Practical considerations in the design of an obstacle detection, mapping and path planning system for small unmanned aircraft systems. International Journal of Unmanned Systems Engineering. 2(3): x-x. This paper discusses some of the practical engineering considerations relevant to the development and implementation of Obstacle Detection, Mapping and Path Planning Systems (ODMAPPS) for small Unmanned Aircraft Systems (UAS). To illustrate the discussion, results are presented for a quad-rotor UAS, which employs a LIght Detection and Ranging sensor for obstacle detection, a dynamic occupancy grid using Bayesian estimation for obstacle mapping, and the depth first search, breadth first search and rapidly exploring random tree algorithms for pa...