Today, autonomous underwater vehicles (AUVs) and remotely operated vehicles (ROV)s are capable of complex work that once required large and costly platforms. These miniature robotic machines, whose size represents significant short and long-term cost savings, also face navigation and control challenges.
Offshore industry expert Ben Kinnaman is well familiar with them.
“In the subsea industry, we don’t have the luxury of strapping on a GPS like our land and air brethren and knowing exactly where we are,” says Kinnaman, CEO and President of Greensea Systems, Inc. “We have to do that through inertial technologies and sensor fusion, an assortment of sensors measuring and observing individual states that fuse together to provide a navigation solution.”
To compensate for the loss of GPS/GNSS in water due to its electromagnetic opacity, observation class AUVs and ROVs are generally equipped with one or more navigation systems, which assist in a dead-reckoning position calculation from the last available surface GPS/GNSS waypoint.
While each individual sensor system has limitations — dropped signals, rate drops, and simple errors — a fully integrated platform can be created with integrated depth, heading-aiding sensors, and navigation-aiding sensors for a reliable, accurate inertial solution.
At the heart of the system is the inertial measurement unit (IMU), which measures orientation and acceleration, providing a baseline value for position relative to starting point.
This combination of navigation, control, and an intuitive user interface has made small vehicles easier to use, and now people who aren’t pilots can accomplish high-level tasks – and get the job done. “The focus can be on the mission and not just on operating the vehicle, thereby improving their situational awareness,” says Kinnaman. Operators can take a step back and get a big picture view of what the data is telling them.
To hear more from Kinnaman about sensor fusion via IMUs such as the KVH 1750 IMU as the core processor for navigation and control, listen to “Realizing New Potentials in Miniature Subsea Robotics”, part of the KVH Unmanned & Autonomous Webinar Series.
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