth,zigbee,they all need the accurate indoor geographic information.With the help of accurate indoor geographic information,indoor navigation system could make specific database in the offline phase,and also show its location and navigation estimation clearly in a smart phone in the online phase.However,if in an unknown indoor environment or we cannot obtain the indoor floor plan,which means it is lack of prerequisites for the indoor positioning technology,so we need a low-cost and rapid indoor floor plan establishment technology.Aiming at the above problems,this paper proposed a method of establishing indoor floor plan,which can achieve the rapid establishment of indoor plan through crowdsourcing IMU data in unknown environment.The main contents are as follows: Firstly,pedestrian trajectories are generated by Pedestrian Dead Reckoning algorithm(PDR).Based on the research of key techniques in PDR algorithm,such as step size estimation,step strategy and heading decision,the accurate PDR trajectories are generated.And based on the measure posture recognition of crowdsourcing users and the starting point detection,we can generate the PDR trajectory by crowdsourcing users in different measurement modes,and further improve the accuracy of trajectories.Secondly,according to the walking habit of indoor users,this paper established a generic indoor walking model.The model divides the indoor environment into striped corridor and corner environment.In the striped corridor environment,the user trajectory distribution conforms to the Gaussian distribution model,that is,majority of trajectory will concentrate on the axis of corridor or nearby.In the corner environment,majority of the user trajectories distribution will tend towards the inside of corridor,its distribution is similar to the Erlang distribution.And through the coordinate system transformation,we fuse the two different distribution models,and establish a homocentric square corridor model,and extended to any right angle corner environment.In addition,this paper cluster the striped corridor data based on the density peak,and according to the 3 sigma principle,we calculate the width of each corridor.So we obtain the important parameters for indoor floor plan establishment.Finally,based on the indoor walking model,this paper proposed an indoor floor plan establishment algorithm based on trajectory density analysis.The algorithm includes hot spot division,trajectory density calculation,hot spot region selection,map boundary generation and linear map generation.In this paper,the Alpha-shape algorithm is used to extract the edge of the reserved hotspot region.So we get the indoor floor plan boundary.And finally with the width of corridor,we can get the straight outline of the accurate indoor floor plan.Comparing with the map in real environment,the method based on the crowdsourcing IMU data in this paper can achieve the aim of indoor floor plan establishment with the low cost and rapid progress,which also can ensure the accuracy of floor plan.So it can obtain the indoor geographic information in the unknown environment,and based on it,it is easy to deploy the indoor navigation system quickly,which extends the application of indoor navigation system.