基于分數(shù)階Fourier變換和子空間正交性，提出了一種低信噪比下線性調(diào)頻信號檢測與參數(shù)估計方法。討論過程中將線性調(diào)頻信號通過適當?shù)姆謹?shù)階Fourier變換得到一個單頻復正弦信號，在此基礎上，利用信號子空間與噪聲子空間的正交性處理其正弦信號，再對線性調(diào)頻信號的檢測和參數(shù)估計轉化為函數(shù)極值求解；最后，利用計算機模擬證實了方法的有效性。
關 鍵 詞 分數(shù)階傅里葉變換; 線性調(diào)頻信號; 子空間正交性; 參數(shù)估計

Abstract Based on the fraction Fouier transform and subspace orthogonality,an approach,which detects and estimates the parameters of the low SNR LFM signal ,is proposed in this paper.The LFM signal is first transformed into a complex sinusoidal signal in term of the fraction Fourier transform,and then using the orthogonality between the subspace of noise and the subspace of the transformed signal,the detection and parameters estimation of LFM signal is achieved by finding the minimum/maximum. Computer simulation confirms its availability.
Key words fraction Fourier transform; LFM signal; subspace orthogonality; parameter estimation