一種應(yīng)用于斜視聚束模式的改進(jìn)極坐標(biāo)格式成像算法
doi: 10.11999/JEIT140564
基金項(xiàng)目:
航空基金(20110181004)和中央高?;究蒲袠I(yè)務(wù)費(fèi)(K5051202016)資助課題
A Modified Polar Format Algorithm Applied to Squinted Spotlight SAR Imaging
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摘要: 極坐標(biāo)格式算法(Polar Format Algorithm, PFA)通常應(yīng)用于正側(cè)視聚束SAR成像,當(dāng)PFA應(yīng)用斜視聚束時(shí),傳統(tǒng)沿視線插值(Line Of Sight Interpolation, LOSI)PFA方法會(huì)導(dǎo)致方位頻譜非等間隔采樣。該文針對上述問題提出一種新的方位頻譜插值方法,根據(jù)斜視聚束的幾何模型可以得到方位頻譜精確的插值形式,從而實(shí)現(xiàn)對方位頻譜等間隔重采樣。在獲得了均勻的頻譜后進(jìn)行2維逆傅里葉變換,便可以得到大范圍的斜視聚束場景。為了驗(yàn)證該文算法的有效性,進(jìn)行了實(shí)驗(yàn)仿真及實(shí)測數(shù)據(jù)驗(yàn)證,該方法與傳統(tǒng)插值的方法進(jìn)行比較,能夠增大斜視聚束場景范圍。
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關(guān)鍵詞:
- 斜視聚束SAR /
- 極坐標(biāo)格式算法 /
- 沿視線插值 /
- 方位重采樣 /
- 非均勻采樣
Abstract: For broadside spotlight Synthetic Aperture Radar (SAR) imaging, Polar Format Algorithm (PFA) is applied widely as a kind of general interpolation algorithm. When PFA is applied to the squinted spotlight, coordinate rotation causes azimuth spectrum uniformly resampled. A new method of interpolation for azimuth spectrum is proposed in this paper and the accurate form of azimuth spectrum interpolation is given according to the geometry of squinted spotlight. Azimuth spectrum is resampled according to the accurate form of interpolation and uniform azimuth spectrum is obtained. Then, two-dimension IFFT is implemented and high resolution squinted spotlight image is obtained. In order to validate the effectiveness, simulation and real data are processed by the proposed method. Compared with traditional interpolation method, the scope of well-focused image is increased. -
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