csi5169-indoor localization-zhang zhang(7059407) (1)
DESCRIPTION
tttTRANSCRIPT
Outline• Introduction
– Definition– Important parameters
• Indoor Localization Methods– Proximity Detection– Triangulation– Scene Analysis
• Indoor Localization Systems– Proximity Based– RF Based– Cameras Based
• Comparison of Common Indoor Localization Systems
Introduction - Defination
Def. Wirelessly locate objects or people inside a building in real time.
• Indoor Positioning Systems (IPS)• Real-time Locating Systems (RTLS)
Introduction - Important Parameters
• Accuracy
• Coverage
• Availability
• Update Rate
• Line of Sight (LoS) and Non Line of Sight (NLoS)
• Costs and System Complexity
Introduction - LoS / NLoS
• Line of Sight (LoS) and Non Line of Sight (NLoS)
Indoor Localization Methods / Algorithm
Methods/Algorithm
Proximity / CoO Triangulation Scene Analysis
Direction based Distance based
Angle based Time basedSignal Property
based
Proximity Detection: Sensors detect and measure reflected Infrared or visiable light or RF wave to detect the presence of an object or person in certain areas.
• Highest Received Signal Strength = Highest Probability
Methods / Algorithm - Proximity / Cell of Origan
Advantages• No complicated algorithms• Easy to implement• Low cost
Disadvantages• Low accuracy - room level• Identification problem
Methods / Algorithm - Proximity / Cell of Origan
ToA: Time of Arrival
• The precise measurement of the arrival time of a signal transmitted from a mobile device to several receiving sensors. • The distance between the mobile device and each receiving sensor can be determined.
Methods / Algorithm - Time based
Advantages• High Accuracy• 2D / 3D
Disadvantages• Precise time synchronization (1 micro-second, 300m error)• Solutions are typically challenged in environments where a large amount of multipath or interference may exist.
Methods / Algorithm - Time based - ToA
TDoA: Time Difference of Arrival
• Using relative Arrival time measurements at each receiving sensor• The synchronization between tag and each sensor is not necessary
Example: • TXC - TXA = 10-8s• TDoAC_A
• TXB - TXA = 10-7s• TDoAB_A
Methods / Algorithm - Time based - TDoA
AoA/DoA: Angle of Arrival / Direction of Arrival (DoA)
• Determining the angle of incidence at which signals arrive at the receiving sensor.
Methods / Algorithm - Angle based - AoA
Methods / Algorithm - Angle based - AoA
More sensors = Higher accuracy
Advantages• No synchronization requirement• Works well in situations with direct line of sight
Disadvantages• Susceptibility to multipath interference
Methods / Algorithm - Angle based - AoA
Signal attenuation can be exploited for distance estimation.
Methods / 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 receiver• PT: Transmitted power strength at the emitter• GT GR: Antenna gains of transmitter and receiver• d: Distance• P: The path loss factor
Methods / Algorithm - Signal Property Based
The path loss factor (P) is related to the environmental conditions P = 2 for free space P > 2 for environments with NLoS multipath P ≈ (4 - 6) for typical indoor environments
In 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
Methods / Algorithm - Signal Property Based
Off-Line
Methods / Algorithm - Fingerprinting
Database
S1
S2
S3
...
S72
M(-35, -50, -48, -60, -58,-24) vs. Database
Methods / Algorithm - Fingerprinting
Advantages• High accuracy• NLoS
Disadvantages• Complicated algorithms• Not easy to implement• High cost
Methods / Algorithm - Fingerprinting
Indoor Localization Systems
WIFI: (a superset of IEEE 802.11 standard) can be used to estimate the location of a mobile device within this network.
Indoor Localization Systems - WIFI
WIFI
Range 50-100m
Accuracy 1m
MethodRSSI Fingerprinting ,
TDoA
NLOS/LOS NLOS
ApplicationOffice Space,
Person, Objects
RFID (Radio Frequency IDentification) system consists of readers with antennas which interrogates nearby active transceivers or passive tags.
