Underground emergency rescue operations require that communication signals can propagate over longer distances and directly penetrate thick earth strata. Additionally, the transceiver terminals need to have relatively flexible and convenient deployment capabilities to adapt to the complex mining environment. Magnetic induction (MI) communication, which features stable transmission channels and imposes no stringent requirements on antenna size, is suitable for achieving reliable through-the-earth (TTE) communication in underground mine environments. This paper proposes a heterogeneous transceiver-based MI communication scheme specifically designed for underground emergency rescue scenarios. Based on the characteristic of weak coupling between transmit and receive coils in MI-TTE communication, an equivalent circuit model corresponding to the transceiver loop is established, thereby constructing a quantifiable analysis model for the transceiver-heterogeneous MI-TTE communication performance using mathematical methods. Through parametric analysis, we systematically investigate how transceiver coil geometry affects channel bandwidth and path loss. Considering receiver noise characteristics, we further compare channel capacity and maximum achievable modulation orders under varying coil configurations and communication distances. The results indicate that the communication bandwidth is primarily limited by the turns of receiving coil. Reducing receiving coil turns yields significant capacity improvements only for short-distance communications, whereas increasing the receiving coil radius can optimize channel capacity globally.
{"title":"Performance analysis of transceiver-heterogeneous magnetic induction emergency through-the-earth communication","authors":"Yifan Wang;Wei Yang","doi":"10.1029/2025RS008341","DOIUrl":"https://doi.org/10.1029/2025RS008341","url":null,"abstract":"Underground emergency rescue operations require that communication signals can propagate over longer distances and directly penetrate thick earth strata. Additionally, the transceiver terminals need to have relatively flexible and convenient deployment capabilities to adapt to the complex mining environment. Magnetic induction (MI) communication, which features stable transmission channels and imposes no stringent requirements on antenna size, is suitable for achieving reliable through-the-earth (TTE) communication in underground mine environments. This paper proposes a heterogeneous transceiver-based MI communication scheme specifically designed for underground emergency rescue scenarios. Based on the characteristic of weak coupling between transmit and receive coils in MI-TTE communication, an equivalent circuit model corresponding to the transceiver loop is established, thereby constructing a quantifiable analysis model for the transceiver-heterogeneous MI-TTE communication performance using mathematical methods. Through parametric analysis, we systematically investigate how transceiver coil geometry affects channel bandwidth and path loss. Considering receiver noise characteristics, we further compare channel capacity and maximum achievable modulation orders under varying coil configurations and communication distances. The results indicate that the communication bandwidth is primarily limited by the turns of receiving coil. Reducing receiving coil turns yields significant capacity improvements only for short-distance communications, whereas increasing the receiving coil radius can optimize channel capacity globally.","PeriodicalId":49638,"journal":{"name":"Radio Science","volume":"60 12","pages":"1-16"},"PeriodicalIF":1.5,"publicationDate":"2025-12-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"145886677","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}
Microwave antennas have recently received significant attention due to the demand for a very simple system capable of rapidly sharing large amounts of data, driven by advances in wireless applications. The primary objective of this study is to determine the optimal geometric design parameters for a microwave antenna, considering Pareto optimality due to the complex nonlinear relationships within the performance metrics. Three different competitive current multi-objective algorithms, MOAE/D, NSGA-III, and SPEA2, were selected as the methodology to achieve this optimization problem, finding all non-dominated solutions. As a key finding, all solutions were displayed by extracting the Pareto front (PF) using the non-dominated solutions. Thus, the most optimal solutions within the selected design parameters range for the specified frequency band can be visualized in a single graph. Among these solutions, several randomly selected Pareto frontiers were simulated within the specified frequency band for S11, demonstrating that this PF was verified. Additionally, the problem was supported by the method of moments, enabling the optimal calculation of the antenna design's S11 (dB) and directivity performance metrics based on the variation of the geometric design values used in the cost function of the design optimization problem. Based on the obtained results, the proposed optimization processes provide an efficient, fast, and reliable solution to the microwave antenna design optimization problem. Since this study has been published in the literature, the proposed strategy can be easily applied to many design problems and yield more effective results.
