基于多普勒域多通道的機載合成孔徑雷達自聚焦算法
doi: 10.11999/JEIT140675
基金項目:
國家863計劃項目(2013AA122201)，國家自然科學基金(41201468)和中國科學院科研裝備研制項目(Y140110213)資助課題
An Autofocus Algorithm Based on Doppler-domain Multichannel for Airborne SAR
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摘要: 在多通道自聚焦(MCA)和傅里葉域多通道自聚焦(FMCA)的基礎上，該文提出一種基于多普勒域多通道的機載合成孔徑雷達自聚焦算法。該算法同樣是直接在線性代數(shù)的理論框架下推導得到，能夠在不迭代的情況下進行相位誤差的估計和補償以實現(xiàn)SAR圖像的聚焦。該算法不像MCA和FMCA那樣在圖像域估計相位誤差，而是在距離壓縮方位多普勒域(方位未壓縮)里進行相位誤差估計。同時該算法不需要SAR成像場景中含有低散射區(qū)的假設，從而使其能夠應用于條帶模式SAR。不同情況下條帶SAR數(shù)據(jù)的處理結果驗證了該算法的有效性和可行性。
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關鍵詞:
- 機載合成孔徑雷達(SAR) /
- 多普勒域多通道自聚焦 /
- 相位誤差估計 /
- 奇異值分解(SVD)
Abstract: On the basis of the MultiChannel Autofocus (MCA) algorithm and the Fourier-domain MultiChannel Autofocus (FMCA) algorithm, an autofocus algorithm for airborne SAR based on Doppler-domain multichannel is proposed. The proposed autofocus algorithm is also directly derived under a linear algebraic framework, allowing the phase error to be estimated and removed in a noniterative fashion to achieve the well-focused SAR image. However, unlike MCA or FMCA applied to the image domain, the proposed autofocus algorithm is used to estimate the phase error in the range compressed azimuth Doppler domain (azimuth uncompressed). In addition, it does not require the assumption of a low-return region contained to the SAR image, which makes it applicable to the strip-map mode SAR. The processing results of strip-map SAR data in different cases demonstrate the validity and feasibility of the proposed autofocus algorithm. -
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