Strong natural hazards together with their societal impact are usually accompanied by multiple physical phenomena which can be an important information source about the underlying processes. In this study we statistically analyze the lithosphere–atmosphere–ionosphere couplings of magnitude Mw5.5+ earthquakes (EQs) in the year 2023 with the aid of sub-ionospheric VLF/LF radio links. The electric field amplitude and phase measurements with a temporal resolution of one second are from the seismo-electromagnetic receiver facility in Graz (GRZ), Austria (Galopeau et al., 2023), which is part of the INFREP network. The spatial extend of the study area has the range [-10°E ≤ longitude ≤ 40°E] and [20°N ≤ latitude ≤ 50°N], in total are 17 EQs according to the United States Geological Survey (USGS) data base, among them the Turkey–Syria EQs (main shocks Mw7.8 and Mw7.5) and the Morocco Mw6.8 EQ. We apply the night-time amplitude method (Hayakawa et al., 2010) for all available paths, of particular importance are the transmitter links TBB (26.70 kHz, Bafa, Turkey), ITS (45.90 kHz, Niscemi, Sicily, Italy), and ICV (20.27 kHz, Tavolara, Italy). Relevant crossings are determined by the size of the Dobrovolsky-Bowman relationship (Dobrovolsky et al., 1979; Bowman et al., 1998).A major finding is the statistically significant electric field variation of the TBB-GRZ link related to the Turkey–Syria EQ sequence. A physical interpretation is based on atmospheric gravity waves (AGWs) which could alter the E-layer in the lower ionosphere during nighttime and modulate the height of the waveguide cavity.References:Galopeau et al., A VLF/LF facility network for preseismic electromagnetic investigations, Geosci. Instrum. Method. Data Syst., 12, 231–237, 2023, https://doi.org/10.5194/gi-12-231-2023Dobrovolsky et al., Estimation of the size of earthquake preparation zones, PAGEOPH 117, 1025–1044, 1979, https://doi.org/10.1007/BF00876083Bowman et al., An observational test of the critical earthquake concept, JGR Solid Earth, 103, B10, 24359-24372, 1998, https://doi.org/10.1029/98JB00792Hayakawa et al., A statistical study on the correlation between lower ionospheric perturbations as seen by subionospheric VLF/LF propagation and earthquakes, JGR Space Physics, 115(A9), 09305, 2010, https://doi.org/10.1029/2009JA015143

A hybrid Highly elliptical orbit (HEO)‐based regional navigation system is optimized by examining the impact of variation of orbital parameters on navigation performance of the system. The principle of optimization is based on the following requirements: L and S band carrier frequency (user/receiver segment) link budget, satellite accessibility and dwell time over the area of interest, geometric configuration of the system, navigation accuracy, and constellation stability. The optimization algorithm is partnered with a dynamic simulation process. The optimal parameters (semi‐major axis, inclination, eccentricity, right ascension of ascending node, etc.) of the HEO‐based regional navigation system have been selected based on the results of the optimization process. The proposed hybrid system with four HEO and one geostationary earth orbit (GEO) satellite is a cost‐efficient and high‐accuracy navigation solution as compared with other regional systems.

Surface charging at geosynchronous altitude is one of the major concerns for satellites and spacecrafts. Spacecraft anomalies are often associated with extreme surface charging events, especially during substorms in which the GEO plasma is better modeled as two temperatures non‐Maxwellian plasma. In such case, we employ two temperature q‐non‐extensive distribution function to determine the onset of spacecraft surface charging which becomes complex since many parameters control the surface charging. We developed a current balance equation which better explains the charging threshold in comparison to a Maxwellian distribution function. The effect of non‐extensive parameters, temperature and density ratio on the current balance equation has been explained. The modified current balance equation predicts the critical and anti‐critical temperatures for various space‐grade materials both analytically and numerically. A significant change is observed in the quantities characterizing the charging current, average yield and density ratio in the presence of non‐extensive two temperature electrons. The mechanism underlying different charging behaviors at or near the threshold is also indicated at various plasma parametric domains. Furthermore, the general conditions of potential jump are also obtained theoretically which predicts the sudden or smooth potential transition.

Power Line Communication (PLC) leverages existing power lines for communication purposes, offering an economically viable alternative to other communication methods that entail the additional expense of establishing new infrastructure. This paper presents a comprehensive analysis of tests conducted on PLCs within the context of the Advanced Metering Infrastructure (AMI) Project, focusing on grid modernization. Addressing the unique challenges posed by power lines requires meticulous planning, particularly in the strategic placement of filters. The study specifically targets two urban areas, subjecting them to thorough examination using a Noise toolkit consisting of a Coupler and a Spectrum Analyzer. The research incorporates three distinct load types—domestic, commercial, and industrial—to conduct a comparative analysis of the results obtained. While PLC has been deployed internationally, there is limited large-scale field data available in the Pakistani context. This study contributes important baseline measurements and technical benchmarks, demonstrating that G3-PLC, operating in the FCC band, is a reliable and scalable solution for smart metering communication in urban distribution networks.