Advances in Space Research最新文献

{"title":"Adaptive finite-time bearing-based formation for high-order systems under false data injection attacks with application to spacecraft","authors":"Yufei Guo,&nbsp;Zixuan Zheng,&nbsp;Yingjie Wang,&nbsp;Yanli Feng,&nbsp;Chen Li,&nbsp;Junhua Zhang","doi":"10.1016/j.asr.2026.04.100","DOIUrl":"10.1016/j.asr.2026.04.100","url":null,"abstract":"<div><div>In this paper, the adaptive finite-time (FT) bearing-based formation tracking control problem of high-order multi-agent systems under false data injection attacks is investigated with application to spacecraft formation. Firstly, considering the absence of attacks, a FT formation controller based on the distributed FT extended state-observer is developed to form bearing-based formation. In addition, considering launching attacks when transmitting information from neighboring agents to local agents when the output information can only be obtained, a FT observer combined with an adaptive attack filter is proposed to estimate the formation via control information of the neighboring agents under attacks. Then, a distributed FT formation controller is designed to achieve and preserve a geometric pattern. The sufficient criteria are derived to ensure that the FT stabilization of the target formation is achieved without attack and presence of attack. Finally, the FT convergence of bearing-based formation is illustrated by spacecraft formation simulations.</div></div>","PeriodicalId":50850,"journal":{"name":"Advances in Space Research","volume":"78 2","pages":"Pages 1610-1626"},"PeriodicalIF":3.2,"publicationDate":"2026-07-15","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"148528950","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":3,"RegionCategory":"地球科学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Design and performance evaluation of CH4/N2O premixed propellant thruster","authors":"Tae Young Lee,&nbsp;Tae gyu Kim","doi":"10.1016/j.asr.2026.04.110","DOIUrl":"10.1016/j.asr.2026.04.110","url":null,"abstract":"<div><div>In this study, a small CH₄/N₂O premixed-propellant thruster was designed, fabricated, and experimentally evaluated through hot-firing tests. Unlike single-tank premixed monopropellant concepts, methane and nitrous oxide were premixed upstream of the thruster over a short residence time and then supplied to the combustion chamber. Ignition was achieved using a low-current plasma igniter, and the mixer, igniter, and combustion chamber were integrated into a single thruster configuration. The propellant flow was controlled through a sonic orifice, and the mass flow rate was measured using a Coriolis mass flow meter.</div><div>To evaluate combustion performance, hot-firing tests were conducted for different combustion-chamber characteristic lengths. Thrust, chamber pressure, specific impulse, characteristic velocity, and their efficiencies were evaluated, and each condition was tested three times. Stable ignition and combustion were achieved under all tested conditions. The total propellant flow rate was 1.67 g/s at an equivalence ratio of 1.75. Among the tested conditions, the best performance was obtained at a characteristic length of 1.23 m, where the mean thrust, characteristic velocity, and specific impulse were 2.537 ± 0.04 N, 1442.74 ± 16.08 m/s, and 154.86 ± 2.17 s, respectively. The corresponding characteristic velocity efficiency and specific impulse efficiency were 91.11 ± 1.01% and 87.90 ± 1.23%.</div><div>These results indicate that combustion performance in the present CH₄/N₂O premixed thruster is strongly influenced by characteristic length, with an optimum near L* = 1.23 m under the present test conditions. The present work provides experimental hot-firing data and practical design insight for the development and optimization of small premixed-propellant thrusters.