Radio Science最新文献_第4页

Quantifying errors in the midpoint transform applied to oblique ionograms 应用于斜电离图的中点变换的量化误差

IF 1.6 4区地球科学

Radio Science Pub Date : 2026-07-01 Epub Date: 2026-08-05 DOI: 10.1029/2026RS008726

Joe Hughes;L. J. Nickisch;Sergey Fridman;Gregory Bullock;Shawn Kraut;Matt Hogan;Victoriya Forsythe

{"title":"Quantifying errors in the midpoint transform applied to oblique ionograms","authors":"Joe Hughes;L. J. Nickisch;Sergey Fridman;Gregory Bullock;Shawn Kraut;Matt Hogan;Victoriya Forsythe","doi":"10.1029/2026RS008726","DOIUrl":"https://doi.org/10.1029/2026RS008726","url":null,"abstract":"It is important to specify the state of the ionosphere for Over-the-Horizon communications and surveillance. Both vertical and oblique ionograms provide valuable data to this end. Oblique ionograms can probe the ionosphere in locations where it would be impractical to build a vertical ionosonde, but their measurements are not straightforward to assimilate. There are essentially two assimilation methods: the first is to transform the oblique ionogram to the corresponding vertical ionogram and assimilate it at the link midpoint. There are a few different ways to perform this transform, all of which introduce errors. The second method is to ingest the oblique ionogram directly. This method does not make these assumptions, but is more computationally expensive and is currently only implemented in the GPS Ionospheric Inversion data assimilation model. This paper quantifies the errors in the first method. This is done by simulating oblique ionograms as well as vertical ionograms at the oblique link midpoint using numerical raytracing. The oblique ionograms are transformed and compared to the verticals. Differences in the critical frequency and the height at which it occurs are studied as a function of latitude, local time, oblique link direction, and mode (O or X). This is done for ground ranges of 2,500, 1,250, 600, 300, 150, and 75 km. For 2,500 km links, we find Root Mean Square Errors for critical frequency of 0.4 MHz (9.9%), and 22 km (9.3%) for hmF2. Shorter links are less affected, but still have significant errors for ground distances over 300 km.","PeriodicalId":49638,"journal":{"name":"Radio Science","volume":"61 7","pages":"1-12"},"PeriodicalIF":1.6,"publicationDate":"2026-07-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"148675472","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

Radiosonde-constrained full-wave modeling framework for near- and far-field electromagnetic propagation in a stratified atmosphere 层状大气中近场和远场电磁传播的无线电探空约束全波建模框架

IF 1.6 4区地球科学

Radio Science Pub Date : 2026-07-01 Epub Date: 2026-08-05 DOI: 10.1029/2025RS008444

Sujit Kumar Chakravarty

引用次数: 0

Design and implementation of an automated safety control system for the Jocelyn Bell Burnell radio telescope 乔斯林·贝尔·伯内尔射电望远镜自动安全控制系统的设计与实现

IF 1.6 4区地球科学

Radio Science Pub Date : 2026-07-01 Epub Date: 2026-08-05 DOI: 10.1029/2026RS008626

Rubén Benítez;Rafael Ruiz;Silvia Diaz

{"title":"Design and implementation of an automated safety control system for the Jocelyn Bell Burnell radio telescope","authors":"Rubén Benítez;Rafael Ruiz;Silvia Diaz","doi":"10.1029/2026RS008626","DOIUrl":"https://doi.org/10.1029/2026RS008626","url":null,"abstract":"Large parabolic antennas used in radio astronomy are mechanically vulnerable to high wind loads, which can compromise both structural integrity and pointing calibration. We present the design, implementation, and validation of an automated safety control system for the 4.5 m Jocelyn Bell Burnell radio telescope at the Public University of Navarre. The system combines a compact meteorological tower measuring wind speed, wind direction, and ambient temperature with a programmable logic controller (PLC) that mediates between the existing antenna rotator controller and the observatory server. The PLC implements a multi-level wind-alert strategy and an emergency stop mechanism, and automatically commands the antenna to a mechanically safe configuration: zenith elevation and azimuth aligned with the incident wind direction. Communication with the commercial rotator controller uses the proprietary Rot2Prog serial protocol over RS-232, whereas communication with the observatory server relies on Modbus/TCP over Ethernet. A web-based human-machine interface allows users to configure wind thresholds and safety timers, visualize meteorological conditions, and manually request safe stops. The integrated system has been deployed on site and successfully tested under realistic operating scenarios, including commanded pointings, emergency stops, and automatic reactions to strong winds. The solution significantly improves the robustness and autonomy of telescope operations by removing the need for continuous human supervision of weather conditions.","PeriodicalId":49638,"journal":{"name":"Radio Science","volume":"61 7","pages":"1-15"},"PeriodicalIF":1.6,"publicationDate":"2026-07-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"148676030","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

