| 摘要: |
| 将太赫兹波用于SAR成像可以解决常规SAR成像帧速低、慢动目标检测困难等问题。太赫兹合成孔径雷达(THz-SAR)与传统微波SAR成像最重要的区别在于运动补偿。因为THz-SAR的工作波长比传统微波SAR要短得多，平台的微小振动会影响成像质量，尤其是高频振动误差。平台的高频振动会在成像结果中引入成对回波，传统SAR成像算法无法实现成对回波的聚焦，也就无法准确估计振动参数，进而构造参考函数补偿高频振动带来的正弦调制相位。首先基于多普勒Keystone变换(DKT)的THz-SAR成像算法实现成对回波的聚焦成像；然后提出小波多分辨分析的方法估计高频振动频率，结合参数空间投影法完成振动幅相的估计，并实现高频振动误差的补偿；最后采用点目标的回波数据仿真验证了所提方法的有效性。 |
| 关键词: 太赫兹 合成孔径雷达 高频振动误差 小波多分辨分析 振动估计 |
| DOI：10.3969/j.issn.1672-2337.2018.05.004 |
| 分类号:TN958 |
| 基金项目:上海市自然科学基金(No.15ZR1439500，16ZR1434900，17ZR1428700)； 国家自然科学基金青年科学基金(No.41601508) |
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| An Improved High Frequency Vibration Compensation Approach for Terahertz SAR |
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XIA Huiting， LI Yinwei， FU Chaowei， WANG Haitao
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1.Shanghai Radio Equipment Research Institute， Shanghai 200090， China;2.Shanghai Engineering Research Center of Target Identification and Environment Perception， Shanghai 200090， China
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| Abstract: |
| The use of terahertz wave in SAR imaging can solve the difficulties of frame rate and detection of slow moving targets in conventional SAR imaging.The most important difference between terahertz SAR (THz-SAR) and conventional SAR is the treatment on motion compensation.For the reason that the wavelength of terahertz SAR is much shorter than that of conventional microwave SAR，the tiny vibration of SAR platform will blur SAR images，especially high frequency components.The high frequency vibration will result in paired echoes in SAR imaging，which cant be focused with traditional SAR imaging algorithms.Thus the vibration parameters cant be estimated precisely enough to construct the reference function to compensate the sinusoidal modulation phase.So we first get focused paired echoes in terahertz SAR imaging through Doppler Keystone transform (DKT)，then propose a frequency estimation method based on wavelet multi-resolution analysis，along with parametric space projection method，to complete the high frequency vibration estimation of terahertz SAR.At last，the numerical tests using the point target echoes validate the proposed method. |
| Key words: terahertz synthetic aperture radar（SAR） high frequency vibration error wavelet multi-resolution analysis vibration estimation |
