基于测地线拟合的改进STFT目标检测方法

Improved STFT Target Detection Method Based on Geodesic Fitting

短时傅里叶变换(STFT)可以实现对具有非平稳特征的海面目标的检测,但其时频分辨率通常较低,导致在低信噪比条件下的检测性能较差。利用功率谱流形上的距离和测地线对STFT后不同时间点的功率谱进行曲线拟合,该过程首先对于单一时间点的功率谱进行了重构,使其更加平滑和准确,其次拟合所得测地线对不同时间点的功率谱实现了时域上的平滑,时间分辨率也得到提高,进而整体提升了STFT的检测性能,最后通过仿真实验验证了所提方法的有效性。

The short-time Fourier transformation(STFT)can detect the sea-surface target with non-stationary characteristics,but its time-frequency resolution is usually low,which results in poor detection performance under low signal noise ratio(SNR)condition.This paper uses the distance and geodesic on the spectrum manifold to fit a curve of power spectrum at different time points obtained through STFT.This process firstly reproduces the power spectrum at single time point and makes it more smoothly and accurately,secondly realizes the smooth for the fitting geodesic to power spectrum at different time points in the time-domain,and the time resolution also is increased,and then the detection performance of STFT is wholly improved,finally the efficiency of the proposed method through simulation experiments is verified.