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摘要: 相较于地基外辐射源雷达,基于卫星信号的外辐射源雷达(即卫星信号外辐射源雷达)具有全球、全时、全天候覆盖等优势,可弥补地基外辐射源雷达在海上覆盖范围不足的限制;相较于中高轨卫星信号,低轨通信卫星信号具有接收功率强、卫星数目多等优势,可为海上目标无源探测提供可观的探测距离与探测精度。面向未来发展需求,该文详细论述了卫星信号外辐射源雷达研究现状与应用前景,给出了以铱星、星链两类低轨通信卫星系统构建高低频宽窄带融合的低轨通信卫星信号外辐射源雷达系统的可行性分析,据此总结了研发低轨通信卫星信号外辐射源雷达系统面临的技术挑战与候选解决思路。上述研究可为广域范围内,外辐射源雷达探测提供重要参考。Abstract: Compared to ground-based external radiation source radar, satellite signal-based external radiation source radar (i.e., satellite signal external radiation source radar) offers advantages such as global, all-time, and all-weather coverage, which can compensate for the limitations of ground-based external radiation source radar in terms of maritime coverage. In contrast to medium and high-altitude satellite signals, Low-Earth Orbit (LEO) communication satellite signals have advantages such as strong reception power and a large number of satellites, which can provide substantial detection range and accuracy for passive detection of maritime targets. In response to future development needs, this paper provides a detailed discussion of the research status and application prospects of satellite signal external radiation source radar, and presents a feasibility analysis for constructing a low-earth orbit communication satellite signal external radiation source radar system using Iridium and Starlink, two types of LEO communication satellite systems, which integrates high and low frequencies with both wide and narrow bandwidths. Based on this, the paper summarizes the technical challenges and potential solutions in the development of low-earth orbit communication satellite signal external radiation source radar systems. The aforementioned research can serve as an important reference for wide-area external radiation source radar detection.
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表 1 基于GNSS信号的外辐射源雷达研究现状
Table 1. Research status of passive radar using GNSS signals
