무선측위기술동향및발전방향 2008/0/8 이형근 PART I 2008/0/8 GNSS TECHNOLOGY 이형근 Summary : SBAS GPS 위성 Recent Trend: GNSS Receiver Network 측위신호 무결성 / 보정신호 사용자수신기 Uplink 안테나 기준국수신기망 (GPS L, L2, Hz) 주처리국 무결성 / 보정정보 4 Summary : GBAS Summary : GRAS GPS GPS 측위신호 측위신호 활주로 사용자수신기 사용자수신기 무결성 / 보정신호 무결성 / 보정신호 VHF 안테나 VHF 안테나망 기준국수신기망 (GPS L, L2, Hz) 주처리국 무결성 / 보정정보 기준국수신기망 (GPS L, L2, Hz) 주처리국 무결성 / 보정정보 5 6
7 8 국내 GPS 수신기망 Prediction : Future GPS/GNSS Network Galileo GLONASS GPS 위성 위성 2 기준국수신기망 (GPS/Galileo, L, L2, L5, 0 Hz) 주처리국 사용자수신기유형 VHF 안테나 사용자수신기유형 2 VHF 안테나 2 Uplink 안테나 Uplink 안테나 2 자료출처 : 국토지리정보원 기준국수신기망 2 (GPS L, L2, Hz) 정보융합센터 2 무결성 / 주처리국 2 보정정보 무결성 / 보정정보 2 정보융합센터 9 0 Prediction : Near Future Utilization of GPS/GNSS Network in Precie Tranportation GPS A4. precie correction algorithm GLONASS Client (Rover) GNSS Receiver Network over TCP/IP for Very Precie Location Information A. reference tation A3. correction meage meaurement interface in pre-defined format (TCP/IP) Server Broadcater A2. correction meage generation K. rover meaurement interface K2. ephemeri proceing K3. earth/time reference dicrepancie K4. precie poitioning algorithm 2
Satellite Uer Trajectory Trajectory Generation Generation Iono. Tropo. Error Error Generation Generation Multipath Error Geration Satellite Blockage Scenario - Monte-Carlo Simulation - Covariance Analyi - Real Data Proceing Iono-free Combi. Divergence -free Combi. Widelane Narrowlane Integer Ambiguity Reolution Integer Ambiguity Validation 수신기망구성 (/2) 수신기망구성 (2/2) Channelwie GNSS Signal Generation Interface for Cutomized File Format RINEX File Interface Fault Detection Mode Setting Channelwie Fault Iolation Filter Poitioning Filter Serial Port Interface Network Interface Server client type Error Computation And Report client type 3 Server 2 Broadcater Server N Server 3 Broadcater Client client type 2 Server Server 4 3 4 Server 의기능 Client 의기능 정확히알려진위치에서연속적인관측을통해 Navigation data, Obervation data 를생성 Broadcater 로전송 2 3 4 Broadcater 로부터보정데이터수신 GPS 수신기로부터 GPS 데이터수신 Proceing 결과를지도에표시 2 4 3 6 5 5 6 Broadcater 의기능 Web erver (Apache) 사용자정보확인및관리 관측데이터 (RINEX) 파일다운로드가능 DataBae (MySQL) Server 의 ID, 위치저장 Client 의신상정보저장 관측데이터저장 TCP/IP Client / Server 와연결 Client 와 Server 간의모든 data tream 을관리 2 시간간격으로 Ephemeri 데이터저장 Accuracy: Epoch-by-Epoch DGPS L Solution error (m) 3 2 0 - -2 epoch-by-epoch SD olution error upper igma val. lower igma val. -3 2.705 2.7 2.75 2.72 2.725 2.73 2.735 2.74 time (ec) x 0 5 7 8 3
Accuracy: L-only Float Solution Accuracy: Integer Solution by L/L2 Differential Meaurement 0.8 0.6 0.4 GAFAS float olution error upper igma val. lower igma val. 0.25 0.2 0.5 0. GAFAS integer olution without integer earch error upper igma val. lower igma val. PRN number 2 8 7 5 4 Satellite et addage or outage error (m) 0.2 0-0.2-0.4-0.6 error (m) 0.05 0-0.05-0. -0.5-0.2 3 2.705 2.7 2.75 2.72 2.725 2.73 2.735 2.74 time (ec) x 0 5-0.8-0.25-2.705 2.7 2.75 2.72 2.725 2.73 2.735 2.74 time (ec) x 0 5 2.705 2.7 2.75 2.72 2.725 2.73 2.735 2.74 time (ec) x 0 5 9 20 PART II TERRESTRIAL 2008/0/8 WIRELESS LOCATION 이형근 SYSTEMS 측위에활용될수있는매체의다양성 CDMA Wirele Network Server witch router Wired backbone network Senor/Ad Hoc Network IEEE 802. 80m, Mbp Short range RF Bluetooth 0m, Mbp InfraRed Radio Frequency Wirele LAN WLAN WLAN 은시각동기에대한고려가포함되어있지않으므로 TOA 와 TDOA 개념을적용하기에난점 일반적으로배열안테나가가용하지않으므로 AOA 적용에도난점 따라서신호세기 (Signal Strength; SS) 를활용한측위방식이선호되고있음 WLAN 신호세기를활용한측위방식은크게전파위치지문을기반으로한방식과신호전파모델을기반으로한측위방식으로분류 전파위치지문방식이정확도면에서우수 위치지문데이터베이스구축을위해서시간과인력이많이소모됨 수십 m 이내중소규모영역의측위에활용이제한됨 23 24 4
RFID RFID 시스템은안테나, 트랜시버, 트랜스폰더등세가지요소로구성 RFID 태그는크게수동 (paive), 능동 (active), 그리고반수동 (emi-paive ) 등으로구분 수동형태그신호는일반적으로수십 cm 에서수 m 정도의거리에도달 수동형 RFID 는감지거리가짧으므로특정한위치에대한 proximity enor 로활용가능하며, 한정된실내공간에균등하게배치할경우측위시스템으로도활용가능하다. 능동형 RFID 신호를 ToA 와같이활용하여거리를측정하는방법이근래에소개됨 UWB 기술적인 UWB 의정의는라디오의대역폭이 500MHz 이상이거나중심주파수의 20% 이상일때를의미 UWB 는매우짧은파형지속시구간에기인하여다중경로현상에영향을받지않음 시분할다중접속의구현에편리 UWB 의중요한특성중의하나로서대역폭내의다양한주파수에서송수신기사이의가시거리를펄스의 "time of flight" 로측정가능 Ranging 을위해서 TWR (two-way ranging) 기법이사용하면거리를 cm 급이내로정밀하게측정가능 A 에서 ranging 메시지를보낼때자기자신의카운터를동작 B 는 A 로부터해당 ranging 메시지를받으면카운터를동작 수신처리시간 T_replyB 시간후에 A 로 ACK 메시지를보냄 A 에서는 B 로부터메시지를받는순간카운터를중단시키고거리값을얻어냄 거리값을얻어낸후에는삼변법에의하여위치계산가능 25 26 지상파기반측위시스템 380MHz 측위신호를활용 TDOA 방식으로위치계산 현재미국, 남미, 동남아일부국가들에서상용서비스를개시 한국의경우 2005 년 3 월에위치서비스를시작 저주파특성에기인하여도달거리가길고지상의장애물에영향을크게받지않음 이동통신측위에비하여요구되는기지국의밀도가낮으며중계기및전력제어영향을받지않음 저비용으로자체적인전국망구축이가능 Ultraonic Location Sytem Active Bat : the ytem ue the uer tranmitter (mall badge) and calculate the 3D poition. Cricket : the receiver ue the received RF and Ultraonic ignal and calculate the poition. 27 28 주파수대역분포 측위에활용될수있는측정치의다양성 29 5
Proximity Signal Strength NODE B/LMU (0,0) NODE B/LMU NODE B/LMU 3 32 AOA - Angle Of Arrival TOA - Time Of Arrival Meaure the angle of arrived ignal between bae tation and mobile tation Location error increae a mobile i far from BS 33 34 TDOA Time Difference Of Arrival 무선측위알고리즘의분류 35 6
위치지문 방식 기하학적 방식 ervice phae x D(x,y) ervice phae + X Xa D + S(X)- I(Xk) S(X) y f(d) D(x,y) meaurement at client location {I(Xk)} y (D) ditorted poition preparation phae map param. Sample unanimou handet automatically urveyed meaurement urveyed location index Signal Strength Signal Strength 2 Signal Strength 3 go to the point (x,y ) and read the z-value x (D) all the urveyed mea. network canner Intalled at a known location NLOS {I(Xk)} I(Xa) preparation phae corrected poition - ditance minimum (correlation maximum) meaurement at client location f(d ) Client aliaed index I(Xk) I(Xk+) I(Xk+2) I(k) I(k+) I(k+2) Handet model Time index Signal Strength Signal Strength 2 moving urveyer equipped with canner/gps receiver NLOS error correc. map Signal Strength 3 TDOA 2 TDOA 3 한국항공대학교(이형근), "이동 단말기의 위치 정보 보정 방법 및 그 장치", 등록번호: 0768573, 대한민국 특허청 Korea Aeropace Univ.