Parametric Fault Detection Method For Systems With Multiplicative Noise And Its Application In Underwater Acoustic Communication Systems

With the development of science and technology, modern engineering projects are becoming more and more intelligent and complicated. So fault detection (FD) technology has become an indispensable part of the technical process. All faults can be classified as either additive faults or multiplicative faults. Additive faults appear, e.g., as offsets of sensors and actuators, whereas multiplicative faults are parameter changes within a process.Parametric fault is also known as process or multiplicative fault. Generally, there are two parametric fault detection methods. One is the parameter estimation method, and the other is the state estimation method. But those researches on parametric fault detection are restricted to the classical linear systems. While in actual systems, like the oil seismic exploration, underwater targets tracking, underwater acoustic communication system and so on, those system models are usually non-linear, and the signal is affected by delay, distortion, and attenuation in the transmission process which are usually described as systems with multiplicative noise instead of classical linear systems. This paper mainly studies the parametric fault detection method for systems with multiplicative noise. And its application in the detection of the turning point of the block changing underwater acoustic channel for sending a new training sequence. Below are the main works of this paper:1. Extend the concept of noise in system with multiplicative noise and make it applicable to more actual system, based on which an optimal state filtering algorithm is proposed. And the constant gain filter algorithm is also given in this paper.2. A new parametric fault model based on systems with multiplicative noise is proposed. Based on the constant gain filter, the relation between the parametric fault and the residual is discussed. Based on the change rule of the residual before and after the fault happens, a new FD(Fault Detection) method is proposed.3. Based on the theory of block fading channel, the system model with multiplicative noise is built based on the characteristics of underwater acoustic channel combining with the mechanism of multiplicative noise. Based on the Parametric Fault Detection Method, this paper studies how to find the accurate time point to send training sequence. And also, a complete set of symbol estimation algorithms for underwater acoustic communication system is given in this paper.