Presentation on theme: "CSI Wireless Networks and Mobile Computing"— Presentation transcript:
1CSI 5169 --- Wireless Networks and Mobile Computing Indoor LocalizationZhang Zhang
2Outline Introduction Definition Important parameters Indoor Localization MethodsProximity DetectionTriangulationScene AnalysisIndoor Localization SystemsProximity BasedRF BasedCameras BasedComparison of Common Indoor Localization Systems
3Introduction - Defination Def. Wirelessly locate objects or people inside a building in real time.Indoor Positioning Systems (IPS)Real-time Locating Systems (RTLS)
4Introduction - Important Parameters AccuracyCoverageAvailabilityUpdate RateLine of Sight (LoS) and Non Line of Sight (NLoS)Costs and System Complexity
5Introduction - LoS / NLoS Line of Sight (LoS) and Non Line of Sight (NLoS)
7Methods / Algorithm - Proximity / Cell of Origan Proximity Detection: Sensors detect and measure reflected Infrared orvisiable light or RF wave to detect the presence ofan object or person in certain areas.Highest Received Signal Strength = Highest Probability
8Methods / Algorithm - Proximity / Cell of Origan AdvantagesNo complicated algorithmsEasy to implementLow costDisadvantagesLow accuracy - room levelIdentification problem
9Methods / Algorithm - Time based ToA: Time of ArrivalThe precise measurement of the arrival time of a signal transmittedfrom a mobile device to several receiving sensors.The distance between the mobile device and each receiving sensorcan be determined.
10Methods / Algorithm - Time based - ToA AdvantagesHigh Accuracy2D / 3DDisadvantagesPrecise time synchronization (1 micro-second, 300m error)Solutions are typically challenged in environments where alarge amount of multipath or interference may exist.
11Methods / Algorithm - Time based - TDoA TDoA: Time Difference of ArrivalUsing relative Arrival time measurements at each receiving sensorThe synchronization between tag and each sensor is not necessaryExample:TXC - TXA = 10-8sTDoAC_ATXB - TXA = 10-7sTDoAB_A
12Methods / Algorithm - Angle based - AoA AoA/DoA: Angle of Arrival / Direction of Arrival (DoA)Determining the angle of incidence at which signals arrive at the receiving sensor.
13Methods / Algorithm - Angle based - AoA More sensors = Higher accuracy
14Methods / Algorithm - Angle based - AoA AdvantagesNo synchronization requirementWorks well in situations with direct line of sightDisadvantagesSusceptibility to multipath interference
15Methods / Algorithm - Signal Property Based Signal attenuation can be exploited for distance estimation.
16Methods / Algorithm - Signal Property Based RSS: Based on the attenuation model, the Received Signal Strength can be used to estimate the distanced of a person or a mobile object.PR: Received signal strength at the receiverPT: Transmitted power strength at the emitterGT GR: Antenna gains of transmitter and receiverd: DistanceP: The path loss factor
17Methods / Algorithm - Signal Property Based The path loss factor (P) is related to the environmental conditionsP = 2 for free spaceP > 2 for environments with NLoS multipathP ≈ (4 - 6) for typical indoor environmentsIn real world application, interference, multipath propagation and presence of obstacles and people leads to a complex spatial distribution of RSS.RSS Indicator (RSSI): averaged PR over a certain sampling period
22RSSI Fingerprinting , TDoA Indoor Localization Systems - WIFIWIFI: (a superset of IEEE standard) can be used to estimatethe location of a mobile device within this network.WIFIRange50-100mAccuracy1mMethodRSSI Fingerprinting , TDoANLOS/LOSNLOSApplicationOffice Space,Person, Objects
23RSSI Fingerprinting, TDoA Indoor Localization Systems - RFIDRFID (Radio Frequency IDentification) system consists of readers with antennas which interrogates nearby active transceivers or passive tags.RFIDActivePassiveRange10-100m1-5mAccuracy1m0.2mMethodRSSI Fingerprinting, TDoAAoA, TDoANLOS/LOSNLOSLOSApplicationMoving ObjectsAssembly Industry
