Unmanned Aerial Vehicles: Embedded Control

Chapter 14

Updated Flight Plan for an Autonomous Aircraft in a Windy Environment ¹

14.1. Introduction

In many autonomous aerial vehicles applications such as surveillance, long flight endurance is highly desirable. From the earliest days of aeronautical experimentations, the natural wind proved itself to be a major parameter to successful flights [BOL 07, ETK81, JIA 08, KRO 07, MCG 07, MCM 06, NEL 07, PAT 94, SEU 00, WIL 05, ZHA 04, ZHA 09]. Down-draft has traditionally been considered unfavorable for autonomous vehicles. The downward flow can cause an aircraft to lose altitude, and the accompanying wind shear can cause an aircraft to lose airspeed [ZHA 09]. The wind mostly affects a trajectory through its speed. In general, the wind speed can be modeled as a sum of two components: a nominal deterministic component (available through meteorological forecasts or measured with a Doppler radar) and a stochastic component, representing deviations from the nominal one. The closed-loop controller takes care of the stochastic part considered as perturbations, while the deterministic component is introduced into the motion planner. The path of the airplane with respect to the moving air frame will be referred to as the air path and with respect to the ground is referred as the ground path.

Mission planning is the process of planning how a mission will be conducted. This encompasses determining the path for the aircraft to fly (path planning) and the operation (task scheduling and planning) ...