Radio Science最新文献_第2页

Landmine detection using electromagnetic time reversal-based methods: 2. performance analysis of TR-MUSIC 利用基于电磁时间反转的方法探测地雷：2. TR-MUSIC 的性能分析

IF 1.6 4区地球科学

Radio Science Pub Date : 2024-10-01 DOI: 10.1029/2024RS007972

Hamidreza Karami;André Koch;Carlos Romero;Marcos Rubinstein;Farhad Rachidi

{"title":"Landmine detection using electromagnetic time reversal-based methods: 2. performance analysis of TR-MUSIC","authors":"Hamidreza Karami;André Koch;Carlos Romero;Marcos Rubinstein;Farhad Rachidi","doi":"10.1029/2024RS007972","DOIUrl":"https://doi.org/10.1029/2024RS007972","url":null,"abstract":"In this paper, a series of numerical simulations are conducted for various 2D and 3D configurations to demonstrate the performance of the Time Reversal Multiple Signal Classification (TR-MUSIC) method. The results reveal the excellent performance of TR-MUSIC, taking into account the effects of noise, soil types (both homogeneous and layered), and their electrical parameters, as well as different types of targets (varying in number, size, shape, and location). Additionally, unlike other electromagnetic TR-based techniques, TR-MUSIC offers very high resolution (on the order of 1/10 or higher) with a reasonable number of sensors, enabling the detection of multiple closely spaced targets. In TR-based methods, reflections from the object(s) or landmine(s) are crucial and are determined by the difference between the constitutive parameters (e.g., permittivity, permeability, and conductivity) of the landmine(s) and their surrounding medium. Therefore, TR-based approaches, similar to conventional GPR-based approaches, are suitable for detecting objects or landmines with significant differences in constitutive parameters compared to their immersion medium. This research primarily focuses on metallic objects or landmines.","PeriodicalId":49638,"journal":{"name":"Radio Science","volume":"59 10","pages":"1-14"},"PeriodicalIF":1.6,"publicationDate":"2024-10-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"142595780","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 extraction of VLF constant-frequency electromagnetic wave frequency based on an improved Vgg16-Unet 基于改进型 Vgg16-Unet 的 VLF 恒频电磁波频率自动提取系统

IF 1.6 4区地球科学

Radio Science Pub Date : 2024-10-01 DOI: 10.1029/2024RS008019

Ying Han;Qingjie Liu;Jianping Huang;Zhong Li;Rui Yan;Jing Yuan;Xuhui Shen;Lili Xing;Guoli Pang

{"title":"Automatic extraction of VLF constant-frequency electromagnetic wave frequency based on an improved Vgg16-Unet","authors":"Ying Han;Qingjie Liu;Jianping Huang;Zhong Li;Rui Yan;Jing Yuan;Xuhui Shen;Lili Xing;Guoli Pang","doi":"10.1029/2024RS008019","DOIUrl":"https://doi.org/10.1029/2024RS008019","url":null,"abstract":"Constant Frequency Electromagnetic Waves (CFEWs) refer to electromagnetic waves with a constant frequency. Man-made CFEWs are mainly used in wireless communication, scientific research, global navigation and positioning systems, and military radar. CFEWs exhibit horizontal line characteristics higher than the background on spectrograms. In this study, we focus on Very Low Frequency (VLF) waveform data and power spectral data collected by the China Seismo-Electromagnetic Satellite (CSES) Electromagnetic Field Detector (EFD). We utilize deep learning techniques to construct an improved Vgg16-Unet model for automatically detecting horizontal lines on time-frequency spectrogram and extracting their frequencies. First, we transform waveform data into time-frequency spectrogram with a duration of 2 s using Short-Time Fourier Transform. Then, we manually label horizontal lines on the time-frequency spectrogram using the Labelme tool to establish the dataset. Next, we establish and improve the Vgg16-Unet deep learning model. Finally, we train and test the model using the dataset. Statistical experimental results show that the error rate of line detection is 0, indicating high reliability of the model, with fewer parameters and fast computation speed suitable for practical applications. Not only do we detect lines through the model, but we also obtain their frequencies. Additionally, in batch-generated power spectrogram of CFEWs, we discover some unstable phenomena such as frequency shifts and fluctuations, which contribute to understanding the propagation mechanism of CFEWs in the ionosphere and improving the accuracy of related systems.","PeriodicalId":49638,"journal":{"name":"Radio Science","volume":"59 10","pages":"1-14"},"PeriodicalIF":1.6,"publicationDate":"2024-10-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"142595787","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