</div></div>","PeriodicalId":50850,"journal":{"name":"Advances in Space Research","volume":"78 2","pages":"Pages 1644-1652"},"PeriodicalIF":3.2,"publicationDate":"2026-07-15","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"148528952","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":3,"RegionCategory":"地球科学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"On the minimum of line width of the backscattered solar Ly-α profile measured by SOHO/SWAN","authors":"Anastasia Titova,&nbsp;Vladislav Izmodenov,&nbsp;Sergey Korolkov","doi":"10.1016/j.asr.2026.04.063","DOIUrl":"10.1016/j.asr.2026.04.063","url":null,"abstract":"<div><div>Solar Ly-<span><math><mrow><mi>α</mi></mrow></math></span> photons are scattered by interstellar hydrogen (H) atoms that penetrate into the heliosphere through the region of the solar wind interaction with the local interstellar medium. The spectra of scattered Ly-<span><math><mrow><mi>α</mi></mrow></math></span> reflect the properties of the velocity distribution of the interstellar H atoms. The spectra of backscattered Ly-<span><math><mrow><mi>α</mi></mrow></math></span> have been reconstructed in anti-sunward directions by Quemerais et al. (<span><span>Quémerais et al., 1999</span></span>, <span><span>Quémerais et al., 2006a</span></span>). One of the spectacular results of this reconstruction was the discovery of the minimum of the width of the backscattered spectra in the direction (nearly) perpendicular to the interstellar flow direction. Originally, the minimum was interpreted as a proof of the secondary interstellar atom presence inside the heliosphere. However, later <span><span>Katushkina and Izmodenov (2011)</span></span>, using a two-population kinetic model of the interstellar H atoms in the heliosphere, demonstrated that the minimum cannot be produced in their quite complete model.</div><div>In this paper, we performed numerical calculations of solar backscattered Ly-<span><math><mrow><mi>α</mi></mrow></math></span> spectra with the same model as in <span><span>Katushkina and Izmodenov (2011)</span></span>. A key novel aspect of the presented analyses is the procedure of the obtaining the width values. Specifically, we obtain the widths following the same approach as in the analysis of SOHO/SWAN data: the numerically computed spectra are truncated at velocities of <span><math><mrow><mo>±</mo><mn>30</mn></mrow></math></span> km/s and subsequently fitted with symmetric Gaussian functions. Our results show that the minimum arises as a direct consequence of applying this procedure to spectra generated by a two-population model. When the same analysis is performed on a single-population model, no such minimum appears. Thus, the longstanding issue of providing a theoretical explanation for the observed minimum is resolved.</div></div>","PeriodicalId":50850,"journal":{"name":"Advances in Space Research","volume":"78 2","pages":"Pages 1702-1710"},"PeriodicalIF":3.2,"publicationDate":"2026-07-15","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"148528956","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":3,"RegionCategory":"地球科学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Refinement of GNSS-PWV conversion coefficients based on the Emardson model in the Tibetan Plateau alpine region","authors":"Jiayi Cheng,&nbsp;Bingbing Zhang,&nbsp;Si Xiong,&nbsp;Yi Shen","doi":"10.1016/j.asr.2026.04.079","DOIUrl":"10.1016/j.asr.2026.04.079","url":null,"abstract":"<div><div>The water vapor conversion factor (K-value) is one of the key parameters in GNSS meteorology that affects the accuracy of retrieving Precipitable Water Vapor (PWV). To address the limited applicability of the Emardson model in the complex terrain and climatic conditions of the Tibetan Plateau alpine region, this study utilized data from 23 radiosonde stations within and around the area from 2010 to 2015. Two enhanced models were developed, the Emardson-QL model, which considers geographic location and temporal variations (annual and diurnal) but not elevation, and the Emardson-QH model, which additionally incorporates elevation. Using 2016 radiosonde observation data as a reference, this study conducted a multidimensional comparative analysis to systematically evaluate the comprehensive performance of the newly developed models against existing regional models for China (Emardson‑I, Emardson‑H), the Global Pressure and Temperature 3rd generation (GPT3), and the fifth‑generation European Center for Medium‑Range Weather Forecasts Reanalysis (ERA5). For K‑value prediction, the Emardson‑QH