基于子孔徑Keystone變換的曲線軌跡大斜視SAR回波模擬
doi: 10.11999/JEIT190674
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陸軍工程大學(xué)石家莊校區(qū)無人機(jī)工程系 石家莊 050003
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陸軍工程大學(xué)石家莊校區(qū)電子與光學(xué)工程系 石家莊 050003
Sub-aperture Keystone Transform Based Echo Simulation Method for High-squint SAR with a Curve Trajectory
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Department of UAV Engineering, Army Engineering University Shijiazhuang Campus, Shijiazhuang 050003, China
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Department of Electronic and Optical Engineering, Army Engineering University Shijiazhuang Campus, Shijiazhuang 050003, China
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摘要: 大機(jī)動(dòng)條件下的曲線軌跡大斜視SAR系統(tǒng)傳遞函數(shù)具有復(fù)雜的多維空變性,現(xiàn)有的高效頻域回波模擬算法均難以實(shí)現(xiàn)擴(kuò)展場(chǎng)景的高精度回波模擬。為此,該文提出一種基于子孔徑Keystone變換的機(jī)動(dòng)SAR回波模擬方法。該方法根據(jù)距離徙動(dòng)校正后的距離壓縮函數(shù)對(duì)場(chǎng)景的距離壓縮回波進(jìn)行快速模擬,然后通過高精度的距離向逆處理實(shí)現(xiàn)擴(kuò)展場(chǎng)景的回波模擬。為減少殘余距離徙動(dòng)對(duì)回波模擬精度的影響,距離向處理過程中采用子孔徑Keystone變換的方法實(shí)現(xiàn)空變距離徙動(dòng)的精確校正。理論分析和仿真結(jié)果表明,所提方法能夠快速高精度地模擬擴(kuò)展場(chǎng)景的機(jī)動(dòng)平臺(tái)大斜視SAR原始回波數(shù)據(jù)。
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關(guān)鍵詞:
- SAR /
- 回波模擬 /
- 曲線軌跡 /
- 子孔徑Keystone變換
Abstract: The system transfer function of high-squint SAR system with curved trajectory has complex multi-dimensional spatial variability. The existing efficient frequency-domain echo simulation algorithms are difficult to achieve high-precision echo simulation of extended scenes. Therefore, a fast echo simulation method based on sub-aperture Keystone transform is proposed for maneuvering SAR. Based on the time-domain range compression function after range cell migration correction, the method calculates efficiently the range compression echo of scene, and then realizes the echo simulation of extended scene by high precision range inverse processing. In order to reduce the influence of residual range cell migration on the accuracy of echo simulation, the method of the Keystone transform of sub-aperture is used in range processing to achieve accurate correction of space-variant range cell migration in extended scenes. The theoretical analysis and simulation results show that the proposed method can quickly and accurately simulate the original echo data of extended scenes for high-squint SAR mounted on a maneuvering platform.-
Key words:
- SAR /
- Echo simulation /
- Curve trajectory /
- Sub-aperture Keystone transform
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表 1 仿真參數(shù)
SAR系統(tǒng)參數(shù) 數(shù)值 運(yùn)動(dòng)參數(shù) 數(shù)值 載頻 15 GHz 斜視角 60° 距離帶寬 300 MHz 平臺(tái)高度 4 km 距離過采樣因子 1.2 中心斜距 13 km 合成孔徑時(shí)間 3 s 速度 (150, 0, –35) m/s 脈沖寬度 5 μs 加速度 (2.2, 1.2, –0.8) m/s2 脈沖重復(fù)頻率 2 kHz 加加速度 (0.2, 0.1, –0.1) m/s3 天線波束寬度 14° 下載: 導(dǎo)出CSV
表 2 點(diǎn)目標(biāo)的方位向測(cè)量指標(biāo)量化分析結(jié)果
點(diǎn)目標(biāo) PARE MWRE PSLRE(dB) ISLRE(dB) 1 1.3e-03 1.0e-04 6.1e-03 –2.8e-03 2 5.2e-06 1.0e-06 7.1e-06 8.7e-06 3 1.2e-05 2.1e-06 1.4e-04 3.2e-05 4 1.5e-04 5.2e-06 6.5e-04 6.8e-05 下載: 導(dǎo)出CSV
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