Radio Science最新文献_第8页

Synthesis of elliptically shaped aperiodic antenna arrays subject to complex design constraints 受复杂设计约束的椭圆形超周期天线阵列的合成

IF 1.6 4区地球科学

Radio Science Pub Date : 2024-03-30 DOI: 10.1029/2023RS007914

J. M. E. Geerarts;G. Theis;A. B. Smolders;D. Caratelli

引用次数: 0

Front matters 前方事项

IF 1.6 4区地球科学

Radio Science Pub Date : 2024-03-30 DOI: 10.1002/rds.21241

引用次数: 0

High-latitude off-great circle propagation associated with the solar terminator 与太阳终结者有关的高纬度偏离大圆传播

IF 1.6 4区地球科学

Radio Science Pub Date : 2024-03-30 DOI: 10.1029/2023RS007917

T. G. Cameron;R. A. D. Fiori;G. W. Perry;J. J. Ruck;T. Thayaparan

{"title":"High-latitude off-great circle propagation associated with the solar terminator","authors":"T. G. Cameron;R. A. D. Fiori;G. W. Perry;J. J. Ruck;T. Thayaparan","doi":"10.1029/2023RS007917","DOIUrl":"10.1029/2023RS007917","url":null,"abstract":"Large-scale ionospheric gradients associated with the solar terminator can deflect high frequency (HF) radio waves to off-great circle paths during the morning and evening, negatively impacting technologies reliant on HF radio wave propagation. For example, geolocation algorithms used by scientific and military over-the-horizon radars (OTHRs) generally assume on-great circle propagation, and thus lateral deviations from the great-circle path can lead to positioning errors. In this study, radio wave propagation is simulated via 3D numerical ray traces though an empirical, high-latitude model ionosphere initialized for a variety of times of the day and year to explore and quantify high-latitude off-great circle propagation associated with the solar terminator. Analysis of these simulations show large scale east-west ionospheric gradients due to the solar terminator can cause lateral deviations in north-directed propagation paths exceeding 20° at sunrise and sunset depending on radio wave frequency, though the largest portion of received signal power tends to experience maximum deflections of 5°. An exploration of the dependence of propagation direction on deflection shows that propagation paths parallel to the solar terminator tend to experience the largest deflections. Since the solar terminator at high latitudes is at an angle with respect to north in the winter and summer, propagation paths oriented west or east of north can experience larger deflections than north oriented paths at sunrise and sunset during these times of year. Impacts of these diurnal deflections on the operation of OTHR and scientific radar are discussed, as well as possible strategies for mitigating them.","PeriodicalId":49638,"journal":{"name":"Radio Science","volume":"59 5","pages":"1-17"},"PeriodicalIF":1.6,"publicationDate":"2024-03-30","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"141140263","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

Application of wide-beam transmission for advanced operations of SuperDARN Borealis radars in monostatic and multistatic modes 应用宽波束传输实现单静态和多静态模式下超级雷达网北极光雷达的高级操作

IF 1.6 4区地球科学

Radio Science Pub Date : 2024-03-30 DOI: 10.1029/2023RS007900

R. A. Rohel;P. Ponomarenko;K. A. McWilliams

{"title":"Application of wide-beam transmission for advanced operations of SuperDARN Borealis radars in monostatic and multistatic modes","authors":"R. A. Rohel;P. Ponomarenko;K. A. McWilliams","doi":"10.1029/2023RS007900","DOIUrl":"10.1029/2023RS007900","url":null,"abstract":"The Super Dual Auroral Radar Network (SuperDARN) consists of more than 30 monostatic high-frequency (HF, 8-20 MHz) radars to study dynamic processes in the ionosphere. SuperDARN provides maps of global-scale ionospheric plasma drift circulation from the mid-latitudes to the poles. The conventional SuperDARN radars consecutively scan through 16 beam directions with a lower limit of 1 minute to sample the entire field of view. In this work, we use the advanced capabilities of the recently developed Borealis digital SuperDARN radar system. Combining a wide transmission beam with multiple narrow reception beams allows us to sample all conventional beam directions simultaneously and to speed up scanning of the entire field-of-view by up to 16 times without noticeable deterioration of the data quality. The wide-beam emission also enabled the implementation of multistatic operations, where ionospheric scatter signals from one radar are received by other radars with overlapping viewing areas. These novel operations required the development of a new model to determine the geographic location of the source of the multistatic radar echoes. Our preliminary studies showed that, in comparison with the conventional monostatic operations, the multistatic operations provide a significant increase in geographic coverage, in some cases nearly doubling it. The multistatic data also provide additional velocity vector components, increasing the likelihood of reconstructing full plasma drift velocity vectors. The developed operational modes can be readily implemented at other fully digital SuperDARN radars.","PeriodicalId":49638,"journal":{"name":"Radio Science","volume":"59 5","pages":"1-17"},"PeriodicalIF":1.6,"publicationDate":"2024-03-30","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"141047304","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

