?????? Location-Based Services

1
??????Location-Based Services

• ???????
• ?????? n9590007 ???

2
????

• Jochen Schiller and Agnès Voisard,
  Location-Based Services
• Johan Hjelm,Creating Location Services for the
  Wireless Web
• ???,"???????????",???????????,no18
• ??????????,??????????, ?????,?115?,PP54-60
• ???,IEEE 802.15 ????- ?????????? ,??????????

3
??
4
LBS(Location Based Service)

• ????????(Mobile Location Technology)
• ????(Location Based ServiceLBS)
• ????????,????????????,???????????,??????
• ??????(Mobile Location Based ServiceMLBS)
• ???????????????????
• ????LBS??,????
• ???????????,
• ?????????????,
• ???????????????

5
LBS???

• ???????
• Location ???
• Personal ???
• Time ???
• ????,????????????
• ???????????
• ??????????????????????,???????
• ??????????????????????????????,????????????
• ?????????????????????,???????????????

6
LBS???

• ?Gravitate Inc.?????,?LBS??????????
• ??????????????????????????????
• ????????????????????????,?????Cell-ID??,???100200
  ??????,????????????
• ??????LBS,????????,?????????????????????????????

7
LBS ????(General LBS communication model)

• ??
• ???
• ?????
• ???

8
???(Positioning Layer)

• ?????????????,???????
• ???? (PDEPosition Determination Equipment )
• ?PDE????,????????,???????
• ????
• ????

9
???(Application Layer)

• ??????????,???????,??
• ????
• ??
• ????

10
??????(Overview of LBS applications and level of
accuracy required)
Application (??) Accuracy (???) Application (??) Accuracy (???)
News(??) Low Gaming (???) Medium
Directions (??) High M-Commerce (????) Medium to High
Traffic Information (????) Low Emergency (????) High
Point of Interest (????) Medium to High Sensitive Goods Transportation (??????) High
Yellow Pages(??) Medium to Low Child Tracking (????) Medium to High
Car Navigation(????) Medium to High Pet Tracking (????) Medium to High
Personal Navigation (????) High Electronic Toll Collection / ????(ETC) Medium to High
Directory Assistance (??????) Medium to High Public Management System ( ??????) Medium to High
Fleet Management (????) Low Remote Workforce Management (???????) Low
Car Tracking (????) Medium to High Local Advertisement (?????) Medium to High
Asset Tracking (????) High Location-Sensitive Billing (??????) Medium to Low
Source Bellocci, V., Genovese, S., Inuaggiato, D., and Tucci, M. (2002, July 18). "Mobile Location-Aware Services 2002 Market Perspective," Ericsson, Division Service Architecture and Interactive Solutions. Source Bellocci, V., Genovese, S., Inuaggiato, D., and Tucci, M. (2002, July 18). "Mobile Location-Aware Services 2002 Market Perspective," Ericsson, Division Service Architecture and Interactive Solutions. Source Bellocci, V., Genovese, S., Inuaggiato, D., and Tucci, M. (2002, July 18). "Mobile Location-Aware Services 2002 Market Perspective," Ericsson, Division Service Architecture and Interactive Solutions. Source Bellocci, V., Genovese, S., Inuaggiato, D., and Tucci, M. (2002, July 18). "Mobile Location-Aware Services 2002 Market Perspective," Ericsson, Division Service Architecture and Interactive Solutions.
11
???????(Categories and examples of LBS
applications.)
Push Services(?) Pull Services (?)
Person-oriented (????) Person-oriented (????) Person-oriented (????)
Communication (??) ?1???????????,????????2 ???????????????? ?1????????????
Information (??) ?3?????????????? ?2???????,????????
Entertainment (??) ?4??????shoot em up?location-based game ,???????? ?3???location-based game,?????????
M-Commerce and Advertising (?????????) ?5???????????????? ?4??????????cool events?

Device-oriented (????) Device-oriented (????) Device-oriented (????)
Tracking (??) ?6?????????,???????,????????7????????,??????? ?5?????????????
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???(Middleware Layer)

• ????????,???????????,?????(P)???????(A)???,???????
  ?AP??
• ???????,????????,?????????,?????????AP??
• ??????,????????,??????????,???????,????AP??????

