Radio Science最新文献_第2页

Obtaining local-tie vectors from short-baseline interferometry between legacy S/X and VGOS telescopes at Ny-Ålesund 从Ny的传统S/X和VGOS望远镜之间的短基线干涉测量获得局部联系矢量-Ålesund

IF 1.6 4区地球科学

Radio Science Pub Date : 2026-09-01 Epub Date: 2026-10-06 DOI: 10.1029/2025RS008586

Rebekka Handirk;Eskil Varenius;Tobias Nilsson;Karine Le Bail;Rubén Bolaño González;Susana Garcia-Espada;Axel Meldahl;Thomas Gasmoe;Silje Agnes Gr⊘slie Wennesland;Oddvar Bråvold Tangen;Halfdan Pascal Kierulf

{"title":"Obtaining local-tie vectors from short-baseline interferometry between legacy S/X and VGOS telescopes at Ny-Ålesund","authors":"Rebekka Handirk;Eskil Varenius;Tobias Nilsson;Karine Le Bail;Rubén Bolaño González;Susana Garcia-Espada;Axel Meldahl;Thomas Gasmoe;Silje Agnes Gr⊘slie Wennesland;Oddvar Bråvold Tangen;Halfdan Pascal Kierulf","doi":"10.1029/2025RS008586","DOIUrl":"https://doi.org/10.1029/2025RS008586","url":null,"abstract":"With the ongoing transition for geodetic Very Long Baseline Interferometry (VLBI) from the use of legacy S/X telescopes to the VLBI Global Observing System (VGOS), it is necessary to connect the new VGOS network to the existing legacy S/X telescopes. One way to do this is through specially designed short-baseline interferometry sessions with the aim to obtain local-tie vectors between these telescope generations at observatories that host both legacy S/X and new generation VGOS telescopes. The dismantling of the legacy S/X telescope NYALES20 at the Ny-Ålesund Geodetic Earth Observatory in August 2023 was preceded by around one and a half years of short-baseline interferometric measurements, referred to as NYTIE, to the new VGOS telescopes NYALE13S and NYALE13N. The results of these measurements are used to connect the old and new networks at this observatory. We present both group and phase delay results of this dedicated measurement campaign. We also analyze the same baselines with data that can be obtained from regular IVS-R1 and IVS-R4 sessions. We find a significant discrepancy between group and phase delay positions in the vertical component. Sensitivity tests attribute this discrepancy to session-dependent differential troposphere effects rather than to telescope deformation modeling. Both group and phase delay results are consistent with a classical geodetic survey using total station and GNSS once the formal uncertainties are rescaled to reflect the observed session-to-session scatter and a residual modeling systematic of 7 mm is taken into account.","PeriodicalId":49638,"journal":{"name":"Radio Science","volume":"61 9","pages":"1-16"},"PeriodicalIF":1.6,"publicationDate":"2026-09-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"149097167","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

Impact of terahertz electromagnetic devices on human tissue: A review of SAR and safety considerations 太赫兹电磁装置对人体组织的影响：SAR和安全考虑的综述

IF 1.6 4区地球科学

Radio Science Pub Date : 2026-08-01 Epub Date: 2026-09-08 DOI: 10.1029/2025RS008496

