基于FrFT和子空間正交的LFM信號(hào)參數(shù)估計(jì)

基于分?jǐn)?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(hào)檢測(cè)與參數(shù)估計(jì)方法。討論過程中將線性調(diào)頻信號(hào)通過適當(dāng)?shù)姆謹(jǐn)?shù)階Fourier變換得到一個(gè)單頻復(fù)正弦信號(hào)，在此基礎(chǔ)上，利用信號(hào)子空間與噪聲子空間的正交性處理其正弦信號(hào)，再對(duì)線性調(diào)頻信號(hào)的檢測(cè)和參數(shù)估計(jì)轉(zhuǎn)化為函數(shù)極值求解；最后，利用計(jì)算機(jī)模擬證實(shí)了方法的有效性。
關(guān) 鍵 詞 分?jǐn)?shù)階傅里葉變換; 線性調(diào)頻信號(hào); 子空間正交性; 參數(shù)估計(jì)

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