13
???(Middleware Layer)
????????????
Postpaid-?? SMS-?? WAP-Wireless Application
Protocol Alarm-?? Prepaid-?? Proxy-?? MLCMultiLev
el Cell
14
??LBS????(industry chain)
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?????(Location markets and segments)
Business Consumer
Vertical market (????) Airports (??)Taxi companies (?????)Police (??)Home repair services (??????)Emergency (????)High-value goods delivery (???????)
Horizontal market (????) Asset tracking (????)Automated toll (??????) Child tracking (????) Tourist security(?????)
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LBS ??(LBS STANDARDS)

• ?? LBS ??????????
• Open Mobile Alliance (OMA)(http//www.openmobileal
  liance.org)
• OMA???????????
• Open GIS Consortium, Inc. (OGC)(http//www.opengis
  .org).
• OGC ???????????
• ?????????????? LBS ??????????

17
LBS ????(The LBS Standards Framework.)
Java??????????
??????
Internet?????
??Third-party????????,????????
????
Web?????
??????????
??OpenLS??????????
???????????
????????????
(Diagram courtesy of OGC.)
UMTS(Universal Mobile Telecommunications
System) GPRS(General Packet Radio
Service) 3GPP(Third Generation Partnership
Project) 3GPP2(Third Generation Partnership
Project 2) TIA(Telecommunication Industry
Association) ETSI(European Telecommunications
Standards Institute) WIFI(Wireless
Fidelity) Bluetooth(??) Parlay-X(Parlay X??,User
??OSA API) OSA(Open Service Access) OMA(Open
Mobile Alliance) LIF(Location Interoperability
Forum) JAIN(Java APIs for Integrated
Networks) IETF(Internet Engineering Task
Force) W3C(The World Wide Web Consortium) WAP(Wire
less Application Protocol )
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??????(MLPMobile Location Protocol )

• ???????????
• ???????????
• ?????
• ??????????

(Diagram courtesy of OMA.)
19
??????(MLPMobile Location Protocol )
???
???
???
(Diagram courtesy of OGC.)
20
?????(Typical service/request response via the
GeoMobility Server. )
????
???????
???????
1.?????Portal,?????
2. Portal?OpenLS ?????????
5.OpenLS???
6. Portal?????????, ???????????????
3. OpenLs????????? ???GMLC????????
Gateway Mobile Location Center /Mobile
Positioning Center
4. GMLC/MPC??MLP?? ??OpenLS????
THIRD-PARTY??
(Diagram courtesy of OGC.)
21
OpenLS??(OpenLS Architecture Detail.)
??
THIRD-PARTY??
Gateway Mobile Location Center /Mobile
Positioning Center
(Diagram courtesy of OGC.)
22
????????(The data flow of a typical
position-dependent application.)
Web server or SMSC-Web???????????(Short Message
Service Center) Application gateway-????? XSLT
transformation engine-Extensible Stylesheet
Language Transformation ?? Information
gateway-???? mapping gateway-???? Location
gateway-???? MPC-????????(Mobile Positioning
Center) billing gateway-???? Management
gateway-????
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??????(Basic Location Techniques)

• ??????????,???????
• ??
• ?????????????(Tag/Badge),?Sensor Network ????????
• ???Sensor Network?????????????????(??)?????,Sensor
  Network?????????????????
• ??
• ????????????,??????
• ???????,????????????????,??????????????,????????
• ????,?????????????,????????????

24
???????(Triangulation, Trilateration, and
Traversing.)
??? (Trilateration) ??????????????
??? (Triangulation) ??????????????
???(Traversing)?????(????),?????????
25
IEEE 802.15.4

• IEEE 802.15.4 ????? ???(Low Rate
  WPAN)??,???????(PHY)?????????????????????(MAC) ?
• ???????????
• ????(Time-of-Arrival TOA)
• ?????(Time-Difference-of-Arrival TDOA)
• ??????(Signal Strength Ranging SSR)
• ???????(Near-Field EM Ranging NFER)
• ????(Angle-of-Arrival AOA)

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????(Time-of-Arrival TOA)

• Two Way Ranging(TWR)
• ????????(Packet)?????????(Half-duplex)?????(Time-m
  ultiplexed)????????????????????????????,???????(Re
  questor)??????????(Timing information)?????
  ??(Responder),?????????????????,???????????
  ?,???????,???????????????????????