Nipun Sharma;Amrit Kaur;Swati Sharma

{"title":"Impact of terahertz electromagnetic devices on human tissue: A review of SAR and safety considerations","authors":"Nipun Sharma;Amrit Kaur;Swati Sharma","doi":"10.1029/2025RS008496","DOIUrl":"https://doi.org/10.1029/2025RS008496","url":null,"abstract":"Terahertz (THz) technology, operating in the 0.1-10 THz band, has gained increasing relevance in wireless communications, biomedical diagnostics, and wearable systems. Its ability to provide high-resolution imaging and non-invasive sensing has made it a promising tool in healthcare. However, strong absorption of THz waves by water-rich biological tissues raises critical concerns regarding biological safety. A key metric for evaluating electromagnetic exposure is the Specific Absorption Rate (SAR), which quantifies the rate of energy deposition in tissues. This review examines the role of THz antennas, sensors, and absorbers in shaping electromagnetic field distributions and their implications on SAR. While flexible and compact THz antennas and sensors demonstrate potential for applications such as COVID-19 detection, fall monitoring, and biosensing, most studies rely on simplified phantoms or simulations, limiting biological realism. Similarly, metamaterial absorbers enhance device sensitivity and control field localization but may inadvertently introduce resonant hotspots that increase localized SAR. Current research highlights a trade-off between device performance and biological safety, further constrained by incomplete dielectric data sets and lack of standardized measurement techniques. This review underscores the urgent need for experimental validation, localized SAR metrics, and updated safety frameworks to ensure the safe deployment of THz-enabled biomedical technologies.","PeriodicalId":49638,"journal":{"name":"Radio Science","volume":"61 8","pages":"1-23"},"PeriodicalIF":1.6,"publicationDate":"2026-08-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"148903047","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

PyRayHF: An open source ray-tracing forward operator for assimilating oblique ionograms PyRayHF：用于吸收斜离子图的开放源代码射线追踪正向算子

IF 1.6 4区地球科学

Radio Science Pub Date : 2026-08-01 Epub Date: 2026-09-08 DOI: 10.1029/2026RS008702

Victoriya V. Forsythe;Henry C. Valentine;Douglas P. Drob;Joseph Hughes;Dustin Hickey;Angeline G. Burrell;Katherine A. Zawdie;Dev Raj Joshi;William Bristow;Evan G. Thomas

{"title":"PyRayHF: An open source ray-tracing forward operator for assimilating oblique ionograms","authors":"Victoriya V. Forsythe;Henry C. Valentine;Douglas P. Drob;Joseph Hughes;Dustin Hickey;Angeline G. Burrell;Katherine A. Zawdie;Dev Raj Joshi;William Bristow;Evan G. Thomas","doi":"10.1029/2026RS008702","DOIUrl":"https://doi.org/10.1029/2026RS008702","url":null,"abstract":"Oblique high-frequency (HF) ionospheric measurements contain valuable information about electron density structure, but remain difficult to assimilate operationally due to the computational cost of ray tracing. PyRayHF is an open-source, fully Python-based framework that addresses such difficulties through the implementation of efficient forward operators for HF propagation and parameter retrieval tailored to dataassimilation (DA) applications. PyRayHF implements magneto-ionic vertical tracing and a hierarchy of twodimensional oblique ray tracing methods, which are verified against one another for internal consistency and validated through comparative analysis with a full three-dimensional Jones-Stephenson ray tracer. Validation results show that all solvers reproduce key observables, including group path and apex location, with typical errors below 10% when compared to the reference solution. For group path, the primary observable in oblique ionogram interpretation, simple stratified Snell's-law formulations perform comparably to gradient-based solvers while being several orders of magnitude faster, making them suitable for DA workflows. To enable efficient assimilation, PyRayHF combines a fast vertical forward operator with a midpoint-based oblique-to-vertical transformation. For transmitter-receiver separations of 1,000–2,000 km, midpoint-derivedfoF2 errors remain below 10%. PyRayHF further provides a parameter-minimization framework that retrieves F2-layer parameters directly from midpoint-converted observations, producing anchor-point measurements suitable for direct assimilation into parametrized systems such as ANCHOR.","PeriodicalId":49638,"journal":{"name":"Radio Science","volume":"61 8","pages":"1-22"},"PeriodicalIF":1.6,"publicationDate":"2026-08-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"148903051","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

An ultra-wideband 12-elements omnidirectional antenna with compact size and low gain variation 一种尺寸紧凑、增益变化小的超宽带12元全向天线

IF 1.6 4区地球科学

Radio Science Pub Date : 2026-08-01 Epub Date: 2026-09-08 DOI: 10.1029/2025RS008566