参考文献 年份 第一作者研究机构 外辐射源 研究内容 备注 [29] 1995 德国 GPS, GLONASS 验证卫星信号与目标回波信号相关性 实验 [30] 1999 昆士兰科技大学 GPS, GLONASS 提取目标三维轨迹实现目标探测 实验 [31] 2002 昆士兰科技大学 GPS 空中目标探测距离理论计算 理论 [32] 2011 保加利亚IICT GPS 功率预算和最大目标探测距离分析 理论 [33,34] 2018 伯明翰大学 Galileo 提出长短时相干-非相关积累融合的长时积累算法 实验 [35] 2019 圣彼得堡国立电子工程技术大学 GPS, GLONASS 几何模型估计及空中目标探测范围计算 理论 [36,37] 2023 罗马大学 Galileo 改进的同时目标探测与定位算法 实验 [38] 2001 解放军电子工程学院 GPS 利用4颗卫星经过目标散射后的时间差估计目标信息 理论 [39,40] 2004 西安电子科技大学 GPS 通过对回波信号进行多普勒补偿提升微弱目标探测能力 理论 [41] 2005 北京理工大学 GNSS 热噪声及同频干扰下目标检测性能分析 理论 [42] 2009 北京航空航天大学 GPS 提出利用导航卫星信号实现空间飞行器的远程定位方法 实验 [43] 2010 国防科技大学 GPS, 北斗 探测距离、模糊函数等对比分析 理论 [44] 2014 南京电子技术研究所 GPS 可探测时间、直达波抑制、辐射源数多角度探测性能分析 理论 [45] 2015 中国空间技术研究院 GPS 多发单收的双基地雷达新体制 理论 [46] 2017 西安电子科技大学 GPS 多星数据融合的微弱回波信号检测算法 理论 [47] 2019 西安电子科技大学 GPS 基于北斗二代卫星信号外辐射源雷达系统的信号处理方法 理论 [48] 2020 香港理工大学 GPS 研究了利用目标运动特点聚集目标回波能量的目标探测方法 实验 [49−51] 2022 电子科技大学 北斗 世界上第一个基于北斗的无源雷达舰艇目标检测海上实验 实验 [52] 2022 北京航空航天大学 GPS 改进的多帧长时积累算法与空中动目标探测 实验 [53] 2023 香港理工大学 GPS 融合图像处理与多普勒历史的长时间移动目标检测处理技术 理论 [54] 2023 国防科技大学 GPS 搭建软件无线电接收平台并对接收的参考信号进行重构 实验 [55] 2024 北京航空航天大学 GPS 两阶段由粗到细的多普勒频移补偿提升长时间积累能力 实验 [56] 2024 北京航空航天大学 GNSS 提出针对GNSS的基于高度角随机模型的定位算法 实验 [57] 2024 北京卫星信息工程研究所 GNSS、北斗 提出多颗北斗卫星协同的相干合成孔径成像方法 实验 表 2 基于DVB-S信号的外辐射源雷达研究现状
Table 2. Research status of passive radar using DVB-S signals
参考文献 年份 第一作者研究机构 外辐射源 研究内容 备注 [58] 1992 伦敦大学 DVB-S 研究了基于马可波罗1号卫星信号的外辐射源雷达回波信号信噪比 实验 [59] 2011 里斯本高等教育学院 DVB-S 测试了DVB-S作为辐射源的探测性能与自适应滤波算法去噪性能 实验 [60−62] 2019 弗劳恩霍夫高频物理和雷达技术研究所 DVB-S 探索了DVB-S作为辐射源时极化分集对ISAR目标探测能力的提升 实验 [63−65] 2020 罗马大学 DVB-S 搭建了基于DVB-S信号的外辐射源雷达试验系统,研究了非相干积累、
相干长时积累与极化分集的探测性能实验 [66] 2022 意大利
RaSS国家实验室DVB-S/S2 探索了基于DVB-S/S2信号的外辐射源雷达探测低轨道空间驻留目标的可行性 理论 [67] 2024 华沙理工大学 DVB-S2 探索了DVB-S作为辐射源时极化分集对探测概率的提升 实验 [68] 2012 中国科学院 DVB-S 基于DVB-S信号的外辐射源雷达几何结构、信号模糊函数及分辨特性 理论 [69,70] 2013 中国科学技术大学 DVB-S 利用APStar-5卫星信号进行外场实验,初步实现了目标回波信号检测 实验 [71] 2014 中国科学技术大学 DVB-S 探究了最大探测距离和距离分辨率性能 实验 [72] 2016 西安电子科技大学 DVB-S 基于多个异构卫星信息融合的微弱回波信号检测 理论 [73,74] 2019 浙江大学 DVB-S 基于加权融合的多信道联合检测方法 理论 [75] 2021 电子科技大学 DVB-S 基于Radon-Fourier变换的多频道积累检测算法 理论 [76] 2023 武汉大学 DVB-S 搭建DVB-S信号接收系统成功接收信号并探测到2km外的目标 实验 表 3 基于铱星、星链信号的外辐射源雷达研究现状
Table 3. Research status of passive radar using Iridium and Starlink signals
参考文献 年份 第一作者研究机构 外辐射源 研究内容 备注 [79] 2002 伯明翰大学 铱星 利用模拟的铱星信号开展空中目标探测实验 理论 [80,81] 2016 伯明翰大学 铱星 模糊函数特性分析 理论 [82] 2019 伯明翰大学 星链 基于雷达方程的探测威力分析 理论 [27,83] 2022 华沙理工大学 星链 基于雷达方程的探测威力分析与软件无线电接收机设计方案 理论 [84−86] 2022 弗劳恩霍夫高频物理和雷达技术研究所 星链
