CAJ | 학술논문

合成孔径雷达(Synthetic Aperture Radar, SAR)是一种相干成像雷达，相干性是保证SAR成像的关键。对相干系统而言，诸多因素会破坏其相干性。该文以环境一号C卫星SAR分系统方案和指标为基础，主要分析了频率源稳定度和脉间定时抖动对系统相干性的影响。环境一号C卫星SAR采用短期稳定度为101.010×-/5 ms的晶振，经过直接倍频与分频提供系统所需的基准频率信号，由短期稳定度引入的方位向随机相位误差对积分旁瓣的影响可忽略。环境一号C卫星SAR定时脉冲前沿抖动优于2 ns (rms)，合成孔径时间内的随机相位误差对方位脉冲压缩旁瓣略有影响。该文通过公式推导和仿真分析证明了HJ-1-C卫星SAR系统相干性设计满足合成孔径雷达成像要求。
합성공경뢰체(Synthetic Aperture Radar, SAR)시일충상간성상뢰체，상간성시보증SAR성상적관건。대상간계통이언，제다인소회파배기상간성。해문이배경일호C위성SAR분계통방안화지표위기출，주요분석료빈솔원은정도화맥간정시두동대계통상간성적영향。배경일호C위성SAR채용단기은정도위101.010×-/5 ms적정진，경과직접배빈여분빈제공계통소수적기준빈솔신호，유단기은정도인입적방위향수궤상위오차대적분방판적영향가홀략。배경일호C위성SAR정시맥충전연두동우우2 ns (rms)，합성공경시간내적수궤상위오차대방위맥충압축방판략유영향。해문통과공식추도화방진분석증명료HJ-1-C위성SAR계통상간성설계만족합성공경뢰체성상요구。
Synthetic Aperture Radar (SAR) is a coherent imaging radar. Hence, coherence is critical in SAR imaging. In a coherent system, several sources can degrade performance. Based on the HJ-1-C SAR system implementation and sensor characteristics, this study evaluates the effect of frequency stability and pulse-to-pulse timing jitter on the SAR coherent performance. A stable crystal oscillator with short-term stability of 101.0 10× - /5 ms is used to generate the reference frequency by using a direct multiplier and divider. Azimuth ISLR degradation owing to the crystal oscillator phase noise is negligible. The standard deviation of the pulse-to-pulse timing jitter of HJ-1-C SAR is lower than 2ns (rms) and the azimuth random phase error in the synthetic aperture time slightly degrades the side lobe of the azimuth impulse response. The mathematical expressions and simulation results are presented and suggest that the coherent performance of the HJ-1-C SAR system meets the requirements of synthetic aperture radar imaging.