Synthetic Inertial Localizer Deviation for Redundant Autoland Control
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Solution Overview
Problem
Existing automated landing systems require redundant multi-mode receivers to compute localizer and glideslope deviations, adding weight and cost to aircraft, and may forfeit control to pilots if signal failures occur, especially below 200 feet where errors can lead to missing the runway.
Innovation Solution
A flight control module that computes an inertial localizer deviation using inertial data from an inertial reference unit, allowing selection of the best localizer deviation signal among received and computed signals to ensure continued automated landing system control in case of failures.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If three independently computed localizer and glideslope deviations are used for redundancy, then reliability is improved, but device complexity and weight increase
Solution Approach 1:
The patent merges the functions of multiple MMRs into a single MMR by combining ground-based localizer/glideslope signals with airborne inertial navigation data. This integration allows the system to achieve the reliability of multiple independent computations without physically installing multiple receivers, thereby reducing device complexity and weight while maintaining triple-redundant localizer deviation computation.
Solution Approach 2:
The single MMR is made multi-functional by enabling it to perform both traditional localizer/glideslope signal reception and synthetic inertial localizer deviation computation. The inertial navigation system, originally designed for general navigation, is adapted to provide localizer deviation data, allowing one piece of equipment to fulfill multiple roles and eliminate the need for separate redundant MMRs.
2Reliability
If three independently computed localizer and glideslope deviations are used for redundancy, then reliability is improved, but aircraft weight increases
Solution Approach 1:
The patent merges the functions of multiple MMRs into a single MMR by combining ground-based localizer/glideslope signals with airborne inertial navigation data. This integration allows the system to achieve the reliability of multiple independent computations without physically installing multiple receivers, thereby reducing device complexity and weight while maintaining triple-redundant localizer deviation computation.
Solution Approach 2:
The system creates a synthetic copy of the localizer deviation signal through inertial navigation computation. Instead of relying on a third physical MMR to provide an independent localizer deviation signal, the system computationally generates a synthetic signal that mirrors what a third receiver would produce, thereby achieving signal redundancy without the weight of additional hardware.
3Object-affected harmful factors
If the automated landing system forfeits control when localizer deviations disagree beyond a threshold, then safety is improved, but ease of operation deteriorates
Solution Approach 1:
The inertial navigation system serves as an intermediary that mediates between the two MMR localizer deviation signals. When the MMR signals disagree or one fails, the inertial navigation system provides a third independent signal that acts as a mediator to maintain automated control. This prevents the system from forfeiting control due to normal signal variations while still detecting true failures through the triad comparison.
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
The solution provides reliable automated landing system control by integrating inertial data to generate an inertial localizer deviation, reducing the need for redundant receivers and ensuring continued operation even if one MMR fails, thereby enhancing safety and reducing aircraft weight and cost.
Implementation Method 1
an inertial reference unit (IRU) that provides inertial data
Data Source
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AI summary
A flight control module (402) for computing localizer deviation (424, 426) during landing of an aircraft (102) is provided. The flight control module (402) includes a communication interface (415) and a processor (434). The communication interface (415) is configured to receive inertial data for the aircraft (102). The processor (434) is coupled to the communication interface (415) and is configured to compute an inertial localizer deviation (436) based on the inertial data.