Navigation situation assessment method in high-density ship areas from the regulatory perspective of mixed maritime traffic scenarios

The future of maritime traffic will enter a transitional period characterised by a blend of manned ships and intelligent ships with varying degrees of autonomy. Existing research on maritime navigation situation assessment primarily focuses on traditional ships or a single-ship perspective, lacking a regulatory-oriented comprehensive assessment framework for high-density ship areas in mixed maritime traffic scenarios. These methods are difficult to meet the actual needs of shore-based supervision. Based on the RFRM (Risk Filtering, Ranking & Management) concept, this paper constructs a key risk indicator system affecting the overall navigation situation in high-density ship areas and designs mapping functions and calculation methods for multiple indicator values. The limitation of single weighting is overcome by integrating subjective and objective weights to form comprehensive weights. The Finite Interval Cloud Model (FICM) is adopted for quantitative rating of navigation situations in high-density areas, addressing the assumption deviation of traditional cloud models that rely on normal distribution. Case validation confirms the effectiveness of the proposed model. The research findings can provide decision support for regulators in supervising ships in mixed scenarios and address the research gaps in regulatory-oriented situation assessment under such scenarios.