Positioning Accuracy: the influence of indoor/outdoor layout Group 8 Nuosang Du Sara

Outline Motivation Key Concepts Problem Statement Related Work & Novelty Approach Validation Limitation Future Work

Motivation Complex layout of building seems to influence the accuracy of positioning, either internal or external layout.

Key Concepts 1. RSSI 2. Trilateration 3. iBeacon 4. Sensors embedded in mobile -Accelerometer -Magnetometer

Problem Statement Input: Given a collection of real position points data and calculated position points data by several positioning technologies in indoor/outdoor place. Output: Plot the dynamic spatio-temporal figure of a mobile movement. Objective: The accuracy of several positioning technologies Constraints: The signal attenuation of positioning technologies and the mobile moving performance

Related Work & Novelty

Approach(cont.) 1. Estimating the distance between a mobile and a device(routers/beacons). RSSI = -(10 * N * log(distance) - M) M = -62 dBm for one meter N is a constant 43

Approach(cont.) 2. Build the coordinates of the mobile by trilateration using three devices (routers/beacons). (From Wikipedia)

Approach(cont.) Static error vs. Dynamic error

Approach(cont.) 3. Use sensors(accelerometer) in mobile to improve the positioning accuracy. Yt = root(x^2 + y^2 + z^2) Exponentially Weighted Moving Average(EWMA): (From Wikipedia)

Approach(cont.) Use magnetic sensor(compass): Delta X = L * sin(G * pi / 180) Delta Y = L * cos(G * pi / 180) L: step length by meter G: Gap from north by degree

Validation(cont.) Screenshot of program in mobile

Validation(cont.) Use Case Study: Keller Hall for outdoor Mall of America for indoor

Validation(cont.) Outdoor Figure From 0 to 50s is away from building From 60s to 100s is near building From 100s to 120s is away from building again

Validation(cont.) Indoor Figure From 0 to 50s is away from blocks(e.g. two walls) From 60s to 100s is near blocks From 100s to 120s is away from blocks again

Limitation 1. The accuracy of sensor is enough for project, but not for expert level 2. May performs poor in high resolution map 3. Not consider the height parameter 4. Not consider the horizontal movement

Future Work 1. Use gyroscope or other sensors to improve accuracy 2. Use the landmarks in buildings to improve accuracy 3. can be extended to 3D positioning 4. can be relative with indoor/outdoor detection

Reference [1] Improving Accuracy of WiFi Positioning System by Using Geographical Information System (GIS); Tussanai Parthornratt, Kittiphan Techakittiroj; 2006 Wireless Telecommunications Symposium [2] From “Where I am” to “Here I am”: Accuracy study on location-based services with iBeacon technology; Tsz Ming Ng; 2015 [3] Hybrid wireless indoor positioning with iBeacon and Wi-Fi; Tao Peng, Xinhong Wang; 11th International Conference on Wireless Communications, Networking and Mobile Computing (WiCOM 2015) [4] An Accelerometer Based Approach for Indoor Localization; Ching-Hsien Hsu, Chia-Hao Yu; Ubiquitous, Autonomic and Trusted Computing, 2009 [5] Indoor position estimation using image sensor based on VLC; Myoung-geun Moon, Su-il Choi; 2014 International Conference on Advanced Technologies for Communications (ATC 2014) [6] Accurate and reliable real-time indoor positioning on commercial smartphones; Gennady Berkovich, Indoor Positioning and Indoor Navigation (IPIN), 2014 [7] Embedded sensors for indoor positioning; Teresa A. Shanklin, Benjamin Loulier; Sensors Applications Symposium (SAS), 2011 IEEE [8] Mixed positioning system guaranteeing the continuity of indoor/outdoor tracking; Hanen Kabaou, Pascal Lorenz; Advances in Computing, Communications and Informatics (ICACCI, 2014) Thank you!