{"title":"Comparison of competitive multi-objective algorithms to find the Pareto front in multiple-criteria antenna optimization problem","authors":"Ahmet Uluslu","doi":"10.1029/2025RS008515","DOIUrl":"https://doi.org/10.1029/2025RS008515","url":null,"abstract":"Microwave antennas have recently received significant attention due to the demand for a very simple system capable of rapidly sharing large amounts of data, driven by advances in wireless applications. The primary objective of this study is to determine the optimal geometric design parameters for a microwave antenna, considering Pareto optimality due to the complex nonlinear relationships within the performance metrics. Three different competitive current multi-objective algorithms, MOAE/D, NSGA-III, and SPEA2, were selected as the methodology to achieve this optimization problem, finding all non-dominated solutions. As a key finding, all solutions were displayed by extracting the Pareto front (PF) using the non-dominated solutions. Thus, the most optimal solutions within the selected design parameters range for the specified frequency band can be visualized in a single graph. Among these solutions, several randomly selected Pareto frontiers were simulated within the specified frequency band for S<inf>11</inf>, demonstrating that this PF was verified. Additionally, the problem was supported by the method of moments, enabling the optimal calculation of the antenna design's S<inf>11</inf> (dB) and directivity performance metrics based on the variation of the geometric design values used in the cost function of the design optimization problem. Based on the obtained results, the proposed optimization processes provide an efficient, fast, and reliable solution to the microwave antenna design optimization problem. Since this study has been published in the literature, the proposed strategy can be easily applied to many design problems and yield more effective results.","PeriodicalId":49638,"journal":{"name":"Radio Science","volume":"60 12","pages":"1-12"},"PeriodicalIF":1.5,"publicationDate":"2025-12-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"145886678","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}
Accurate estimation of vertical electron density profiles in the electrodynamically complex equatorial and low-latitude ionosphere remains a persistent challenge, primarily due to the scarcity of direct topside observational data with sufficient temporal and spatial coverage. Therefore, reconstructing topside profiles using bottomside ionosonde parameters is essential for capturing ionospheric behaviour in these regions. In this study, bottomside real height profiles derived from digital ionosonde measurements from Tirunelveli, an equatorial station in India, using the standard POLynomial ANalysis (POLAN) algorithm was used as basis for topside reconstruction. Key ionospheric parameters including the scale height at the F2 peak were extracted. Reconstruction was performed for two years of contrasting solar activity (2014 (high) and 2020 (low)) using both α-Chapman and semi-Epstein formulations, with the latter incorporating a linearly varying topside scale height. Additionally, scale heights derived from the Reinisch-Huang (R-H) method were used to validate the POLAN-derived outputs. All reconstructed profiles were evaluated independently using in situ electron density measurements from Swarm satellites over the Indian region. Results demonstrate that using realistic topside scale height gradients derived from COSMIC Radio Occultation (RO) profiles significantly improves reconstruction accuracy, especially when semi-Epstein formulation is applied. Further, seasonal analyses indicate better agreement of the reconstruction approach during high solar activity, with a larger fraction of profiles falling within a ±20% deviation from Swarm observations. These findings highlight the potential of integrating empirical topside scale height variations into reconstruction models to achieve a more accurate representation of the topside ionosphere, particularly over the Indian region.
