海洋盐度卫星L波段一维综合孔径辐射计数字子系统关键性能测试方法
doi: 10.11728/cjss2026.01.2025-0014 cstr: 32142.14.cjss.2025-0014
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石玥伦 女, 1999年10月出生于北京市, 现为中国科学院大学硕士研究生. 研究专业为电子与通信工程, 主要研究领域为微波辐射计系统测试等. E-mail: syl991018@126.com -
唐月英 女, 1966年7月生于湖南省怀化市, 现为中国科学院国家空间科学中心正高级工程师, 硕士生导师. 主要研究方向为复杂航天电子技术, FPGA软件技术, 系统控制与信号处理. E-mail:tangyueying@mirslab.cn
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Key Performance Test Methods for Digital Subsystem of L-band One-dimensional Synthetic Aperture Radiometer for Ocean Salinity Satellite
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摘要: 针对中国首颗海洋盐度卫星主被动探测仪(MICAP) L波段一维综合孔径辐射计分布式数字子系统的高精度测试需求, 聚焦分布式架构下多节点同步、软硬件耦合误差分离等难题. 测试过程中, 利用多机同步触发和FPGA的ILA (Integrated Logic Analyzer)工具, 实现24路AD原始数据对齐, 解决了分布式架构下原始数据无汇聚点的难题; 同时提出硬件性能与整体性能双向印证的测试方法, 完成了软硬件解耦效果的评估. 实测结果显示, 幅度一致性≤0.4 dB, 相位一致性≤1°, 相关偏置≤–38 dB, 各项指标均符合任务要求. 研究成果已应用于MICAP工程研制, 为星载分布式数字子系统的性能验证与优化提供了关键技术支撑.Abstract: The Microwave Imager Combined Active and Passive (MICAP), the first ocean salinity detection satellite in China, realizes the global scale measurement of key geophysical elements such as ocean salinity and soil moisture through multi-factor fusion inversion. The high-sensitivity L-band one-dimensional Synthetic Aperture Radiometer (SAR), serving as the primary detector for MICAP, features a digitally implemented subsystem with a distributed architecture that constitutes the core module of the radiometer’s receiving chain. The subsystem’s key performance indicators directly affect the measurement accuracy of both the radiometer and MICAP in detecting ocean salinity, thus the mission imposes stringent performance requirements. This study addresses the high-precision performance testing needs of the distributed digital subsystem, focusing on challenges such as synchronized multi-node data acquisition under a distributed framework and separation of hardware-software coupling performance. The testing method employs multi-device synchronous triggering and the Integrated Logic Analyzer (ILA) tool embedded in the FPGA of front-end data acquisition units to achieve synchronous capture of original AD sampling data from 24 channels across multiple individual units. This solution resolves the absence of original data aggregation points among multiple front-end data acquisition units in the distributed architecture. Furthermore, the study proposes a bidirectional verification framework for both hardware and system-level performance. The hardware performance is tested by analyzing raw acquired data, while the integrated hardware-software performance is evaluated by processing the end-to-end scientific data packets. This methodology achieves decoupled testing of the hardware and software performance of the distributed digital subsystem. The actual test results, including amplitude consistency ≤0.4 dB, phase consistency ≤1º, and correlation bias ≤–38 dB, meet the mission's specified requirements. The research results have been applied to the MICAP engineering development, providing critical technical support for the performance verification and optimization of the distributed digital subsystem of ocean salinity satellite synthetic aperture radiometer.
