Research On Context Awareness In Indoor And Outdoor Seamless Positioning

In recent years,with the development of mobile Internet and location technology,location-based service appears more and more in people's lives.The global satellite navigation system has been widely used in the outdoor environment;however,it is difficult to provide positioning service in an indoor environment due to the problem of signal attenuation.At the same time,with the popularity of intelligent terminals,smartphone-based indoor positioning methods have also become a hotspot.However,people's daily activities are usually from outdoor to indoor or in turn.Therefore,indoor and outdoor seamless positioning will be the future trend of navigation and positioning.Context means information that is closely related to the user,such as time,location,environment,actions,etc.Comprehensive judgments of user's current activities can be get through the context awareness.Context awareness can play an important role in the indoor and outdoor seamless positioning,for it can not only improve the positioning accuracy,but also provide users with more intelligent location services and better user experience.This paper focuses on the context-aware in indoor and outdoor seamless positioning system.In indoor and outdoor positioning systems,the environment and the user's own actions will affect the positioning results.This paper mainly analyzes the following three kinds of context awareness:Continuous judgment of indoor and outdoor based on GPS signal:To achieve seamless indoor and outdoor positioning,it needs to distinguish indoor or outdoor.This paper uses GPS signal to distinguish indoor and outdoor environment.The first step is to establish the offline model,and then use KNN algorithm to identify.In this paper,a hidden Markov model is introduced to modify the indoor and outdoor environment recognition process to improve the accuracy of the recognition.Finally,we discuss the improvement of our model when applying scene judgment to seamless positioning.Identification of floor number based on air pressure fingerprint:Floor number is important information for indoor positioning.In this paper,a floor detection method based on barometric pressure is used.First,an offline pressure value fingerprint library is established.Compare with the fingerprint library to get the target floor.Because of the time variability of air pressure,this paper presents a new method to update the air pressure offset by detecting the floor change process,and eliminates the air pressure offset error caused by the long residence time on the same floor.Complex motion recognition based on acceleration:In the smartphonebased indoor and outdoor seamless positioning system,inertial navigation is a commonly used algorithm,and the users' behavior can greatly affect the results of inertial navigation.Different from traditional motion recognition,this paper takes the user's motion pattern and mobile phone usage pattern into account,and uses the linear acceleration and gravity acceleration to extract and select the eigenvalues.Then the performances of several different classification algorithms are discussed.Finally,the application of motion recognition in inertial navigation is discussed and verified by experiment...