27
????(Time-of-Arrival TOA)

• One Way Ranging(OWR)
• ?????(Terminals)? ???????????(Common
  clock),??????????????,?????????????

??
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?????(Time-Difference-of-Arrival TDOA)

• TDOA?????TOA??????????(Anchor terminals)???????,??
  ???????????
• ???TDOA???TOA??OWR??,???????????????????(Re-synchr
  o nized),????????(Beacon signal)??????????????????
  ??????? ????????????(coordinator)???????????,?????
  ????????? coordinator(??????)?????

29
?????(Time-Difference-of-Arrival TDOA)
????

• ?? TDOA ? OWR ???????????
• ???(Active),? TDOA-A?????(Source device)
  ????(Token)
• ???(Passive),? TDOA-P ?????(Destination
  device)????,???? ???????????

30
??????(Signal Strength Ranging SSR)

• ?????????(Free space propagation
  model)?,????????

• ???? (large-scale)????,????????????????????(Invers
  e square law),??

31
??????(Signal Strength Ranging SSR)

• ?????????????(Mean large-scale path
  loss)????????????? ???????????

• n ?????????(exponent),???????????????

32
???????(Near-Field EM Ranging NFER)

• ????(RF signal)??????????,??????????(E-field)???(H
  -field)????
• ?????????,?????????(Phase difference)??? 90 ?
  ??????????????(0.5?),????????????????????????????

????????????? 0.05? ? 0.5???, ??????????0.08??0.3?
???
33
???????(Near-Field EM Ranging NFER)

• ??NFER???????????,???????????(???????????????) ?
• ?????????????????,?????????????????????????(phase
  offset)???,?????????????,????????????????????

34
????(Angle-of-Arrival AOA)

• AOA?????????,?????TOA?TDOA???????,AOA?????????????
  ???????????,?????????????(far field)????????,?????
  ?????????????(??)???? AOA ????
• ?????????????????(? 10 ??p/2),???????????????????

35
????(Angle-of-Arrival AOA)

• ?????????,?????????????????????????,??????????????
  ????????????????????????(Antenna pattern)?

36
?????????
?? ??
TOA ??????????,??????????,??????????????
TDOA ??????????,??????????,??????????????
SSR ?????????????,???????????,?????????????(Shadowing effect)?????????
NFER ???????????????????????????
AOA ?????????,???????(Line-of-sight)???,????????,??????,???????????,????????????
37
??????(????????)

• ??????(Satellite based)???
• ????,???????????
• ????????(GPS)
• ??????(Network based)???
• ??????????????

38
??????(?????????)

• ?????(network-based positioning)
• ?????????????????????
• ???????????3??????????????????
• ?????(TDOA)????????(E-OTD)????????
• ?????(terminal-based positioning)
• ????3?????????
• ?GPS????GPS(A-GPS)???
• ??????

39
?????????

• ??????(GPS)
• ????GPS (A-GPS, assisted GPS)
• ???(COO, Cell of Origin)
• ???(AOA, Angle of Arrival)
• ????(TDOA, Time Difference of Arrival)
• ???????(E-OTD, Enhanced Observed Time Difference)
  
• ???????(UL-TOA, uplink time of arrival)
• ??????(CGI, cell global identity)??????(Location
  Pattern Matching)
• ??????(Location Pattern Matching)
• ????????????? (E-FLT, enhanced forward link
  triangulation)

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GPS??
???3??????????????
3??????2???,??????,????????
41
GPS??
????????????,???1µs,????300??(?????30???),????????
???,????????????????,????????????????,?????????4??
???????GPS?24?????(??6??,???4?),???????
3????????
?4?????????
42
??GPS??
????????GPS??? L1??-1575.42MHz(?)? L2??-1227.60MH
z(???)? L3??-1381.05MHz(?)? L4??-1841.40MHz(???)(?
)? L5??-1176.45MHz(???)(?)?

