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Design Method of Dynamic Channelization for Space-based Spectrum Sensing
RAO Jiacheng, HUANG Yonghui, ZHOU Li
, Available online  , doi: 10.11728/cjss2026.03.2025-0026
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Abstract:
The proliferation of electromagnetic devices in orbital environments has made electromagnetic spectrum sensing a critical capability for modern space-based systems. As space-based communication networks expand and electromagnetic interference becomes increasingly complex, advanced spectrum monitoring solutions are essential. This paper addresses the cross-channel signal processing challenge in wideband spectrum sensing, particularly for space-based platforms with limited computational resources and stringent real-time processing requirements. A dynamic channelization system incorporating perfect reconstruction polyphase filter banks is proposed to enable efficient wideband signal decomposition and parallel processing. The architecture features an analysis-synthesis joint processing framework that reduces onboard computational complexity while preserving signal integrity. An Optimized Constant False Alarm Rate (Optimized-CFAR) detection algorithm is developed to improve detection performance under varying noise conditions. The system employs a time-frequency domain joint cross-channel decision method for precise reconstruction of signals spanning multiple frequency channels. The polyphase filter bank design minimizes aliasing and distortion while ensuring computational efficiency for satellite implementation. Experimental results demonstrate significant performance improvements. At a 15 dB signal-to-noise ratio, the system achieves 98.6% detection probability, substantially outperforming conventional methods. The reconstructed signal fidelity reaches 0.972, indicating excellent preservation of signal characteristics. The cross-channel decision algorithm effectively resolves signal boundary ambiguities, enabling accurate identification and reconstruction of wideband signals exceeding individual channel bandwidths. The proposed system provides an efficient solution for space-based spectrum monitoring applications. The integration of Optimized-CFAR detection with polyphase filtering techniques offers a scalable framework for real-time wideband spectrum analysis suitable for orbital deployment, enhancing electromagnetic spectrum awareness capabilities for space-based communication and surveillance systems.
An Accurate Detection Method for Fruits and Vegetables in the Space Station Cargo Bay
LI Wenqin, SUI Tingting, ZHANG Zhang, WU Huiying, CHANG Liang
, Available online  , doi: 10.11728/cjss2026.03.2025-0080
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Machine vision technology remains in its nascent stage for practical application in space station cargo bay management, with limited research currently addressing target detection in space station environments. To overcome detection accuracy limitations caused by confined spaces, obstructions, and lighting conditions in cargo bays, this study proposes an enhanced YOLOv11-based algorithm for fruit and vegetable detection: LEBR-YOLO. Drawing on successful implementations of existing visual detection techniques, this approach refines the original convolutional neural network architecture by integrating spatial and edge information via a dual-layer attention mechanism, thereby enhancing processing efficiency for high-resolution feature maps. Specifically, it improves feature extraction capabilities by modifying the original convolutional module into an efficient input feature extraction layer that fuses spatial and edge information. Concurrently, a dual-layer attention mechanism is incorporated to significantly boost the model’s processing efficiency for high-resolution feature maps. An enhanced lightweight shared deformable detection module is introduced, which adopts a shared convolutional architecture combined with deformable convolutions; a dynamic adjustment mechanism integrating category loss and bounding box loss is also employed to improve detection performance under occlusion. Transfer learning is used as an optimization technique to compensate for dataset limitations, reducing computational costs while enhancing model generalization. Experiments demonstrate that this model significantly improves object detection under occlusion: on a custom fruit and vegetable dataset, it achieves 95.3% accuracy, 88.6% recall, and 93.9% mAP@0.5, while maintaining low model complexity. This meets the detection requirements for the Tianzhou cargo spacecraft during in-orbit operations. This approach proves highly effective for detecting fruits and vegetables in space stations, enhancing detection accuracy, substantially reducing false positives and false negatives, and elevating the automation level of on-board resource management.