model achieved a near‑zero mean bias (0.00032) and a lower root mean square (0.00262), outperforming other models. Compared to the baseline model, the QH model achieved a 23.6% improvement in accuracy relative to the Emardson‑H model. In global model comparisons, the QH model demonstrated improvements in bias control of 76.6% and 82.8% over GPT3 and ERA5, respectively. In GNSS‑PWV retrieval applications, the Emardson‑QH model attained a mean root mean square of 0.17655 mm, representing a 20.5% accuracy improvement over the Emardson‑H model (0.22131 mm) and also surpassing GPT3 (0.20628 mm) and ERA5 (0.19115 mm). This study provides a reliable technical solution for high-precision GNSS atmospheric water vapor retrieval in the Tibetan Plateau alpine region, offering significant reference value for enhancing the accuracy of meteorological forecasting and climate change research in this area.</div></div>","PeriodicalId":50850,"journal":{"name":"Advances in Space Research","volume":"78 2","pages":"Pages 768-791"},"PeriodicalIF":3.2,"publicationDate":"2026-07-15","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"148529120","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":3,"RegionCategory":"地球科学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Improved precise point positioning with the latest BDS-3 broadcast ephemeris","authors":"Jianhui Liu,&nbsp;Cheng Wang,&nbsp;Fengyu Xia,&nbsp;Chuang Shi","doi":"10.1016/j.asr.2026.04.085","DOIUrl":"10.1016/j.asr.2026.04.085","url":null,"abstract":"<div><div>Global navigation satellite system (GNSS) technology is being progressively improved for effectively transmitting the high-accuracy broadcast orbit and clock messages. Recently, broadcast ephemeris-based precise point positioning (BE-PPP) has attracted increasing interest in real-time positioning and low Earth orbit satellite orbit determination. This study systematically evaluates the accuracy improvements of the latest BDS-3 broadcast ephemeris and demonstrates that the BDS-3 orbital rotation error is negligible in multi-GNSS joint BE-PPP solutions. The experimental data includes broadcast and precise products from June 2022 to May 2025, as well as GNSS observations collected in February, May, and November 2023, and February 2024. Comprehensive analyses of Helmert parameters, the root-sum-square (RSS) of their linear components, and signal-in-space range error (SISRE) demonstrate that the accuracy of BDS-3 broadcast orbits significantly improved from August 2023, and its monthly average RSSs are similar to those of Galileo and GPS. The monthly root mean squares (RMSs) of three-dimensional (3D) broadcast orbit error and SISREorb for BDS-3 exhibit trends consistent with RSSs, and the RMSs of SISRE excluding systematic errors for BDS-3, Galileo, and GPS are 0.31, 0.22 and 0.39 m, respectively. For BE-PPP solutions, the 3D positioning accuracy of static and simulated kinematic processing with enhanced broadcast ephemeris for BDS-3 in November 2023 and February 2024 are improved by over 22.1% and 13.6%, and 6.5% and 4.3%, respectively. The GPS, Galileo and BDS-3 joint BE-PPP solution using the enhanced BDS-3 broadcast ephemeris can effectively disregard the BDS-3 broadcast orbit rotation error compared to the traditional method. In November 2023, the 3D RMSs of the three-system joint BE-PPP static and simulated kinematic solutions are 18.6 cm and 30.9 cm when neglecting the BDS-3 rotational error, but increase to 21.0 cm and 32.6 cm when this error is taken into account.</div></div>","PeriodicalId":50850,"journal":{"name":"Advances in Space Research","volume":"78 2","pages":"Pages 872-887"},"PeriodicalIF":3.2,"publicationDate":"2026-07-15","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"148529121","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":3,"RegionCategory":"地球科学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Hyperspectral image classification using an optimized multi-layer perceptron-autoencoder bidirectional long short-term memory with Bhattacharyya wingsuit flying search optimization","authors":"Rajat Kumar Arya,&nbsp;Surbhi Vijh,&nbsp;Krati Rastogi Gupta,&nbsp;Upendra