• ???20??????????,???2???
• L1(1575.42 MHz) PPS?SPS
• L2(1227.6 MHz) ?PPS
• ??????(Precise Positioning Service (PPS))
• P Code
• ????22 m,????27.7 m
• ?????????

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??GPS??

• ?????? (Standard Positioning Service (SPS))
• ??C/A-Code(Coarse/Acquisition Code),??????? (SA
  Selective Availability )????
• ????100 m,????156 m
• ??????
• 2000?5??,?SA???????????????????,??????????25m,????
  43 m?

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??GPS??
Service ???? ????
PPS 22 m 27.7 m
SPS with SA 100 m 156 m
SPS without SA 25 m 43 m

• GPS???
• ??
• IIA/IIR??(L1/L2)
• ??
• IIR/M(L1?? L2????)
• IIF(L5)
• D-GPS???30?50?????????
• ??
• GPS III
• 2012???????
• 2025??

45
DGPS (Differential GPS)

• ?????,2000?5?L2????,D-GPS???10??????????????????
• GPS???,????????????,??????
• ????????(X1,Y1)?
• ??????????????(X2,Y2)?
• ????????((X1-X2),(Y1-Y2))?
• USER???????????(X3,Y3)?
• USER??????????
• USER????((X1-X2),(Y1-Y2))?????????(X3,Y3)?
• ??????USER??????????,???????????,???????RTCM???

46
DGPS ???
Adapted from Mobile Computing by Jörg Roth,
dpunkt-Verlag (2002).
47
WAAS(Wide Area Augmentation System )

• ?????DGPS???
• ????
• ???????????,???????????????????????
  Inmarsat-3,??Inmarsat-3?????USER?
• ????????
• ??????

Adapted from Mobile Computing by Jörg Roth,
dpunkt-Verlag (2002).
48
WAAS???
Adapted from Mobile Computing by Jörg Roth,
dpunkt-Verlag (2002).
49
???????

• ??GLONASS(Globalnaya Navigationnaya Sputnikovaya
  Sistema)
• ??
• GPSWAAS EGNOS (European Geostationary
  Navigation Overlay System)
• GALILEO
• ????????????

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????GPS??

• ???????
• 1. GPS?????
• ???????????????????????????
• ???????????????????????? 
• 2.GPS???????????
• ?GPS??,????????(DSP)?CPU???
• ??????????????????????
• ???????????????,??????????????????????? 
• 3.?SoC???????
• ?GPS???????????????,??????????IC??????????,????SoC
  ?????????GPS?????????????I/O??????

51
??????????(AGPS,Assisted GPS)

• GPS???
• GPS?2????500w??,????10-13w
• ?????????????
• ????
• A-GPS
• FCC ??????E911??????
• ????????????GPS??,?????????????????
• ?GPS?????(correlator)???,???????GPS??????

52
AGPS????

• ?????(Mobile-based)
• ???????GPS???????????A-GPS???????????????????,????
  ?????????,???????????????????????
• ?????(Mobile-assisted)
• A-GPS???????????????????,?????????????,?????,?????
  ??????

53
A-GPS????
1.??????GPS ??????????
3.???????????
2.????????? ??????
4.???????? ??????
54
??A-GPS

• ??
• ???(?5-20M)
• ???????????5-10???
• ????????????GPS??????
• A-GPS?????????,????????GPS?????,?????????

• ??????????????
• ????????????
• ????????GPS?????
• ??GSM/ GPRS/ UMTS(WCDMA)??

55
A-GPS????????
???????IEK-ITIS????(2005/10)
56
??????(Network based)????
57
Cell-ID(Cell site IDentification)

• ??GSM/GPRS/UMTS(WCDMA)??
• ???(COO)??
• ???,?????
• ??????????gt??
• ??????????????(BTS base transceiver
  station)???,?????????(Cell)????,?????2-20km???????
  ??(Micro-cell)???,?????????

58
Cell-ID(Cell site IDentification)

• Cell-ID???
• ??TA(Timing Advance,?????)
• GSM/GPRS?????
• ??RTT( Round Trip Time,??????)
• UMTS?????