一网基于雷达方程的探测威力与模糊函数特性分析、
软件无线电接收机设计方案理论 [87] 2023 国防科技大学 星链 基于雷达方程的探测威力、可观测时间与距离-多普勒徙动分析 理论 [88,89] 2024 电子科技大学 OFDM 基于低轨星座OFDM信号的外辐射源雷达信号处理算法仿真验证 理论 [90] 2024 华沙理工大学 星链 无源SAR成像试验验证 试验 [91] 2024 武汉大学 星链 验证了在低轨卫星照射源前向散射区进行目标探测的有效性 试验 [92] 2024 重庆大学 铱星 基于雷达方程的探测威力与模糊函数特性分析、改进的杂波抑制算法 理论 表 4 国内外典型低轨星座的轨道参数概述
Table 4. System parameters of typical LEO constellations
时间 星座名称 运营单位 轨道高度
(km)星座构型 卫星数量
(计划)星间链路 应用场景 2015 星链 美国太空探索技术公司 328~614 独特轨道 40000 +有 宽带互联网
物联网2016 铱星 美国铱星公司 780 近极轨道 66 有 物联网 2016 轨道通信 美国卫星通信公司 800~ 1000 倾斜轨道 100+ 有 宽带互联网
物联网2016 哨兵 欧洲航天局 693 倾斜轨道 12 有 国防 2016 一网 一网卫星公司 1200 近极轨道 1980 无 高速电信网络 2018 行云工程 中国航天科技集团 800 1400 倾斜轨道 80 有 窄带物联网 2018 虹云工程 中国航天科工集团 1040 倾斜轨道 156 有 天基WiFi 2018 鸿雁星座 1100 近极轨道 360 有 宽带互联网
物联网2019 柯伊伯 美国亚马逊 610/630 倾斜轨道 3236 有 宽带互联网
物联网表 5 国内外典型卫星星座的信号参数概述
Table 5. System parameters for typical satellite signals
低轨星座
(建设时间)轨道高度
(km)工作频段
(用户下行链路)信号带宽 通信体制 调制方式 单波束覆
盖范围是否
全球覆盖EIRP
(dBW)铱星
(2019年)780 L: 1616 ~1626.5 MHz31.50 kHz TDMA,FDMA BPSK,QPSK 480~
670 km是 28~45 星链
(2016年)550 X: 10.7~12.7 GHz 250 MHz MF-TDMA、OFDMA 16-256APSK 20~50 km 是 27.6~32.3 GPS
(1993年)20200 L: 1575.42 MHz、1227.60 MHzL1: 2.046MHz
L5: 10.23MHzCDMA BPSK 38%地表 是 28 北斗
(2020年)21500
(MEO)L: 1561.098 MHzB1I: 4.092MHz、
B3I: 20.46 MHzCDMA BPSK 38%地表 是 40 DVB-S
(1994年)36000 X: 10.7~12.7 GHz 7 MHz, 36 MHz
54 MHz, 72 MHzMF-TDMA QPSK 40%地表 否,仅陆地或近海 51~54 DVB-S2
(2005年)36000 X: 10.7~12.7 GHz 54 MHz MF-TDMA 4/8PSK, 16/32APSK 40%地表 否,仅陆地或近海 52 DVB-S2X
(2014年)36000 X: 10.7~12.7 GHz 250~
500 MHzMF-TDMA 2-8 PSK,
16-256APSK40%地表 否,仅陆地或近海 52 INMARSAT4
(2012年)36000 L: 1525 ~1559 MHz200 kHz MF-TDMA QPSK, 16QAM 40%地表 否,+/–75o 67 INMARSAT5
(2013年)Ka: 19.7~20.2 GHz 40 MHz MF-TDMA 4/8PSK, 16/32APSK 40%地表 否,+/–75o 51~54 表 6 铱星轨道参数
Table 6. Iridium orbit parameters
轨道信息 参数 轨道平面数量 6个 每个轨道面卫星数量 11(+1)颗 地面备份卫星数量 9颗 轨道周期 101 min 轨道高度 780 km 轨道倾角 86.4° 相邻轨道夹角 31.6/22° 运行速度 277088 km/h最大可视时间 15 min 卫星飞行速度 7.46 km/s 可见半角 27° 最大斜高 3249 km最大斜距 6498 km最大地表范围 5940 km表 7 铱星用户链路通信体制
Table 7. Iridium user-link communication parameters