{"title":"A novel approach of reconstructing the topside ionosphere using ionosonde and COSMIC scale height gradients: Validation with swarm measurements","authors":"K. Siba Kiran Guru;S. Sripathi;Rajesh Kumar Barad","doi":"10.1029/2025RS008356","DOIUrl":"https://doi.org/10.1029/2025RS008356","url":null,"abstract":"Accurate estimation of vertical electron density profiles in the electrodynamically complex equatorial and low-latitude ionosphere remains a persistent challenge, primarily due to the scarcity of direct topside observational data with sufficient temporal and spatial coverage. Therefore, reconstructing topside profiles using bottomside ionosonde parameters is essential for capturing ionospheric behaviour in these regions. In this study, bottomside real height profiles derived from digital ionosonde measurements from Tirunelveli, an equatorial station in India, using the standard POLynomial ANalysis (POLAN) algorithm was used as basis for topside reconstruction. Key ionospheric parameters including the scale height at the F<inf>2</inf> peak were extracted. Reconstruction was performed for two years of contrasting solar activity (2014 (high) and 2020 (low)) using both α-Chapman and semi-Epstein formulations, with the latter incorporating a linearly varying topside scale height. Additionally, scale heights derived from the Reinisch-Huang (R-H) method were used to validate the POLAN-derived outputs. All reconstructed profiles were evaluated independently using in situ electron density measurements from Swarm satellites over the Indian region. Results demonstrate that using realistic topside scale height gradients derived from COSMIC Radio Occultation (RO) profiles significantly improves reconstruction accuracy, especially when semi-Epstein formulation is applied. Further, seasonal analyses indicate better agreement of the reconstruction approach during high solar activity, with a larger fraction of profiles falling within a ±20% deviation from Swarm observations. These findings highlight the potential of integrating empirical topside scale height variations into reconstruction models to achieve a more accurate representation of the topside ionosphere, particularly over the Indian region.","PeriodicalId":49638,"journal":{"name":"Radio Science","volume":"60 12","pages":"1-20"},"PeriodicalIF":1.5,"publicationDate":"2025-12-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"145886674","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}
This study examines the propagation characteristics of the new FR3 frequency band (Upper midband) in indoor environments under both line-of-sight (LoS) and non-line of sight (NLoS) conditions, using theoretical analysis and experimental measurements. For comparison, the measured radio channels are reconstructed using advanced ray-tracing techniques with fine-tuning of all propagation mechanisms. The proposed Path Loss (PL) Floating-Intercept (FI) models show an error variance of 0.53 dB for measured PL and 5.5 dB for simulated PL in the LoS scenario. A convergence analysis for the LoS case reveals that simulating more than four reflections is unnecessary to minimize the error in Relative Received Power (RRP) between measurements and simulations. Additionally, the mean RMS delay spread (RMS DS) values observed were 3.86 ns from measurements and 4.17 ns from ray-tracing simulations. In the NLoS scenario, the proposed PL FI model exhibits an error variance of 6.9 dB for the measured PL and 28.5 dB for the simulated PL. Meanwhile, the mean RMS DS values were 15.18 ns from measurements and 11.86 ns from simulations. Additionally, the results indicate a decreasing trend in RMS DS values with increasing frequency across the FR3 band in NLoS conditions. The simulations also reveal channel sparsity under NLoS conditions, indicating a reduction in the number of significant multipath components. This is primarily caused by severe attenuation and the dominance of only a few strong paths, as demonstrated by the results of the proposed model.
{"title":"Theoretical and experimental study of indoor propagation in the FR3 band for LoS and NLoS scenarios","authors":"Fabián Correa-Quinchía;José-María Molina-García-Pardo;Juan Pascual-García;Maria-Teresa Martinez-Ingles","doi":"10.1029/2024RS008206","DOIUrl":"https://doi.org/10.1029/2024RS008206","url":null,"abstract":"This study examines the propagation characteristics of the new FR3 frequency band (Upper midband) in indoor environments under both line-of-sight (LoS) and non-line of sight (NLoS) conditions, using theoretical analysis and experimental measurements. For comparison, the measured radio channels are reconstructed using advanced ray-tracing techniques with fine-tuning of all propagation mechanisms. The proposed Path Loss (PL) Floating-Intercept (FI) models show an error variance of 0.53 dB for measured PL and 5.5 dB for simulated PL in the LoS scenario. A convergence analysis for the LoS case reveals that simulating more than four reflections is unnecessary to minimize the error in Relative Received Power (RRP) between measurements and simulations. Additionally, the mean RMS delay spread (RMS DS) values observed were 3.86 ns from measurements and 4.17 ns from ray-tracing simulations. In the NLoS scenario, the proposed PL FI model exhibits an error variance of 6.9 dB for the measured PL and 28.5 dB for the simulated PL. Meanwhile, the mean RMS DS values were 15.18 ns from measurements and 11.86 ns from simulations. Additionally, the results indicate a decreasing trend in RMS DS values with increasing frequency across the FR3 band in NLoS conditions. The simulations also reveal channel sparsity under NLoS conditions, indicating a reduction in the number of significant multipath components. This is primarily caused by severe attenuation and the dominance of only a few strong paths, as demonstrated by the results of the proposed model.","PeriodicalId":49638,"journal":{"name":"Radio Science","volume":"60 12","pages":"1-20"},"PeriodicalIF":1.5,"publicationDate":"2025-12-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"145886649","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}
