| Location and navigation services are the basis for various services and promotion.People often need to visit a location again in the shopping malls,lost seeking,medical treatment and other application scenarios.However,for public safety,privacy protection and other issues,indoor maps or ichnography are generally not open to the public.Therefore,how to design an indoor navigation system without indoor map or ichnography has become the urgent problem to solve.Based on the propagation characteristics of Wi-Fi signals in indoor environment and wireless access points distribution characteristics,this paper proposes a method of replacing the indoor floor plan with the scanned Wi-Fi signal strength sequence and designs an indoor navigation system without map-assisted.Main tasks are as follows,(1)To improve the robust and decrease the noise of dynamic collecting Wi-Fi information,this paper proposes a subsequence matching algorithm based on the segmented dynamic time regular(SDTW)using the motion constraint and the path constraint information which are embedded into the fingerprint information.(2)This method establishes a mapping between RSS and indoor path.By using the similarity of the AP sets that scanned before and after on the same way to achieve coarse location,the subsequence matching algorithm based SDTW is used for getting the relative position of the object relative to the target point.Combining with the number of steps and direction information collected by the mobile phone,system achieves the self-navigation service that object from the current location to the target location.(3)Through the designed prototype system on Android system,a comprehensive test of the various aspects of the system performance was implemented.The experimental results show that the proposed map-free indoor location and navigation system can meet the navigation requirements of users when they visit a certain location once again,and the method adopted by the system is low and easy to expand. |
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