Development of a Guidance System for AUV Chemical Plume Tracing

In autonomous underwater vehicle (AUV) chemical plume tracing applications, the mission objective is to trace chemical plumes to the chemical source in a turbulent flow environment and to accurately estimate the chemical source location. AUV´s capable of such feats would have applicability in searching for environmentally interesting phenomena, unexploded ordnance, undersea wreckage, and sources of hazardous chemicals or pollutants. A typical AUV chemical plume tracing system includes an adaptive mission planner (AMP) that rapidly responds to the sensor inputs to generate a trajectory for the AUV to trace the plume. Because the AUV has velocity (< 2 m/s) and heading rate (< 10 degree/s) constraints and the vehicle navigation system has navigation fixes, a guidance system is necessary for the AUV to generate heading and speed commands within the constraints to achieve the trajectory desired by the AMP. This article describes the development and field test results of the guidance system for a REMUS AUV to find a chemical plume, trace the chemical plume to its source, maneuver to reliably declare the source location, and map the plume source area after declaration of the source location. Three sets of in-water field tests with the Navy successfully demonstrated the plume tracing and post-declaration mapping capability on a REMUS AUV with the guidance system described herein