Joseph Hughes;Ian Collett;Anastasia Newheart;Camella Nasr;Ryan Blay;Connor Johnstone;Jeffrey Steward;Ethan Miller;Wesley Leong
Ionospheric data assimilation is the art of combining imperfect data with incomplete models to estimate the state of the ionosphere. The three most common data types are ionosonde measurements, Ground-to-GNSS (Global Navigation Satellite System), TEC (Total Electron Content) measurements, and RO (Radio Occultation) TEC measurements. Despite the ubiquitous use of these measurement types, scant research exists on the relative merits of each measurement type. This study evaluates the impact of assimilating all possible combinations of these three measurement types. To do this, we simulate representative data for all three measurement types using an electron density truth model, and then ingest all possible combinations of data in separate assimilation runs. Since we assimilate ground TEC in an absolute and relative sense, this yields 11 combinations. The performance of each assimilation run is assessed by how well each analysis replicates the truth model's vertical TEC (vTEC), critical plasma frequency of the F2 layer (foF2), the height at which it occurs (hmF2) and HF propagation metrics. When considering vTEC, foF2, and hmF2, we find that absolute ground TEC data is the most useful for specifying vTEC and that Radio Occultation data is the most useful when specifying foF2 and hmF2. Somewhat surprisingly, we find that adding absolute ground TEC can worsen predictions of foF2 and hmF2. Our analysis of HF propagation shows that ionosonde and RO data are quite valuable, and that ingesting ground TEC in a relative sense is better than absolute, regardless of what additional data (RO, Ionosonde) is present.
{"title":"Relative merits of ionosondes, ground GNSS TEC, and radio occultations for ionospheric data assimilation","authors":"Joseph Hughes;Ian Collett;Anastasia Newheart;Camella Nasr;Ryan Blay;Connor Johnstone;Jeffrey Steward;Ethan Miller;Wesley Leong","doi":"10.1029/2025RS008316","DOIUrl":"https://doi.org/10.1029/2025RS008316","url":null,"abstract":"Ionospheric data assimilation is the art of combining imperfect data with incomplete models to estimate the state of the ionosphere. The three most common data types are ionosonde measurements, Ground-to-GNSS (Global Navigation Satellite System), TEC (Total Electron Content) measurements, and RO (Radio Occultation) TEC measurements. Despite the ubiquitous use of these measurement types, scant research exists on the relative merits of each measurement type. This study evaluates the impact of assimilating all possible combinations of these three measurement types. To do this, we simulate representative data for all three measurement types using an electron density truth model, and then ingest all possible combinations of data in separate assimilation runs. Since we assimilate ground TEC in an absolute and relative sense, this yields 11 combinations. The performance of each assimilation run is assessed by how well each analysis replicates the truth model's vertical TEC (vTEC), critical plasma frequency of the F2 layer (foF2), the height at which it occurs (hmF2) and HF propagation metrics. When considering vTEC, foF2, and hmF2, we find that absolute ground TEC data is the most useful for specifying vTEC and that Radio Occultation data is the most useful when specifying foF2 and hmF2. Somewhat surprisingly, we find that adding absolute ground TEC can worsen predictions of foF2 and hmF2. Our analysis of HF propagation shows that ionosonde and RO data are quite valuable, and that ingesting ground TEC in a relative sense is better than absolute, regardless of what additional data (RO, Ionosonde) is present.","PeriodicalId":49638,"journal":{"name":"Radio Science","volume":"60 12","pages":"1-13"},"PeriodicalIF":1.5,"publicationDate":"2025-12-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"145886700","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}
I. Doria;P. Cappuccio;D. Durante;I. di Stefano;D. Bernacchia;R. Lasagni Manghi;M. Zannoni;L. Iess
We present and compare different techniques to isolate the dispersive noise contribution from radiometric observables in deep space missions. These techniques have been tested using range and Doppler data collected during five superior solar conjunctions of ESA's (European Space Agency) BepiColombo spacecraft in its cruise phase. First, we present the state-of-the-art of BepiColombo multifrequency link calibration scheme, which leverages on three 2-way links in X/X, X/Ka and Ka/Ka band. Then we compare its performance with alternative dual-link schemes, based on a combination of only two of the three links listed above. Our analyses find that the best dual-link configuration, achieved with the method reported in Mariotti and Tortora (2013, https://doi.org/10.1002/rds.20024), is the X/X + Ka/Ka configuration, which on average decreases the RMS noise with respect to the non-calibrated Ka/Ka residuals by ∼64% for BepiColombo's Doppler data (compressed at 60 s) and by 37% for range data (at integration time of 2 s). Finally, our analysis points out that during radio tracking passes characterized by a low plasma content, the dual link configuration X/X + Ka/Ka provides better performance on range data with respect to the classic full triple link configuration. This can be explained by the higher thermal noise contribution on range measurements due to the smaller integration time with respect to Doppler data: in fact, with the triple link scheme we have a contribution from the thermal noise of the three links while with the dual link configurations only from two.