Optimizing HAARP beam pattern for generation of strong F-region field-aligned irregularities 优化HAARP波束模式产生强f区场对准不规则性

IF 1.6 4区地球科学

Radio Science Pub Date : 2026-07-01 Epub Date: 2026-08-05 DOI: 10.1029/2025RS008343

T. S. Anderson;E. H. Lay;I. T. Cummings;C. A. Jeffery;P. A. Bernhardt;M. McCarrick;W. A. Bristow;S. J. Briczinski

{"title":"Optimizing HAARP beam pattern for generation of strong F-region field-aligned irregularities","authors":"T. S. Anderson;E. H. Lay;I. T. Cummings;C. A. Jeffery;P. A. Bernhardt;M. McCarrick;W. A. Bristow;S. J. Briczinski","doi":"10.1029/2025RS008343","DOIUrl":"https://doi.org/10.1029/2025RS008343","url":null,"abstract":"Field-aligned irregularities (FAIs) are the signatures of plasma turbulence and convection in the mid- and high-latitude F-region ionosphere, and also provide coherent backscatter targets for HF radars. To serve irregularity generation and characterization studies, we conducted experiments at the High-frequency Active Auroral Research Program (HAARP) in August 2023 with the goal of identifying the optimal HAARP beam pattern for reliable generation of intense FAIs over a large geographic region. The HAARP beam patterns we tested were the commonly-used narrow beam, also known as L0, as well as the wider L1 and L2 “twisted” beam patterns. The size and intensity of the FAI region generated by each HAARP beam pattern was quantified using the Kodiak Island Super Dual Auroral Radar Network (SuperDARN) radar. Stimulated electromagnetic emissions (SEE) from heater wave-FAI scattering were also recorded using a receiver located near HAARP. The L1 beam pattern was found to produce the strongest SuperDARN backscatter over the largest region. Although the heater frequency was intended to be tuned a few hundred kHz below the F-region critical frequency (foF2) during each experiment, difficulty in estimating foF2 during the campaign likely resulted in HAARP heating at significantly different frequency ranges around foF2 during each experiment. Although this additional free parameter complicated data analysis for this study, the SuperDARN and SEE measurements have led to further inquiry into the role heater frequency plays in the artificial generation of FAIs.","PeriodicalId":49638,"journal":{"name":"Radio Science","volume":"61 7","pages":"1-15"},"PeriodicalIF":1.6,"publicationDate":"2026-07-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"148676097","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

Mutual radio occultation experiment between Mars orbiters: Algorithms implementation and validation 火星轨道飞行器间相互无线电掩星实验：算法实现与验证

IF 1.6 4区地球科学

Radio Science Pub Date : 2026-07-01 Epub Date: 2026-08-05 DOI: 10.1029/2024RS007970

B. Nava;Y. Migoya-Orué;A. Kashcheyev;B. Sánchez-Cano;O. Witasse;H. Svedhem;J. Parrott;S. M. Radicella;C. Wilson;D. Titov;C. O. Ao