59
E-OTD(Enhanced Observed Time Difference)

• ??GSM/GPRS??
• ??1.5??????1?LMU (Location Measurement Unit)?
• ??????3??????????,?????????
• LMU?????????
• ?????LMU
• ???????

60
OTDOA(Observed Time Difference of Arrival)

• ??UMTS(WCDMA)??
• ?E-OTD????(??GSM/GPRS??)
• ?E-OTD?????????????LMU?

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Hybrid(A-GPS)

• ??GSM/GPRS/UMTS(WCDMA)??
• ?A-GPS??,??????
• Cell-ID
• E-OTD
• OTDOA
• ex A-GPS Cell-ID

???
????
62
??????(Indoor positioning systems.)
???
???
???
??????
???
??/???
???/???
???
???
Adapted from Mobile Computing by Jörg Roth,
dpunkt-Verlag (2002).
63
WLAN(Wireless local area network )

• ?? (Indoor)?WLAN(IEEE 802.11)???????
• ????????????
• ???
• ????
• ??????????????
• ???????
• ????????,?????

64
WLAN??-???????

• ??RADAR??
• ???????
• ????,????????,????????????
• ????,?????????????????????,????????,???????
• ??????????????????(NNSS Nearest Neighbors
  Signal Strength)

65
????????? (Video-Based Systems)
????
????????
????
66
???????(Comparison of positioning systems.)
Name ?? ??/?? Mechanism Medium ??
GPS ?? ?? TOA / TOA ??? 25 m
DGPS ?? ?? TOA / TOA ??? 3 m
WAAS ?? ?? TOA / TOA ??? 3 m
GSM ?? ???? COO, AOA, TOA ??? Cell, distance in 555 m steps
MPS ?? ???? COO, AOA, TOA ??? 150 m
Nibble ?? ?? Signal Strength ??? 3 m
Active Badge ?? ?? COO ??? Cell
WIPS ?? ?? COO ??? Cell
SpotON ?? ?? Signal Strength ??? 3 m
Active Bat ?? ?? TOA ???/??? 0.1 m
Cricket ?? ?? TOA ???/??? 0.3 m
RFID ?? ?? COO ??? Cell
Visual Tag ?? ???? Video ?? Depends on camera resolution
67
??

• ??????????
• ????????????
• ?????????????????
• ????????(????????)?
• ?????????
• ????????
• ?????????
• Gartner??,?2010?,????????????????????????,???60??
  ??????????????????(follow-me Internet)????????????
  ???????????????

68
????

• Q A

69
???? OpenLS????????

• WAP-Wireless Application Protocol
• ANSI-American National Standards Institute
• DTD-Document Type Definition
• GMLC-Gateway Mobile Location Center
• GMT-Greenwich Mean Time
• HTTP-Hypertext Transfer Protocol
• HTTPS-HTTP Secure
• LCS-Location Services
• MLC-Mobile Location Center

• MLP-Mobile Location Protocol
• MPC-Mobile Positioning Center
• MS-Mobile Station
• MSID-Mobile Station Identifier
• SSL-Secure Socket Layer
• TLS-Transport Layer Security
• URI-Uniform Resource Identifier
• URL-Uniform Resource Locator
• UTM-Universal Transverse Mercator
• WGS-World Geodetic System
• XML-Extensible Markup Language

70
????2006???????????

• ???Gartner?????10??????
• Web 2.0
• ?????? (SNA)
• Ajax
• ??
• Mashup
• Real World Web
• ????GPS???
• ?????????????????????????
• ??????(SMN)
• ????(AA)
• ?????????(EDA)
• ?????????(MDA)
• ??????

71
???????????????

• ?????????(Mobile Positioning System MPS)
• ????????GIS???(Geographical Information
  System)??????????????????
• MPS???????Mobile Positioning Center
  (MPC),???????????????????????
• ???????????????????,??????????????????????????,???
  ?????????????????
• ????MPS ?????????????????????????,??GSM?TDMA??????
  ??????????
• ???????????????????????,?????????????????,????????
  ???????????????