{"title":"Comparison of plasma calibration techniques to enhance radiometric observables performance: BepiColombo MORE test case","authors":"I. Doria;P. Cappuccio;D. Durante;I. di Stefano;D. Bernacchia;R. Lasagni Manghi;M. Zannoni;L. Iess","doi":"10.1029/2025RS008441","DOIUrl":"https://doi.org/10.1029/2025RS008441","url":null,"abstract":"We present and compare different techniques to isolate the dispersive noise contribution from radiometric observables in deep space missions. These techniques have been tested using range and Doppler data collected during five superior solar conjunctions of ESA's (European Space Agency) BepiColombo spacecraft in its cruise phase. First, we present the state-of-the-art of BepiColombo multifrequency link calibration scheme, which leverages on three 2-way links in X/X, X/Ka and Ka/Ka band. Then we compare its performance with alternative dual-link schemes, based on a combination of only two of the three links listed above. Our analyses find that the best dual-link configuration, achieved with the method reported in Mariotti and Tortora (2013, https://doi.org/10.1002/rds.20024), is the X/X + Ka/Ka configuration, which on average decreases the RMS noise with respect to the non-calibrated Ka/Ka residuals by ∼64% for BepiColombo's Doppler data (compressed at 60 s) and by 37% for range data (at integration time of 2 s). Finally, our analysis points out that during radio tracking passes characterized by a low plasma content, the dual link configuration X/X + Ka/Ka provides better performance on range data with respect to the classic full triple link configuration. This can be explained by the higher thermal noise contribution on range measurements due to the smaller integration time with respect to Doppler data: in fact, with the triple link scheme we have a contribution from the thermal noise of the three links while with the dual link configurations only from two.","PeriodicalId":49638,"journal":{"name":"Radio Science","volume":"60 12","pages":"1-14"},"PeriodicalIF":1.5,"publicationDate":"2025-12-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"145886703","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}
The integration of artificial intelligence (AI) with weather radar systems marks a transformative advancement in remote sensing. This study introduces an AI-powered radar system that utilizes Long Short-Term Memory (LSTM) neural networks to predict the in-phase (I) and quadrature (Q) components of radar signals, enabling faster, and more accurate radar observations By synthesizing extended time series from a subset of real-time measurements, the AI radar enhances measurement accuracy and spatial resolution without requiring longer dwell times. The proposed technique reduces data collection time and storage demands while maintaining the statistical and spectral characteristics of radar signals. Applied to both simulated and measured radar data, the AI radar demonstrates promising results in improving signal prediction and radar observations across ground-based, airborne, and spaceborne platforms. This innovation paves the way for more efficient radar technologies, with potential applications in weather monitoring, military systems, and resource-constrained environments.
