The goal was to design a terrain-aided, all-weather filter, capable of real-time and global navigation, subject to several design objectives (incl. robustness wrt flight dynamics, terrain, and radar sensors). The algorithms combine nonlinear least squares (maximum likelihood) and Kalman filtering approaches.
Radar Altimeter Model, Extensions
These modules extend the functionality of the radar altimeter model (RAM), and include:1) Wrapper extension‘s goal is to automate terrain map (DEM) preparation for the measurement model while refreshing DEM only when needed (adaptive), accounting for attitude and radar angles (applicable to phase-array radars), providing control over computational efficiency (refresh frequency f and DEM data…
Toolkit for Digital Elevation Models
A set of software tools for processing DEMs (digital elevation models). Uses GDAL api, includes:1) DEM Downloader,where user specifies horizontal position and radius, and required DEM resolutions. Metadata are then retrieved using USGS-documented web API, processed, and finally DEMs are downloaded from remote server, with degenerate tiles further processed and/or merged.2) DEM Processor,which transforms from…
Gravity-Based Navigation
Frequency-Based Radar Altimeter Model
Radar Altimeter Model
The goal of this work is to develop mathematical models for terrain-aided navigation, such as radar altimetery and phased arrays, of high accuracy and fidelity. Potential applications include helicpoter landing and low-altitude flights, including nap-of-the-earth (aka ground-hugging).
Alternative Navigation Feasibility Study of DME/DME Systems
The DME/DME analysis includes line-of-sight (LOS) analysis, the coverage both en-route and in terminal areas, and optimal transmitter placement based on polygonal computational geometry. The aim is to assess the feasibility of VHF/UHF terrestrial navigation in GNSS-denied environments. To determine which airports are DME/DME-approach-enabled, we Check LOS (terrain included) in AAR (airport approach region). Check…
APNT & eLoran: Mathematical Analysis of Low-frequency Terrestrial Radionavigation in GNSS-denied Environments
To predict performance metrics for an LF navigation system at a particular location we need to develop and combine multiple models. The Groundwave Propagation Model, computes signal attenuation due to non-uniform surface conductivity and terrain elevation along the path from transmitter to receiver. The Markov Chain model for global transmitter availability is developed next; the…
Numerical Analysis of a Diffuse Plasma Discharge
I extended the in-house code for a 1D fluid model of a silent discharge in a parallel-plate geometry and subsequently developed and coded an extensive 2D fluid model. The code supports simulations of various cold plasmaconfigurations, from dielectric barrier discharges to extreme-field nanosecond streamers. The fluid model is solved with finite-difference and finite-volume methods on…
An axisymmetric unstructured finite volume method applied to the numerical modeling of an atmospheric pressure gas discharge
We develop a finite volume method based on unstructured triangular and/or quadrangular meshes for the numerical modeling of gas discharges at atmospheric pressure. The discretization of the computational domain is performed with median-dual control-volumes. Gradient calculations at the faces of the control-volumes are based on finite-element interpolation using shape functions. An FCT method was chosen…