GNSS Tropospheric Delay Compensation via Grid Cell Segmentation
Find Innovative SolutionsGenerate Solutions
Solution Overview
Problem
GNSS signal propagation through the troposphere causes significant delays and inaccuracies in position fix due to ray bending, which existing methods fail to accurately compensate for, leading to location determination errors of several meters.
Innovation Solution
A method involving a GNSS receiver that determines zenith delays using current weather information for geographical areas along the signal path, adjusts these delays based on the satellite's elevation angle, and sums them to calculate the tropospheric delay, thereby improving location accuracy.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If traditional GNSS positioning methods are used without tropospheric compensation, then the device complexity remains low, but the measurement precision deteriorates with location determination errors of several meters
Solution Approach 1:
The patent segments the tropospheric path into multiple discrete cells along the signal propagation path. Each cell's tropospheric delay is calculated independently using weather data, and the total delay is obtained by summing the individual cell delays. This segmentation allows for precise localised compensation while maintaining computational efficiency through modular processing.
Solution Approach 2:
The patent introduces an intermediary computational layer that calculates tropospheric delays based on weather data and signal path geometry. This intermediary processing step mediates between the raw GNSS signals and the final position calculation, compensating for atmospheric effects without requiring complex hardware modifications.
2Measurement precision
If zenith delays are determined for multiple cells along the signal path using current weather information, then the measurement precision improves, but the loss of time increases due to additional computational steps
Solution Approach 1:
The patent performs preliminary calculations of zenith delays for each cell using available weather data before the final position fix is computed. By pre-calculating these delay values and storing them in association with the grid cells, the system avoids redundant computations during real-time positioning, thus reducing the time loss while maintaining high precision.
Solution Approach 2:
The patent calculates tropospheric delays for all cells along the signal path, which may be more detailed than strictly necessary. However, this excessive action ensures that sufficient precision is achieved for all possible signal paths, and the system can selectively use only the relevant cell delays for each specific positioning calculation, balancing precision with computational efficiency.
3Measurement precision
If path delays are determined by adjusting zenith delays for each cell based on elevation angle, then the measurement precision improves, but the device complexity increases
Solution Approach 1:
The patent changes the parameter of zenith delay by applying elevation angle adjustments to each cell's delay value. This parameter transformation accounts for the geometry of the signal path through the troposphere, converting vertical zenith delays into slant path delays. This mathematical parameter change provides accurate path delay compensation without requiring complex physical models or additional hardware.
Applied Scientific Principles
This section explains which scientific principles are used to turn an abstract innovation direction into a practical engineering solution.
Function Achieved in This Case
This approach significantly reduces User Equivalent Range Error (UERE) caused by the troposphere, achieving higher accuracy in location determination by compensating for tropospheric effects, especially at lower satellite elevations where effects are more pronounced.
Implementation Method 1
GNSS signals propagating through the troposphere are subjected to ray bending, which increases a signal path length and causes a delay
Data Source
Figure 1
Figure 2A~2B
Figure 3
AI summary
A method of reducing tropospheric effects in GNSS positioning includes determining a tropospheric delay by: determining zenith delays for geographical areas along a path of GNSS signal travel between a GNSS satellite and the first location of the electronic device, the zenith delays determined using current weather information of the geographical areas, the geographical areas traversed by the path represented by cells of a grid, the cells comprising a selected size; determining path delays for the geographical areas by adjusting the zenith delays based on an angle of the GNSS satellite relative to the electronic device; and summing the path delays to determine the tropospheric delay.