Based on the vibration data of underwater structures and passive sonar equations, a method for evaluating the detected state and maximum detected distance of underwater structures is proposed, thereby solving the problem in which it is difficult to quickly estimate the sound source level and evaluate the detected state of underwater structures.

The operational transfer path analysis (OTPA) method is used to forecast the self-noise level of underwater targets in real time. Singular value decomposition （SVD）and principal component analysis (PCA) are used to eliminate errors such as the crosstalk of measurement data. Combined with the propagation characteristics and environments of underwater sound waves, the detected state and maximum detected distance of underwater structures in the current environment are evaluated by the detection model.

The validity of the detection model is demonstrated in a lake test which determines that it has an average error of less than 2 dB, and the estimated detected state and maximum detected distance are in good agreement with the measurement results in most frequency bands.

This study can provide a basis for assessing the acoustic stealth situation of underwater structures.