  This article establishes the Exploration-RRT algorithm: A novel
general-purpose combined exploration and pathplanning algorithm, based on a
multi-goal Rapidly-Exploring Random Trees (RRT) framework. Exploration-RRT
(ERRT) has been specifically designed for utilization in 3D exploration
missions, with partially or completely unknown and unstructured environments.
The novel proposed ERRT is based on a multi-objective optimization framework
and it is able to take under consideration the potential information gain, the
distance travelled, and the actuation costs, along trajectories to
pseudo-random goals, generated from considering the on-board sensor model and
the non-linear model of the utilized platform. In this article, the algorithmic
pipeline of the ERRT will be established and the overall applicability and
efficiency of the proposed scheme will be presented on an application with an
Unmanned Aerial Vehicle (UAV) model, equipped with a 3D lidar, in a simulated
operating environment, with the goal of exploring a completely unknown area as
efficiently and quickly as possible