(H.K. Lee), "METHOD AND APPARATUS FOR CORRECTING LOCATION INFORMATION OF MOBILE COMMUNICATION TERMINAL", Appl.(PCT), Dec. 2006. 37 Meaurement DataBae (MDB) 38 GSM/GPRS Core Network Element LMU NODE B/LMU RNC GMLC RNC 측위를 위한 시스템 구성 RNC NODE B/LMU NODE B/LMU Node B: bae tation LMU: location meaurement unit RNC: radio network controller MSC: mobile ervice witching centre VLR: viitor location regiter GMLC: gateway mobile location center TGS: telegeoinfomatic erver 40 CDMA Core Network Element BTS WLAN Network Element : wirele acce point : wirele network card BSC MPC BSC PDE MSC/HLR Location Server collection of SS value BSC BTS BTS index HW model Time index Signal Strength Signal Strength 2 Signal Strength 3 BTS : Bae Tranceiver Sytem BSC : Bae Station Controller MSC : Mobile Switching Center HLR : Home Location Regiter VLR : Viitor Location Regiter MPC : Mobile Poitioning Center PDE : Poition Determination Entity 4 I(k) I(k+) I(k+2) NLOS error correc. map Meaurement DataBae (MDB) 42 7
Acce Point (AP) An AP act a a central tranmitter and receiver of WLAN radio ignal Multiple wirele client are can be connected to wired network through AP Stationary Emitter (SE) Emitter without Networking Capability Network Scanner (NS) niffer, tumble Mobile Client with Network Interface Card Meaurement Databae Location Service Server 비시선각오차극복을위한기준측정치수집방식 43 비시선각오차발생개형 알려진위치에측정치수집장치설치 Outdoor non-line-of-ight path Indoor node B (bae tation) line-of-ight path (obtructed by building) handet (mobile tation) : auxiliary localization device : wirele acce point : wirele network card 45 46 별도의측위장치를활용하여전영역에대하여조사원이측정치수집 지도에표시하면서전영역에대하여조사원이측정치수집 - 실외의경우 GPS 활용가능 - 실내의경우에는적절한측위장치가없음 : auxiliary localization device : wirele acce point : wirele network card : wirele acce point : wirele network card 47 48 8
신호원근방에서대해서만조사원이측정치수집 통신망과연계하여대용량무작위측정치수집및분석 * 측정치수집과정에서지도및별도측위수단활용하지않음 D(x,y) : wirele acce point : wirele acce point : wirele network card : wirele network card : wirele network card at approximately known location 49 50 기준측정치의시변성 52 기준측정치의시변성에대처하기위한측위알고리즘구조 time t i z,2,2 z,, X( 2, t ) X(.., t ) i X ( K, ti ). i z ( u, ti) z 2 K,L u,l vt ( i, ) t i + t i + 2 z,2,2 z, z,2 z,, X( 2, t i X(.., t. ) + ) i + z ( u, t i + ) z 2,L u,, L X( 2, t i X(.., t. i + 2) + 2) z ( u, t i + 2) z 2,L u,l,2 X ( K, t i + ) K vt ( i +, ) X ( K, t i + 2) K vt ( i + 2, ) 53 54 9
AP 송신신호세기 ( 최대신호세기 ) 다양성 이기종신호원출력특성 56 이기종송신신호세기의고려 () : AP 규격활용 이기종송신신호세기의고려 (2) : 최대측정치실측 UNICORN BW-850 에이엘테크 ANYGATE RG3500-A Meaurement DataBae (MDB) Index HW model Time index SS_ SS_2 I() I(2) I(3) I(N) AP_2 SS_J Reference Meaurement AP_2 proximity condition: maximum SS(AP_2) value 57 58 신호세기수집환경 이기종이동기기수신감도특성 9 9 8 45 9 45 0 37 37 2 3 7 20 24 36 74 73 60 0
이기종이동기기의수신신호세기비교 () 이기종이동기기의수신신호세기비교 (2) corridor X-NOTE Tohiba 32 호 6 62 이기종이동기기의수신신호세기비교 (3) 다양한 AP 에대한수신신호세기차분비교 322 호 63 64 근거리영역다양한 AP 에대한수신신호세기차분비교 위치지문방식에서이동기기신호세기바이어스고려유무에따른최근접기준측정치식별개형 (a) 바이어스가없는경우 (b) 바이어스가존재하지만이를고려하지않은경우 65 66
