Introducing Sunfish
The SUNFISH AUV®
Emerging at the frontier of underwater exploration, the SUNFISH AUVⓇ is a groundbreaking achievement in autonomous robotics, revolutionizing how we study Earth’s most challenging aquatic environments – submerged cave systems. With an integrated array of sensors and the ability to orient itself in any direction, this pioneering AUV combines autonomous navigation, real-time 3D mapping, and precision maneuvering in confined spaces to chart these labyrinths in unprecedented detail.
One recent expedition the Sunfish team embarked on took place in the aquatic caverns of Jackson Blue Springs State Park, located in Marianna, Florida. When technical issues arose with the SUNFISH AUV’s analog vision system during initial field tests, the engineering team began searching for a more reliable and cost-effective solution. Unsatisfied with approximately 20-30 other camera manufacturers evaluated, the team was recommended equipment from DeepWater Exploration’s advanced subsea camera systems, which utilizes USB 2.0 connectors. Soon after, the Sunfish team decided to integrate DWE’s exploreHD Heavy, equipped with a backside illuminated sensor for low light conditions. The shift to a digital vision system proved successful, providing the Sunfish team with improved features, reliability, maintainability, and ease-of-integration – all while reducing system costs.
The Challenge - Coax Cable Failure
In collaboration with the University of South Florida and divers from the Woodville Karst Plain Project (WKPP), Sunfish was tasked to navigate and map the intricate cave systems while testing nitrate levels within various passageways. Operating within a narrow timeframe, the experienced engineering team was successful in integrating new nitrate and GNSS sensors, and writing custom software to automatically perform the mapping with data from the sensors.
However, a new obstacle presented itself when the SUNFISH AUV’s original nose camera began to have connectivity issues during field testing. Although their camera didn’t experience flooding, the team suspected that the camera’s analog coax cable had deteriorated, the replacement of which would cost around $3,200 with a long lead time. At this point, the Sunfish team began looking for solutions from a new camera manufacturer, with an emphasis on low latency, reliability, and maintainability.
The Solution - exploreHD Heavy
Upon discovering solutions provided by DeepWater Exploration, the Sunfish team admittedly had initial skepticism since they were unfamiliar with any subsea camera manufacturer utilizing a USB 2.0 signal. Despite that, the cable impedance of USB 2.0 (90ohm) being similar to that of a CAT5 cable (100ohm) made them compatible, which meant the team could take a chance on the exploreHD Heavy without needing to procure custom cables.
The Sunfish team successfully implemented the exploreHD Heavy camera using a MCBH8 connector to their main pressure housing, chosen for the high reliability of SubConn connectors as well as their CAT5 compatibility. The DeepWater Exploration team accommodated their specific connector requirements, ensuring a seamless integration process.
The exploreHD Heavy’s RTP video stream enabled straightforward software integration with the standard ROS package the Sunfish team was already familiar with. The simple stream format allowed the team to easily implement their existing code for a heads up display (HUD) which overlaid critical mission data.
SUNFISH's HUD
The Benefits - Features, Work, and Cost Savings
The integration of the exploreHD Heavy delivered significant advantages in cost, time, and operational efficiency compared to Sunfish’s previous camera solutions, including both IP and analog.
exploreHD Heavy mounted as SUNFISH's nose camera
Traditional analog vision systems used by the SUNFISH AUV typically required an additional ~$3,000 in parts, on top of the price of the camera itself. These parts included frame grabbers, underwater cables/connectors, coax cables, and crimpers. Along with higher expenditure, roughly a month of labor was required for implementation with difficulties arising from installing Linux kernel modules, properly crimping analog cables, and having to mount all components inside the housing.
Similarly, IP cameras require an additional ~$1,000 in parts for cables, connectors, and ethernet crimpers. Labor for IP cameras was more varied, depending on how customized the API was, usually falling within 1-2 weeks for more straightforward requests and up to 3 months for highly customized APIs.
In comparison, the plug-and-play experience offered by the exploreHD Heavy gives teams the ability to go from unboxing to streaming within minutes. Along with easy integration, there’s no need for maintaining kernel modules required for analog frame grabbing, and no need for the extra bulk and power draw required for IP cameras.
Beyond work and cost savings, the exploreHD Heavy provided many performance benefits including exceptional low-light image quality, field of view, latency, and low color distortion – all while ensuring reliability and simple maintainability through its USB connection.
Low-light footage taken from the exploreHD Heavy
Key Detail: The SUNFISH AUV has its array of sensors located along the topside and bottom of its hull. With 6-degrees of maneuverability, the AUV is capable of independently rotating about any axis and orientating its sensors in any direction. In the clip above, this functionality is displayed as the SUNFISH AUV performs multiple rolls to quickly scan all surfaces around it, even in confined spaces. As photos and geometric data are acquired, sophisticated artificial intelligence is utilized to create real-time 3D maps of the environment.
Looking Ahead - Sunfish’s Future Developments
True to their values of “going where no one has gone before”, Sunfish continues to push the boundaries of underwater exploration by surveying the most complex underwater environments. With a lineup of missions planned for 2025 supporting various water municipalities, each expedition promises new discoveries and insights as the SUNFISH AUV ventures through distinct passageways.
The SUNFISH AUV truly sets itself apart in the industry with its sophisticated sensor array and unique capabilities. Utilizing a combination of sonar, vision, and water chemistry detection, the AUV constructs detailed georeferenced 3D maps while maintaining complete coverage of any surfaces that surround it. This comprehensive ability, combined with its advanced maneuverability, makes the SUNFISH AUV an invaluable tool for underwater exploration, inspection, and environmental monitoring. With a reliable vision system now firmly established, the SUNFISH AUV continues to illuminate the hidden wonders of underwater cave systems while setting new standards for autonomous underwater exploration.