参数 数值 带宽 31.5 kHz 功率 200W 速率 128 kbit/s(星-移动端)、1.5 Mbit/s(星-Iridium OpenPort终端)、8 Mbit/s(高速Ka-Band服务将可用于较大的固定和可移动终端) 调制方式 QPSK(DEQPSK) 波束 高椭圆形波束(固定) 单卫星波束覆盖 4700 km(直径) 极化方式 右旋圆极化 多址方式 FDMA/TDMA/SDMA/TDD 纠错编码方式 FEC卷积码 脉冲成型方式 40%均方根升余弦脉冲成型 表 8 星链通信体制
Table 8. Starlink communication parameters
参数 数值(上行) 数值(下行) 用户链路带宽 125 MHz×4 250 MHz×8 调制方式 256APSK(编码率3/4) 16APSK(编码率3/4) 功率 66.89 dBm(卫星段天线最大发射功率)
2.44 W(用户终端天线)波束 圆形波束(可单独成形与控制) 卫星波束覆盖 2800 km2 极化方式 右旋圆极化 表 9 符号解释
Table 9. Symbol definition
参数 含义 $ {D_{{\text{dir}}}} $ 卫星信号照射到直达波接收天线时的功率密度 $ {P_{\mathrm{t}}} $ 卫星信号发射功率 $ {G_{\mathrm{t}}} $ 卫星天线方向增益 $ {R_0} $ 卫星距离地面的高度 $ {L_{\mathrm{t}}} $ 传输损耗 $ {\text{EIRP}} $ 卫星等效全向辐射功率 A 接收天线等效面积 $ \lambda $ 卫星信号载波波长 G 接收天线增益 $ {P_{{\text{dir}}}} $ 直达波信号功率 $ {G_{{\text{proc}}}} $ 相干处理增益 $ {P_{\text{N}}} $ 接收机噪声功率 K 玻尔兹曼常数 T 接收机噪声温度 B 接收机带宽 F 接收机噪声系数 $ {\text{SN}}{{\text{R}}_{{\text{dir}}}} $ 直达波信噪比 f 载波频率 $ {D_{{\text{re}}}} $ 目标回波信号的功率密度 R 目标到接收天线的距离 表 10 卫星信号外辐射源雷达系统链路参数
Table 10. Link budget parameters of passive radar using satellite signals
系统组成 参数 一网 铱星II 星链 GPS DVB-S 外辐射源 EIRP (dBW) 37 28 22 24 51.7 $ {R_0}({\text{km}}) $ 1200 780 330 20200 36000 $ f ({\text{GHz}}) $ 11.7 1.626 11.7 1.56 12 接收系统 $ G/{\text{dB}} $ 25 25 30 25 30 $ K{\mathrm{J}}({}^\circ) $ 1.38×10–23 1.38×10–23 1.38×10–23 1.38×10–23 1.38×10–23 $ T/{\text{K}} $ 290 290 290 290 290 $ B({\text{MHz}} )$ 250 31.5kHz 250 10.23 36 $ F({\text{dB}}) $ 3 3 3 3 3 $ {\text{Loss}}({\text{dB}}) $ 5 5 5 5 5 $ {T_{\rm{int} }}({\text{s}} )$ 0~2 0~2 0~2 0~2 0~2 $ {\text{SN}}{{\text{R}}_{{\text{min}}}}({\text{dB}}) $ 8.2 8.2 8.2 8.2 8.2 目标 $ \sigma /{{\text{m}}^{\text{2}}} $ 10/50/100 10/50/100 10/50/100 10/50/100 10/50/100 表 11 卫星信号外辐射源雷达系统直达波功率
Table 11. SNR of direct wave of passive radar using satellite signals
外辐射源(卫星) 直达波功率$ {P_{{\text{dir}}}}{\text{(dBm}}) $ 一网 –88.4 铱星 –76.5 星链 –87.2 GPS –108.4 DVB-S –98.5 表 12 回波通道的信号特性
Table 12. Simulate the signal characteristics of the echo channel
类型 时延范围(μs) 多普勒范围(Hz) 杂噪比(dB) 多普勒杂波 0~30 –400~400 –5~30 目标 25~60 –800~–300, 300~800 –20~–10 -
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