J. Cao;Z. Dai;J. Deng;Z. Ding;Z. Ma;H. Wang

引用次数: 0

Data-driven wave distribution function method based on generalization error minimization 基于概化误差最小化的数据驱动波分布函数方法

IF 1.6 4区地球科学

Radio Science Pub Date : 2026-08-01 Epub Date: 2026-09-08 DOI: 10.1029/2025RS008562

Haruto Katsuda;Mamoru Ota;Yoshiya Kasahara

引用次数: 0

An electromagnetic-coupled LHCP stacked antenna design in L band for deep tumor detection 用于深部肿瘤检测的L波段电磁耦合LHCP叠加天线设计

IF 1.6 4区地球科学

Radio Science Pub Date : 2026-08-01 Epub Date: 2026-09-08 DOI: 10.1029/2026RS008681

S. Tripathy;V. Mukherjee;P. K. Mishro

{"title":"An electromagnetic-coupled LHCP stacked antenna design in L band for deep tumor detection","authors":"S. Tripathy;V. Mukherjee;P. K. Mishro","doi":"10.1029/2026RS008681","DOIUrl":"https://doi.org/10.1029/2026RS008681","url":null,"abstract":"Early detection of tumors improve treatment efficiency and the prognosis of tumor recurrence. Microwave imaging (MWI) is an effective modality in detection of tumor. Yet, this is challenged by strong signal attenuation and scattering caused by the dielectric heterogeneity of the human head. In this paper, we report a left-hand circularly polarized stacked antenna operating in the L-band (1.1—1.6 GHz) designed to improve signal penetration and reduce multipath interference. The reported antenna comprises of an electromagnetic coupling (EMC) stacked configuration with dual radiating patches separated by a foam spacer, a modified ground plane, and low-loss Rogers RT/duroid 6010 substrates. Strategic slotting in both the radiating patches and ground plane improves current distribution and impedance matching. This results in an average VSWR of 1.2 and a minimum return loss of − 45 dB at resonance. Full-wave simulations and experimental validation demonstrate stable circular polarization, improved radiation sensitivity, and enhanced detection capability for deep-seated tumors as small as 2 mm. These findings indicate that the proposed antenna design is well-suited for integration into non-invasive MWI-based diagnostic systems.","PeriodicalId":49638,"journal":{"name":"Radio Science","volume":"61 8","pages":"1-16"},"PeriodicalIF":1.6,"publicationDate":"2026-08-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"148903066","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

Reflection equivariant Crayfish quantum neural network based channel estimation in massive multiple input multiple output OFDM 基于反射等变小龙虾量子神经网络的大规模多输入多输出OFDM信道估计

IF 1.6 4区地球科学

Radio Science Pub Date : 2026-08-01 Epub Date: 2026-09-08 DOI: 10.1029/2026RS008680

R. J. Kavitha;E. Elakkiyachelvan

{"title":"Reflection equivariant Crayfish quantum neural network based channel estimation in massive multiple input multiple output OFDM","authors":"R. J. Kavitha;E. Elakkiyachelvan","doi":"10.1029/2026RS008680","DOIUrl":"https://doi.org/10.1029/2026RS008680","url":null,"abstract":"This study presents Reflection equivariant Crayfish Quantum Neural Networks (RCQNNs), reflection equivariant, optimized through the Crayfish Optimization Algorithm, toward efficient channel estimation, in a massive multiple-input, multiple-output orthogonal frequency-division multiplexed (MIMO-OFDM) system spectrum. Massive MIMO and OFDM have become two very important technologies in modern wireless communications, improving the efficiency of spectral and data rates. High-dimensionality of wireless channels has also made accurate channel estimation a significant challenge in such systems. In this respect, the research projects Reflection Equivariant Quantum Neural Networks (REQNNs) for using quantum neural networks (QNNs) to reflect equivariance in the network, capturing how symmetries appear inside a wireless channel. The REQNN framework guarantees that reflection symmetry holds in the model, which should be seen to generalize better and show higher prediction competency of channel states. The system further optimizes the Crayfish Optimization Algorithm to mimic crayfish behavior in nature as an input for fast fine-tuning of network parameters. Through it, the solutions are converged quickly, thus boosting network operation efficiency. Simulation results reveal that the proposed REQNN outperforms conventional models like CNN, MMV-LAMP, and FPN in MSE, PSNR, and computational efficiency. The proposed REQNN also achieves up to an 80% MSE reduction compared to existing methods and delivers up to 20 dB of PSNR increment, thus better reflecting its superior accuracy in channel estimation. Moreover, cryptography's time consumption during encryption and decryption is reduced to 1.42 and 1.34 s, respectively, which further streamlines real-time applicability in real-world situations for the MIMO OFDM channels.","PeriodicalId":49638,"journal":{"name":"Radio Science","volume":"61 8","pages":"1-21"},"PeriodicalIF":1.6,"publicationDate":"2026-08-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"148903147","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

