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Imaging of the ionosphere and plasmasphere using GNSS slant TEC obtained from LEO satellites 利用低轨道卫星获得的GNSS倾斜TEC对电离层和等离子层进行成像

IF 1.6 4区地球科学

Radio Science Pub Date : 2024-12-31 DOI: 10.1029/2024RS008058

Lucas Schreiter;Andreas Brack;Benjamin Männel;Harald Schuh;Daniel Arnold;Adrian Jäggi

{"title":"Imaging of the ionosphere and plasmasphere using GNSS slant TEC obtained from LEO satellites","authors":"Lucas Schreiter;Andreas Brack;Benjamin Männel;Harald Schuh;Daniel Arnold;Adrian Jäggi","doi":"10.1029/2024RS008058","DOIUrl":"https://doi.org/10.1029/2024RS008058","url":null,"abstract":"Satellites with dual-frequency Global Navigation Satellite Systems (GNSS) receivers can measure integrated electron density, known as slant Total Electron Content (sTEC), between the receiver and transmitter. Precise relative variations of sTEC are achievable using phase measurements on L1 and L2 frequencies, yielding an accuracy of around 0.1 TECU or better. However, CubeSats like Spire LEMUR, with simpler setups (e.g., patch antennas) and code noise in the order of several meters, face limitations in accuracy. Their precision, determined by phase observations, remains in the 0.1–0.3 TECU range. With a substantial number of observations and comprehensive coverage of lines of sight between Low Earth Orbit (LEO) and GNSS satellites, global electron density can be reconstructed from sTEC measurements. Utilizing 27 satellites from various missions, including Swarm, Gravity Recovery And Climate Experiment Follow-On, Jason-3, Sentinel 1/2/3, COSMIC-2, and Spire CubeSats, a cubic B-spline expansion in magnetic latitude, magnetic local time, and altitude is employed to model the logarithmic electron density. Hourly snapshots of the three-dimensional electron density are generated, adjusting the model parameters through non-linear least squares based on sTEC observations. Results demonstrate that including Spire significantly enhances estimates, showcasing exceptional agreement with in situ observations from Swarm and Defense Meteorological Satellite Program LEO satellites. The model outperforms contemporary climatological models, such as International Reference Ionosphere (IRI)-2020 and the neural network-based NET model. Validation efforts include comparisons with ground-based sTEC measurements, space-based vertical TEC from Jason-3 altimetry, and global TEC maps from the Center for Orbit Determination in Europe and the German Research Center for Geosciences (GFZ).","PeriodicalId":49638,"journal":{"name":"Radio Science","volume":"59 12","pages":"1-19"},"PeriodicalIF":1.6,"publicationDate":"2024-12-31","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"142905943","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":4,"RegionCategory":"地球科学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

引用次数: 0

Front matters 前面问题

IF 1.6 4区地球科学

Radio Science Pub Date : 2024-12-31 DOI: 10.1002/rds.21248

引用次数: 0

Efficient storage of embedded element patterns for low frequency radio telescopes 低频射电望远镜嵌入式元件模式的有效存储

IF 1.6 4区地球科学

Radio Science Pub Date : 2024-12-31 DOI: 10.1029/2024RS008080

David B. Davidson;Adrian T. Sutinjo

{"title":"Efficient storage of embedded element patterns for low frequency radio telescopes","authors":"David B. Davidson;Adrian T. Sutinjo","doi":"10.1029/2024RS008080","DOIUrl":"https://doi.org/10.1029/2024RS008080","url":null,"abstract":"The use of spherical modes offers an efficient solution for storing embedded element patterns with significant angular structure for large scale arrays, such as the Square Kilometer Array (SKA)-Low radio telescope. These patterns are required for calibration of the numerous stations comprising the telescope, each containing several hundred elements, and operating over a 7:1 bandwidth. However, implementation is significantly complicated by the many differences in the notation used in the literature for the Legendre special functions. The differing phasor conventions used in electrical engineering and physics further complicate this. This paper synthesizes much of the existing literature on this topic, paying special attention to these issues. Mathematical implementation issues are also addressed. A number of suitable tests using canonical dipole radiators to verify correct implementation are outlined. The paper concludes with tests on an individual SKALA4 antenna and a full-scale SKA-Low prototype station comprising 256 of these antennas. The storage saving afforded is some three orders of magnitude; this is very significant for a full SKA-Low station. Supporting material summarizes differing formulations and conventions encountered in the literature.","PeriodicalId":49638,"journal":{"name":"Radio Science","volume":"59 12","pages":"1-15"},"PeriodicalIF":1.6,"publicationDate":"2024-12-31","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"142905913","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":4,"RegionCategory":"地球科学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

