分布式孔径相参合成原理、发展与技术实现综述

刘兴华; 王国玉; 徐振海; 汪连栋

doi:10.12000/JR23195

分布式孔径相参合成原理、发展与技术实现综述

doi: 10.12000/JR23195

刘兴华^{1, 2, ,},
王国玉^{1, 3, 4},
徐振海³,
汪连栋¹

1.
电子信息系统复杂电磁环境效应国家重点实验室洛阳 471003
2.
军事科学院军事科学信息研究中心北京 100142
3.
国防科技大学电子信息系统复杂电磁环境效应国家重点实验室长沙 410073
4.
北京航空航天大学北京 100191

基金项目: 中国博士后科学基金(2023M734290)

详细信息

作者简介:
刘兴华，博士，在站博士后，研究方向为分布式雷达协同探测、阵列信号处理等

王国玉，博士，教授，研究方向为空天电磁对抗仿真与试验评估、空间目标电磁感知、太空与电磁安全等

徐振海，博士，研究员，研究方向为阵列雷达设计与处理技术

汪连栋，博士，研究员，研究方向为电磁场与微波技术、电子信息装备试验与评估等

通讯作者:
刘兴华 xinghua217@163.com

责任主编：鲁耀兵 Corresponding Editor: LU Yaobing
1¹⁾最早由声学领域的研究者提出，2004年被引入电磁学领域^[11]。
2²⁾分布式孔径部署范围远大于传统相控阵阵面，相对近距离探测场景下，孔径间观测视角上的差异或带来极化不匹配、大气效应差异，甚至收发式孔径还可能引入目标散射差异等。这些因素带来的相参性退化比较复杂，且高度依赖于探测的环境和孔径分布范围。后续的讨论暂假定分布式孔径相对探测场景是集中式布置的(co-located)，近似忽略视角差异带来一系列的相参性退化。
3³⁾理想情况下，各孔径发射的信号相同，均为 \begin{document}${s(t) {\mathrm{e}}^{{\mathrm{j}}2\pi f_{{\mathrm{c}}} t}} $\end{document} 。然而，由于孔径间非理想同步的原因，导致实际发射的信号存在差异，变为 \begin{document}${ s_{1}^{{\mathrm{t}}}({{t)}}} $\end{document} 和 \begin{document}${ s_{2}^{{\mathrm{t}}}({{t}}) }$\end{document} ，但信号仍具有相参性，经恰当的时移和相移，就能对准时间和相位并趋于一致。⁴⁾若时频同步偏差是时变的，需各孔径有高稳的振荡源并定时进行闭环式校正，即视变化的同步偏差是随时间阶梯变化的。
4⁵⁾比如利用固定位置发射的信号作为外部标校源，对孔径位置偏差、初相偏差等进行标定。⁶⁾由于成本的考虑，美国国土防御传感器取消了该X波段雷达选项，改为建造S波段的远程识别雷达(Long Range Discrimination Radar, LRDR)，但在论证中“堆叠式”TPY-2一直作为LRDR的替代方案存在。⁷⁾Have Stare为X波段碟型雷达，曾部署于范登堡空军基地，后转移到挪威的瓦尔多，更名为GLOBUS II。
5⁸⁾用于解释和补偿差分多普勒预测误差、天线间的初相差异，以及未确定的剩余相位偏差。
6⁹⁾同步以太网较传统以太网的区别在于，其网络中的每个节点时钟都经过内部的锁相环电路锁定到主节点，来消除相位抖动。
7¹⁰⁾对坐标轴 \begin{document}${ \varepsilon_{\tau_{n}}-\varepsilon_{\psi_{n}} }$\end{document} 进行尺度变换，记 \begin{document}$ { x={\mathrm{c}} / B x_{\varepsilon_{ \tau_n}}, y=\lambda / 360^{\circ} y_{\varepsilon_{ \psi _{n}}}}$\end{document} ， \begin{document}$ { (x_{\varepsilon_{ \tau _{n}}}, y_{\varepsilon_{ \psi _{n}}})} $\end{document} ，(x, y)分别为尺度变换前后的坐标值。由于坐标轴尺度变换相当于对图片进行拉伸或缩放，并不改变过原点的斜率 \begin{document}${k=\alpha \cdot y_{\varepsilon_{\tau n}}/x_{\varepsilon_{\psi_{n}}} \cdot B/f_{\mathrm{c}}}$\end{document} ，其中 \begin{document}${k}$\end{document} 和 \begin{document}${\alpha}$\end{document} 为常数。那么，从A点拉伸或缩放到B点的过程中，为保持 \begin{document}$ { k }$\end{document} 恒定， \begin{document}${ y_{\varepsilon_{ \tau _{n}}}/x_{\varepsilon_{ \psi _{n}}}}$\end{document} 减小的过程，就是相对带宽 \begin{document}$ { B / f_{{\mathrm{c}}} }$\end{document} 增加的过程。¹¹⁾光学时频传输得益于光原子钟的更高的跃迁钟频率，使得时频计量较微波原子钟高了3到4个数量级，频率不确定度达10^–18～10^–19 s^–1。
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出版历程
- 收稿日期: 2023-10-07
- 修回日期: 2023-11-19
- 网络出版日期: 2023-12-12
- 刊出日期: 2023-12-28