Mishra","doi":"10.1016/j.asr.2026.04.086","DOIUrl":"10.1016/j.asr.2026.04.086","url":null,"abstract":"<div><div>Convolutional neural networks (CNNs) and recurrent neural networks (RNNs) have adequately performed the hyperspectral image classification (HSIC) task. However, CNNs struggle to capture global features, and RNNs struggle to capture local features and long-range dependencies. This study proposes a novel HSIC method, called optimized multi-layer perceptron autoencoder bidirectional long short-term memory (MLP-AE-BiLSTM), to overcome these challenges. The proposed method integrates the MLP-AE to prevent overfitting and preserve spatial and spectral correlations, and the BiLSTM to model backward and forward spectral dependencies. First, the morphological operation is used to preprocess the HSI dataset, emphasizing the objects within it. We developed an Improved SIFT (I-SIFT) to capture more effective spatial features and utilize HOG and effective spectral feature extraction methods to obtain rich, fused spectral and spatial features. To improve the training efficiency and generalization, we developed a Bhattacharyya wingsuit flying search (BWFS) optimization to optimize the parameters of BiLSTM. The proposed optimized MLP-AE-BiLSTM model has been evaluated on the publicly available HACARUS dataset, achieving better accuracy (97.89%) than state-of-the-art methods. The source code for this study is available at <span><span>https://github.com/RajatArya22/MLP-AE-BiLSTM</span><svg><path></path></svg></span>.</div></div>","PeriodicalId":50850,"journal":{"name":"Advances in Space Research","volume":"78 2","pages":"Pages 888-900"},"PeriodicalIF":3.2,"publicationDate":"2026-07-15","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"148529126","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":3,"RegionCategory":"地球科学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"A new model of the Ajisai spin axis motion derived from the photometric patterns","authors":"L. Shakun,&nbsp;N. Koshkin,&nbsp;E. Korobeynikova,&nbsp;S. Melikyants,&nbsp;S. Strakhova,&nbsp;V. Dragomiretsky,&nbsp;V. Marsakova,&nbsp;A. Ryabov,&nbsp;S. Terpan","doi":"10.1016/j.asr.2026.04.061","DOIUrl":"10.1016/j.asr.2026.04.061","url":null,"abstract":"<div><div>Studying the kinematic and dynamic behavior of space objects (SOs), including their translational and rotational motion, is a key task in space situational awareness (SSA). Therefore, developing effective methods for measuring rotational parameters of SOs is crucial for understanding the evolution and stability of the growing population of artificial satellites.</div><div>We recently proposed a new technique for determining the rotation axis of a SO – the <em>photometric pattern method</em>. When the same section of light curve, termed <em>photometric pattern</em>, is identified in two or more different light curves of a spinning satellite, this indicates that the spin-axis direction, the Sun direction vector, and the observer direction vector form identical geometric configurations. When the photometric pattern arises from specular reflections, its shape depends solely on the angle between the spin axis and the phase angle bisector (PAB). With sufficient observations obtained over a short period, several types of identical photometric patterns can be used to determine the mean direction of the satellite’s spin axis in that interval.</div><div>In this study, we apply the photometric pattern method to analyze the evolution of the spin axis of the Japanese geodetic satellite Ajisai over the wide period 2009–2024. We demonstrate how unique photometric patterns (i.e. unique sequences of specular flares) can be automatically identified in Ajisai’s light curves without any a priori information about the satellite’s shape. Using these data, we determine the instantaneous direction of Ajisai’s spin axis and compute the angular distance between the axis and the normals to the mirrors responsible for each photometric pattern. This angular distance, representing the mirror latitude in the body-fixed frame, is derived directly from the morphological light-curve analysis rather than from assumptions about the satellite’s shape.