Localization in Wireless Sensor Networks (WSNs) not only provides a node with its geographical location but also a basic requirement for other applications such as geographical routing. Although a rich literature is available for localization in static WSN, not enough work is done for mobile WSNs, owing to the complexity due to node mobility. Most of the existing techniques for localization in mobile WSNs use Monte-Carlo Localization (MCL), which is not only time-consuming but also memory intensive. They, consider either the unknown nodes or anchor nodes to be static.