24Indoor Localization Systems - ZigBee ZigBee is a wireless technology particularly designed for applications which demand low power consumption and low data transmission.ZigBeeRange20-30mAccuracy2mMethodRSSINLOS/LOSNLOSApplicationWarehouse management
26SystemsAccuracyCoverageMethodsNLoS/LosPower ConsumeCostRemarksGPS10-50mPoor IndoorToANLoSHighUnstableProximity3-5mRoom levelLoSLowID?Cameras Networks0.5mBuilding levelScene AnalysisWIFI1mRSSI Fingerprinting/TDoAWIFI CoveredRFID(Active)MedLong Distance(Passive)0.2mTDoA/ AoANo Data ExchangeBluetooth1-2mHigh DataRateZigBee2mLow Data Rate
27References Z. Farid, R. Nordin, and M. Ismail, "Recent Advances in Wireless Indoor Localization Techniques and Systems," Journal of Computer Networks and Communications, vol. 2013, 2013. R. Mautz, "Indoor positioning technologies," Habilitation Thesis, Department of Civil, Environmental and Geomatic Engineering, Institute of Geodesy and Photogrammetry, Habil. ETH Zürich, Zurich, 2012. H. Koyuncu and S. H. Yang, "A survey of indoor positioning and object locating systems," IJCSNS International Journal of Computer Science and Network Security, vol. 10, pp , 2010. A. Aboodi andW. Tat-Chee, “Evaluation ofWiFi-based indoor (WBI) positioning algorithm,” in Proceedings of the 3rd FTRA International Conference on Mobile, Ubiquitous, and Intelligent Computing (MUSIC ’12), pp. 260–264, June 2012. S. Chan and G. Sohn, ¡°Indoor localization using Wi-Fi based fingerprinting and trilateration techiques for LBS applications,¡± in Proceedings of the 7th International Conference on 3D Geoinformation, Quebec, Canada, May 2012.
28Question 1 5 2 1 3 4 The RSSI pattern is shown below. 3 Wifi routers 9 refernces pointsQ: Where is M(1.2, 2.6, 4.5) in this pattern?52134
29Question 1 5 2 1 3 4 Q: Where is M(1.2, 2.6, 4.5) in this pattern? A: Measured RSSI of Wifi one is 1.2.Red zone (referenced RSSI of Wifi one is 1) are possible locations.52134
30Question 1 5 2 1 3 4 Q: Where is M(1.2, 2.6, 4.5) in this pattern? A: Measured RSSI of Wifi two is 2.6.Green zone (referenced RSSI of Wifi two is 3) are possible locations.52134
31Question 1 The intersection of three zones is the location of M. 5 2 1 Q: Where is M(1.2, 2.6, 4.5) in this pattern?A: Measured RSSI of Wifi three is 4.5.Blue zone (referenced RSSI of Wifi two is 5) are possible locations.The intersection of three zones is the location of M.52134
32Question 2 5 2 1 3 4 The RSSI pattern is shown above. 3 Wifi routers 9 refernces pointsQ: Where is M(5, 2, 1) in this pattern?Is there any methods to increase the acceracy by optimizeing the system?52134
33Question 2Q: Is there any methods to increase the acceracy of this system?A: More Wifi routers, more reference points.1243
34Question 3 A company with 3 buildings. Building A: Working Office (Wifi coverd)Building B: Assembly linesBuilding C: WarehouseQ: Building A: Locating persons + high rate data transmissionBuilding B: Accurate positioning products + no data transmissionBuilding C: Locating forklifts + low rate data transmissionWhich indoor localization system will you choose for Building A, Building B,Building C, respectively? why?
35Question 3 A company with 3 buildings. Building A: Working Office (Wifi coverd)Building B: Assembly linesBuilding C: WarehouseQ: Building A: Locating persons + high rate data transmissionBuilding B: Accurate positioning products + no data transmissionBuilding C: Locating forklifts + low rate data transmissionWhich indoor localization system will you choose for Building A, Building B,Building C, respectively? why?Answers:A: WIFI. Wife covered, high data rate, mobile phone.B: RFID(Passive). Small tag size, high acceracy, low cost.C: ZigBee. Low power consumption, low cost, low data rate