</div><div>Finally, our analysis revealed systematic differences between the spin-axis directions determined in this study and those predicted by the <span><span>Kucharski et al. (2016)</span></span> model based on their analysis of laser ranging observations from 2003 to 2014. To address these discrepancies, we developed an empirical model combining nutation and precession, which reproduces the measured spin-axis directions over the 15-year interval with an average residual of <span><math><mrow><mn>0.066</mn><mi>°</mi></mrow></math></span>, comparable to the uncertainty of individual determinations.</div></div>","PeriodicalId":50850,"journal":{"name":"Advances in Space Research","volume":"78 2","pages":"Pages 1297-1317"},"PeriodicalIF":3.2,"publicationDate":"2026-07-15","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"148528976","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":3,"RegionCategory":"地球科学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Compact high-isolation frequency-reconfigurable C/X-band MIMO antenna for multi-mission UAV and satellite communications","authors":"Emine Ceren Gözek,&nbsp;Fikret Tokan,&nbsp;Muharrem Karaaslan","doi":"10.1016/j.asr.2026.04.054","DOIUrl":"10.1016/j.asr.2026.04.054","url":null,"abstract":"<div><div>Unmanned aerial vehicles (UAVs) require compact and lightweight antenna systems capable of supporting multiple mission profiles; however, achieving high isolation and frequency agility within a single structure remains challenging. This paper presents a compact 8-port (4-4) frequency-reconfigurable MIMO antenna designed on a low-cost FR-4 substrate, integrating a neutralization-line-based decoupling mechanism with PIN-diode-controlled radiating elements.</div><div>The proposed antenna operates in two reconfigurable modes: C-band for UAV telemetry and data transmission, and X-band covering frequency ranges commonly used by SAR and SatCom systems. Measurement results indicate stable radiation behavior across the operating bands. The design achieves a stable peak realized gain of 6.24 dBi, an ECC in the range of 0.005–0.03, and a DG of approximately 10 dB, thereby ensuring reliable MIMO performance under all operating conditions. The ability to switch between frequency bands without hardware modification makes the proposed design a compact and efficient RF front-end solution for multi-mission UAV platforms and adaptive satellite communication systems.</div></div>","PeriodicalId":50850,"journal":{"name":"Advances in Space Research","volume":"78 2","pages":"Pages 1580-1591"},"PeriodicalIF":3.2,"publicationDate":"2026-07-15","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"148528945","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":3,"RegionCategory":"地球科学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Real-time orbit determination of Sentinel-6A using different broadcast ephemeris error compensation methods","authors":"Aoming Wang,&nbsp;Chunbo Wei,&nbsp;Zhiyong Huang,&nbsp;Tao Jiang,&nbsp;Defeng Gu","doi":"10.1016/j.asr.2026.04.094","DOIUrl":"10.1016/j.asr.2026.04.094","url":null,"abstract":"<div><div>Broadcast ephemeris error compensation is crucial for real-time orbit determination (RTOD). This study analyzes one month of actual Sentinel-6A flight data to evaluate the orbit accuracy, convergence, and computational cost of two compensation methods: the pseudo-ambiguity and the explicit signal-in-space range error (SISRE) parameter approaches. A new processing strategy that accounts for ephemeris switching is proposed to enhance accuracy and accelerate convergence. Our evaluation shows that by early 2024, the SISRE for GPS had improved to 33.1 cm, while the SISRE for Galileo was below 12 cm. Analysis of line of sight (LOS) errors reveals that ephemeris switches lead to discontinuities in the LOS errors, with GPS exhibiting larger but less frequent jumps compared to Galileo’s smaller, more frequent ones. Orbit determination assessments indicate that the explicit SISRE parameter method consistently delivers higher accuracy than the pseudo-ambiguity parameter method, albeit with a longer convergence time. The computational cost for the explicit SISRE parameter method increases by a negligible 1.6%. The dual-constellation