Landing Guidance Reference Paths for Displaced Runway Thresholds
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Solution Overview
Problem
Existing aircraft navigation systems for non-precision approaches lack accuracy when dealing with displaced or additional landing threshold points, leading to reduced landing accuracy and increased pilot workload due to the inability to store multiple threshold points in navigation databases.
Innovation Solution
A landing system that calculates a reference path using a missed approach point's altitude to determine the anchor point, allowing for accurate guidance even when the relevant landing threshold point is not stored in the navigation database, and employs autopilot functions to steer the aircraft automatically.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Device complexity
If the navigation database stores only one landing threshold point per runway, then the device complexity is reduced, but the accuracy of landing guidance is compromised when dealing with displaced or additional threshold points
Solution Approach 1:
The patent introduces a displaced threshold point indicator as an intermediary element that links the stored landing threshold point to the actual displaced threshold point. This indicator contains displacement information that allows the system to calculate the correct reference path to the actual threshold without storing multiple threshold points in the navigation database, thus resolving the contradiction between database simplicity and guidance accuracy.
2Ease of operation
If the system uses the stored landing threshold point to calculate the reference path, then the ease of operation is improved, but the landing accuracy deteriorates when the threshold is displaced or additional
Solution Approach 1:
The patent applies preliminary action by pre-calculating and storing the displaced threshold point indicator in the navigation database before the approach. This indicator contains the necessary displacement information from the stored threshold point to the actual displaced threshold point. During the approach, the system uses this pre-stored indicator to adjust the reference path calculation, maintaining ease of operation while achieving landing precision even for displaced or additional thresholds.
3Ease of operation
If the pilot manually steers the aircraft during non-precision approaches, then the ease of operation is improved, but the pilot workload increases due to reduced guidance accuracy
Solution Approach 1:
The patent implements feedback by calculating the reference path using the displaced threshold point indicator, which provides accurate guidance information back to the autopilot system. The autopilot then uses this accurate reference path to automatically steer the aircraft, reducing pilot workload while maintaining ease of operation. The feedback loop ensures that the autopilot receives correct guidance data even when thresholds are displaced or additional, enabling automated steering without increasing pilot burden.
Data Source
AI summary
A landing system for an aircraft and a method of calculating a reference path. The landing system can calculate a reference path for use during a non-precision approach to a runway, the reference path including a course, flight path angle, and anchor point. The anchor point has a longitude, a latitude and an altitude. The landing system is configured to extract from a navigation database a missed approach point corresponding to a first landing threshold point of the runway. The missed approach point has a longitude, a latitude and an altitude. The landing system is configured such that calculation of the reference path includes setting the altitude of the anchor point with use of the altitude of the missed approach point. The system may be used when approaching a runway having a displaced landing threshold point, the location of the point not being stored in the navigation database.