一種基于方位譜重采樣的大斜視子孔徑SAR成像改進(jìn)Omega-K算法
doi: 10.11999/JEIT141383
基金項(xiàng)目:
國(guó)家自然科學(xué)青年基金(61101245)和中央高校基本科研業(yè)務(wù)費(fèi)專項(xiàng)資金(K5051302046)
Modified Omega-K Algorithm for Sub-aperture High Squint SAR Imaging Based on Azimuth Resampling
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摘要: 斜視SAR數(shù)據(jù)兩維波數(shù)域支撐區(qū)具有斜拉特性,并且斜視角越大,斜拉越明顯;在大斜視成像時(shí),常規(guī)Omega-K成像直接選取矩形支撐區(qū)進(jìn)行處理,支撐區(qū)利用率低,難以滿足成像分辨率要求。針對(duì)子孔徑大斜視SAR數(shù)據(jù)成像,該文提出一種基于方位譜重采樣的改進(jìn)Omega-K算法。該算法通過(guò)坐標(biāo)軸旋轉(zhuǎn),實(shí)現(xiàn)波數(shù)譜支撐區(qū)利用率的最大化,針對(duì)伴隨的方位空變問(wèn)題,采用方位譜重采樣方法校正空變性,實(shí)現(xiàn)方位統(tǒng)一聚焦。另外,由于對(duì)于子孔徑數(shù)據(jù)處理,考慮位置支撐區(qū)受限,不同于傳統(tǒng)Omega-K方法,改進(jìn)Omega-K算法在方位波數(shù)域成像,避免了位置域成像需要的大量補(bǔ)零操作,提高了處理效率。點(diǎn)目標(biāo)數(shù)據(jù)仿真和實(shí)測(cè)數(shù)據(jù)處理驗(yàn)證了該文算法的有效性與實(shí)用性。
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關(guān)鍵詞:
- SAR成像 /
- 大斜視 /
- 子孔徑 /
- 方位譜重采樣 /
- 改進(jìn)Omega-K算法
Abstract: Due to the skew Region Of Support (ROS) of the two-dimensional wavenumber domain for high squint SAR data, conventional Omega-K algorithm can not exploit the ROS efficiently enough and degrades the resolution when choosing the square region to process. So a modified Omega-K algorithm is proposed in this paper to deal with the high squint SAR data for sub-aperture imaging. The maximum usage of ROS is obtained by the coordinate axis rotation. For the following azimuth dependence, the method of azimuth resampling is adopted to realize the uniform focusing. Compared with the traditional Omega-K method, the modified Omega-K algorithm is focused in azimuth wavenumber-domain because of the limitation of the azimuth sub-aperture ROS in order to avoid zero padding operation, and increase efficiency. Simulation results and raw data processing validate the effectiveness of the proposed algorithm.-
Key words:
- SAR imaging /
- High squint /
- Sub-aperture /
- Azimuth resampling /
- Modified Omega-K algorithm
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