combination achieves the best overall performance in both accuracy and convergence speed. When the proposed ephemeris switching strategy is applied, the pseudo-ambiguity parameter method sees its three-dimensional (3D) root mean square (RMS) error decrease from 9.2 cm to 8.6 cm, marking a 6.8% accuracy improvement. Its convergence time is shortened by 4.9%, from 9.5 to 9.1 min. The explicit SISRE parameter method, meanwhile, achieves a 5.4% improvement in accuracy as its 3D RMS reduces from 8.8 cm to 8.3 cm, and its convergence time is cut by a significant 20.0%, from 16.73 to 13.39 min. In summary, accounting for ephemeris switching enhances both orbit accuracy and filter convergence. The explicit SISRE method under this strategy achieves optimal performance, with RMS values of 6.5 cm (A), 4.4 cm (C), 2.7 cm (R), and 8.3 cm (3D). This represents a 10.2% improvement in 3D accuracy over the pseudo-ambiguity parameter method without switching. The achieved radial accuracy of 2.7 cm and 3D accuracy of 8.3 cm are particularly relevant for high-accuracy applications.</div></div>","PeriodicalId":50850,"journal":{"name":"Advances in Space Research","volume":"78 2","pages":"Pages 943-956"},"PeriodicalIF":3.2,"publicationDate":"2026-07-15","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"148529085","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":3,"RegionCategory":"地球科学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Prediction of ZTD based on a parameter separation strategy and a graph convolutional network method for regions with sparse GPS stations","authors":"Mingkun Su,&nbsp;Yuyang Zhang,&nbsp;Zhao Li,&nbsp;Pengfei Xia,&nbsp;Xiaoshu Hao,&nbsp;Ze Wang,&nbsp;Yanrong Zhai","doi":"10.1016/j.asr.2026.04.103","DOIUrl":"10.1016/j.asr.2026.04.103","url":null,"abstract":"<div><div>ZTD (Zenith Tropospheric Delay) prediction plays an important role in GPS (Global Positioning System) positioning and weather monitoring. However, accurate ZTD prediction remains a major challenge due to the differences in the characteristics of its components, and its application is also limited in regions with sparse GPS stations. ZTD mainly consists of ZHD (Zenith Hydrostatic Delay) and ZWD (Zenith Wet Delay), whose fluctuation characteristics differ significantly from each other. Therefore, a parameter separation strategy is proposed to predict these two components separately by combining a period component extraction method with the Informer model to improve prediction accuracy and efficiency. Moreover, to obtain ZTD values at any location in regions with sparsely distributed GPS stations, a Graph Convolutional Network (GCN) method is adopted in this study. The performance of the proposed method is evaluated using datasets collected from 2013 to 2023 at eight GPS stations in Hong Kong, China. Experimental results show that: (1) after applying the parameter separation strategy, the MAE (Mean Absolute Error) and RMSE (Root Mean Square Error) of the predicted ZTD decreased from 8.77 mm to 7.61 mm and from 12.69 mm to 6.68 mm compared to the traditional method. The improvement rate is approximately 13.23% for MAE and 47.36% for RMSE, respectively. (2) The ZTD prediction accuracy at any point using the GCN method achieves about 8.80 mm for MAE and 12.88 mm for RMSE, which is comparable to that of the traditional method based directly on GPS observations. (3) The prediction accuracy of ZTD is strongly affected by seasonal variations. The MAE and RMSE are larger in the rainy season than in the non-rainy season. Specifically, the highest prediction accuracy occurs in winter, moderate accuracy in spring, and the lowest accuracy in summer and autumn. In conclusion, the proposed method effectively improves ZTD prediction accuracy and can be applied in regions with sparsely distributed GPS stations.</div></div>","PeriodicalId":50850,"journal":{"name":"Advances in Space Research","volume":"78 2","pages":"Pages 1061-1075"},"PeriodicalIF":3.2,"publicationDate":"2026-07-15","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"148529092","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":3,"RegionCategory":"地球科学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}