Some optimizations of WiFi- Based Indoor Positioning Hanqing Liu
Research Related 02 01 Background Work CONTENTS Our Follow-up 04 03 Project Work
Research Background
Research Background I ndoor localization The implement of positioning in indoor environment. W HY? The signal from the satellite is too weak. How ? Using wireless communication, base station positioning, inertial navigation to form indoor location positioning system 4
Related Work
Basic Concept Received Signal Strength I ndication( RSSI ) The basis of Wifi-based indoor positioning system! Can be predicted by a LDPL m odel . LDPL Model If Pi and γi are known, then an RSS m easurem ent pij can be converted into the distance dij. 6
A Basic Positioning Method Triangular positioning and LDPL Model The LDPL Model provide a connection between the location of the user and RSS. The cross point does not always occur in real case! 7
Some Advanced Scheme of Indoor Positioning Fingerprint-based positioning Offline phase: a site survey is conducted to collect the vectors of RSSI. Online phase: a user samples or measures an RSSI vector at his/ her position and reports it to the server. 8
Some Advanced Scheme of Indoor Positioning Peer Assisted Positioning The device broadcasts a special audio signal. Distance between peers is calculate based on TOA. SLAM The training phase The operating phase 9
Our Project
Our indoor positioning based on RSS 1 1
Stage 1: Triangular Positioning Only 1 2
Stage 2: Triangular Positioning With Some Optimizations 1 .Estim ating position based on position history. 2 . Estim ating RSS value Prediction = last_est + kg* (rssi- through Kalm an filtering last_est) 1 3
Follow-up Work
Follow-up work of project To find W HY? 1 .Pressure test Bottleneck! 2 .Adjustm ent of API 1 5
Pressure Test Bottleneck: 1 .Connection to DB 2 .Max Connection to Apache 3 . CPU 1 6
THANKS
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