| 摘要: |
| 神舟四号(SZ-4)高度计在国内首次提供了星载雷达高度计回波波形数据。本文中作者分析了SZ-4高度计回波波形的特点,完成波形数据的预处理,并在此基础上完成初步的信息提取。在数据预处理方面,通过SZ-4高度计水陆边界处波形的特点,提出了波形最大幅度控制的方法,筛选回波波形。在波形归一化处理过程中,发现SZ-4高度计波形中存在双峰现象,并指出第二个峰为异常波形区。在波形信息提取方面,利用波形重新跟踪得到的半功率点计算出SZ-4高度计高度跟踪补偿误差,并根据高度计天线指向角和回波波形下降沿斜率之间的关系,从波形后沿提取天线指向角信息。分析结果表明,SZ-4高度计天线指向比较平稳,而跟踪补偿由于变化较大,在计算海面高度时,应作为一项误差源被考虑到。 |
| 关键词: 神舟四号高度计 回波波形 波形重跟踪 高度跟踪补偿 指向角 |
| DOI： |
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| 基金项目:国家高技术研究发展计划项目(遥感应用模块检测与验证技术研究),2005AA604150号 |
附件 |
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| THE PRETREATMENT AND INFORMATION RETRIEVAL OF WAVEFORM DATA OF CHINESE SPACECRAFT SHENZHOU-4 BORNE ALTIMETER |
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JI Yong-Gang1, ZHANG Jie1, ZHANG You-Guang2, MENG Jun-Min1
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1.First Institute of Oceanography, State Oceanic Administration, Qingdao, 266061;2.National Satellite Ocean Application Service, Beijing, 100081
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| Abstract: |
| The space borne altimeter flown on Chinese spacecraft Shenzhou-4 has provided waveform data for the first time in China. The data pre-process is necessary before the waveform data are used to retrieve parameters, such as wind speed and significant wave height. First, the waveforms near land-ocean borders were analyzed to eliminate abnormal waveforms. Second, the waveforms were averaged to remove thermal noise. Finally, normalized waveforms were obtained for further application. After re-tracking the waveforms, the range retracking correction and the altimeter antenna pointing angle were calculated. The results show that the most abnormal waveforms could be cleared by limiting the maximum amplitude. In normal waveforms, double peaks were found, of which the second one is abnormal. Meanwhile, the antenna pointing angle is relatively stable while the range retracking correction varies considerably so that it should be considered as an error source when extracting the sea surface height. |
| Key words: Shenzhou-4 spaceborne altimeter, Echo waveform, Waveform retracking, Range retracking correction, Antenna pointing angle |
