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Mesobot, an autonomous underwater vehicle, addresses specific unmet needs for observing and sampling a variety of phenomena in the ocean's midwaters. The midwater hosts a vast biomass, has a role in regulating climate, and may soon be exploited commercially, yet our scientific understanding of it is incomplete. Mesobot has the ability to survey and track slow-moving animals and to correlate the animals' movements with critical environmental measurements. Mesobot will complement existing oceanographic assets such as towed, remotely operated, and autonomous vehicles; shipboard acoustic sensors; and net tows. Its potential to perform behavioral studies unobtrusively over long periods with substantial autonomy provides a capability that is not presently available to midwater researchers. The 250-kilogram marine robot can be teleoperated through a lightweight fiber optic tether and can also operate untethered with full autonomy while minimizing environmental disturbance. We present recent results illustrating the vehicle's ability to automatically track free-swimming hydromedusae (Solmissus sp.) and larvaceans (Bathochordaeus stygius) at depths of 200 meters in Monterey Bay, USA. In addition to these tracking missions, the vehicle can execute preprogrammed missions collecting image and sensor data while also carrying substantial auxiliary payloads such as cameras, sonars, and samplers.

Studies of marine physical, chemical, and microbiological processes benefit from observing in a Lagrangian frame of reference. Some of these processes are related to specific density or temperature ranges. We have developed a method for a Tethys-class long-range autonomous underwater vehicle (LRAUV) (which has a propeller and a buoyancy engine) to track a targeted isothermal layer (within a narrow temperature range) in a stratified water column when operating in buoyancy-controlled drift mode. In this mode, the vehicle shuts off its propeller and autonomously detects the isotherm and stays with it by actively controlling the vehicle's buoyancy. The LRAUV starts on an initial descent to search for the target temperature. Once the temperature falls in the target center bracket, the vehicle records the corresponding depth and adjusts buoyancy to hold that depth. As long as the temperature stays within a tolerance range, the vehicle continues to hold that depth. If the temperature falls out of the tolerance range, the vehicle will increase or decrease buoyancy to reacquire the target temperature and track it. In a June 2015 experiment in Monterey Bay, CA, USA, an LRAUV ran the presented algorithm to successfully track a target isotherm for 13 h. Over the isotherm tracking duration, the LRAUV mostly remained in the 0.5 $^\circ $ C (peak-to-peak) tolerance range as designed, even though the water column's stratification kept changing. This work paves the way to coupling an LRAUV's complimentary modes of flight and drift—searching for an oceanographic feature in flight mode, and then switching to drift mode to track the feature in a Lagrangian frame of reference.

One of the greatest challenges to understanding ecosystem dynamics in the open ocean is predicting where and when hot spots of biological activity exist and then observing and sampling those features for days to weeks, as they move in a complicated trajectory. It is difficult to apply traditional research vessel-based techniques at the relevant temporal and spatial scales when the biological features could be spinning in an eddy, rising and falling on internal waves, or even actively migrating. To address this challenge the Monterey Bay Aquarium Research Institute (MBARI) is developing an observing system based on a collaborating group of autonomous underwater vehicles (AUVs) and an Unmanned Surface Vehicle (USV). Building on the capabilities of the Long Range AUV (LRAUV) and a Liquid Robotics SV-3 Wave Glider, MBARI has begun deploying arrays of LRAUVs configured with complementary sensors that work together as an Open Ocean, Autonomous Vehicle-based Lagrangian Observatory.

Mesobot, a new class of autonomous underwater vehicle, will address specific unmet needs for observing slow-moving targets in the midwater ocean. Mesobot will track targets such as zooplankton, fish, and descending particle aggregates using a control system based on stereo cameras and a combination of thrusters and a variable buoyancy system. The vehicle will also be able to collect biogeochemical and environmental DNA (eDNA) samples using a pumped filter sampler.

In 2017 a team from MBARI and Stanford University deployed an AUV in Sermilik Fjord in Greenland to map the walls of icebergs. 24 missions were run over a period of a week, and a detailed 3D map of a specific iceberg was obtained. This paper describes the design of the control and obstacle-avoidance system and subsequent field operations.

The Monterey Bay Aquarium Research Institute (MBARI, Moss Landing, CA) has developed a 54-cm-diameter (21-in) docking AUV and companion docking station. This program resulted in four consecutive successful autonomous homing and docking events in the open ocean, which included downloading data, uploading a new mission plan, recharging the battery, and complete power cycling of the AUV. We describe the design, simulation, and at-sea test of the homing and docking control system.

This paper presents the development effort toward demonstrating acoustic tracking and homing with a long-range AUV (LRAUV) at the Monterey Bay Aquarium Research Institute (MBARI). The acoustic tracking system uses a directional acoustic transponder (DAT) from Teledyne Benthos, backed by an acoustic baffle made from syntactic acoustic damping material (SADM). We discuss sensor integration into the LRAUV system, procedures and results from an in-house calibration, and field tests with both anchored and towed transponders.

Most existing propeller-driven, cruising AUVs operate with a support ship and have an endurance of about one day. However, many oceanographic processes evolve over days or weeks, requiring propeller-driven vehicles be attended by a ship for complete observation programs. The Monterey Bay Aquarium Research Institute (MBARI) developed the 105 kg propeller-driven Tethys AUV to conduct science missions over periods of weeks or even months without a ship [1]. Here we describe a three week deployment covering 1800 km at a speed of 1 m/s, supporting sensor power levels averaging 5 watts. Unlike buoyancy driven gliders, Tethys uses a propeller that allows level flight and a variable speed range of 0.5 – 1.2 m/s. The extended endurance enables operations in remote locations like under the ice, across ocean basins in addition to enabling continuous presence in smaller areas. Early success led to the construction of a second Tethys-class AUV with a third in planning. An AUV docking station that can be mated to a cabled observatory or standalone mooring is in development to further extend Tethys endurance.

The Benthic Rover is an autonomous, bottom-crawling vehicle being developed at the Monterey Bay Aquarium Research Institute (MBARI) to conduct long-term deep-ocean ecological research. In 2009 MBARI researchers deployed the Rover on the Monterey Accelerated Research System (MARS) cabled observatory for component and operational testing. MARS is located near-shore in the Monterey Bay near Monterey, CA, at a depth of approximately 900 meters, providing the power reliability and network accessibility similar to an on-shore laboratory. By enabling immediate feedback and the ability to quickly re-program control software and re-configure mission scripts, MARS facilitates a kind of “in-situ rapid proto-testing”. MBARI researchers were able to run numerous experimental procedures and analyze results in a relatively short timeframe, converging on desired operational profiles quickly and at very low cost. This paper will cover recent development work on the Benthic Rover with emphasis on the deployment and testing on MARS.

The Tethys autonomous underwater vehicle (AUV) is a 110 kg vehicle designed for long-range, high- endurance operations. Performance goals include supporting a payload power draw of 8 W for a range of 1000 km at 1 m/s, and a power draw of 1 W for 4000 km at 0.5 m/s. Achieving this performance requires minimizing drag and maximizing propulsion efficiency. In this paper, we present the design of the propulsion system, explore the issues of propeller-hull interactions, and present preliminary test results of power consumption and efficiency. In recent underwater experiments, the propulsion system's power consumptions were measured in both Bollard pull tests and during the vehicle's flights. Preliminary results of power consumptions and efficiency are shown to be close to the theoretical predictions.

Thermoclines play a key role in ocean circulation, marine ecology, and underwater acoustics. In oceanographic surveys, it is often desirable to detect the thermocline and track its spatio-temporal variation. Mobility of an autonomous underwater vehicle (AUV) makes it an efficient platform for thermocline tracking. In this paper, we present a fully autonomous algorithm for detecting and tracking the thermocline by an AUV. The key is detection of the peak gradient of temperature. We have tested the algorithm by post-processing data from a previous Dorado AUV survey over the northern Monterey Bay shelf. We are in preparation for field tests of the algorithm on the newly developed long-range AUV Tethys.

Rover is a bottom-crawling, autonomous vehicle capable of making continuous time-series measurements at abyssal depths up to 6000 m for periods exceeding six months. The Rover control system and instrumentation suite are being designed at the Monterey Bay Aquarium Research Institute (MBARI), building on the earlier rover work of Smith and associates at the Scripps Institution of Oceanography. The vehicle weighs 68 kg in water and crawls on two wide tracks with a combined surface contact area of about one square meter; this provides good traction while minimizing the disturbance to benthic sediments. A typical mission scenario is to take measurements for a few days at each site before picking up the instruments and moving forward ~10 m to a new site. Up to fifty sites may be visited in a single mission. Engineering field tests have been performed with the Rover in the Monterey Bay in California (890 m depth), and at Station M, 220 km west of the central California coast (4200 m depth). Rover operations have been observed with the ROVs Ventana and Tiburon, and with the manned submersible DSV Alvin. Knowledge gained from these engineering deployments has resulted in numerous modifications and improvements to The Rover.

The Monterey Bay Aquarium Research Institute (MBARI) has developed an AUV docking station for a 21-inch (54 cm) diameter AUV. The system was designed for operation with cabled undersea observatories in water depths up to 4 km deep and has been demonstrated in the open ocean, though at much shallower depths. The program demonstrated successful autonomous homing and docking, data downloads, uploading of new mission plans, battery recharging, and complete power cycling of the AUV. We describe the design, and at-sea tests.

