Over the past two years, the Baltic Sea has been the stage for a series of incidents that put the vulnerability of undersea infrastructure squarely in the spotlight: from damage to communication cables (C-Lion1, Estlink 2) to the now well-known cases of the vessels Yi Peng 3 and Eagle S. These episodes exposed a very concrete problem: how do you tell a “suspicious” vessel behavior from ordinary maritime traffic, in time to act, in one of the busiest sea areas in Europe?
That is the question addressed in our new paper, “Maritime Anomaly Detection in Baltic Sea AIS Trajectories via Ensemble Methods and Probabilistic Roadmaps,” published in IEEE Access by Gabriele Oliva, Andrea Tomei, and Roberto Setola.
The idea
At the core of the framework is the use of Probabilistic Roadmaps (PRMs), a technique originally developed for robotic motion planning, here adapted to model navigable routes in the Baltic Sea from AIS data and satellite imagery. The result is a graph representing “normal” navigation corridors, onto which real vessel trajectories are projected to extract geometric, kinematic, and context-aware features, such as proximity to submarine cables or deviations from efficient routes.
To compensate for the scarcity of labeled anomalies in real-world data, the team generated synthetic anomalous trajectories using four complementary techniques, building a balanced dataset of real trajectories and and synthetic ones.
The results
These features feed an ensemble classifier (Random Forest, LightGBM, XGBoost, and SVM combined via soft voting). Tree-based models exceed a ROC AUC of 0.81 on validation, with Random Forest reaching 73.2% accuracy and the ensemble achieving the highest precision (76%).
The most telling test, however, came from applying the model to real-world cases: the trajectories of Yi Peng 3 and Eagle S were flagged as anomalous with 100% consensus across all models, correctly picking up on the prolonged dwell times and speed changes near the cables involved in the incidents.
Watch the video
The video shows the framework in action, from building the roadmap over the Baltic Sea to the trajectory-analysis dashboard and the ensemble model’s results. Go to the Video
Commenti recenti