Localization Algorithms Using Wireless Communication Systems For efficient Localization Based Services, development of accurate localization algorithm has to be preceded. In this paper, research trend of localization algorithm using Ultra WideBand (UWB) radio is reported and hybrid localization algorithm using delay parameters is proposed. As communication for localization, the UWB is compared with other systems. After introducing localization algorithms using UWB, proposed hybrid algorithms are presented. In our proposed hybrid algorithm, anchor nodes determined the existence of line-ofsight path from measured delay parameters. Then, using time of arrival and received signal strength information, calculated range estimation results are sent to the central processor. The performance of our algorithm is compared to existing algorithms using simulation and it is confirmed that about 20% of localization error of conventional localization algorithm using TOA is reduced in localization algorithm with three base stations. Keywords : Location Based Service, Localization algorithm, Ultra WideBand, Wideband channel characteristics, and CRLB (Cramer-Rao Lower Bound) I
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1 σ 2 var(θ ) : CRLB I(θ) N1 s[n;θ] 2 Σ ( ) n0 θ 1 σ 2 N 0 B 2B x(t)s(tτ 0 )w(t), 0tT s(t) T s w(t) x(t) r 0 T x(n )s(n τ 0 )w(n ) x[n]s(nτ 0 )w[n] B 1 w[n] σ 2 2B N 0 B τ 0 tτ 0 T s w[n], 0nn 0 1 x[n] s(n τ 0 )w[n], n 0 nn 0 M1 w[n] n 0 MnN1 τ 0 M n 0 θτ 0 σ 2 σ 2 var(τ 0 ) N1 s[n;τ 0 ] 2 M1 ds(t) 2 Σ ( ) Σ ( ) n0 τ 0 n0 dt tn 0 σ 2 N 0 2 var(τ 0 ) 1 Ts ds(t) 2 ds(t) 2 0 ( ) Ts dt 0 ( ) dt dt dt N 0 2 var(τ 0 ) (2πf) 2 S(f ) 2 df N 0 1 8π 2 β 2 ε 8π 2 SNRβ 2 β f 2 S(f ) 2 df f 2 S(f ) 2 df β S(f ) 2 ε df dcτ 0 c var(d) (1) 2 2π SNR β PL10nlog 10 dx σ X σ N(0, σ 2 sh )
f (PL;d) 1 (PL10nlog 10 d) 2 f (PL;d) exp{ } 2πσ sh 2 2σ sh 2 2 ln f (PL;d) 10 2 n 2 1 I(d)E [ ] ( ) ( ) d 2 ln 10 σ sh d 2 Final report Tech. Rep. Doc. IEEE 802.15-04-0662-02- 004a, 2005. [9] A. Mallat et al., ''UWB based positioning in multipath channels: CRBs for AOA and for hybrid TOA-AOA based methods,'' proc. of ICC2007, Jun., 2007, pp. 5775-5780. [10] Chin-Der Wann and Hao-Chun Chin, ''Hybrid TOA/RSSI wireless location with unconstrained nonlinear optimization for indoor UWB channels,'' proc. of WCNC20, Mar. 2007, pp. 3940-3945. 1 ln 10 σ var(d) sh d (2) I(d) 10 n [1] S. Gezici et al., ''Localization via Ultra-Wideband radios: a look at positioning aspects for future sensor networks,'' IEEE signal processing magazine, Vol. 12, Issue 5, Jul. 2005, pp. 70-84. [2] B. Alavi, and K. Pahlavan, ''Modeling of the TOA-based distance measurement error using UWB indoor radio measurements,'' IEEE communication letters, Vol. 10, Issue 4, Apr. 2006, pp. 275-277 [3] I. Oppermann et al.,''uwb wireless sensor networks: UWEN - a practical example,'' IEEE communication magazine, Vol. 42, Issue 12, Dec. 2004, pp. S27-S32. [4],,, 22, 3, 6 2007, pp. 20-28. [5], (LBS),, 615, 8 2007. [6],, SKtelecommunication Review, 16, 2, 2006, pp. 188-202. [7] S. M. Kay, ''Fundamentals of statistical signal processing: Estimation Theory,'' Prentice Hall PTR, pp. 27-82 [8] A. F. Molisch et al., IEEE 802.15.4a channel Model-