R ecently, quadrotors gained popularity due to their high maneuverability, cost and vertical takeoff/landing capabilities. Nevertheless, they also have disadvantages such as they have a limited flight time and small payload capabilities. In addition to these, a major part of the energy of a quadrotor is spent against gravity for hovering. Still, they are one of the most adopted air vehicles for commercial and research purposes. Most of the time UAV's (Unmanned Aerial Vehicles) are used in outdoor applications such as surveillance, search/rescue and patrolling. Recently, UAV's started to find uses in indoor environments. Material handling in manufacturing and inspection in harsh environments are to name a few[1] of these applications. One of the most promising applications is to utilize them in urban relief and disaster operations where a UAV moves autonomously avoiding obstacles in GPS-denied buildings to help human operators for rescue operations.In order to navigate in an indoor environment, a map of the environment is needed. However, in most of the cases either the map is unknown or some partial information about the environment is available. Indoor mapping process can be performed by using seve-Article History: