Underwater glider fleet control and applications: State of the art and future prospects

A review led by Runfeng Zhang of Tianjin University of Technology lays out where underwater glider (UG) fleets stand after roughly two decades of work, and where they are heading. It was accepted on 5 February 2026 and appears in Ocean, an open-access journal published by Tsinghua University Press.

The ocean covers 71 percent of the planet's surface, yet only about 5 percent of its depths have been charted. Gliders fill part of that gap. They travel by shifting buoyancy rather than running propellers, which lets them operate for six to twelve months over more than 3,000 kilometres. A single glider, though, cannot cover a whole eddy, a typhoon track, or a coastal current. Earlier reviews stopped at the individual platform. The authors say that misses the field's real direction: gliders working as a network.

The review sorts fleet applications into two groups. The first is observing ocean phenomena: marine mammals, typhoons, strong currents, mesoscale eddies, and temperature and salinity. The second is detecting underwater targets through acoustic sensing and ambient-noise profiling. It then walks through the technologies that hold a fleet together: coordination control, task allocation, path planning, and fleet communication, plus the shore-based systems used to pilot the gliders.

The observation examples are specific. Acoustic gliders have recorded whale calls and tracked marine mammals off Southern California for years. Fleets have followed typhoons between 10 and 100 kilometres across, including 14 typhoons in the Kuroshio region near Taiwan. In the South China Sea, a dozen gliders reconstructed the three-dimensional temperature and salinity structure of mesoscale eddies. Campaigns in the Kuroshio and the Mediterranean have done the same for currents and eddies.

For detection, fleets listen. They carry vector hydrophones that capture both sound pressure and direction, which lets them localize underwater sources and separate biological signals from the gliders' own noise. Coordination draws on leader-follower and virtual-structure schemes, game-theoretic task allocation, and path planning that increasingly uses reinforcement learning and improved A* search. Fleet communication, mostly acoustic, lets gliders share what they have sampled and stay in formation where satellite links do not reach.

The outlook is where the paper gets concrete. One proposal is a self-healing formation that keeps a mission running even when 30 percent of the gliders fail, by rewiring the remaining members' roles and topology. Another is energy-aware reconfiguration: the leader role rotates so no single glider drains first, and the fleet temporarily splits to route around high-resistance water before rejoining. The authors write that these ideas, together with satellites, surface vehicles, and seabed sensors, point toward marine cybernetic ecosystems that observe the ocean as one distributed system.

The review's other contributors are Bing He of Monash University, Ruize Pan, and Jutao Wang of Tianjin University of Technology; Xu Wan of Tianjin University and Laoshan Laboratory in Qingdao; and Jijia Sang of Harbin Engineering University.

The work was supported by the China Postdoctoral Science Foundation (2025M770292), the Opening Project of the Key Laboratory of Marine Smart Equipment (KF-92-25102), and the China Institute of Navigation's Young Elite Scientists Sponsorship Program (YESSCIN2026012), among other grants.

DOI Link:

https://doi.org/10.26599/OCEAN.2026.9470023

About Ocean:

Ocean (ISSN 3008-1203) is an international peer-reviewed journal that offers open access and serves as a multidisciplinary platform for the state-of-the-art research and practice in the domains of oceanscience, technology, and engineering. The journal is dedicated to publishing articles, reviews and perspectives in these areas, with the goal of promptly disseminating and promoting theoretical, numerical, site-based, and experimental advancements in the context of global sustainability.