Indoor Localization Systems - RFID
RFID Active Passive
Range 10-100m 1-5m
Accuracy 1m 0.2m
MethodRSSI Fingerprinting,
TDoAAoA, TDoA
NLOS/LOS NLOS LOS
Application Moving Objects Assembly Industry
ZigBee is a wireless technology particularly designed for applications which demand low power consumption and low data transmission.
Indoor Localization Systems - ZigBee
ZigBee
Range 20-30m
Accuracy 2m
Method RSSI
NLOS/LOS NLOS
ApplicationWarehouse
management
• Images → Cameras
• Cameras → Database
• Database → Virtual Map
Indoor Localization Systems - Cameras
Systems Accuracy Coverage Methods NLoS/LosPower
ConsumeCost Remarks
GPS 10-50mPoor
IndoorToA NLoS High High Unstable
Proximity 3-5mRoom level
Proximity LoS Low Low ID?
Cameras Networks
0.5mBuilding
levelScene Analysis LoS Low High ID?
WIFI 1mBuilding
level
RSSI Fingerprinting
/TDoANLoS High High
WIFI Covered
RFID
(Active)1m
Building level
RSSI Fingerprinting
NLoS Med MedLong
Distance
RFID
(Passive)0.2m
Room level
TDoA/ AoA LoS Low LowNo Data
Exchange
Bluetooth 1-2mBuilding
levelRSSI
FingerprintingNLoS Low Med
High Data
Rate
ZigBee 2mBuilding
levelRSSI
FingerprintingNLoS Low Low
Low Data Rate
References
[1] 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.
[2] R. Mautz, "Indoor positioning technologies," Habilitation Thesis, Department of Civil, Environmental and Geomatic Engineering, Institute of Geodesy and Photogrammetry, Habil. ETH Zürich, Zurich, 2012.
[3] 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. 121-128, 2010.
[4] 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.
[5] 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.
Question 1The RSSI pattern is shown below.• 3 Wifi routers• 9 refernces points
Q: Where is M(1.2, 2.6, 4.5) in this pattern?
5
2 1
3
4 1
1
4 2
5
2 1
2
3 3
1
3 3
3
1 2
1
1 3
1
2 5
1
2 3
Question 1
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.
5
2 1
3
4 1
1
4 2
5
2 1
2
3 3
1
3 3
3
1 2
1
1 3
1
2 5
1
2 3
Question 1
5
2 1
3
4 1
1
4 2
5
2 1
2
3 3
1
3 3
3
1 2
1
1 3
1
2 5
1
2 3
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.
Question 1
5
2 1
3
4 1
1
4 2
5
2 1
2
3 3
1
3 3
3
1 2
1
1 3
1
2 5
1
2 3
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.
Question 2The RSSI pattern is shown above.• 3 Wifi routers• 9 refernces points
Q: Where is M(5, 2, 1) in this pattern? Is there any methods to increase the acceracy by optimizeing the system?
5
2 1
3
4 1
1
4 2
5
2 1
2
3 3
1
3 3
3
1 2
1
1 3
1
2 5
1
2 3
Question 2Q: Is there any methods to increase the acceracy of this system?
A: More Wifi routers, more reference points.
1
2
4
1
4
2 3
Question 3
A company with 3 buildings.• Building A: Working Office (Wifi coverd)• Building B: Assembly lines• Building C: Warehouse
Q: Building A: Locating persons + high rate data transmission Building B: Accurate positioning products + no data transmission Building C: Locating forklifts + low rate data transmission Which indoor localization system will you choose for Building A, Building B, Building C, respectively? why?
Question 3
A company with 3 buildings.• Building A: Working Office (Wifi coverd)• Building B: Assembly lines• Building C: Warehouse
Q: Building A: Locating persons + high rate data transmission Building B: Accurate positioning products + no data transmission Building C: Locating forklifts + low rate data transmission Which 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
Thank you!Thank you!