Radar Antenna Elevation Error Estimation Method
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Solution Overview
Problem
Conventional altitude estimation systems, such as those using barometers and GPS, lack the accuracy needed for reliable aircraft altitude information during the final phase of approach and landing, and are not suitable for synthetic vision aided landings without additional equipment or location-specific augmentation systems.
Innovation Solution
An onboard radar system that measures the elevation angle to the runway and computes the aircraft's altitude using a combination of radar returns, runway altitude data, and trigonometric principles, correcting for errors in the pointing angle to provide precise altitude information.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If GPS and barometer based systems are used for altitude estimation, then the system is simple and widely applicable, but the measurement precision is insufficient (accurate only to within 200 feet)
Solution Approach 1:
The patent replaces conventional barometric and GPS-based altitude estimation systems with a radar-based measurement system. The radar system uses electromagnetic waves to directly measure the angle to the runway and calculate altitude, achieving foot-level precision without requiring complex augmentation systems or additional equipment beyond the radar itself.
2Measurement precision
If additional augmentation systems are installed to achieve high accuracy altitude information, then the measurement precision improves, but the device complexity and cost increase
Solution Approach 1:
The patent makes the radar system perform multiple functions: it not only provides weather detection but also serves as a precision altitude measurement system for approach and landing. By utilizing the existing radar hardware for dual purposes, the system achieves high-accuracy altitude information (within feet) without requiring separate augmentation systems, thereby reducing overall device complexity and cost.
3Measurement precision
If conventional radar systems are used without error correction, then the device complexity is low, but the measurement precision is degraded due to antenna pointing errors
Solution Approach 1:
The patent implements a feedback mechanism where the measured angles to multiple runway points are used to calculate the runway slope, which then feeds back to correct the antenna pointing angle errors. This self-correcting process compensates for elevation errors without requiring external reference systems, maintaining device simplicity while achieving high measurement precision through iterative error 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 method enhances altitude estimation accuracy, reducing errors and enabling reliable synthetic vision aided landings without the need for additional equipment or location-specific systems, providing accurate altitude information during all phases of flight.
Implementation Method 1
radar returns from the runway
Data Source
AI summary
Methods and systems of determining the altitude of an aircraft are provided. The method includes receiving data associated with aircraft position, a position of a first point and a second point on the runway, and an altitude of the first point and the second point, radar returns from the runway. The method includes determining a first range and second range between the aircraft, and the first point and the second point. The method includes determining a first angle and a second angle between the first point and second point, and the aircraft. The method includes determining a corrected angle. The method includes determining the altitude of the aircraft based on the corrected angle, the runway altitude of at least one of the first point and the second point, and at least one of the first range and the second range.