Height Above Terrain Confidence Calculation
Find Innovative SolutionsGenerate Solutions
Solution Overview
Problem
Existing altitude estimation methods for mobile devices, such as barometric-based systems, face challenges in accurately determining height above terrain (HAT) due to errors in reference altitudes and terrain height measurements, which can lead to imprecise location determination, especially in urban environments, potentially affecting emergency response times and user navigation.
Innovation Solution
A method to characterize height-above-terrain confidence by determining uncertainties in height above a reference altitude and terrain height, using error values from pressure sensors and terrain database accuracy, and combining these uncertainties to calculate the overall uncertainty in HAT, thereby providing a more accurate measurement.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If barometric-based positioning system is used to estimate altitude, then altitude can be computed using pressure sensor measurements, but measurement precision deteriorates due to errors in reference altitudes and terrain height measurements
Solution Approach 1:
The system computes confidence values for height above terrain estimates by propagating errors from pressure sensor measurements and terrain database inaccuracies. This feedback mechanism allows the system to quantify measurement uncertainty and adjust positioning reliability based on actual error propagation, thereby resolving the contradiction between achieving altitude estimation precision and maintaining height above terrain confidence
Solution Approach 2:
The patent transforms the problem by introducing confidence as a computed parameter derived from error propagation analysis. By changing the parameter set to include uncertainty measurements alongside altitude estimates, the system can simultaneously report both precision and reliability metrics, resolving the contradiction between these two competing requirements
2Measurement precision
If reference-level pressure estimates are combined from multiple sensors, then reference-level pressure estimate accuracy improves, but device complexity increases
Solution Approach 1:
The system performs multiple functions using the same pressure sensor network: it既 estimates altitude for individual devices, combines measurements to create reference-level pressure estimates, and simultaneously computes confidence values for these estimates. This multi-functionality approach improves measurement precision without proportionally increasing device complexity, as the same hardware infrastructure supports multiple computational tasks
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 enhances the accuracy of height-above-terrain measurements by quantifying measurement confidence, reducing errors and improving location determination in complex environments, such as urban areas, by propagating errors and using quadrature combinations of uncertainties.
Implementation Method 1
altitude can be computed using a measurement of pressure from a calibrated pressure sensor of a mobile device along with ambient pressure measurement(s) from a network of calibrated reference pressure sensors
Data Source
AI summary
A method involves determining, at a mobile device or a service, an uncertainty in height above a reference altitude, an estimated 2D position of the mobile device, and an uncertainty in terrain height above the reference altitude using the estimated 2D position. An uncertainty in height above terrain, of the mobile device, is determined at the mobile device or a server using the uncertainty in height above the reference altitude and the uncertainty in terrain height above the reference altitude.