引用次数: 0

Automatic segmentation model and parameter extraction algorithm for lightning whistlers 雷电口哨自动分割模型及参数提取算法

IF 1.6 4区地球科学

Radio Science Pub Date : 2024-11-01 DOI: 10.1029/2024RS007984

Tian Xiang;Moran Liu;Shimin He;Xiang Wang;Chen Zhou

{"title":"Automatic segmentation model and parameter extraction algorithm for lightning whistlers","authors":"Tian Xiang;Moran Liu;Shimin He;Xiang Wang;Chen Zhou","doi":"10.1029/2024RS007984","DOIUrl":"https://doi.org/10.1029/2024RS007984","url":null,"abstract":"Based on the magnetic field data recorded by the ZH-1 electromagnetic satellite, we cerat a training set of 1,300 spectrograms containing the dispersion spectrum of lightning whistlers (LW). The Segment Anything Model (SAM) in the field of image segmentation is trained through the training set to obtain a fine-tuned SAM model that can be used to detect and segment the dispersion spectrum of LW at pixel level. All track regions of LW are effectively separated from other non-lightning whistlers regions in the spectrograms after being segmented by the model. The segmentation effect is excellent and detection accuracy is 96.89%, which is better than the previous segmentation model for LW based on ground station data. Then we apply the traditional image processing methods to extract the dispersion spectrum of LW one by one, and develop an algorithm to automatically extract the physical parameters of each LW. The root mean square error between the automatically extracted dispersion parameter and the manually extracted dispersion parameter is only 0.1654 s\u0000<sup>1/2</sup>\u0000. The model and algorithm studied in this paper are employed to analyze the dispersion of LW received by the ZH-1 satellite over China. It is found that the whistlers dispersion received by satellites during summer in the northern hemisphere and summer in the southern hemisphere shows opposite trends with receiving latitude. Both trends can be explained by the relationship between the dispersion and the length of propagation paths of LW.","PeriodicalId":49638,"journal":{"name":"Radio Science","volume":"59 11","pages":"1-14"},"PeriodicalIF":1.6,"publicationDate":"2024-11-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"142777717","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":4,"RegionCategory":"地球科学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

引用次数: 0

Spatial-temporal analysis of inter tropical discontinuity influence on radio signal behavior in Nigeria 热带间断性对尼日利亚无线电信号行为影响的时空分析

IF 1.6 4区地球科学

Radio Science Pub Date : 2024-11-01 DOI: 10.1029/2024RS008006

I. Emmanuel;O. S. Ojo;G. O. Emmanuel;K. D. Adedayo

引用次数: 0

Electromagnetic energy propagation through rock of low loss tangent 电磁能在低损耗切线岩石中的传播

IF 1.6 4区地球科学

Radio Science Pub Date : 2024-11-01 DOI: 10.1029/2024RS008076

B. A. Austin

引用次数: 0

Advanced hybrid optimization algorithms for energy efficient cloud resource allocation 节能云资源分配的先进混合优化算法

