Abstract—Wireless Sensor Networks (WSNs) have revolutionized the world of distributed systems and enabled many new applications. And, measurement data or information exchanges happened in WSNs without location information are meaningless. It is extremely urgent to establish and maintain low cost and high efficient localization schemes for real-time large-scale surveillance systems. In this work, an improved DV-hop (Distance Vector-hop) based localization scheme IDV-hop (improved DV-hop) embedded in WLS (weighted least square) method is proposed for the purpose of surrounding surveillance, object localization for early warning, rescue operations and restructuring plan et al. Two critical parameters, correction coefficient k_c and weighted coefficient w_s,i, are introduced into IDV-hop scheme to improve location performance. And then, NS-2 simulations demonstrate that analysis results match well with simulation results. Besides, performance comparisons of IDV-hop scheme with other DV-hop based schemes are also proposed. Analysis and comparison results show that localization delay and accuracy of IDV-hop is improved largely relative to other schemes, especially for higher node density.