Radio-quiet ionosonde observations for monitoring absorption in the HF band 监测高频波段吸收的无线电静音电离空探空观测

IF 1.6 4区地球科学

Radio Science Pub Date : 2026-08-01 Epub Date: 2026-09-08 DOI: 10.1029/2026RS008688

T. G. W. Verhulst;A. Buzás;D. Altadill;A. Segarra;V. de Paula;V. Barta

引用次数: 0

Front matters 前面问题

IF 1.6 4区地球科学

Radio Science Pub Date : 2026-08-01 Epub Date: 2026-09-08 DOI: 10.1029/rds.70082

引用次数: 0

Validation of ANCHOR ionospheric data assimilation model using GIRO ionosondes within PyVALION software PyVALION软件中使用GIRO电离层探空仪验证ANCHOR电离层数据同化模型

IF 1.6 4区地球科学

Radio Science Pub Date : 2026-08-01 Epub Date: 2026-09-08 DOI: 10.1029/2025RS008522

Victoriya V. Forsythe;Katherine A. Zawdie;Dustin Hickey;Angeline G. Burrell

{"title":"Validation of ANCHOR ionospheric data assimilation model using GIRO ionosondes within PyVALION software","authors":"Victoriya V. Forsythe;Katherine A. Zawdie;Dustin Hickey;Angeline G. Burrell","doi":"10.1029/2025RS008522","DOIUrl":"https://doi.org/10.1029/2025RS008522","url":null,"abstract":"Accurate specification of the ionosphere is essential for mitigating the impacts of space weather on communication, navigation, and surveillance systems. ANCHOR is a newly developed ionospheric data assimilation (DA) model from the U.S. Naval Research Laboratory that fuses measurements from ionosondes, radio occultation, and Global Navigation Satellite System (GNSS) receivers into a PyIRI-based background via a Kalman filter. To support model validation in both reproduction and standardization, PyVALION (Python VALidation for IONosphere) is introduced—a community-oriented tool built on a forward-operator framework that projects model output into observation space for statistically robust comparison. Currently, PyVALION directly supports validation of models producing NmF2, hmF2, and thickness parameters B0 and B1, with extension to other parameters for future releases. ANCHOR's performance is assessed using electron density parameters (NmF2 and hmF2) from the Global Ionospheric Radio Observatory (GIRO) ionosonde network. Four multi-day geophysical events are analyzed to evaluate model behavior under varying solar and geomagnetic conditions. Results show that ANCHOR significantly reduces both bias and root mean square error (RMSE) relative to the PyIRI background. Separating day and night conditions reveals that background bias is larger during daytime, and data assimilation proves particularly effective at correcting this bias when it is most significant. A controlled synthetic experiment confirms that forward-operator errors in PyVALION are negligible compared to observed residuals, validating its use as a precision-grade evaluation tool. These findings establish PyVALION as a reproducible and scalable framework for ionospheric model assessment and confirm ANCHOR's capability to enhance real-time ionospheric specification.","PeriodicalId":49638,"journal":{"name":"Radio Science","volume":"61 8","pages":"1-18"},"PeriodicalIF":1.6,"publicationDate":"2026-08-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"148902740","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