Realizing orthogonal modes in compact cavity-backed dual-polarized antenna through simple feeding structures for millimeter-wave AiP applications 通过用于毫米波 AiP 应用的简单馈电结构，在紧凑型腔背双极化天线中实现正交模式

IF 1.6 4区地球科学

Radio Science Pub Date : 2024-10-01 DOI: 10.1029/2024RS008042

Tzu-Ming Huang;Yi-Cheng Lin

引用次数: 0

Channel estimation for deep space communications under the effect of solar scintillation 太阳闪烁影响下的深空通信信道估计

IF 1.6 4区地球科学

Radio Science Pub Date : 2024-10-01 DOI: 10.1029/2024RS008038

Guanjun Xu;Lianning Cai;Xianqiang Li;Yanli Shao;Zhaohui Song

引用次数: 0

An assessment of HF radio wave propagation in antarctica for a radio link between McMurdo and south pole station 南极洲高频无线电波传播评估，用于麦克默多和南极站之间的无线电链路

IF 1.6 4区地球科学

Radio Science Pub Date : 2024-10-01 DOI: 10.1029/2022RS007632

B. Liu;G. W. Perry;A. T. Chartier

{"title":"An assessment of HF radio wave propagation in antarctica for a radio link between McMurdo and south pole station","authors":"B. Liu;G. W. Perry;A. T. Chartier","doi":"10.1029/2022RS007632","DOIUrl":"https://doi.org/10.1029/2022RS007632","url":null,"abstract":"In this work, we analyze data collected by an HF transmitter/receiver radio link, operating as an oblique ionosonde between the McMurdo Station (transmitter) and South Pole Station (receiver) at 4.1, 5.1, 6.0, 6.4, and 7.2 MHz between 28 February and 14 March 2019. To help contextualize the link's data we have performed numerical raytrace simulations to help understand the observations. By considering both the data and simulations, we have identified both single- and two-hop E- and F-region propagation modes in the data, where the multi-hop modes were observed in the hours around sunrise and sunset in the 4.1 and 5.1 MHz channels. This is an unexpected result given the accepted wisdom that multi-hop modes, which require a ground scatter component, cannot be supported in Antarctica because of the highly absorptive ice covering much of the continent. Our results show that multi-hop propagation modes can be supported in the region under specific ionospheric conditions—around sunrise and sunset—if the mode's ground scatter component is collocated with the Transantarctic Mountains. The mountains are located along the great-circle path between the link's transmitter and receiver. However, the combination of favorable ionospheric and ground scattering conditions makes the detection of the multi-hop mode a rare occurrence in the data set analyzed here. These findings are critical to data analysis efforts of any current or future oblique ionosonde systems operating in Antarctica and other regions such as the Arctic.","PeriodicalId":49638,"journal":{"name":"Radio Science","volume":"59 10","pages":"1-17"},"PeriodicalIF":1.6,"publicationDate":"2024-10-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"142595781","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

Ultra-wide band antipodal vivaldi antenna using metasurface lens for gain and front-to-back ratio (FBR) improvement 使用元面透镜提高增益和前后比 (FBR) 的超宽带反波段维瓦尔第天线

IF 1.6 4区地球科学

Radio Science Pub Date : 2024-10-01 DOI: 10.1029/2024RS008115

Muhammad Fitra Zambak;Safpbri Johari;Mohd Najib Mohd Yassin;Arif Marwardi Ismail;Abdullah Alghaihab

