SONAR EMILY Autopilot System

Hydronalix produces several unmanned surface vessels for civilian and military use. The sonar variant of its Emergency Integrated Lifesaving Lanyard, or EMILY, is equipped with a Humminbird Helix-9 chirp transducer that transmits acoustic imagery for underwater surveying and recovery missions. For the transducer to generate accurate imagery, the vessel must travel below four knots. This project implements an autopilot that steers EMILY between waypoints through the Helix’s ground station interface. With this autopilot, the operator can plot and initialize a search track while maintaining the ability to take immediate control as mission conditions demand.The autopilot functions on a closed feedback loop by reading heading information from the GPS, determining heading error, then calculating the rudder deflection to correct course. An additional inertial measurement unit measures EMILY’s vertical accelerations, which the autopilot integrates to determine the sea state condition before transmitting the data to the operator. The autopilot runs on an Arduino processor chip and its algorithm is based on open source autopilot code libraries published by Arduino and Adafruit. The autopilot enables EMILY to autonomously complete a search pattern at speeds compatible with its sensor payload.