Review of Principles, Development and Technical Implementation of Coherently Combining Distributed Apertures

LIU Xinghua^{1, 2
, ,},
WANG Guoyu^{1, 3, 4},
XU Zhenhai³,
WANG Liandong¹

1.
State Key Laboratory of Complex Electromagnetic Environment Effects on Electronics & Information System, Luoyang 471003, China
2.
Center for Information Research, Academy of Military Sciences, Beijing 100142, China
3.
State Key Laboratory of Complex Electromagnetic Environment Effects on Electronics & Information System, National University of Defense Technology, Changsha 410073, China
4.
Beihang University, Beijing 100191, China

Funds: The Postdoctoral Science Foundation of China (2023M734290)

More Information

Corresponding author: LIU Xinghua, xinghua217@163.com

摘要

摘要: 分布式孔径相参合成通过对多个分散布置小孔径的收/发信号进行相参调整，使协同的分布式系统可以用相对低的成本获得比拟于大孔径的功率孔径积，是替代大孔径的可行技术选择。该文首先阐述了分布式孔径相参合成的概念和实现原理，根据是否需要合成目的地处的外部信号输入，将相参合成的实现架构分为闭环式和开环式两类；然后，较为全面地综述了分布式孔径相参合成在导弹防御、深空遥测遥控、超远距离雷达探测、射电天文多领域发展应用情况；进一步阐述相参合成必要且用于对准各孔径收发信号时间和相位的关键技术，包括高精度分布式时频传递和同步技术，以及相参合成参数估计、测量标定和预测技术；最后对分布式孔径相参合成研究进行了总结和展望。
- 分布式孔径相参合成 /
- 分布式阵列 /
- 时频传递 /
- 相参性退化校正
Abstract: Coherently combining distributed apertures adjusts the transmitted/received signals of multiple distributed small apertures, allowing coordinated distributed systems to obtain high power aperture products at much lower cost than large aperture. This is a promising and viable technology as an alternative to using large apertures. This study describes the concept and principles of coherently combining distributed apertures. Depending on whether external signal inputs at the combination destination are necessary, the implementation architecture of coherent combination is classified into two categories: closed- and open-loop. The development of coherently combining distributed apertures and their application in fields such as missile defense, deep space telemetry control, radar detection over ultralong range, and radio astronomy are then comprehensively presented. Furthermore, key techniques for aligning the time and phase of the transmitted/received signals for each aperture are elaborated, which are also necessary for coherently combining distributed apertures, including high-precision distributed time-frequency transfer and synchronization, and coherently combining parameters estimation, measurement and calibration, and prediction. Finally, summary is presented, and the scope of future works in this field is explored.
- Coherently combining distributed apertures /
- Distributed array /
- Time-frequency transfer /
- Coherence degradation correction

HTML全文

图 1 将大孔径分解为更小、更便宜的小孔径构成的分布式系统

Figure 1. Decompose large-aperture into distributed systems consisting of smaller and cheaper mini-apertures

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图 2 分布式孔径相参合成示意

Figure 2. Schematic diagram of coherently combining distributed apertures

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图 3 相参合成实现架构

Figure 3. Implementation architecture of coherent combination

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图 4 分布的多雷达孔径相参合成概念^[5]

Figure 4. Conceptual architecture for coherently combining multiple radar apertures^[5]

