Research On The Method Of Unknown Parameter Pulse Detection And Time-delay Estimation

The signal processing software is designed and realized in this dissertation, which is based on the buoy platform of the underwater positioning system under active operating mode. The software mainly deal with the beacon signal sent by cooperation sound source and unknown parameter seeking pulse sent by the target. The main work includes detecting signals, estimating time-delay and other important parameter of the signals, and sending the processed data to the control and display subsystem by wireless.To detect signal and estimate the parameter, the adaptive Notch filter is applied to extract the signal's envelope. An envelope and width detector is used to detect signal and estimate the time-delay of signal. To reduce the problem of pulse-interfere and frequency leak between near channels, the Variance of Instantaneous Frequency Detector (VIFD) is employed. In no antagonistic condition, to reduce the miss probability results from signal opposite-phase stacking in acoustic coherent multi-path channels, an algorithm of detecting signal is improved. The method of separating group and opening window is used to measure time-delay of the direct pulse.In the environment of antagonistic warfare, the relation between seeking signal sent by target and simulated signal sent by the enemy equipment is analyzed, which includes the direct pulse and superimposed situation of these signals. A novel method is proposed, which is based on the matching of time-delay and the Doppler of the signal, so as to distinguish the direct pulse of target's seeking signal from the simulated disturbance. This method is proved to be effective and feasible through theoretical analysis, computer simulation and experiment.The signal processing software is realized on the working platform of the positioning system, which is designed by C language and assembly language. To improve the effective of the software, the Notch filter and VIFD are realized by assembly language. The design and realization of every functional module about the software is discussed in the dissertation, and the management and allocations of DSP resource is also introduced. The algorithm is proved to be robust and effective by trial in SongHua Lake in JiLin province.