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Cellular Positioning
Pabitra kumar chhatai
Reg no- xxxxxxxxx
GUIDED BY: Ast.prof Dillip kumar
bhadra
Dept. of : Electro...
Outline
2

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Introduction.
Positioning Systems.
Global positioning system(GPS).
Differential glob...
What is cellular positioning ?
3

Determining the position of a Mobile Station
(MS),using
location sensitive parameters .
...
Why we need cellular positioning ?
4

To provide location based services like...
 Tracking criminals.
 Providing emergen...
Types of positioning systems.
5

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

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
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Mobile centric systems.
Positioning technology inserted inside the
cell.
C...
Positioning of a mobile.
6

Dept of : Electronics & Telecommunication.,KIT,BBSR
What is GPS ?
7

Global positioning system(GPS).
 A network of satellites that continuously
transmit coded information, w...
Differential GPS(DGPS)
8





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By placing additional GPS receiver(called
reference station)
A technique where a data r...
DGPS
9

Dept of : Electronics & Telecommunication.,KIT,BBSR
10

Wide Area Augmentation
Signal.
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



Wide Area Augmentation Signal.
A satellite navigation system designed by the...
WAAS
11

Dept of : Electronics & Telecommunication.,KIT,BBSR
Accuracy of positioning system
12

Range

100 m

GPS
With SA

15 m

GPS
Without SA

3-5 m

DGPS

<3m

Dept of : Electronic...
Methods of measurement
13

Time Of Arrival(TOA)
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

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Estimated by distance between transmitter and
receiver.
Transmitt...
TOA
14

Dept of : Electronics & Telecommunication.,KIT,BBSR
Location probability figures
15

Dept of : Electronics & Telecommunication.,KIT,BBSR
TOA
16

Specific positioning
Algorithms
Measurements
Estimated position
d1,d2,d3
Xm, Ym
 Where distance between MS and BS...
17

Time Different Of
Arrival(TDOA)
Hyperbolic system.
 Converted to a constant distance difference to
two base stations....
TDOA
18

Specific positioning
Algorithms
Measurements
Estimated position
d32,d31
Xm, Ym
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

Al least 3 BSs are required ...
TDOA
19

Dept of : Electronics & Telecommunication.,KIT,BBSR
Signal Strength
20

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Distributed Receiving System(monitoring
post).
Distributed Transmission System(Sing po...
Signal Strength at diff. distance
21

Dept of : Electronics & Telecommunication.,KIT,BBSR
Angle Of Arrival(AOA)
22

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

Measuring the direction angles.
Least two antenna array systems
The position of the ce...
AOA
23

Dept of : Electronics & Telecommunication.,KIT,BBSR
Comparison OF 4 methods
Measurement Type
24

Advantages

Disadvantages

Time of Arrival (TOA)

• time measurement
required...
Conclusion
25

We have described about accurate
positioning of mobile telephones, which can be
used for several applicatio...
26

Questions ?
“Thank YOU”
Dept of : Electronics & Telecommunication.,KIT,BBSR
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positioning