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图 5 第谷中心峰分别位于干涉条纹峰值和偏离干涉条纹峰值150°的距离-多普勒图像对比^[38]

Figure 5. Doppler-delay images comparison where Tycho central peak appears to be located just at the peak of the array fringe-pattern and with 150° offset^[38]

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图 6 5个1.2 m天线的上行链路合成阵列及偏差标定校准方案^[39]

Figure 6. Five 1.2 m Ku-band antennas coherent uplink array and bias calibration scheme^[39]

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图 7 “深空先进雷达能力”计划概念示意

Figure 7. Conceptual architecture of Deep Space Advanced Radar Capability (DARC) project

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图 8 甚大天线阵中多个小孔径接收相参合成，并在时间和频谱维进一步积累合成^[47]

Figure 8. Small aperture in the Very Large Array (VLA) coherently combining on receive, and future accumulating in time and spectral dimension^[47]

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图 9 Two-way交换时间戳的方式实现时间同步

Figure 9. Time synchronization by two-way timestamps exchange

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图 10 不同同步偏差条件下， $ {G_{{\text{loss}}}} $ 不低于0.5 dB的概率

Figure 10. Probability that $ {G_{{\text{loss}}}} $ no less than 0.5 dB as a function of synchronization error

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图 11 同时考虑时间和相位同步偏差时， $ {G_{{\text{loss}}}} $ 不低于0.5 dB的概率

Figure 11. Probability that $ {G_{{\text{loss}}}} $ no less than 0.5 dB, when jointly considering time and phase synchronization error

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图 12 基于非合作目标反射回波估计相参合成参数原理

Figure 12. Principle of coherent combination parameters based on reflection echoes from non-cooperative target

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图 13 基于位置固定已知多普勒域可分的多参考点对孔径位置偏差标定

Figure 13. Aperture position bias calibration based on multiple reference points with known fixed position and resolved in the Doppler domain

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图 14 合成目的地动态位置导致孔径间传播路径差改变

Figure 14. Dynamic positions of coherent combination destination lead to changes in propagation path difference between apertures

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图 15 合成目的地运动带来的时变相位差 $\Delta \varPhi $ 及外推预测补偿^[31]

Figure 15. Time-varying phase differences $\Delta \varPhi $ due to combination destination motion, and extrapolation prediction for compensation^[31]

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表 1 闭环式和开环式架构对比

Table 1. Closed-loop vs. open-loop architectures

实现架构	外部馈源输入	孔径精确位置	时频同步	相参性退化因素	波束形成位置
闭环式	必需，且一定源于合成目的地	非必需	非必需(信号“反转”合成类方法必需)	统一考虑	只能指向馈源方向
开环式	可能需要，输入不做限定且一般不源于合成目的地⁴	必需	必需	拆分考虑	可自由切换

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表 2 X波段典型雷达比较^[22]

Table 2. Comparison of typical radars in X-band^[22]

雷达	T/R组件数	T/R组件平均发射功率	天线孔径(m²)	相对功率孔径积	相对探测距离	电扫范围(°)
TPY-2	25344	3.2 W	9.2	0.0012	0.19	±60
“堆叠式”TPY-2	50688	3.2 W	18.4	0.0098	0.31	±60
SBX	45264	2.0 W	249.0	1.0000	1.00	±12
GBR-P	16896	1.2 W	105.0	0.0400	0.45	±11
Have Stare⁴	--	70.0 kW (总)	573.0	4.1000	1.40	--

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表 3 典型时频传递方案的指标^[53,67-70]

Table 3. Indicators of typical time-frequency transfer methods^[53,67-70]

时频传递方案	时间准确度	频率稳定度	特点
长波^[67]	～1 μs	1×10^–12@1 d	覆盖范围广，传递距离可达3000 km
TWSTFT^[67]	～ns	1×10^–14@1 d	需要租用卫星使用时间及接收设备
White Rabbit^[68]	<ns	2×10^–15@1 d	需要千兆同步以太网
光载射频^[69]	～ps	1.6×10^–18@1 d	长距离传输需要中继
自由空间光学频率梳传递^[70]	100 fs	4×10⁻¹⁹@10000 s	需要瓦级功率的高稳定光学频率梳，以及纳瓦级高灵敏度的线性光学采样
无线稀疏双音^[53]	～ps	～10^–15@1 d	高精度测量基线长度并结合PLL电路实现小范围节点间的时频传递

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