Instruments to detect the occurrence of energetic sediment transport events within submarine canyons are being developed. Submarine canyons are known to act as conduits for transporting sediment from the continents into the deep sea. Because the sediment primarily moves in discrete energetic events, determining the occurrence of events and the quantity of sediment involved in these transports has been difficult. Instruments placed at sites known to experience transport events are frequently lost, along with their data. In an effort to address this problem, the Monterey Bay Aquarium Research Institute (MBARI) has developed a Self Triggering Event Detector (STED). This presentation will deal specifically with the design, development, testing, and initial deployments of the proto-type STED system. The STEDs are placed in the axis of the Monterey Canyon at locations known to experience frequent sediment transport events. A combination of MBARI (Paull et al, 2003) and USGS (Xu et al, 2004) experiments demonstrate that the maximum currents on the floor of the canyon are less than 60 cm/sec under normal conditions. However, during sediment transport events, current velocities of over 200 cm/sec are sustained for several minutes. When a STED platform experiences currents in excess of 200 cm/sec, one meter above the sea bed, a positive buoyant science package is released to the surface. Included in this science package is an ARGOS Pop-off satellite transmitter that will time stamp the event and can be adapted to provide essential scientific data. Elements of the STED system include: a benthic platform, current detecting/triggering mechanism, Argos satellite transmitter, Homer Pro beacon, and instrument suite. The base is a robust structure constructed of heavy gauge steel which rests on the seafloor. An aluminum tower one meter in height is attached to the base and supports the triggering/release mechanism. The triggering/release mechanism rotates and functions as does a weather vane, always pointing into the prevailing current. When a current velocity exceeds the 200 cm/sec threshold, a trigger plate, forced to face into the current by the vane assembly, triggers the release, permitting the positive buoyant instrument suite to float upwards through the water column to the surface. Upon reaching the surface the ARGOS transmitter establishes satellite contact and down loads the acquired data. The unique identification of each ARGOS transmitter establishes the time and location in the canyon where an event/s has occurred. The Homer Pro beacons will allow these sites to be surveyed by ROV after an event has been detected. Requirements include: ease of manufacture (expendable), deployable and serviceable by ROV, remain functional for up to three years, survive currents up to the 200 cm/sec release threshold, and reliably release and deliver the instrument package to the surface. A goal of this project is to deploy several on these systems within the Monterey Canyon. To accomplish this it is necessary to design a system that is simple, affordable, and relatively easy to manufacture. These systems will be deployed by ROV, driving weight constrains of 91 kg in air and 45 kg in sea water. In the event of a release and the survival of the platform, the system can be rearmed by ROV intervention. To validate the system, significant testing was conducted in the MBARI 1,500.000 liter test tank. Two STED devices were deployed in depths of 290 and 520 m on May 30, 2006. On June 19, 2006 a release occurred at the 550 m site. Investigation revealed an event had taken place resulting in the transport of this platform 500 m down canyon

Nekton Research is developing a 4-7/8" diameter, 39" long UUV for the neutralization of mines in shallow water. The Ranger RN UUV can be hand-launched from a small boat, navigate on its own with GPS or acoustic long baseline navigation, and autonomously locate and home to mines. Alternatively, Ranger RN can be tracked and controlled remotely through an acoustic link. Current vehicle and field tests are described

Nekton Research and Florida Atlantic University are currently (July '02) integrating a hovering module with the Morpheus AUV. This module, which uses flexible oscillating fin thruster technology, provides Morpheus with the ability to stop, hold station and operate in heave and sway. Such capabilities will allow Morpheus to execute numerous delicate tasks such as mine classification. Herein, we discuss the foundations of this work and present results from initial sea trials.

Nekton Research and Florida Atlantic University have integrated a hovering module onto the Morpheus UUV. This module uses flexible oscillating fin thruster (OFT) technology. It provides Morpheus with the ability to stop, hold station and operate in heave and sway. These capabilities, previously unavailable, will allow Morpheus to execute delicate tasks such as mine classification. Herein, we discuss the development of the OFTs for Morpheus, results from sea trials and ideas for how to add OFTs to existing vehicles engaged in MCM operations but without the ability to hover.

The ranger micro-UUV from Nekton Research has been deployed successfully in various multi-agent mission demonstrations, including formation flying to map a salinity front and adaptive cooperation to localize the origins of test plumes. The low cost and simplicity of using the 5 kg Rangers make possible multiagent missions and algorithm testing that is beyond the economic reach of alternative UUVs. Efficiency and utility of the Ranger-UMAP multiagent system derives in part from fleet logistical interface and control software (FLICS) software created for preparation, deployment, monitoring, midmission retasking, and recovery of multiple vehicles used in cooperative missions.

Phytoplankton patches in the coastal ocean have important impacts on the patterns of primary productivity, the survival and growth of zooplankton and fish larvae, and the development of harmful algal blooms (HABs). We desire to observe microscopic life in a phytoplankton patch in its natural frame of reference (which is moving with the ocean current), thereby permitting resolution of time-dependent evolution of the population. To achieve this goal, we have developed a method for a Tethys-class long range autonomous underwater vehicle (AUV) (which has a propeller and a buoyancy engine) to detect, track, and sample a phytoplankton patch in buoyancy-controlled drifting mode. In this mode, the vehicle shuts off its propeller and actively controls its buoyancy to autonomously find the peak-chlorophyll layer, stay in it, and trigger water sampling in the layer. In an experiment in Monterey Bay, CA in July 2015, the Makai AUV, which was equipped with a prototype 3rd-generation Environmental Sample Processor (3G-ESP), ran the algorithm to autonomously detect the peak-chlorophyll layer, and drifted and triggered ESP samplings in the layer.