Witold Rohm results 14
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Identifying healthy urban zones for GNSS-based tropospheric delay estimation using 3D ray-tracingNARA Subscribed
Global Navigation Satellite System (GNSS) based tropospheric sensing offers great potential for high-resolution weather forecasting, especially in dense cities where conventional infrastructure is limited. However, Zenith Tropospheric Delay (ZTD) estimation is challenged by multipath interference and non-line-of-sight (NLOS) conditions. This study presents a ray-tracing–assisted method to identify “healthy zones” for robust ZT...
TropoDeep: a deep learning-based model for InSAR tropospheric correction on large-scale interferograms using GNSS and WRF outputsNARA Subscribed
This study introduces TropoDeep, an advanced model based on Super-Resolution Generative Adversarial Networks (SRGAN), developed to downscale the outputs of the Weather Research and Forecasting (WRF) model in order to improve displacement measurements from Interferometric Synthetic Aperture Radar (InSAR) in California and Nevada. TropoDeep improves differential Slant Tropospheric Delay (dSTD) resolution by leveraging High-Resol...
Machine learning-based tropospheric delay prediction for real-time precise point positioning under extreme weather conditionsNARA Subscribed
Satellite signals from the Global Navigation Satellite System (GNSS) are refracted as they pass through the troposphere, owing to the variable density and composition of the atmosphere, causing tropospheric delay. Typically, tropospheric delay is treated as an unknown parameter in GNSS data processing. Given the growing need for real-time GNSS applications, accurate tropospheric delay predictions are crucial to improve Precise...
The current GNSS meteorology literature focuses on ground-based and space-based GNSS observations separately, without exploring potential synergies. In this study, we propose combining the two data sources using GNSS tomography to overcome current limitations in (1) horizontal resolution of GNSS space-based, (2) low vertical resolution of GNSS ground-based tropospheric retrievals when the number of GNSS ground-based observatio...
GNSS signal ray-tracing algorithm for the simulation of satellite-to-satellite excess phase in the neutral atmosphereNARA Subscribed
Traditionally, GNSS space-based and ground-based estimates of tropospheric conditions are performed separately. It leads to limitations in the horizontal (e.g., a single space-based radio occultation profile covers a 300 km slice of the troposphere) and vertical resolution (e.g., ground-based estimates of troposphere conditions have spacing equal to stations’ distribution) of the tropospheric products. The first stage to achie...
Kalman filter-based integration of GNSS and InSAR observations for local nonlinear strong deformationsNARA Subscribed
The continuous monitoring of ground deformations can be provided by various methods, such as leveling, photogrammetry, laser scanning, satellite navigation systems, Synthetic Aperture Radar (SAR), and many others. However, ensuring sufficient spatiotemporal resolution of high-accuracy measurements can be challenging using only one of the mentioned methods. The main goal of this research is to develop an integration methodology...
Parameterisation of the GNSS troposphere tomography domain with optimisation of the nodes’ distributionNARA Subscribed
Water vapour is a highly variable constituent of the troposphere; thus, its high-resolution measurements are of great importance to weather prediction systems. The Global Navigation Satellite Systems (GNSS) are operationally used in the estimation of the tropospheric state and assimilation of the results into the weather models. One of the GNSS techniques of troposphere sensing is tomography which provides 3-D fields of wet re...
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