Location accuracy on collaborative positioning in wireless sensor networks

The accurate node location is necessary for wireless sensor network applications in both the military and civilian areas. In this paper, we use the Cramer-Rao Bound (CRB) to verify that node localization algorithms based on received signal strength (RSS) and time of arrival (TOA) are both reasonable. The varying number of blindfolded nodes as well as the hybrid of RSS and TOA ranging methods are used to investigate the localization effect. Meanwhile, the maximum likelihood estimation (MLE) is applied to estimate the location accuracy. Simulation results demonstrate that both the localization algorithms based on RSS and TOA are absolutely effective, and the localization are much more accurate with either increasing blindfolded nodes or decreasing the certain parameters value. The node localization based on hybrid RSS/TOA ranging method results in 0.846m average RMS error and 0.229m average RMS CRB, which illustrates that it is much more accurate than the node locating based on RSS and TOA individually.