Estimation of GPS-based ionospheric indices by GIX, SIDX, and ROTI during the St. Patrick’s Day geomagnetic storm event in the Indian low latitude region Srilatha Talluri, Ravi Kumar Mokkapati, Swapna Raghunath, Venkata Ratnam Devanaboyina Journal of Applied Geodesy, 2025 The disturbance in ionospheric conditions caused by geomagnetic storms leads to problems with the ground, satellite communication, and navigation technology. The Ionospheric perturbations affect the accomplishment of the Global Navigation Satellite System (GNSS), namely accuracy, continuity, availability, and integrity. During the ionosphere’s disturbance level, the Precision and safety of GNSS applications are essential to obtain data about space weather conditions. Along different GNSS satellite receiver paths, GNSS receivers are particularly vulnerable to expeditious changes in Total Electron Content (TEC) and critical spatial variations. The ionospheric indices, namely the Gradient Ionosphere Index (GIX), Rate of TEC Index (ROTI), and the Sudden Ionospheric Disturbance Index (SIDX), are employed for monitoring ionospheric conditions. The ionospheric disturbances can be assessed using GIX and SIDX without prior data. These indices have been modeled and validated based on GNSS observations provided by the Indian region. This research work examines the effects of the ionosphere on the St. Patrick’s Day geomagnetic storm (17th March 2015) by inspecting TEC variations from March 14 to 19, 2015, using spatial and temporal indices for GNSS stations at Trivandrum, Hyderabad, Mumbai, Kolkata, Bhopal, Delhi positioned in the Indian subcontinent. In low-latitude regions, the highest GIX, ROTI, and more negative SIDX values started recording from 1,200 h UT to 1,500 h UT on 17th March 2015. On 17th March 2015, during the storm’s main phase, the selected stations showed GIX values ranging from 47.2 to 103.3 m TECU/km. On Recovery Day 19th March 2015, GIX readings range from 38.1 to 60 m TECU/km, this research plays a part in understanding ionospheric gradients in the equatorial and low latitudes, where it is applicable for improving Ground Based Augmentation Systems (GBAS) and GPS-aided GEO Augmented Navigation (GAGAN) effective for aircraft landing.
Bridging the gap between AI and human emotion: a multimodal recognition system Ganta Neeraja, Jakkula Sai Surya Teja, M. Ravi Kumar, J. Lakshmi Prasanna, Parvez M. Muzammil, et al. Control and Cybernetics, 2024 This study introduces a novel system that integrates voice and facial recognition technologies to enhance human-computer interaction by accurately interpreting and responding to user emotions. Unlike conventional approaches that analyze either voice or facial expressions in isolation, this system combines both modalities, o ering a more comprehensive understanding of emotional states. By evaluating facial expressions, vocal tones, and contextual conversation history, the system generates personalized, context-aware responses, fostering more natural and empathetic AI interactions. This advancement significantly improves user engagement and satisfaction, paving the way for emotionally intelligent AI applications across diverse fields.
Evaluating the single-frequency static precise point positioning accuracies from multi-constellation GNSS observations at an Indian low-latitude station Anantha Srinivas Aginiparthi, Ram Kumar Vankadara, Ravi Kumar Mokkapati, Sampad Kumar Panda Journal of Applied Geodesy, 2024 Multiple constellations and their combinations in the global navigation satellite systems (GNSS) provide a great opportunity for single-station precise point positioning (PPP) models. The PPP models are of more importance for GNSS users as they are cost-effective with reasonable accuracy. There are abundant models in the market that use different data processing techniques based on the location and constellations used. In this study, we used the precise point positioning (PPP) software Net_Diff to verify the positioning accuracy at a low latitude Indian location using individual global satellite constellations (GPS, GLONASS, Galileo, BeiDou) and their combinations with GPS fixed. The ionospheric correction models such as GIM and Klobuchar are applied in the post-processing to determine the positioning accuracy. The Kalman filter method is applied to model the input data along with including the noise to derive the position solution. The results revealed that the GPS showed constant residual error for both quiet and disturbed days. In terms of single constellation Galileo produced less residuals in WGS 84 and ECEF coordinate systems whereas in the multi-constellation combination GPS, Galileo and GLONASS resulted in residuals of lesser magnitudes compared to the other combinations considered in this study. The RMS and STD of the residuals confirmed the high precision for Galileo and low precision for BeiDou constellations at the location.
Exploring the viability of secondary absorber materials in perovskite solar cell structures through computational analysis J Lakshmi Prasanna, Atul Kumar, M Ravi Kumar, Santhosh Chella Physica Scripta, 2024 Perovskite solar cells (PSCs) are at the forefront of next-generation photovoltaic technology due to their high efficiency and cost-effectiveness. To further enhance their performance, we investigate the integration of a second absorber layer alongside the conventional perovskite layer. Through extensive simulation techniques, we explore the effectiveness of silicon, Copper Indium Gallium Selenide (CIGS), and additional perovskite layers in forming a Double layered absorber perovskite solar cell (DLAPSC) structure. Our analysis of key performance metrics reveals MASnI3 as the most promising second absorber material, offering superior performance attributed to favorable band alignment and enhanced charge transport properties. In contrast, CIGS and Si layers exhibit inferior performance due to comparatively narrow bandgaps, leading to increased resistive losses. The perovskite/perovskite DLAPSC shows significant promise, achieving a notable power conversion efficiency of 41.56%. This study emphasizes the importance of meticulous parameter optimization and material selection in advancing PSC technology, highlighting the potential of DLAPSCs for renewable energy applications.
Estimation of bit error rate in 2×2 and 4×4 multi-input multioutput-orthogonal frequency division multiplexing systems Mokkapati Ravi Kumar, Jagupilla Lakshmi Prasanna, Aravindhan Alagarsamy, Tadiboyina Mouni Pravallika, Kandimalla Jyothsna, et al. International Journal of Electrical and Computer Engineering, 2023 <span lang="EN-US">Multiple-input, multiple-output orthogonal frequency-division multiplexing (MIMO-OFDM) systems with multiple input antennas and multiple output antennas in dynamic environments face the challenge of channel estimation. To overcome this challenge and to improve the performance and signal-to-noise ratio, in this paper we used the Kalman filter for the correct estimation of the signal in dynamic environments. To obtain the original signal at the receiver end bit error rate factor plays a major role. If the signal to noise ratio is high and the bit error rate is low then signal strength is high, the signal received at the receiver end is almost similar to the </span><em><span lang="EN-US">i<sup>th</sup></span></em><span lang="EN-US"> transmitted signal. The dynamic tracking characteristic of Kalman filter is used to establish a dynamic space-time codeword and a collection of orthogonal pilot sequences to prevent interference among transmissions in this paper. Using the simulation, the Kalman filter method can be compared to the other channel estimation method presented in this paper that can track time-varying channels rapidly.</span>
IoT based Soldier Health and Position Tracking System J Lakshmi Prasanna, M. Ravi Kumar, Chella Santhosh, S V Aswin Kumar, P. Kasulu Proceedings 6th International Conference on Computing Methodologies and Communication Iccmc 2022, 2022
Face Mask Detection Using LabView1 Chella Santhosh, M Ravi Kumar, J Lakshmi Prasanna, I. Ram Kumar, U Vinay Kumar, et al. International Journal of Online and Biomedical Engineering, 2021
