서론 I.
USN (Ubiquitous Sensor Network) . , , RFID (Radio-Frequency IDentification)/USN [1-5]. RFID , , , , , , , , , , . RFID/USN . GPS (Global Positioning System) . GPS 1970
3 , , 24 , , , * (Corresponding Author) : 2009. 10. 12., : 2009. 11. 25., : 2010. 1. 12. : ([email protected]) : ([email protected]) : ([email protected]) ( ) 2008 (R01-2008-000-20844-0). . , [3-5]. RF cricket, active badge,
(radar), 3 Easy Living RFID
. , , , [6]. (smart space) RFID . RFID . RSSI[1,2], 3 TDOA[3,4], 3
TOA (Time Of Arrival)[5],
AOA (Angle Of Angle)[6] AOA TOA
. , , NLOS( ) [3,7], (multi-path fading) [8] , .
Error Revision of the Unknown Tag Location in Smart Space
,
,
*(Myung Hwan Tak, Suk Kun Jee, and Young Hoon Joo)
Abstract: In this paper, we propose the location measurement algorithm of unknown tag based on RFID (Radio-Frequency IDentification) by using RSSI (Received Signal Strength Indication) and TDOA (Time Difference of Arrival) and extended Kalman filter in smart space. To do this, first, we recognize the location of unknown tag by using the RSSI and TDOA recognition methods. Second, we set the coordinate of the tag location measured by using trilateration and SX algorithm. But the tag location data measured by this method are included complex environmental error. So, we use the extended Kalman filter in order to revise error data of the tag location. Finally, we validate the applicability of the proposed method though the simulation in a complex environment.
RSSI TDOA SX [9] . , . . 위치 측정 시스템 II. . 1 . 3 . . . 2 SX . , , . 위치측정 및 오차 보정 III. 위치 측정 1.
1.1 RSSI (Received signal Strength Indication)
RSSI 2 , . (1) Friis . × (1) , , , . (2) . × × (2) c . . 삼변측량법 1.2 (Trilateration) . 3 3 ,, . ,, (3) . 1. .
FIg. 1. Block diagram for location measurement system.
2. RSSI .
Fig. 2. Location recognition by RSSI.
3. .
(3)
1.3TDOA (Time Difference of Arrival)
TDOA 3 ( ) . 4 3 2 . 알고리즘 1.4 SX . . 5 TDOA (4) . (4) i j . (5) (4) (5) (6) . (6) (7) . (7)
(8) ⋯ ≠ (6) (8) (4) (9) .
⋮
⋮ (9) A
⋮ ⋮ (9) (x,y) (10) .
⋮ ⋮
⋮
⋮ (10) 위치 측정 오차 보정 2. ( , ) , , , . . . . 확장 칼만필터 2.1 RSSI TDOA , NLOS . . Kalman Kalman . 4. TDOA .Fig. 4. Location recognition by TDOA.
5. .
⋯ (11) .
(11) . 3 RSSI TDOA SX . (12) .
(12)
. (13) . (13) h , 0 . . (13) (14) . (14) , . 6 . 시뮬레이션 및 결과 고찰 IV. RF 433MHz × [m/s], 3 . , . 7 RSSI TDOA . 8 RSSI TDOA . 9 RSSI TDOA 1. .Table 1. Extended Kalman filter.
6. .
Fig. 6. Performance process of extended Kalman filter.
7. RSSI TDOA .
Fig. 7. Simulation result of RSSI and TDOA.
8. RSSI + TDOA . Fig. 8. Simulation result of RSSI + TDOA.
. 2 5m 20 . 2 . 결론 V. RSSI TDOA 3 . RSSI TDOA 1 2 . . 참고문헌
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[14] , , , “
,” Journal of Information Technology Applications and Management, vol. 13, no. 4, pp. 57-70, 2006.
9. .
Fig. 9. Error revision using extended Kalman filter.
2. 5m .
Table 2. Simulation result when recognizing 5m distance tag.
5(m) 1 2 3 20
RSSI 3.726 2.203 6.237 …… 4.769 TDOA 6.050 5.249 4.044 …… 3.085 RSSI+TDOA 4.888 3.726 5.141 …… 2.509 RSSI+TDOA+EKF 4.895 4.745 5.012 …… 0.954
탁 명 환 2009 . 2009 ~ . , , . 주 영 훈 1982 , 1984 , 1995 ( , , ). 1986 ~1995 ( ) . 1998 2 ~1999 1 . 1995 ~ . Post BK21 . 2009
, International Journal of Control, Automation, Systems (IJCAS) Editor. ,
-, , , . 지 석 근 1985, 1990, 1997 ( , , ). 1990 ~ . . , .
