Ocean circulation plays a vital role in Earth's energy balance by redistributing heat globally and influencing climate. Driven by differences in seawater temperature and salinity, circulation involves dense, cold, salty water sinking and driving deep ocean currents (thermohaline circulation), while warmer, less saline water stays near the surface. These heat transport processes are sensitive to changes from evaporation, precipitation, and ice melt, which can disrupt circulation, affecting climate and marine ecosystems. This study proposes a new method to estimate seawater salinity and temperature using quad-polarimetric synthetic aperture radar (quad-PolSAR) data, which are key factors influencing ocean circulation. The method is based on the relationship between the seawater surface's complex dielectric constant and its physical properties, analyzed at the radar's operating frequency. It employs SAR target decomposition theory and a multi-component scattering model to isolate the single-bounce backscattering signal from the sea surface. Two data sets are used to verify the proposed method: a simulated data set at L-band (1.27 GHz) and real Radarsat-2 data at C-band (5.405 GHz) from the Strait of Gibraltar. Results show accurate estimation of seawater electromagnetic properties with strong agreement to ground truth. The study finds that L-band performs better than C-band, which is affected by multivalued functions. Environmental and system impacts are accounted for using additive Gaussian noise, and the method's sensitivity to signal-to-noise ratio is analyzed. This research offers a valuable tool for monitoring ocean conditions relevant to global climate systems.
{"title":"Novel electromagnetic method to retrieve ocean surface salinity and temperature using polarimetric SAR data","authors":"A. E. Farahat;K. F. A. Hussein","doi":"10.1029/2025RS008406","DOIUrl":"https://doi.org/10.1029/2025RS008406","url":null,"abstract":"Ocean circulation plays a vital role in Earth's energy balance by redistributing heat globally and influencing climate. Driven by differences in seawater temperature and salinity, circulation involves dense, cold, salty water sinking and driving deep ocean currents (thermohaline circulation), while warmer, less saline water stays near the surface. These heat transport processes are sensitive to changes from evaporation, precipitation, and ice melt, which can disrupt circulation, affecting climate and marine ecosystems. This study proposes a new method to estimate seawater salinity and temperature using quad-polarimetric synthetic aperture radar (quad-PolSAR) data, which are key factors influencing ocean circulation. The method is based on the relationship between the seawater surface's complex dielectric constant and its physical properties, analyzed at the radar's operating frequency. It employs SAR target decomposition theory and a multi-component scattering model to isolate the single-bounce backscattering signal from the sea surface. Two data sets are used to verify the proposed method: a simulated data set at L-band (1.27 GHz) and real Radarsat-2 data at C-band (5.405 GHz) from the Strait of Gibraltar. Results show accurate estimation of seawater electromagnetic properties with strong agreement to ground truth. The study finds that L-band performs better than C-band, which is affected by multivalued functions. Environmental and system impacts are accounted for using additive Gaussian noise, and the method's sensitivity to signal-to-noise ratio is analyzed. This research offers a valuable tool for monitoring ocean conditions relevant to global climate systems.","PeriodicalId":49638,"journal":{"name":"Radio Science","volume":"61 1","pages":"1-25"},"PeriodicalIF":1.5,"publicationDate":"2026-01-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"146116782","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}
An ionospheric over-the-horizon propagation experiment was carried out in Taiwan to investigate characteristics of ionospheric F layer skywave propagation at frequencies 4–12 MHz. Experimental results show that there are prominent diurnal variations in the incident angle, virtual height and plasma frequency at reflection height, which are essentially regular and stable during daytime from 06 to 19 LT and random and irregular during nighttime from 23 to 05 LT. The peak-to-peak amplitude variations in the incident angles during daytime are in a range of 4°–5°, and those for virtual heights are 40–70 km. These parameters are validated by comparing true horizontal distance with those deduced from transmission curve equation, and the results show that mean relative errors are smaller than 0.8% and relative uncertainties are in a range of 1.17%—3.6%. One intriguing transient phenomenon occurring around sunrise is that virtual height and incident angle both change dramatically with respective peak descending rate of about 83 km/hr and maximum increasing rate of about 9°/hr is especially noted and discussed in this article. In addition to F layer propagation, the experimental results of the sporadic E (Es) layer propagation in Taiwan area is also shown and discussed.
{"title":"The first results of ionospheric skywave propagation experiment over Taiwan","authors":"Hung-Shi Lin;Ching-Lun Su;Kang-Hung Wu;Yen-Hsyang Chu","doi":"10.1029/2025RS008420","DOIUrl":"https://doi.org/10.1029/2025RS008420","url":null,"abstract":"An ionospheric over-the-horizon propagation experiment was carried out in Taiwan to investigate characteristics of ionospheric F layer skywave propagation at frequencies 4–12 MHz. Experimental results show that there are prominent diurnal variations in the incident angle, virtual height and plasma frequency at reflection height, which are essentially regular and stable during daytime from 06 to 19 LT and random and irregular during nighttime from 23 to 05 LT. The peak-to-peak amplitude variations in the incident angles during daytime are in a range of 4°–5°, and those for virtual heights are 40–70 km. These parameters are validated by comparing true horizontal distance with those deduced from transmission curve equation, and the results show that mean relative errors are smaller than 0.8% and relative uncertainties are in a range of 1.17%—3.6%. One intriguing transient phenomenon occurring around sunrise is that virtual height and incident angle both change dramatically with respective peak descending rate of about 83 km/hr and maximum increasing rate of about 9°/hr is especially noted and discussed in this article. In addition to F layer propagation, the experimental results of the sporadic E (Es) layer propagation in Taiwan area is also shown and discussed.","PeriodicalId":49638,"journal":{"name":"Radio Science","volume":"61 1","pages":"1-15"},"PeriodicalIF":1.5,"publicationDate":"2026-01-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"146116917","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}
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}
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