Ionospheric Slant TEC Analysis Using GNSS Delay Models
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Solution Overview
Problem
Existing methods for analyzing and visualizing ionospheric slant total electron content (TEC) using global navigation satellite systems (GNSS) are inefficient and introduce errors due to the use of crude models like the thin shell approximation, which affects the accuracy of ionospheric delay estimation and integrity bounds in satellite-based augmentation systems.
Innovation Solution
The development of a method that estimates ionospheric slant TEC using historical GNSS data, allowing for the calculation of Ionospheric Grid Delay (IGD) and Grid Ionospheric Vertical Error (GIVE) through various delay estimation models, including planar fit, kriging, conical domain, and multi-cone models, enabling more accurate and efficient analysis and visualization of ionospheric conditions.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Device complexity
If the thin shell approximation model is used for ionospheric delay estimation, then the calculation process is simplified, but the accuracy of ionospheric slant TEC analysis deteriorates
Solution Approach 1:
The patent transforms the ionospheric delay estimation from a simplified thin shell model to a three-dimensional conical domain model with variable electron density parameters. This allows the system to accurately represent the ionosphere's actual structure while maintaining computational efficiency through analytical solutions for TEC integration along conical raypaths.
Solution Approach 2:
The invention transitions from two-dimensional planar approximations to three-dimensional conical domain modeling. This dimensional change enables accurate representation of slant TEC along arbitrary raypaths while providing analytical solutions that avoid the computational complexity of full three-dimensional numerical integration.
2Adaptability or versatility
If multiple delay estimation models (planar fit, kriging, conical domain, multi-cone) are implemented, then the accuracy and versatility of ionospheric analysis is improved, but the device complexity and computational requirements increase
Solution Approach 1:
The patent creates a unified framework that integrates multiple delay estimation models (planar fit, kriging, conical domain, multi-cone) within a single system architecture. This universal platform allows flexible selection and comparison of different models for various ionospheric conditions and application requirements, enhancing versatility while managing complexity through standardized interfaces.
Solution Approach 2:
The system dynamically selects and switches between different delay estimation models based on operational requirements, data availability, and ionospheric conditions. This dynamic adaptability allows the system to optimize performance for specific applications without requiring all models to be actively executed simultaneously, thereby managing computational complexity.
3Reliability
If historical GNSS data is used for estimating ionospheric slant TEC, then the accuracy and reliability of navigation systems is improved, but the data processing time and computational resources increase
Solution Approach 1:
The patent performs preliminary processing of historical GNSS data to create pre-computed ionospheric delay models and lookup tables. This preliminary action enables rapid estimation of slant TEC during actual navigation operations by querying pre-processed data rather than performing complex calculations in real-time, thus improving reliability without significant processing time penalties.
Solution Approach 2:
The invention replaces computationally intensive real-time numerical integration with analytical solutions and pre-processed data structures. By substituting complex mechanical computation with mathematical analytics and cached results, the system achieves high reliability estimates with reduced processing time and computational resource requirements.
Data Source
AI summary
A method, system, apparatus, and computer program product provide the ability to analyze ionospheric slant total electron content (TEC) using global navigation satellite systems (GNSS)-based estimation. Slant TEC is estimated for a given set of raypath geometries by fitting historical GNSS data to a specified delay model. The accuracy of the specified delay model is estimated by computing delay estimate residuals and plotting a behavior of the delay estimate residuals. An ionospheric threat model is computed based on the specified delay model. Ionospheric grid delays (IGDs) and grid ionospheric vertical errors (GIVEs) are computed based on the ionospheric threat model.