IF 1.6 4区地球科学

Radio Science Pub Date : 2024-11-01 DOI: 10.1029/2024RS008012

M. Suresh Kumar;D. Mansoor Hussain;M. Rohini;S. Oswalt Manoj

{"title":"Advanced hybrid optimization algorithms for energy efficient cloud resource allocation","authors":"M. Suresh Kumar;D. Mansoor Hussain;M. Rohini;S. Oswalt Manoj","doi":"10.1029/2024RS008012","DOIUrl":"https://doi.org/10.1029/2024RS008012","url":null,"abstract":"Cloud computing is highly sought after for its dynamic resource allocation capabilities and pay-per-use model. However, previous research has identified several challenges, such as lower coverage, high integration rates, longer computation times, and complex operators, all of which are associated with NP-hard problems. These issues negatively impact the efficiency of resource allocation and scheduling, leading to slower processes, inefficiencies in multi-objective optimization, lower throughput, and higher power consumption. To address these challenges, we propose a unique Hybridized Optimization Algorithm that integrates Crow Swarm Optimization (CSO), Cuckoo Search Optimization (CSO), and Cat Hunting Optimization (CHO). Initially, Particle Swarm Optimization (PSO) and the Crow Search Algorithm (CSA) handle the exploitation and exploration phases to balance task loads. Subsequently, Cuckoo Search Optimization (CSO) enhances resource utilization and addresses NP-hard issues, while Cat Hunting Optimization (CHO) refines the search from global to local optimal spaces to achieve the best values. The results demonstrate that the proposed hybrid technique effectively reduces user request waiting times, lowers energy consumption, and decreases execution times on cloud servers compared to baseline approaches, thereby significantly improving overall system performance.","PeriodicalId":49638,"journal":{"name":"Radio Science","volume":"59 11","pages":"1-20"},"PeriodicalIF":1.6,"publicationDate":"2024-11-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"142777715","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":4,"RegionCategory":"地球科学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

引用次数: 0

Mathematical model of a rectangular double negative meta-structure for 5G applications 5G应用中矩形双负元结构的数学模型

IF 1.6 4区地球科学

Radio Science Pub Date : 2024-11-01 DOI: 10.1029/2024RS008036

M. J. Alam;S. I. Latif

{"title":"Mathematical model of a rectangular double negative meta-structure for 5G applications","authors":"M. J. Alam;S. I. Latif","doi":"10.1029/2024RS008036","DOIUrl":"https://doi.org/10.1029/2024RS008036","url":null,"abstract":"This article introduces the mathematical formulation of a proven rectangular double negative (DNZ) metamaterial (MTM) structure using a lumped element circuit model in terms of RLC components for millimeter-wave (mmWave) 28 GHz applications. The structure is developed on a 0.254 mm-thick substrate material: Rogers RT/duroid 5880 with an area of 8.7 mm\u0000<sup>2</sup>\u0000. The model accounts for different losses inherent in the system; a series resistance to take into account the losses in the conductor and a shunt resistance to describe the losses in the dielectric substrate, addressing the finite conductivity of conducting materials, the finite resistivity of the dielectric material, and the presence of a dielectric substrate with metallic rings on top. By incorporating these factors, it is possible to precisely predict the resonance frequency associated with this specific structure, however limits the formulation from being applied to other shapes. Numerical validation demonstrates a good agreement with analytical predictions, affirming the model's reliability. The study provides a robust analytical foundation and numerical validation for the double negative metamaterial unit cell, advancing the mmWave 5G wireless technology field.","PeriodicalId":49638,"journal":{"name":"Radio Science","volume":"59 11","pages":"1-8"},"PeriodicalIF":1.6,"publicationDate":"2024-11-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"142777716","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":4,"RegionCategory":"地球科学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

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Front matters 前面问题

IF 1.6 4区地球科学

Radio Science Pub Date : 2024-11-01 DOI: 10.1002/rds.21247

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Effects of tropospheric turbulence on radio signal data passing atmospheric communication links 对流层湍流对通过大气通信链路的无线电信号数据的影响

IF 1.6 4区地球科学

Radio Science Pub Date : 2024-11-01 DOI: 10.1029/2023RS007895

I. Bronfman;Y. Ben-Shimol;N. Blaunstein

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