Direct digital RF transceiver technology for millimeter-wave DBF systems 毫米波 DBF 系统的直接数字 RF 收发器技术

IF 1.6 4区地球科学

Radio Science Pub Date : 2024-03-30 DOI: 10.1029/2023RS007802

Noriharu Suematsu

引用次数: 0

Novel scheme for GPU-accelerated finite-difference time-domain simulation of electromagnetic wave interaction with magnetic plasma GPU 加速时域有限差分模拟电磁波与磁性等离子体相互作用的新方案

IF 1.6 4区地球科学

Radio Science Pub Date : 2024-03-30 DOI: 10.1029/2023RS007862

Shimin He;Moran Liu;Ting Feng;Yiyun Wu;Xiang Wang;Chen Zhou;Ting Lan;Haiyin Qing

引用次数: 0

Design and characterization of the engineering model of the spectrometer onboard LuSEE-Night 设计和鉴定 LuSEE-Night 星上光谱仪的工程模型

IF 1.6 4区地球科学

Radio Science Pub Date : 2024-03-30 DOI: 10.1029/2023RS007925

Emi Tamura;Jack Fried;Sven Herrmann;Paul O'Connor;Eric J. Raguzin;Anze Slosar

引用次数: 0

Power spectral characteristics of in-situ irregularities and topside GPS signal intensity at low latitudes using high-sample-rate swarm echo (e-POP) measurements 利用高采样率蜂群回波（e-POP）测量低纬度原地不规则性和顶层 GPS 信号强度的功率谱特征

IF 1.6 4区地球科学

Radio Science Pub Date : 2024-03-30 DOI: 10.1029/2023RS007885

Ali Mohandesi;David J. Knudsen;Susan Skone;Richard B. Langley;Andrew W. Yau

{"title":"Power spectral characteristics of in-situ irregularities and topside GPS signal intensity at low latitudes using high-sample-rate swarm echo (e-POP) measurements","authors":"Ali Mohandesi;David J. Knudsen;Susan Skone;Richard B. Langley;Andrew W. Yau","doi":"10.1029/2023RS007885","DOIUrl":"10.1029/2023RS007885","url":null,"abstract":"Ionospheric density structures at low latitudes range in size from thousands of kilometers down to a few meters. Radio frequency (RF) signals, such as those from global navigation satellite systems, that propagate through irregularities suffer from rapid fluctuations in phase and intensity, known as scintillations. In this study, we use the high-sample-rate measurements of the Swarm Echo (CASSIOPE/e-POP) satellite's GPS Occultation (GAP-O) receiver taken after its antenna was re-oriented to vertical-pointing, simultaneously with e-POP Ion Mass Spectrometer surface current observations as a proxy for plasma density, to obtain the spectral characteristics of GPS signal intensity and in-situ irregularities at altitudes from 350 to 1,280 km. We show that the power spectra of both measurements can generally be characterized by a power law. In the case of density irregularities, the spectral index with the highest occurrence rate is around 1.7, which is consistent with previous studies. Also, all the power spectra of GPS signal intensity in this study show a single spectral index near 2. Moreover, roll-off frequencies estimated in this work range from 0.4 to 2.5 Hz, which is significantly higher than Fresnel frequencies calculated from ground GPS receivers at low latitudes (between 0.2 and 0.45 Hz). Part of this increase is due to the 8 km/s orbital velocity of Swarm Echo near perigee. Another key difference is that variations in the GPS signals in this study are dominated by the topside ionosphere, whereas GPS signals received from ground are affected mostly by the relatively dense F-region plasma in the 250-350 km altitudinal range.","PeriodicalId":49638,"journal":{"name":"Radio Science","volume":"59 5","pages":"1-11"},"PeriodicalIF":1.6,"publicationDate":"2024-03-30","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"141035540","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

D-CDA: A denoise and change detection approach for flood disaster location from SAR images D-CDA：利用合成孔径雷达图像进行洪水灾害定位的去噪和变化检测方法