A Wide Temperature Range Sodium Solid-state Battery Resistant to Extreme Environments for Deep Space Exploration
YANG Caizhen, LI Zongyou, ZHANG Jianguo, YU Qiyao
, Available online  , doi: 10.11728/cjss2026.03.2025-0075
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To address the urgent demand for energy storage systems with wide-temperature-range adaptability and high safety under extreme environments such as deep space exploration and polar observation, a novel organic–inorganic composite sodium solid electrolyte has been developed for constructing high-performance sodium solid-state batteries. The electrolyte was synthesized by combining methylammonium lead chloride (MAPbCl3) with a perovskite structure as the inorganic ion conductor, Sodium Alginate (SA) as the flexible polymer backbone, and Ethoxylated Trimethylolpropane Triacrylate (ETPTA) as a multifunctional crosslinker. Through in-situ Ultraviolet (UV)-initiated polymerization, a dense and robust composite polymer network was formed, ensuring homogeneous dispersion of inorganic fillers and intimate interfacial contact. Electrochemical characterization revealed that the as-prepared composite electrolyte exhibited a high ionic conductivity of 5.65×10–4 S·cm–1 and a sodium-ion transference number of 0.65 at room temperature, which are significantly higher than those of conventional ex-situ mixed systems. The assembled NVP|MSE-s|Na all-solid-state battery delivered excellent cycling stability, retaining 71.5% of its initial capacity after 500 cycles at 50 mA·g–1 and maintaining good electrochemical performance across a wide temperature range from –40 ℃ to 80 ℃. Even at subzero temperatures, the cell showed stable charge/discharge behavior and suppressed dendritic growth. Further analyses confirmed that the in-situ formed composite structure effectively enhanced interfacial compatibility, thermal stability, and mechanical integrity, leading to reduced interfacial impedance and improved long-term cycling durability. These synergistic effects enabled the electrolyte to withstand harsh thermal and mechanical conditions while maintaining fast Na+ transport. This work demonstrates that integrating perovskite-type inorganic conductors within a UV-cured polymer matrix via in-situ polymerization is an effective strategy for constructing wide-temperature solid electrolytes. The proposed composite electrolyte system holds great promise as a safe and reliable energy storage solution for sodium solid-state batteries in extreme environments, particularly for applications such as deep space exploration, polar expeditions, and aerospace electronics.
Doppler Spectrum Analysis and Centroid Estimation of Ka-band Spaceborne Sea Surface Scatter Echoes
YU Miaomiao, ZHU Di, DONG Xiaolong, ZHANG Jingyu
, Available online  , doi: 10.11728/cjss2026.03.2025-0072
Abstract(690) FullText HTML (162) PDF 4373KB(103)
Abstract:
The ocean surface dynamic parameters reflect important air-sea interaction processes, such as the material and energy balance, and climate change. Under spaceborne measurement conditions, it is necessary to study the echo Doppler spectrum characteristics formed by the high operating speed of the satellite in conjunction with the sea surface dynamic parameters. In this paper, a time-varying dynamic sea surface model is established via the existing linear random superposition theory to simulate ocean surfaces. Based on the satellite parameters defined by the Ocean Surface Current multiscale Observation Mission (OSCOM), this work derives echo Doppler spectra involving different wind parameter effects under medium-incidence-angle Bragg scattering conditions. As wind speed increases, the sea surface roughness and root mean square height increase accordingly, resulting in the stronger backscatter modulation, and the echo Doppler shift increases significantly. When observed along the track, the echo Doppler centroid of the Doppler spectrum with wind direction is slightly asymmetric at the downwind and upwind, and reaches a minimum at a 90° wind direction. The analysis results of the wind fetch show that when the wind speed is 10 m·s–1 and the length of wind fetch increases from a-10 km-developing wave to a fully-developed wave, the velocity of the sea surface increases, and the tilt modulation of the long wave increases, resulting in the Doppler shift increases, and the estimated Doppler centroid difference is 0.56 m·s–1. Finally, this study considers the contribution of breaking waves to the co-polarized backscatter and analyzes the influence of both the Doppler centroid and velocity estimation. Analysis of echo Doppler spectrum under the condition of wave breaking shows that when the wind speed is 10 m·s–1 and the observation azimuth is the same as the wind direction, the Doppler centroid offset is about 71.4 Hz, resulting in a deviation of about 0.3 m·s–1 for the radial velocity estimation compared with the case without considering the breaking wave.