{"title":"Ultra-wide band antipodal vivaldi antenna using metasurface lens for gain and front-to-back ratio (FBR) improvement","authors":"Muhammad Fitra Zambak;Safpbri Johari;Mohd Najib Mohd Yassin;Arif Marwardi Ismail;Abdullah Alghaihab","doi":"10.1029/2024RS008115","DOIUrl":"https://doi.org/10.1029/2024RS008115","url":null,"abstract":"This paper addresses the limited gain of conventional Antipodal Vivaldi Antenna (AVA) at higher frequencies. We propose a novel Metamaterial Lens Vivaldi Antenna (MLVA) design that overcomes this limitation by integrating an exponentially tapered antenna lens and a strategically placed Near Zero Refractive Index (NRZI) metamaterial lattice. The MLVA achieves exceptional wideband performance with a — 3 dB gain bandwidth exceeding 148.6% from 3.7 to 25 GHz. The result demonstrates a peak realized gain of 11.8 dBi at 11.2 GHz, compared to 9.1 dBi conventional AVA, especially beyond 5 GHz. The compact MLVA design measures only 120 × 78 × 1.524 mm\u0000<sup>3</sup>\u0000 (1.48 × 0.96 × 0.0188λ\u0000<inf>0</inf>\u0000<sup>3</sup>\u0000) λ\u0000<inf>0</inf>\u0000 where free-space wavelength is the lowest frequency and is fabricated on RO4350 B substrate with a 50-Ω SMA connector. Key features of the design include exponential flaring, and trapezoidal lens geometries chosen for their inherent ability to effectively collimate and direct the spherical wavefront. The incorporation of a dielectric lens and metasurface further enhances gain and Front-to-Back Ratio (FBR) by directing the majority of energy in the end-fire direction. Experimental results validate the effectiveness of the proposed design, confirming simulation predictions. These outstanding characteristics make the MLVA a promising candidate for diverse wireless communication and radar applications demanding high data rates across a broad frequency range.","PeriodicalId":49638,"journal":{"name":"Radio Science","volume":"59 10","pages":"1-15"},"PeriodicalIF":1.6,"publicationDate":"2024-10-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"142595828","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

Landmine detection using electromagnetic time reversalbased methods: 1. classical TR, iterative TR, DORT and TR-MUSIC 使用基于电磁时间反演的方法探测地雷： 1. 经典 TR、迭代 TR、DORT 和 TR-MUSIC

IF 1.6 4区地球科学

Radio Science Pub Date : 2024-10-01 DOI: 10.1029/2024RS007971

Hamidreza Karami;André Koch;Carlos Romero;Marcos Rubinstein;Farhad Rachidi

{"title":"Landmine detection using electromagnetic time reversalbased methods: 1. classical TR, iterative TR, DORT and TR-MUSIC","authors":"Hamidreza Karami;André Koch;Carlos Romero;Marcos Rubinstein;Farhad Rachidi","doi":"10.1029/2024RS007971","DOIUrl":"https://doi.org/10.1029/2024RS007971","url":null,"abstract":"In this paper, we present a review and classification of the published works on the use of Electromagnetic Time Reversal (EMTR)-based methods to locate landmines. Different approaches for landmine localization using EMTR are investigated. Specifically, the classical time-domain EMTR, iterative EMTR, EMTR-DORT (Décomposition de l’Opérateur du Retournement Temporel), and EMTR-MUSIC (Multiple SIgnal Classification) are implemented using different numerical techniques. The main properties of the mentioned EMTR-based approaches are reviewed and the TR-MUSIC method is selected as the most promising approach for the problem of interest, among all the reviewed methods. In the TR-MUSIC method, the transfer matrix is calculated in the first step. Then, the singular value decomposition of the transfer matrix is performed. In the last step, the location of the landmines is obtained through the evaluation of the pseudospectrum. As opposed to other EMTR-based techniques, TR-MUSIC features very high resolution (in the order of 1/10 or higher) with a reasonable number of sensors, allowing the detection of multiple closely spaced targets.","PeriodicalId":49638,"journal":{"name":"Radio Science","volume":"59 10","pages":"1-13"},"PeriodicalIF":1.6,"publicationDate":"2024-10-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"142595779","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 前方事项

IF 1.6 4区地球科学

Radio Science Pub Date : 2024-10-01 DOI: 10.1002/rds.21246

引用次数: 0

Stochastic analysis of epithelial/absorbed power density in multilayered planar skin model with uncertain tissue electric properties 具有不确定组织电特性的多层平面皮肤模型中上皮/吸收功率密度的随机分析

