Information Technology Journal1812-56381812-5646Asian Network for Scientific Information10.3923/itj.2011.239.245WuHaibo DengMusheng XiaoLiaoliang WeiWei GaoAng 22011102Localization is significant for various applications in Wireless Sensor Networks. It is found that the estimated hop-distance will affect localization result. In this study, we propose a Cosine Theorem-based DV-hop localization algorithm (CTDV-hop) to improve localization precision. After estimating the average hop-distance by the traditional DV-hop technique, we select the middle node between every two anchor-pairs in the transmission route one by one. Then the estimated hop-distance is adjusted by the angle between the anchor-pairs to that selected middle node. We hence obtain the improved localization results and can accurately locate even the distribution of nodes is non-uniform. The simulation results illustrate that the CTDV-hop algorithm effectively improves the localization precision without extra energy consumption in networks.]]>Xiao, L.L. and H.B. Wu,2010Bulusu, N., J. Heidemann and D. Estrin,2000Gao, A., W. Wei and Z.X. Wang,2010Gao, A., W. Wei and X. Xiao,2010Girod, L., V. Bychovskiy, J. Elson and D. Estrin,2002Harter, A., A. Hopper, P. Steggles, A. Ward and P. Webster,2002Niculescu, D. and B. Nath,2003Bahl, P. and V.N. Padmanabhan,2000Nicolescu, D. and B．Nath, 2001Nagpal, R., H. Shrobc and J. Bachrach,2003Shang, Y., W. Ruml, Y. Zhang and M.P.R.J. Fromherz,2003He, T., C. Huang, B.M. Blum, J.A. Stankovic and T. Abdelzaher,2003Chandrasekhar, V., W.K.G. Seah, Y.S. Choo and H.V. Ee,2006Medidi, M., R.A. Slaaen, Y. Zhou, C.J. Mallery and S. Medidi,2006Wu, C.H., W. Sheng and Y. Zhang,2006