Cold Optical Design of 10 THz Focal Plane Imaging System for Space Applications
LI Jiahui, MA Yuexue, ZHU Haotian, QUAN Jia, LIU Ziyao
, Available online  , doi: 10.11728/cjss2026.03.2025-0088
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In passive space exploration, the target signals are typically extremely weak and the detection system needs to achieve high sensitivity and low noise requirements. To satisfy these demands, cold optics has become indispensable. This method integrates optical components (such as lenses and mirrors) into cryogenic environments and combines them with cryogenic detectors to fulfill the detection needs. However, conventional optical design is constrained by the limited cooling capacity of spaceborne instruments. The research presents a cold optical model based on multi-reflection and optimizes the window size design according to this model. The cold optical experiment conducted in this research demonstrates a strong correlation between the predicted results and the experimental results, thereby confirming the effectiveness of the proposed model. The optimization of the window size is a critical factor in reducing thermal leakage and improving the overall performance of the system. From an optical perspective, the optical path delivers the desired signal; however, from a thermal perspective, it also introduces heat, imposing a thermal load on the cryogenic system. Engineering design must therefore strike a balance between these competing optical and thermal constraints. This research not only advances the field of cold optics but also provides a practical solution for the design of high sensitivity, low-noise detection systems in space applications. The proposed model and experimental validation offer a robust foundation for the development of more efficient and reliable cold optical systems, contributing to the advancement of space exploration technology. The method and results presented in this paper can serve as a reference for further research and development in the field of cold optical systems.
Validation and Discrepancy Analysis of Sea Surface Mean Square Slope Measured by SWIM and CYGNSS
LANG Shuyan, HU Weiping, LI Xiuzhong, LI Yuyang, ZHAO Xinhua
, Available online  , doi: 10.11728/cjss2026.03.2025-0076
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The Mean Square Slope (MSS) of the sea surface is a key parameter for characterizing sea surface roughness in the field of marine microwave remote sensing, and it is of great significance for studying the air-sea coupling process and marine meteorological monitoring. This paper conducts a comparative analysis of the MSS retrieved by the Surface Waves Investigation and Monitoring (SWIM) on the China-France Oceanography Satellite (CFOSAT) and the Cyclone Global Navigation Satellite System (CYGNSS). SWIM retrieves the MSS by fitting the two-dimensional normalized radar backscatter cross-section under different incident angles and azimuth angles. CYGNSS obtains the MSS caused by local winds by subtracting a correction amount on the basis of preliminary observations. In this paper, after collocating the data from SWIM and CYGNSS in January 2023, a direct comparison has been made. It is found that the MSS derived from SWIM is higher than that retrieved by CYGNSS under low wind speeds, while when the wind speed exceeds approximately 7 m·s–1, the MSS derived from CYGNSS is higher than that given by SWIM. This is mainly attributed to the differences in the microwave bands of the two and the correction amount of the MSS generated by swell subtracted during the retrieval process of CYGNSS. After correcting the SWIM MSS using the Elfouhaily spectrum model, the bias between the two is approximately 0.03, and the random root mean square error is 0.0323. This error is caused by the MSS generated by swell and the differences in the cutoff wavelength. The research results clarify the differences and error sources of the MSS retrieved by the two spaceborne sensors, providing an important reference for the calibration of MSS data and subsequent marine research and applications.
Temperature Drift Performance of Fluxgate Sensor with Open-loop Measurement
JIANG Jiao, ZHOU Bin
, Available online  , doi: 10.11728/cjss2026.03.2025-0055
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The magnetic fluxgate sensor exhibits a significant temperature effect in its practical applications. This paper presents an in-depth analysis of the working principles of both open-loop and closed-loop measurement circuits commonly used with magnetic fluxgate sensors. Based on this theoretical foundation, the study focuses on how the sensor's intrinsic characteristics vary with temperature under open-loop conditions. The objective is to provide experimental evidence that can guide the design and optimization of temperature drift suppression techniques in closed-loop configurations. By building upon the fundamental operational principles of the magnetic fluxgate sensor, the paper derives and compares the circuit transfer functions for both open-loop and closed-loop measurement systems. It is demonstrated that the error sources present in open-loop measurements are more directly reflective of the sensor's own performance characteristics, as they are not masked by feedback mechanisms inherent in closed-loop designs. To achieve accurate and reliable open-loop signal detection, a dual-operational amplifier (dual-op-amp) bandpass filter was employed to isolate the second harmonic signal, followed by phase-locked amplification to precisely measure both the amplitude and phase of the open-loop output. Performance temperature tests were designed based on the distinct behaviors of different sensor parameters under thermal variation. Experimental results obtained over a temperature range from –40℃ to +80℃ show that the zero-point drift of the magnetic fluxgate sensor remains within ±0.5 nT, while the phase shift reaches up to 60°. Additionally, the open-loop gain varies by approximately ±5%, and the noise level fluctuates between 4～7 pT·Hz1/2 at 1 Hz. Although the signal phase is the only parameter that undergoes a substantial change in open-loop measurements, the phase-sensitive demodulation mechanism in closed-loop systems is highly responsive to such variations. Consequently, the observed phase drift has been experimentally verified to result in significant zero-point drift in closed-loop measurements.
Balloon-borne Astronomical Observations in Antarctica
ZHOU Jianghua, CHENG Junfei, CAI Rong, LIU Jifeng, YANG Yanchu, GAN Qingbo, YAN Daikang, HUANG Wanning, LI Yijian, LU Ying, CUI Yuxuan
, Available online  , doi: 10.11728/cjss2026.03.2025-0191
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Antarctica is widely regarded as one of the most favorable natural laboratories for astronomy, owing to its exceptionally low atmospheric water vapor and correspondingly high transmittance across multiple wavebands. Beyond these radiative advantages, the Antarctic summer provides a unique operational regime for stratospheric scientific balloons: continuous daylight and a relatively stable polar vortex support long-duration, near-constant-float-altitude flights with circumpolar trajectories. These conditions enable balloon platforms to deliver space-like observing environments at substantially lower cost, with the added benefits of rapid iteration, recoverable payloads, and flexible mission design. Since 1984, the U.S. Antarctic balloon program - launched primarily from McMurdo Station - has carried out hundreds of balloon-borne experiments, with astronomical and astrophysical missions forming a major fraction of the overall portfolio. The resulting body of work spans two broad domains: particle astrophysics and electromagnetic (photon) astronomy. Representative themes include measurements of the Cosmic Microwave Background (CMB), terahertz observations and broadband spectral imaging of Galactic targets, and particle-oriented investigations such as neutrino-related observations and searches for antimatter components. Together, these missions have helped advance frontier science while simultaneously maturing key enabling technologies for near-space instrumentation, including long-duration platform operations, pointing and stabilization, low-noise detector readout, cryogenic subsystems, background suppression strategies, and robust telemetry, recovery, and reflight capability. Building on publicly available literature and mission records, this paper provides a systematic review of Antarctic balloon-borne astronomical experiments, organizing prior efforts by observing band, scientific objective, and payload and instrument class. By synthesizing the scientific drivers and the evolution of mission concepts, the review also highlights how Antarctic ballooning serves as a practical bridge between ground-based facilities and space missions-de-risking high-impact hardware and observation strategies in a repeatable, lower-cost environment.Finally, we discuss prospects for developing China’s Antarctic balloon infrastructure. Establishing a dedicated polar balloon capability and conducting long-duration circumpolar balloon astronomy campaigns would strengthen China’s competitiveness in near-space astrophysics, accelerate technology readiness through iterative fielding, and enhance China’s scientific visibility and influence in Antarctic research.
Intelligent Identification and Key Parameter Extraction of Middle and Upper Atmospheric Disturbances Based on All-sky Airglow Imaging Observations of the Chinese Meridian Project
LAI Chang, WANG Pengchao, LI Qinzeng
, Available online  , doi: 10.11728/cjss2026.03.2025-0081
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To address the demand for efficient processing of massive airglow images in the Meridian Project, this study developed a machine-learning-based method for automatic identification and parameter extraction of Atmospheric Gravity Waves (AGWs) and Medium-Scale Traveling Ionospheric Disturbances (MSTIDs). A Convolutional Neural Network (CNN) classification model was employed to filter clear-night-sky images, achieving accuracies of 99% (OH airglow) and 96.9% (OI airglow). Wave structures were localized using a Fast Region-Based CNN with an Intersection-over-Union (IoU) value exceeding 75%. For AGWs, parameters including wavelength, propagation direction, and horizontal phase velocity were extracted via 2D Fourier transform, while Canny edge detection and linear fitting were applied to MSTIDs. Analysis of the extracted parameter dataset revealed long-term trends of atmospheric waves: At the Dandong station (40.0°N, 124.0°E), OH airglow observations showed a bimodal seasonal distribution of AGW occurrence, with peaks during both winter and summer, with propagation directions being predominantly southwestward in winter and northeastward in summer. At the Xinglong station (40.2°N, 117.4°E), 94% of MSTID events detected via OI airglow exhibited southwestward propagation (azimuths of 200°～230°). These statistical characteristics align with established patterns in the literature, validating the reliability of the dataset. This tool resolves the inefficiency and subjectivity of traditional manual analysis, providing robust data support for long-term atmospheric wave studies. The associated algorithms and datasets will be open-sourced.