IF 1.6 4区地球科学

Radio Science Pub Date : 2024-10-01 DOI: 10.1029/2024RS007988

Anna Susnjara Nejasmic;Dragan Poljak

{"title":"Stochastic analysis of epithelial/absorbed power density in multilayered planar skin model with uncertain tissue electric properties","authors":"Anna Susnjara Nejasmic;Dragan Poljak","doi":"10.1029/2024RS007988","DOIUrl":"https://doi.org/10.1029/2024RS007988","url":null,"abstract":"Stochastic analysis of the absorbed power density (APD) on skin surface exposed to radiation of halfwave dipole at 10, 30 and 90 GHz and for different antenna-body distances is presented. Skin tissue is modeled as a half-space consisting of one layer (skin) or three layers (skin, fat and muscle) whose permittivities and conductivities are uncertain. Deterministic part is based on numerical solution of Pocklington equation via Galerkin Bubnov Indirect Boundary Element method (GB-IBEM) and numerical integration of the corresponding field integrals. Uncertainty from tissue electric parameters is propagated to APD via nonintrusive Stochastic Collocation method (SCM) in order to compute stochastic moments of APD. For 1-layered model APD stochastic moments are computed with 3 deterministic simulations. On the other hand APD mean and variance for 3 layered model are successfully computed with 13 deterministic simulations while skewness and kurtosis require 85 deterministic simulations. The ratio of APD standard deviation and mean decreases with frequency thus indicating that the uncertainty in the tissue electric properties has smaller effect on APD uncertainty at higher frequencies. Finally, sensitivity analysis carried out for both 1-layered and 3-layered models indicates the same conclusions. At 10 GHz skin permittivity and conductivity are the two most important parameters. However, as frequency increases the impact of skin conductivity prevails. This indicates that in frequency range 10-90 GHz the APD uncertainty quantification and sensitivity analysis can be carried out by using only 2-dimensional stochastic model.","PeriodicalId":49638,"journal":{"name":"Radio Science","volume":"59 10","pages":"1-15"},"PeriodicalIF":1.6,"publicationDate":"2024-10-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"142595830","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

A software tool for the true height analysis of ionograms using the iterative gradient correction (IGC) method 使用迭代梯度校正法（IGC）分析离子图真实高度的软件工具

IF 1.6 4区地球科学

Radio Science Pub Date : 2024-10-01 DOI: 10.1029/2024RS007955

M. Ankita;S. Tulasi Ram

{"title":"A software tool for the true height analysis of ionograms using the iterative gradient correction (IGC) method","authors":"M. Ankita;S. Tulasi Ram","doi":"10.1029/2024RS007955","DOIUrl":"https://doi.org/10.1029/2024RS007955","url":null,"abstract":"Deriving the precise true height electron density profile from the measured ionosonde virtual heights is quite a challenging problem. Recently, Ankita and Tulasi Ram (2023, https://doi.org/10.1029/2023RS007808) presented a new method, Iterative Gradient Correction (IGC) method, for true height analysis that uses HF radio wave propagation path computations to reconstruct the true height profile. Through iterative corrections on electron density gradients between successive points, the IGC method minimizes errors below a specified tolerance at each point and reconstructs a complete electron density profile. The derived profiles from the IGC method are found to be accurate when compared with Incoherent Scatter Radar and Global Navigation Satellite System—Radio Occultation observations. To facilitate true height analysis by IGC method for a wider user community, a MATLAB-based software has been developed and is outlined in this report. The software can be installed on any Windows platform and is designed with a user-friendly interface for easy and efficient application by the users. It can analyze multiple scaled ionograms in a single run and outputs the real height profiles in ASCII format. Further, the software also captures important ionospheric parameters such as the base altitudes and peak frequencies of E- and F-layers (e.g., hE, hF, foE, and foF2) etc., from the computed true height profiles and tabulates in a separate output file for the ready use. The software also provides the option for extrapolation of true height profile into top-side ionosphere up to a user-specified height and reconstructs the complete vertical electron density profile.","PeriodicalId":49638,"journal":{"name":"Radio Science","volume":"59 10","pages":"1-10"},"PeriodicalIF":1.6,"publicationDate":"2024-10-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"142595842","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