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图 1 L波段一维综合孔径辐射计数字子系统功能
Figure 1. Functional block diagram of the digital subsystem of the L-band one-dimensional synthetic aperture radiometer
图 2 分布式数字子系统硬件相位一致性、幅度一致性测试环境
Figure 2. Phase and amplitude consistency testing environment for distributed subsystem
图 3 幅度、相位一致性测试方法验证测试环境
Figure 3. Verification test environment of amplitude and phase consistency testing methods
图 4 数字子系统幅度与相位一致性测试环境
Figure 4. Amplitude and phase consistency test environment of the digital subsystem
图 5 数字子系统通道相关偏置测试环境
Figure 5. Correlation offset test environment of the digital subsystem
图 7 单机$ \mathrm{A} $通道$ 1\text{某次测试} $的相频曲线
Figure 7. Phase-frequency curve of Channel 1 of Unit 1 in a test
图 8 单机A通道1某次测试的幅频曲线
Figure 8. Amplitude-frequency curve of Channel 1 of Unit 1 in a test
表 1 相位一致性测试方法验证结果
Table 1. Verification results of phase consistency testing methods
第1次测试 第2次测试 两路AD输入信号相位差 $ {\delta }_{1}=3{^{\circ}} $ $ \delta _{1}^{'}=4{^{\circ}} $ FFT法测得的相位差 $ \Delta \varphi =3.28{^{\circ}} $ $ \Delta {\varphi }^{'}=4.29{^{\circ}} $ 互相关法测得的相位差 $ \Delta \varphi =3.29{^{\circ}} $ $ \Delta {\varphi }^{'}=4.30{^{\circ}} $ 
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表 2 各通道初相位及平均相位之差
Table 2. Initial phase of each channel and the difference between eask channel and the average phase
通道序号 A1 A2 A3 A4 A5 A6 B1 B2 B3 B4 B5 B6 平均 初相位/(°) 112.31 111.92 112.43 112.17 111.81 112.30 111.44 112.37 111.68 111.19 111.76 112.13 111.96 与平均初相位
之差/(°)0.35 –0.04 0.47 0.21 –0.15 0.34 –0.52 0.41 –0.28 –0.77 –0.20 0.17 －
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表 3 FFT初相位法相位一致性测试结果
Table 3. Phase consistency test results by FFT initial phase method
通道序号 A1 A2 A3 A4 A5 A6 B1 B2 B3 B4 B5 B6 5次测试结果平均值/(°) 0. 33 –0.06 0.36 0.19 –0.17 0.31 –0.35 0.31 –0.30 –0.55 –0.22 0.15
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表 4 互相关测试方法计算相位一致性结果 [单位: (°)]
Table 4. Phase consistency results by cross-correlation test method [unit: (º)]
通道
序号A2 A3 A4 A5 A6 B1 B2 B3 B4 B5 B6 A1 0.39 0.03 0.13 0.51 0.02 0.68 0.02 0.64 0.88 0.55 0.19 A2 － 0.42 0.25 0.11 0.37 0.39 0.37 0.24 0.50 0.16 0.21 A3 － － 0.17 0.53 0.05 0.71 0.05 0.66 0.91 0.59 0.21 A4 － － － 0.36 0.12 0.54 0.12 0.49 0.74 0.41 0.04 A5 － － － － 0.48 0.18 0.49 0.13 0.38 0.05 0.33 A6 － － － － － 0.66 0.01 0.61 0.86 0.53 0.16 B1 － － － － － － 0.67 0.05 0.20 0.13 0.51 B2 － － － － － － － 0.61 0.86 0.53 0.16 B3 － － － － － － － － 0.25 0.08 0.46 B4 － － － － － － － － － 0.33 0.70 B5 － － － － － － － － － － 0.38
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表 5 幅度一致性测试结果
Table 5. Test results of amplitude consistency
通道序号 A1 A2 A3 A4 A5 A6 B1 B2 B3 B4 B5 B6 功率/dBm 3.59 3.56 3.58 3.54 3.47 3.65 3.52 3.67 3.70 3.47 3.60 3.67
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表 6 数字子系统整体幅度一致性测试结果
Table 6. Test results of the overall amplitude consistency of digital subsystem
通道序号 1 2 3 4 5 6 7 8 9 10 11 12 幅度与平均
值差/dB0.05 0.14 0.00 0.17 0.07 0.30 0.01 0.03 0.04 0.13 0.13 0.18
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表 7 数字子系统相关偏置测试结果 (单位: dB)
Table 7. Correlation offset test results of digital subsystem (unit: dB)
通道序号 1 2 3 4 5 6 1 － –39.56 － － － － 2 － － –39.5 － － － 3 － － － –39.15 － － 4 － － － － –38.77 － 5 － － － － － –39.29 6 － － － － － －
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表 8 测试结果汇总
Table 8. Summary of test results
性能项 相位一致性/(°) 幅度一致性/dB 相关偏置/dB 指标
要求硬件
性能整体
性能指标
要求硬件
性能整体
性能指标
要求整体
性能测试结果 ≤0.91 ≤0.91 ≤0.93 ≤0.4 0.23 0.30 ≤–35 –38
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