{"title":"Mutual radio occultation experiment between Mars orbiters: Algorithms implementation and validation","authors":"B. Nava;Y. Migoya-Orué;A. Kashcheyev;B. Sánchez-Cano;O. Witasse;H. Svedhem;J. Parrott;S. M. Radicella;C. Wilson;D. Titov;C. O. Ao","doi":"10.1029/2024RS007970","DOIUrl":"https://doi.org/10.1029/2024RS007970","url":null,"abstract":"Radio occultation (RO) is a very powerful technique as it offers great opportunities to study planetary atmospheres, providing information about their ionosphere and neutral atmosphere. Standard methods use a radio link at S and/or X bands between a spacecraft orbiting a planet and a ground station on the Earth. At Mars, such measurements have been conducted since the 60s. Three most recent data sets are from Mars Global Surveyor, Mars Express and the Mars Atmosphere and Volatile Evolution satellites. Furthermore, the possibility to obtain information about the Martian atmosphere with mutual RO events, using data from NASA Mars Odyssey and Mars Reconnaissance Orbiters, has been demonstrated by NASA scientists in 2015. Taking advantage of two European spacecraft in orbit around Mars, the ESA is currently performing an experiment that consists of mutual radio occultations between Mars Express (MEX) and ExoMars Trace Gas Orbiter (TGO). In preparation for MEX and TGO data inversion and analysis, a simulation-based strategy has been adopted and an algorithm, including the associated software, able to retrieve vertical electron density profiles from Doppler shift measurements has been implemented and validated. Subsequently, to test the mentioned algorithm with experimental data, the same three mutual RO events considered by NASA scientists have been re-processed. In this work, the research activities carried out through the simulation studies and the results obtained by the application of the mentioned inversion algorithm to experimental data are presented.","PeriodicalId":49638,"journal":{"name":"Radio Science","volume":"61 7","pages":"1-11"},"PeriodicalIF":1.6,"publicationDate":"2026-07-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"148675744","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 : 2026-07-01 Epub Date: 2026-08-05 DOI: 10.1029/rds.70077

引用次数: 0

An unexpected challenge in GNSS-reflectometry: Experimental investigation of EMI from LED street lighting on signal quality gnss反射测量中意想不到的挑战：LED路灯照明EMI对信号质量的实验研究

IF 1.6 4区地球科学

Radio Science Pub Date : 2026-06-01 Epub Date: 2026-07-03 DOI: 10.1029/2026RS008603

Ömer Kasar;Utkan Mustafa Durdağ;Alperen Gece

{"title":"An unexpected challenge in GNSS-reflectometry: Experimental investigation of EMI from LED street lighting on signal quality","authors":"Ömer Kasar;Utkan Mustafa Durdağ;Alperen Gece","doi":"10.1029/2026RS008603","DOIUrl":"https://doi.org/10.1029/2026RS008603","url":null,"abstract":"Global Navigation Satellite Systems (GNSS) are crucial for positioning and increasingly valuable for remote sensing via GNSS-Reflectometry (GNSS-R), which utilizes signals reflected from the Earth's surface to monitor parameters like sea level, soil moisture, and snow depth. This low-cost, passive method provides continuous data, though its accuracy depends heavily on antenna characteristics and electromagnetic environmental conditions. In this study, a 3D-printed dual-ridged horn antenna with gains of 9 dB (L1 band) and 8 dB (L2 band) was used in a 24-hr measurement campaign. Surprisingly, a nearby LED streetlight induced significant electromagnetic interference (EMI) during nighttime operation. Active lighting periods resulted in dramatically reduced Signal-to-Noise Ratio (SNR), frequent signal dropouts, and distorted skyview, with spectrum analyzer measurements confirming that high-frequency switching of LED driver circuits causes electromagnetic interference in the GNSS L1 band. Average SNR dropped from 42 to 28 dB, sometimes falling below 25 dB, while morning SNR values exhibited recovery upon deactivation of the LED system. To mitigate the impact of these signal anomalies, a statistical jump detection mechanism was implemented to identify and flag EMI-induced transitions. This study highlights the vulnerability of GNSS-R stations to urban EMI and introduces an automated detection approach to ensure data integrity in affected environments.","PeriodicalId":49638,"journal":{"name":"Radio Science","volume":"61 6","pages":"1-10"},"PeriodicalIF":1.6,"publicationDate":"2026-06-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"148443200","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

Kinematic phase-referencing VLBI for precise positioning of the Tianwen-2 probe 用于“天文二号”探测器精确定位的运动相位参考VLBI

IF 1.6 4区地球科学

Radio Science Pub Date : 2026-06-01 Epub Date: 2026-07-03 DOI: 10.1029/2026RS008690

Fengxian Tong;Weimin Zheng;Yong Huang;Juan Zhang;Peijia Li;Yan Sun;Wenbin Wang;Zhanghu Chu

