Research On Power Spectrum And Its Application In Broadband ADCP Signal Detection

Our sea area is three million square kilometers, which is rich in resources, and has great economic significance. In addition, the strategic position of the marine becomes increasingly more important. However, obtaining marine resources and grasping marine strategic position need to process and utilize the marine information, in which broadband ADCP (Acoustic Doppler Current Profiler) plays a very important role. After getting marine information with broadband ADCP, we need to process it. Power spectrum estimation is an important part in information processing fields, and therefore, the power spectrum estimation of broadband ADCP signal is also very important.This paper is mainly about power spectrum estimation of broadband ADCP signal, including center frequency estimation and bandwidth estimation. Firstly, filter, normalize and centralize the broadband ADCP signal. Secondly, detect the starting point and the end point of the broadband ADCP signal, and extract the signal segments. Thirdly, estimate the center frequency of the broadband ADCP signal. Finally, get the signal bandwidth of the broadband ADCP signal. The work mainly contains:1. Use filtering technology to filter the broadband ADCP signal. Through the comparison of IIR filter and FIR filter, IIR filter maybe make the filtered signal mutated, so it is better to choose FIR filter with a good linear phase characteristics to filter the broadband ADCP signal to reduce the negative influence of noise on the power spectrum estimation.2. Compare several commonly used endpoint detection methods, select the better method for computing with better returning result, short-term energy method, identify the segments of the signal and noise, and extract the signal segments.3. Compare and analyze several commonly used power spectrum estimation methods to select the power spectrum estimation method, the MUSIC method with high precision characteristies, based on the correlation matrix decomposition to estimate the center frequency, with good result. At the same time, analyze the signal with FFT method.4. Combine the center frequency of the broadband ADCP obtained with the MUSIC method and the Fourier spectrum of the signal, take the center frequency of MUSIC method as the center in the Fourier spectrum with the bilateral extending way to compute the bandwidth of the broadband ADCP signal.