嫦娥七号月球微波成像雷达地面标定方法
doi: 10.11728/cjss2026.02.2025-0119 cstr: 32142.14.cjss.2025-0119
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岳海霞 女, 1975 年5月出生, 现为中国科学院空天信息创新研究院副研究员, 主要研究方向为合成孔径雷达系统设计、信号模拟及集成测试关键技术研究. E-mail: yuehx@aircas.ac.cn
作者简介:
Ground Calibration Method for the Chang’E-7 Lunar Microwave Imaging Radar
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摘要: 探月工程四期嫦娥七号搭载的月球微波成像雷达未来在轨运行后, 不会在月面布控定标器, 因此无法实现在轨外场定标. 为确保获得月面高精度影像数据, 提出了一种地面标定方法. 该方法结合雷达系统内定标+内场性能标定, 在地面测试中通过在全温环境下测量内定标网络温度特性获取内定标精度、内定标通道一致性, 在暗室中获取内定标常数, 借助暗室构建内场无线收发环境实现系统发射和接收通道绝对收发增益和收发通道稳定度的精确标定. 地面标定获取的基础数据可用于在轨内定标常数、绝对和相对辐射精度、极化通道一致性等指标的校准, 为高分辨率月面探测提供保障.Abstract: After the Chang’E-7 lunar microwave imaging radar in the fourth phase of the Lunar Exploration Project is put into on-orbit operation in the future, calibration devices will not be deployed on the lunar surface, making on-orbit External calibration impossible. To ensure the acquisition of high-precision lunar surface image data, a ground calibration method is proposed. This method combines the internal calibration of the radar system with the performance calibration in the inner field. During ground testing, the internal calibration accuracy and the consistency of internal calibration channels are obtained by measuring the temperature characteristics of the internal calibration network under a full-temperature environment. The internal calibration constants are acquired in an anechoic chamber. By constructing a wireless transceiver environment in the inner field with the help of the anechoic chamber, the absolute transceiver gains and the stability of the transceiver channels of the system are accurately calibrated. The basic data obtained through ground calibration can be used for the calibration of indicators such as on-orbit internal calibration constants, absolute and relative radiation accuracy, and polarization channel consistency, providing guarantee for high-resolution lunar surface exploration.
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图 2 无线闭环绝对定标常数测试
Figure 2. Test diagram for wireless closed-loop absolute calibration constant
表 1 月球微波成像雷达主要技术参数
Table 1. Main technical parameters of the lunar microwave imaging radar
名称 主要参数和性能 最高分辨率/m 1 工作频段 Ku波段, L波段 幅宽/km 5～20 极化方式 单极化, 简缩极化, 全极化 
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表 2 地面标定试验项目
Table 2. Ground calibration test items
试验项目 试验内容 内定标性能 内定标精度 内定标通道幅相一致性标定精度 内定标常数 内场性能 收发绝对增益 极化通道幅相不平衡度
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表 3 内定标精度
Table 3. Internal calibration accuracy
定标网络组成 变化量/dB L波段 Ku波段 组合定标单元幅度变化量 0.073 0.140 天线定标网络幅度变化量(双程) 0.044 0.112 穿舱电缆幅度变化量(双程) 0.116 0.400 内定标精度 0.140 0.440
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表 4 有源增益内定标常数测试结果
Table 4. Test results of active gain internal calibration constants
定标项目 定标常数测量值 热敏电阻温度值 L波段/dB Ku波段/dB 全阵面发射定标 ($ {C}_{\text{t}} $) H极化 115.19 121.53 综合电子单机温度: 31℃
天线温度遥测值: 19℃V极化 115.23 121.39 全阵面接收定标 ($ {C}_{\text{r}} $) H极化 113.46 115.36 V极化 113.44 115.47 参考定标 ($ {C}_{\text{d}} $) H极化 116.38 121.22 V极化 116.53 121.36 内定标常数 ($ {C}_{\text{a}} $) H极化 112.27 115.67 V极化 112.14 115.50
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表 5 无线闭环绝对收发增益测试结果
Table 5. Test results of wireless closed-loop absolute transmit and receive gain
定标项目 闭环增益测量值 L波段/dB Ku波段/dB 无线闭环 H极化 115.35 118.10 V极化 114.70 118.60 喇叭天线增益 H极化 11.16 21.32 V极化 11.19 21.18 接收MGC H极化 48.14 44.44 V极化 48.80 44.08 脉压处理增益 71.87 75.85 光延迟线衰减 58.60 60.59 空间传输衰减因子(双程) 41.16 41.16 系统收发绝对增益 H极化 192.79 191.70 V极化 192.74 192.12
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表 6 极化通道幅相不平衡度测试结果
Table 6. Test results of amplitude and phase imbalance in polarization channels
定标项目 测试数据 L波段 Ku波段 发射极化通道幅度不平衡度/dB –0.02 0.11 发射极化通道相位不平衡度/(º) 0.13 –0.63 接收极化通道幅度不平衡度/dB 0.04 –0.14 接收极化通道相位不平衡度/(º) –0.48 –0.73
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