{"title":"Artificial intelligence weather radar","authors":"Jothiram Vivekanandan;Gwo-Jong Huang","doi":"10.1029/2025RS008417","DOIUrl":"https://doi.org/10.1029/2025RS008417","url":null,"abstract":"The integration of artificial intelligence (AI) with weather radar systems marks a transformative advancement in remote sensing. This study introduces an AI-powered radar system that utilizes Long Short-Term Memory (LSTM) neural networks to predict the in-phase (I) and quadrature (Q) components of radar signals, enabling faster, and more accurate radar observations By synthesizing extended time series from a subset of real-time measurements, the AI radar enhances measurement accuracy and spatial resolution without requiring longer dwell times. The proposed technique reduces data collection time and storage demands while maintaining the statistical and spectral characteristics of radar signals. Applied to both simulated and measured radar data, the AI radar demonstrates promising results in improving signal prediction and radar observations across ground-based, airborne, and spaceborne platforms. This innovation paves the way for more efficient radar technologies, with potential applications in weather monitoring, military systems, and resource-constrained environments.","PeriodicalId":49638,"journal":{"name":"Radio Science","volume":"60 12","pages":"1-9"},"PeriodicalIF":1.5,"publicationDate":"2025-12-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"145886675","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}
State estimation techniques play an important role in predicting signal stability and estimating the primary variables in a system. State estimation using conventional methods predicts the state vectors with still random errors, such as those of the Wiener and Kalman, due to its parametric limitations in stationary and nonstationary environments. The Kalman filter is recognized as a linear-quadratic estimator. These measures, over a period of observation, include random noise, producing estimates of unknown variables that are more accurate than a single measurement. It generates the output of joint probability distribution function estimations over the variables for each time frame. This study proposes a Hybrid Kalman filter-based state estimation, applicable on a conditional of linear functions on a Gaussian random process and Gaussian random variables. The proposed Hybrid Kalman filter works to model the movement control differences of transmitted and received signals due to the time delay. This approach provides a realistic model to estimate the current state and produce updated state variables. A newly designed mobile station receiver was tested to receive transmitted signals from a 128-element array satellite antenna via an 8-element array antenna integrated with a Hybrid Kalman filter. This transceiver was validated at a frequency of 11 GHz, operating data rates of 1.28 Gbps for the bandwidth of 1.28 GHz to eliminate the multipath effects and reduce inter-symbol interference. The performance result of the simulation process shows the efficiency of the Hybrid Kalman filter when the 5G wireless network integrations are in a highly multipath environment.
{"title":"Mobile transceiver design with Hybrid Kalman filter for 5G wireless networks of satellite communications","authors":"Ravandran Muttiah","doi":"10.1029/2025RS008246","DOIUrl":"https://doi.org/10.1029/2025RS008246","url":null,"abstract":"State estimation techniques play an important role in predicting signal stability and estimating the primary variables in a system. State estimation using conventional methods predicts the state vectors with still random errors, such as those of the Wiener and Kalman, due to its parametric limitations in stationary and nonstationary environments. The Kalman filter is recognized as a linear-quadratic estimator. These measures, over a period of observation, include random noise, producing estimates of unknown variables that are more accurate than a single measurement. It generates the output of joint probability distribution function estimations over the variables for each time frame. This study proposes a Hybrid Kalman filter-based state estimation, applicable on a conditional of linear functions on a Gaussian random process and Gaussian random variables. The proposed Hybrid Kalman filter works to model the movement control differences of transmitted and received signals due to the time delay. This approach provides a realistic model to estimate the current state and produce updated state variables. A newly designed mobile station receiver was tested to receive transmitted signals from a 128-element array satellite antenna via an 8-element array antenna integrated with a Hybrid Kalman filter. This transceiver was validated at a frequency of 11 GHz, operating data rates of 1.28 Gbps for the bandwidth of 1.28 GHz to eliminate the multipath effects and reduce inter-symbol interference. The performance result of the simulation process shows the efficiency of the Hybrid Kalman filter when the 5G wireless network integrations are in a highly multipath environment.","PeriodicalId":49638,"journal":{"name":"Radio Science","volume":"60 11","pages":"1-23"},"PeriodicalIF":1.5,"publicationDate":"2025-11-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"145646101","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}
Gabriel O. Jerez;Manuel Hernández-Pajares;Daniele B. M. Alves;João F. G. Monico
Global Navigation Satellite Systems radio occultation (RO) is a valuable and relevant source of information from the atmosphere. Many efforts have been made to provide methods of validation of RO profiles, however, no clear methodology for filtering the profiles from RO can be easily found. In this study, we present strategies to filter RO electron density profiles over a low latitude region. Different methods are applied considering minimum values, manual filtering, hmF2 range, and discrepancies with reference to the Chapman profile. The assessment is performed by means of ionosonde data for two years (2014–2015). The results show that assuming a minimum electron density limit slightly smaller than zero consistently with electron density estimation errors under very low actual values can provide significant improvements. In this study, the use of a —105 el/cm3 limit led to better rates of retained profiles (65% vs. 32%) and a reduction in foF2 root mean square (RMS) (12% vs. 7%) compared to the exclusion of all profiles with negative values. When considering only electron density values above 100 km in altitude, there is still a significant loss of about 20% in the number of profiles with the same reference values (84% vs. 63%), with a similar performance in thefoF2 RMS. The best performance is obtained with the strategies: hmF2 range of occurrence (200–450 km) and the outliers identification (5 standard deviations limit), leading to afoF2 RMS reduction of about 26% and 19%, and a hmF2 RMS reduction of 34% and 25%, respectively, while keeping 91% and 82% of the original profiles.
