| 高低轨双星时频模糊雷达信号的频差估计算法 |
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| 引用本文： | 姚山峰,贺青,夏畅雄,欧阳鑫信.高低轨双星时频模糊雷达信号的频差估计算法[J].宇航学报,2019,40(1):61-68. |
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| 作者姓名： | 姚山峰 贺青 夏畅雄 欧阳鑫信 |
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| 作者单位： | 盲信号处理重点实验室，成都 610041 |
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| 基金项目： | 国防科技重点实验室基金（9140C860104） |
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| 摘 要： | 针对高低轨双星定位系统中，雷达信号定位参数估计结果同时存在时差与频差模糊的问题，分析了相参脉冲串信号的模糊特性；利用粗略配对的脉冲串获得到达时间差序列，避免了对时域高度密集的脉冲进行配对的难题；在此基础上，提出了对时差序列进行中心差分计算频差粗估值实现频差模糊消除的方法；推导得出了频差粗值误差随着辐射源载频的增加、脉冲到达时间测量误差的增大、时差差分间隔的减小而增大的结论。仿真结果表明，频差粗值误差与理论值一致；通过设置合理的差分间隔，得到无模糊的频差粗值以后，频差精估精度逼近CRLB。新算法便于工程实现，对长基线定位系统中雷达信号的频差估计具有一定参考价值。
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| 关 键 词： | 相参脉冲串 频差模糊 时差差分 高低轨双星定位 |
| 收稿时间： | 2018-01-29 |
A Novel Method for DFO Estimation of Radar Signals with DTO/DFO Ambiguity in GEO LEO Dual Satellite Geolocation System |
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| YAO Shan feng,HE Qing,XIA Chang xiong,OUYANG Xin xin.A Novel Method for DFO Estimation of Radar Signals with DTO/DFO Ambiguity in GEO LEO Dual Satellite Geolocation System[J].Journal of Astronautics,2019,40(1):61-68. |
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| Authors: | YAO Shan feng HE Qing XIA Chang xiong OUYANG Xin xin |
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| Affiliation: | National Key Laboratory of Blind Signals Processing, Chengdu 610041, China |
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| Abstract: | In a GEO-LEO dual-satellite geolocation system, the estimations of the differential time offset (DTO) and differential frequency offset (DFO) are ambiguous at the same time. Aiming at this problem, the ambiguity of the coherent pulse trains signal is analyzed. And, the sequence of the differential time of arrival (TOA) is obtained by the roughly paired pulse trains to avoid the difficulty of the pulse match with high-density in the time domain. The coarse DFO whose ambiguity is eliminated is estimated by the central difference of DTO, and the performance of the coarse DFO estimation is derived. The result shows that the estimation error increases with the increasing of the carrier frequency of the emitter, the increasing of the error of the TOA and the decreasing of the time interval of the differential DTO. The numerical simulations have demonstrated that the coarse DFO estimation error is consistent with the theoretical value, and the estimation accuracy of the DFO approximates the Cramer-Rao lower bound (CRLB) when the coarse DFO estimation without ambiguity is obtained by setting the appropriate differential interval. The new approach is convenient for engineering implementation, and could provide good references for DFO estimation of the radar signal in a long base line location system. |
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| Keywords: | Coherent pulse trains DFO ambiguity central difference of DTO GEO-LEO dual-satellite geolocation |
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