"The ArduSub project is a fully-featured open-source solution for remotely operated underwater vehicles (ROVs) and autonomous underwater vehicles (AUVs). ArduSub is a part of the ArduPilot project, and was originally derived from the ArduCopter code. ArduSub has extensive capabilities out of the box including feedback stability control, depth and heading hold, and autonomous navigation.

ArduSub is designed to be safe, feature-rich, open-ended, and easy to use even for novice users.

ArduSub works seamlessly with Ground Control Station software that can monitor vehicle telemetry and perform powerful mission planning activities. It also benefits from other parts of the ArduPilot platform, including simulators, log analysis tools, and higher level APIs for vehicle management and control.

ArduSub is on the leading edge of marine robotics and intended for anyone who wants to operate a vehicle below the water's surface. There is support for many different ROV configurations, and adding a custom design is simple."

https://www.ardusub.com/