全球导航卫星系统的无线电掩星（RO）是一个有价值和相关的大气信息来源。许多努力已经提供了验证RO配置文件的方法，但是，没有明确的方法可以很容易地从RO中过滤配置文件。在这项研究中，我们提出了在低纬度地区过滤RO电子密度剖面的策略。考虑最小值、手动过滤、hmF2范围和参考查普曼剖面的差异，应用了不同的方法。评估是通过两年（2014-2015年）的电离探空仪数据进行的。结果表明，假设最小电子密度极限略小于零，与非常低的实际值下的电子密度估计误差一致，可以提供显着的改进。在这项研究中，与排除所有负值的剖面相比，使用-105 el/cm3的限制导致了更好的剖面保留率（65%对32%）和foF2均方根（RMS）降低（12%对7%）。当只考虑海拔100公里以上的电子密度值时，具有相同参考值的剖面数量仍然有大约20%的显着损失（84% vs. 63%），在fof2 RMS中具有相似的性能。hmF2发生范围（200-450 km）和异常值识别（5个标准差限）策略的效果最好，在保持原始剖面91%和82%的情况下，afoF2 RMS分别降低约26%和19%，hmF2 RMS分别降低34%和25%。
{"title":"Impact of filtering methods in the assessment of COSMIC electron density profiles over the Brazilian region: Excluding profiles with negative values is the best strategy?","authors":"Gabriel O. Jerez;Manuel Hernández-Pajares;Daniele B. M. Alves;João F. G. Monico","doi":"10.1029/2024RS008192","DOIUrl":"https://doi.org/10.1029/2024RS008192","url":null,"abstract":"Global Navigation Satellite Systems radio occultation (RO) is a valuable and relevant source of information from the atmosphere. Many efforts have been made to provide methods of validation of RO profiles, however, no clear methodology for filtering the profiles from RO can be easily found. In this study, we present strategies to filter RO electron density profiles over a low latitude region. Different methods are applied considering minimum values, manual filtering, hmF<inf>2</inf> range, and discrepancies with reference to the Chapman profile. The assessment is performed by means of ionosonde data for two years (2014–2015). The results show that assuming a minimum electron density limit slightly smaller than zero consistently with electron density estimation errors under very low actual values can provide significant improvements. In this study, the use of a —10<sup>5</sup> el/cm<sup>3</sup> limit led to better rates of retained profiles (65% vs. 32%) and a reduction in foF<inf>2</inf> root mean square (RMS) (12% vs. 7%) compared to the exclusion of all profiles with negative values. When considering only electron density values above 100 km in altitude, there is still a significant loss of about 20% in the number of profiles with the same reference values (84% vs. 63%), with a similar performance in thefoF<inf>2</inf> RMS. The best performance is obtained with the strategies: hmF<inf>2</inf> range of occurrence (200–450 km) and the outliers identification (5 standard deviations limit), leading to afoF<inf>2</inf> RMS reduction of about 26% and 19%, and a hmF<inf>2</inf> RMS reduction of 34% and 25%, respectively, while keeping 91% and 82% of the original profiles.","PeriodicalId":49638,"journal":{"name":"Radio Science","volume":"60 11","pages":"1-13"},"PeriodicalIF":1.5,"publicationDate":"2025-11-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"145646104","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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