A Maximum A-posteriori Probability Decoding Algorithm for the CCSDS Punctured Convolutional Codes
GU Xuechen, FAN Yanan, YAN Yi, LI Xue, YAO Xiujuan
, Available online  , doi: 10.11728/cjss2026.03.2025-0058
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CCSDS punctured convolutional codes suffer from bit-error-rate performance degradation using the Viterbi decoding algorithm. Aiming at this issue, this paper proposed a maximum a-posteriori probability decoding algorithm for these codes. The algorithm takes a forward and backward update process of the likelihood messages based on the trellis graph, to obtain the maximum a-posteriori log-likelihood ratio for the corresponding input bits, reducing the loss of channel likelihood information caused by puncturing, thereby improving the performance of the punctured convolutional code. As shown by the simulation results, the proposed algorithm can achieve an even lower bit-error-rate for the CCSDS punctured convolutional codes and improve the encoding gain, and the higher the code rate, the more significant the bit error rate reduction. Compared with the Viterbi decoding algorithm, the proposed decoding algorithm provides a coding gain of about 0.2 dB and 0.6 dB for code rates of 5/6 and 7/8 respectively. Its computational complexity is comparable to that of the Viterbi decoding algorithm, thus it has good engineering application value, which can be used to improve the reliability of existing space telecommunication systems.
Impact Crater Database of 10 Landing Regions from Apollo and Chang’E Missions: Construction and Distribution Patterns of Small Impact Crater Databases
LIU Fangchao, ZHANG Li, GUO Dijun, LIU Bin, XIE Bin, LYU Ying-Bo, CHEN Jian, LING Zongcheng
, Available online  , doi: 10.11728/cjss2026.03.2025-0135
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Among the celestial bodies within the solar system, the Moon maintains the most pristine conditions of impact craters. Some landing sites on the lunar surface have in-situ exploration data and experimental measurement results from the returned samples, providing distinguished meanings to understand the impact events and their reshaping effects on the lunar surface. Small craters play a significant role in the formation and evolution of lunar regolith. However, existing lunar impact crater databases lack comprehensive coverage of small-scale impact craters with diameters less than 100 m. Therefore, this study produced ten mosaic images of 20 km×20 km in width, using the high-resolution Lunar Reconnaissance Orbiter Camera Narrow Angle Camera images acquired under solar incidence angles between 50° and 70°. These images cover ten lunar landing sites, including six Apollo missions and four Chang’E missions. An improved YOLO11+SAHI deep learning model was then applied to automatically extract craters with diameters ≥15 m within these regions. After manual verification, a high-quality crater database containing 359844 records was constructed. Compared with existing datasets, the proposed database demonstrates superior crater completeness. Based on this database, the density distribution and diameter-frequency characteristics of small-sized impact craters were further calculated and analyzed. This dataset can provide robust support for studies of lunar geological chronology, impact flux evolution, surface process, and sample interpretation. In addition, it supplies a valuable training and validation resource for future artificial intelligent models of detecting the impact craters.
Design of Finite Frequency Domain Disturbance Rejection Controller for the Drag-free Spacecraft in Space-borne Gravitational Wave Detection
XU Qianjiao, CUI Bing, WANG Pengcheng, XIA Yuanqing, ZHANG Yonghe
, Available online  , doi: 10.11728/cjss2024.05.2024-0022
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In space-borne gravitational wave detection, there are technical challenges in designing the controller for the drag-free spacecraft with dual test masses. These difficulties arise from constraints within the limited measurement frequency domain and the necessity for a high-precision control index. In this paper, a design method of disturbance rejection controller in the finite frequency domain based on the generalized Kalman-Yakubovich-Popov (GKYP) lemma is proposed. Firstly, to address the performance constraints within the designated frequency band of the detection mission, a finite frequency domain control performance index in the form of a frequency response function is constructed. This index is meticulously developed by amalgamating the sensitivity and complementary sensitivity control indexes. Then, a control structure with fixed-order characteristics for output feedback is proposed, and a method for selecting controller parameters based on the GKYP lemma is established. By this, a finite frequency domain disturbance-resistant controller design method is constructed. In contrast to current drag-free controller design methods, the proposed approach significantly diminishes the conservatism in the control index. This realizes the precise design of the controller in the specified frequency band, ultimately resulting in a reduction in the order of the controller. Finally, numerical simulations demonstrate that the proposed method successfully meets the control performance index for each loop of the drag-free system even in the presence of complex disturbances and noises.

Journal Introduction

ISSN 2097-7689       CN 11-1783/V

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