Development of High-Resolution Signal Analysis for Radar Echoes by Using the Wavelet Transform

为了分析雷达目标的散射响应，提出了一种基于小波变换的雷达回波时频分析方法。这种方法的优点是它可以提供信号的自适应谱图。与短时傅里叶变换和传统的小波变换不同，时间和频率分辨率会进行调整以最佳匹配信号。因此，自适应谱图，一种新的信号能量分布在联合时频域，可以得到。当然，这种新的信号能量分布是非负的、无交叉项干扰的并且具有高分辨率。为了证明该方法的有效性，数值模拟。结果表明：1.与短时傅立叶变换和传统的小波分析等时频分析方法相比，该方法能够提供自适应的谱图，是一种有效的时频分析方法.通过适当选择基函数的参数，可以控制时间和频率分辨率.通过选择适当的信号分解层次，可以降低雷达信号中噪声的影响.对于频散信号的分析，时频平面上表示频散的曲线不能清晰显示。这个问题目前正在调查中。

In order to analyze scattering responses from radar targets, a new method for time-frequency analysis of radar echoes using the wavelet transform is proposed. The advantage of this method is that it can provide an adaptive spectrogram of signals. Unlike the short-time Fourier transform and the conventional wavelet transform, the time and frequency resolution and are adjusted to best match the signal. Therefore, an adaptive spectrogram, a new signal energy distribution in the joint time-frequency domain, can be obtained. Of course, this new signal energy distribution is non-negative, cross-term interference free, and of high resolution. In order to demonstrate the effectiveness of this method, numerical simulations are presented. As a results, following results are obtained :1. The present method is effective compare with other time-frequency techniques such as the short-time Fourier transform and conventional wavelet analysis, because it can provides an adaptive spectrogram.2. Time and frequency resolution can be controlled by the appropriate selection of the parameters of basis functions.3. The effects of noise included in radar signals can be decreased by the appropriate selection of the signal decomposition level.4. The curved lines indicating the frequency dispersion cannot be displayed clearly in the time-frequency plane for the analysis of frequency dispersive signals. This problem is currently under investigation.