IF 1.6 4区地球科学

Radio Science Pub Date : 2024-03-30 DOI: 10.1029/2023RS007846

Runbo Xie;Guang Yang;Yuping Zhang;Dongzhe Han;Meng Huang;Shuai Liu;Wangze Lu

{"title":"D-CDA: A denoise and change detection approach for flood disaster location from SAR images","authors":"Runbo Xie;Guang Yang;Yuping Zhang;Dongzhe Han;Meng Huang;Shuai Liu;Wangze Lu","doi":"10.1029/2023RS007846","DOIUrl":"https://doi.org/10.1029/2023RS007846","url":null,"abstract":"Floods are among the most devastating natural disasters worldwide. Such disasters are often accompanied by strong precipitation and other weather factors, making it more difficult to identify affected areas. Moreover, synthetic aperture radar (SAR) technology can capture images in a 24-hr window and penetrate clouds and fog. Change detection (CD) technology based on SAR images is generally utilized to locate disaster-stricken areas by analyzing the differences between pre- and post-disaster images. However, this method faces two main challenges: the presence of speckle noise, which reduces the difference detection accuracy, and the lack of a suitable SAR data set for flood disaster CD. Therefore, this study proposes a novel two-stage approach for locating flood disaster areas, known as the denoising-change detection approach (D-CDA). The first stage comprises a nine-layer denoising network with an encoder-decoder structure known as the SAR denoising network (SDNet). It utilizes a multiresidual block and a parallel convolutional block attention module to extract features during the encoding process to suppress the noise component. In the second stage, a novel convolution neural network is proposed to detect the changes between bitemporal SAR images, namely, the coordinate attention fused network, which combines the siamese network and UNet++ as the backbone, and fuses coordinate attention modules to enhance the change features. Moreover, a CD data set (Zhengzhou flood data set) was constructed using Sentinel-1 SAR images based on the 2021 flood disaster in Zhengzhou, China. Simulations verify the effectiveness of the proposed method. The experimental results indicate that D-CDA achieves favorable detection performance in locating flood disaster areas.","PeriodicalId":49638,"journal":{"name":"Radio Science","volume":"59 5","pages":"1-18"},"PeriodicalIF":1.6,"publicationDate":"2024-03-30","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"141181888","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

Wavelet Analysis of Differential TEC Measurements Obtained Using LOFAR 利用 LOFAR 获取的 TEC 差分测量结果的小波分析

IF 1.6 4区地球科学

Radio Science Pub Date : 2024-03-30 DOI: 10.1029/2023rs007871

Ben Boyde, Alan Wood, G. Dorrian, Frits Sweijen, Francesco de Gasperin, Maaijke Mevius, Kasia Beser, David Themens

{"title":"Wavelet Analysis of Differential TEC Measurements Obtained Using LOFAR","authors":"Ben Boyde, Alan Wood, G. Dorrian, Frits Sweijen, Francesco de Gasperin, Maaijke Mevius, Kasia Beser, David Themens","doi":"10.1029/2023rs007871","DOIUrl":"https://doi.org/10.1029/2023rs007871","url":null,"abstract":"Radio interferometers used to make astronomical observations, such as the LOw Frequency ARray (LOFAR), experience distortions imposed upon the received signal due to the ionosphere as well as those from instrumental errors. Calibration using a well‐characterized radio source can be used to mitigate these effects and produce more accurate images of astronomical sources, and the calibration process provides measurements of ionospheric conditions over a wide range of length scales. The basic ionospheric measurement this provides is differential Total Electron Content (TEC, the integral of electron density along the line of sight). Differential TEC measurements made using LOFAR have a precision of <1 mTECu and therefore enable investigation of ionospheric disturbances which may be undetectable to many other methods. We demonstrate an approach to identify ionospheric waves from these data using a wavelet transform and a simple plane wave model. The noise spectra are robustly characterized to provide uncertainty estimates for the fitted parameters. An example is shown in which this method identifies a wave with an amplitude an order of magnitude below those reported using Global Navigation Systems Satellite TEC measurements. Artificially generated data are used to test the accuracy of the method and establish the range of wavelengths which can be detected using this method with LOFAR data. This technique will enable the use of a large and mostly unexplored data set to study traveling ionospheric disturbances over Europe.","PeriodicalId":49638,"journal":{"name":"Radio Science","volume":"28 24","pages":""},"PeriodicalIF":1.6,"publicationDate":"2024-03-30","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"140364463","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