{"title":"Kinematic phase-referencing VLBI for precise positioning of the Tianwen-2 probe","authors":"Fengxian Tong;Weimin Zheng;Yong Huang;Juan Zhang;Peijia Li;Yan Sun;Wenbin Wang;Zhanghu Chu","doi":"10.1029/2026RS008690","DOIUrl":"https://doi.org/10.1029/2026RS008690","url":null,"abstract":"China's Tianwen-2 probe, launched on 29 May 2025, will sample asteroid 2016 HO3 and exploring comet 311P. The precise positioning of the Tianwen-2 probe will benefit its mission goals. Phase-referencing VLBI imaging offers significant potential to improve the positional precision of deep space probes. However, traditional phase-referencing VLBI imaging assumes a nearly constant angular position, thereby limiting positioning precision for moving targets, particularly with sparse arrays or long-duration observations. To enhance the tracking precision of moving targets, an improved Kinematic Phase-Referencing (KPR) VLBI method is investigated. By directly integrating a kinematic orbital model—parameterized by polynomial coefficients—into the phase-referencing VLBI process, KPR-VLBI removes the need for the nearly constant-position assumption. Observations of the Tianwen-2 probe were carried out using the five stations of the Chinese VLBI Network to validate the KPR-VLBI method. Results indicate that the final angular position precision is at the sub-milliarcsecond level, which is primarily constrained by tropospheric and ionospheric errors as well as calibrator position errors, while the 1σ formal error of angular position is better than 10 micro-arcseconds. Furthermore, compared with conventional phase-referencing VLBI imaging, KPR-VLBI is able to effectively suppress sidelobes arising from the target motion in synthesized images, thereby leading to more reliable results.","PeriodicalId":49638,"journal":{"name":"Radio Science","volume":"61 6","pages":"1-12"},"PeriodicalIF":1.6,"publicationDate":"2026-06-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"148443170","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

Frequency standard contributions to limitations on the signal-to-noise ratio in very long baseline interferometric observations 在很长的基线干涉观测中，频率标准对信噪比有限制

IF 1.6 4区地球科学

Radio Science Pub Date : 2026-06-01 Epub Date: 2026-07-03 DOI: 10.1029/2025RS008476

E. A. Burt;T. A. Ely;G. C. Bower;T. J. W. Lazio;M. Anderson;S. Hernandez

{"title":"Frequency standard contributions to limitations on the signal-to-noise ratio in very long baseline interferometric observations","authors":"E. A. Burt;T. A. Ely;G. C. Bower;T. J. W. Lazio;M. Anderson;S. Hernandez","doi":"10.1029/2025RS008476","DOIUrl":"https://doi.org/10.1029/2025RS008476","url":null,"abstract":"Since its observation in 2019, the first image of a super-massive black hole using Very Long Baseline Interferometry (VLBI) with an Earth-scale baseline has generated much scientific and public interest. Work is now underway to extend the baseline into space to obtain higher image resolution. Operating one or more VLBI nodes in space will require the use of frequency standards that are space-qualified, greatly reducing the number of options available. The coherence function C(T) is the metric usually used to determine the viability of a frequency standard. Here we show that C(T) is a useful but not sufficient metric for gauging frequency standard performance in VLBI and instead derive an expression for the clock-limited VLBI visibility S/N. We evaluate this expression for real frequency standards and find only the Ultra-Stable Oscillator (USO) and hydrogen maser to be viable for upcoming high-frequency VLBI with the USO only useful for very limited integration times (30 seconds at 90 GHz, 10 seconds at 230 GHz, 5 seconds at 345 GHz, and not viable at 630 GHz). The maser extends these, but may have prohibitive size for a space mission. We also evaluate emerging frequency standard technologies and find the optical local oscillator portion of optical clocks to be very promising (conservatively >100 seconds at 90 GHz, 60 seconds at 230 GHz, 40 seconds at 345 GHz, and 22 seconds at 630 GHz) when accounting for both performance and potential operation in space.","PeriodicalId":49638,"journal":{"name":"Radio Science","volume":"61 6","pages":"1-47"},"PeriodicalIF":1.6,"publicationDate":"2026-06-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"148443136","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

Machine learning models for ionospheric foF2 prediction: A comparative analysis 电离层foF2预测的机器学习模型：比较分析

IF 1.6 4区地球科学

Radio Science Pub Date : 2026-06-01 Epub Date: 2026-07-03 DOI: 10.1029/2025RS008336

R. Atici;Z. Pala

引用次数: 0