Method of Chaos Judgment for Ship Radiated Characteristic Signal and Its Application

The ship radiated noise has the characteristics of chaos. The ship radiated noise of different target classes has different phase space trajectories. However, it is difficult to meet subsequent target recognition needs based on phase space trajectories alone. This paper first analyzes the characteristics of chaotic system, and briefly analyzes several traditional methods of chaos judgment. Subsequently, the paper proposed a small data volume orbit tracking method to determine whether the ship's radiated noise has chaos characteristics, and the maximum Lyapunov exponent of the observed signal is calculated. The algorithm first calculates the time delay and embedding dimension to reconstruct the whole phase space, and then calculates the maximum Lyapunov exponent according to the average period of time series and the least square method. This algorithm is very suitable for solving the maximum Lyapunov exponent when the system equation is unknown and the number of time series observed is small. This provides a new theory and method for the subsequent detection and target recognition of ships and underwater targets.