In this paper a novel algorithm is proposed for nearly precise localization of a mobile sensor node from less number of low cost anchor nodes, using the received signal strength Index (RSSI) of a very high frequency wireless signal. Often the loss of signal, called as the shadow fading generates spurious data in RSSI, due to Gaussian noise, which is removed using entropy function. The viability of the proposed system is practically experimented. The error analysis is done using analysis of variance (ANOVA) method for the proper validation of results obtained.