BTS CDMA Location Server/DB BSC BSC MPC MSC/HLR BTS BTS BSC 이기종인프라 / 측정치에대한측위신호융합 outdoor environment indoor environment WiBro Location Server/DB WLAN Location Server/DB UWB Location Server/DB RFID Location Server/DB Central Location Server/DB 68 이기종측정치 DB 의활용방안 : Signal Feature ( 최단거리, 최대신호세기 ) Meaurement databae tructure Alia for privacy I() I(2) I(3) I(N) : arbitrary index number for each mobile tation Time index : time when each meaurement i acquired Handet model : affect RF enitivity TDOA (:Nb-) : time difference of arrival FDOA (:Nb-) : frequency difference of arrival TOA (:Nb) : time of arrival FOA (:Nb) : frequency of arrival AOA (:Nb) : angle of arrival TSS (:Nb) : tranmitted ignal trength RSS (:Nb) : received ignal trength SNR (:Nb) : ignal-to-noie ratio N: number of meaurement et Nb: number of node B Alia for privacy (arbitrary index number) Handet model Time index TDOA (:Nb-) TOA (:Nb) AOA (:Nb) Tranmitted SS(:Nb) Received SS(:Nb) SNR(:Nb) I() I(2) I(3) I(N) proximity condition: Reference Location (node B) Range (TSS,RSS,node B) 0 Reference Meaurement identified by meaurement characteritic claification 69 70 이기종측정치 DB 의활용방안 : Geometric Feature ( 교차로에대한윤곽 ) Meaurement Databae Alia for privacy (arbitrary index number) Handet model Time index TDOA (:Nb-) TOA (:Nb) AOA (:Nb) I() I(2) I(3) I(N) Reference Meaurement in the neighborhood of local maximum Feature Map LR+LM Corrected LE Core Network LM* EI** LM Handler EI Control LM Control EI Control Meaurement Databae Environment Databae** Tranmitted SS(:Nb) Received SS(:Nb) SNR(:Nb) Reference Location (road junction) Ideal Map Corrected LE LR+LM Map Parameter for Broadcating CR+LM Corrected LM LR+LM Corrected LE Cater Location Area Map Type Ditorted LE with Requeting Map Type Correction to LM Map Parameter Analyi Reult Analyzer Analyi Aid (if available) Correction Map*** LM : Location Meaurement EI : Environmental Information LR : Location Requet CR : Correction Requet LE : Location Etimate * Gathered LM are for Mobility Management for Handover - for Location Baed Service -upon Requet ** EI contain coordinate of BTS - coordinate of fixed ignal tranmitter and receiver - road/building map (optional) *** Correction Map are built on ditorted LE domain 7 72 2
기타향후발전방향 privacy decentralization to conider computational burden, accuracy, ecurity, and reliability meaurement verification (fault detection) acce point authentication intallation and upgrade eaine Reference Meaurement Databae Update For ufficient reference information, automatic location meaurement collection i deirable Old Databae + New Databae -> Updated Databae Should conider patial and temporal variation Homogeneou databae update (ame type of meaurement) Heterogeneou databae update (different type of meaurement, meaurement at different frequecie) 74 감사합니다 75 3