Aircraft Altitude Correction Using Forecast Pressure Data
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Solution Overview
Problem
Current altitude measurement methods, such as barometric altimeters, are inaccurate due to variations in atmospheric pressure and temperature, leading to errors in aircraft altitude reporting, which can impact multilateration systems and air traffic surveillance.
Innovation Solution
Utilizing forecast atmospheric pressure data from services like NOAA's Rapid Update Cycle (RUC) to calculate altitude correction data, which is then applied to correct aircraft-reported altitudes, enabling more accurate three-dimensional position determination and reducing errors in multilateration systems.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Device complexity
If barometric altimeter is used to measure aircraft altitude, then the device is simple and cost-effective, but the measurement precision deteriorates due to atmospheric pressure and temperature variations
Solution Approach 1:
The patent introduces forecast atmospheric pressure data as an intermediary element to correct the raw barometric altitude measurements. This external pressure forecast data acts as a mediator between the simple barometric altimeter and the desired accurate altitude, allowing the system to maintain device simplicity while achieving improved measurement precision through data correction
Solution Approach 2:
The patent applies parameter changes by using forecast atmospheric pressure data to dynamically adjust and correct the altitude measurements. Instead of changing the physical device, the system changes the pressure parameter reference from static standard atmosphere to dynamic forecast data, thereby improving measurement accuracy while keeping the device simple
2Device complexity
If Standard Atmospheric Model is used to convert pressure to altitude, then the conversion process is simple, but the reliability deteriorates due to non-constant surface pressure, temperature, and air composition
Solution Approach 1:
The patent applies preliminary action by obtaining forecast atmospheric pressure data in advance before performing the altitude conversion. This pre-acquired pressure forecast information is then used to correct the altitude calculations, improving reliability while maintaining the simplicity of the conversion process
Solution Approach 2:
The system implements feedback by using forecast pressure data to continuously correct altitude measurements. The forecast data provides a reference that feeds back into the conversion process, allowing the system to adjust for atmospheric variations and improve reliability without increasing process complexity
3Ease of operation
If QNH altimeter setting is applied based on nearby barometric reading, then the adjustment process is simple, but the measurement precision deteriorates when atmospheric conditions vary across different locations served by the same ATC
Solution Approach 1:
The patent applies universality by replacing the location-specific QNH setting with a comprehensive forecast pressure data model that covers a broader geographic area. This universal pressure forecast approach serves multiple locations simultaneously with consistent, scientifically-based pressure data, improving precision while maintaining ease of operation through automated correction
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 improves the accuracy of aircraft altitude measurements, reducing errors and enhancing the reliability of multilateration systems and air traffic control by using forecast data to correct altitude biases.
Implementation Method 1
The standard way to estimate the altitude of an aircraft leading up to the advent of GPS is the aneroid altimeter. This device actually does not measure altitude but rather the atmospheric pressure outside the cabin. Since atmospheric pressure decreases as altitude increases, pressure data can be converted to altitude data based on the Standard Atmospheric Model tables or formulas.
Data Source
AI summary
A technique for reducing altitude error involves determining a corrected altitude for an aircraft using forecast atmospheric pressure data available, for example, from a weather forecasting service. The forecast atmospheric pressure data includes, for a number of points in time and for a number of geographic locations, a set of pressure levels and corresponding altitude values. Altitude correction data is periodically calculated from the forecast atmospheric pressure data for each of a number of geographic grid points. Upon receiving aircraft position information and an aircraft altitude measurement for an aircraft, one or more of the geographic grid points corresponding to the aircraft position are identified, and a corrected altitude of the aircraft is determined based on the altitude correction data of the one or more geographic grid points.