  1. 1. 1 Cellular Positioning Pabitra kumar chhatai Reg no- xxxxxxxxx GUIDED BY: Ast.prof Dillip kumar bhadra Dept. of : Electronics & Telecommunication 30.11.2012 Koustuv institute of Technology , BBSR
  2. 2. Outline 2             Introduction. Positioning Systems. Global positioning system(GPS). Differential global positioning system (DGPS). Wide Area Augmentation Signal(WAAS). Method of Measurement. Time of Arrival(TOA). Time Differential of Arrival(TDOA). Signal Strength(SS). Angle of Arrival(AOA). Comparison Of 4 methods Conclusion Dept of : Electronics & Telecommunication.,KIT,BBSR
  3. 3. What is cellular positioning ? 3 Determining the position of a Mobile Station (MS),using location sensitive parameters . GNNS(Global Navigation Satellite System)  A network of satellites that used for positioning and navigation around the globe.  US- Global Positioning System(GPS)  Russian- GLObal NAvigation Satellite System(GLONASS)  European-GALILEO System Dept of : Electronics & Telecommunication.,KIT,BBSR
  4. 4. Why we need cellular positioning ? 4 To provide location based services like...  Tracking criminals.  Providing emergency services .  Military - defence system .  Map-making.  Navigation-car navigation system .  Mountain climbing . Dept of : Electronics & Telecommunication.,KIT,BBSR
  5. 5. Types of positioning systems. 5       Mobile centric systems. Positioning technology inserted inside the cell. Currently there 200 millions of cell phones with out GPS receiver. Network centric systems. Positioning technology resides in the network. This type of systems are compatible with the phones currently in use. Dept of : Electronics & Telecommunication.,KIT,BBSR
  6. 6. Positioning of a mobile. 6 Dept of : Electronics & Telecommunication.,KIT,BBSR
  7. 7. What is GPS ? 7 Global positioning system(GPS).  A network of satellites that continuously transmit coded information, which makes it possible to precisely identify locations on earth by measuring distance from satellite.  Developed in 1980s by U.S Department of defence.  24 satellites approximately 20200 km above the earth  Dept of : Electronics & Telecommunication.,KIT,BBSR
  8. 8. Differential GPS(DGPS) 8    By placing additional GPS receiver(called reference station) A technique where a data receiver at a known location is used to correct the data at an unknown location. DGPS corrected solution is significantly more accurate , typical DGPS accuracy is 1-5 meters. Dept of : Electronics & Telecommunication.,KIT,BBSR
  9. 9. DGPS 9 Dept of : Electronics & Telecommunication.,KIT,BBSR
  10. 10. 10 Wide Area Augmentation Signal.     Wide Area Augmentation Signal. A satellite navigation system designed by the U.S Federal Aviation Administration(FAA) to boost the accuracy of GPS satellite navigation . Wide Area refers to a network of 25 ground reference stations cover the U.S and some of Canada and Mexico. Each station connected to a master station. Dept of : Electronics & Telecommunication.,KIT,BBSR
  11. 11. WAAS 11 Dept of : Electronics & Telecommunication.,KIT,BBSR
  12. 12. Accuracy of positioning system 12 Range 100 m GPS With SA 15 m GPS Without SA 3-5 m DGPS <3m Dept of : Electronics & Telecommunication.,KIT,BBSR Positioning System WASS
  13. 13. Methods of measurement 13 Time Of Arrival(TOA)    Estimated by distance between transmitter and receiver. Transmitted by the MS and received at multiple BSs. Requirement: -Position of satellite -Timestamp Dept of : Electronics & Telecommunication.,KIT,BBSR
  14. 14. TOA 14 Dept of : Electronics & Telecommunication.,KIT,BBSR
  15. 15. Location probability figures 15 Dept of : Electronics & Telecommunication.,KIT,BBSR
  16. 16. TOA 16 Specific positioning Algorithms Measurements Estimated position d1,d2,d3 Xm, Ym  Where distance between MS and BS = Propagation time * Propagation velocity.  Al least 3 BSs are required to find the exact position of MS. Dept of : Electronics & Telecommunication.,KIT,BBSR
  17. 17. 17 Time Different Of Arrival(TDOA) Hyperbolic system.  Converted to a constant distance difference to two base stations.  Intersection of two hyperbolas.  Requirement: -Geographical coordinates. -Precisely synchronized clocks.  Dept of : Electronics & Telecommunication.,KIT,BBSR
  18. 18. TDOA 18 Specific positioning Algorithms Measurements Estimated position d32,d31 Xm, Ym   Al least 3 BSs are required to find the exact position of MS from a couple of TDOAs. When the TOT of MS is unavailable. Dept of : Electronics & Telecommunication.,KIT,BBSR
  19. 19. TDOA 19 Dept of : Electronics & Telecommunication.,KIT,BBSR
  20. 20. Signal Strength 20        Distributed Receiving System(monitoring post). Distributed Transmission System(Sing post.) Similar to TOA. Measures signal attenuation. Path-loss ∆P(dB)=10α.log(f/c)-10βlog(4πd). Okumura-Hata model (OH). Long distance model. Dept of : Electronics & Telecommunication.,KIT,BBSR
  21. 21. Signal Strength at diff. distance 21 Dept of : Electronics & Telecommunication.,KIT,BBSR
  22. 22. Angle Of Arrival(AOA) 22     Measuring the direction angles. Least two antenna array systems The position of the cell phone is determined by the intersection of the two bearings of the cell sites. Require: -Two dimensional positioning -Antennas installation -Interconnection of antennas Dept of : Electronics & Telecommunication.,KIT,BBSR
  23. 23. AOA 23 Dept of : Electronics & Telecommunication.,KIT,BBSR
  24. 24. Comparison OF 4 methods Measurement Type 24 Advantages Disadvantages Time of Arrival (TOA) • time measurement required for TDMA/CDMA network operation • simple computations • synchronized network required receiver must know time of transmission • expensive measurement Time Difference of Arrival (TDOA) •time measurement required for TDMA/CDMA network operation • receiver does not need time of transmission • synchronized network required expensive measurement • complex calculations Signal Strength • low cost measurements •low accuracy in large cells • simple computations •low accuracy in large cells Angle of Arrival (AOA) Dept of : Electronics•simple computations & Telecommunication.,KIT,BBSR • specialized antennae • low accuracy in large
  25. 25. Conclusion 25 We have described about accurate positioning of mobile telephones, which can be used for several applications.  The important considerations to be undertaken while selecting a location based technology are location accuracy , implementation cost, reliability, increasing functionality.  Dept of : Electronics & Telecommunication.,KIT,BBSR
  26. 26. 26 Questions ? “Thank YOU” Dept of : Electronics & Telecommunication.,KIT,BBSR

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