Adaptive Protection Limit Calculation for Aircraft Safety
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Solution Overview
Problem
The existing methods for calculating protection limits around a vehicle's position using satellite data are inaccurate and delayed, leading to increased protection volumes that reduce aircraft availability and introduce inaccuracy due to speed variations.
Innovation Solution
A method that determines a protection limit at a future time by distributing a safety threshold between position and speed thresholds, using statistical errors and maximum acceleration to calculate a low protection limit that ensures compliance with safety thresholds over a time horizon, with a preferred distribution of 80% for position and 10% for speed.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If the protection volume is increased to account for speed variations and calculation delays, then safety is improved, but aircraft availability is reduced
Solution Approach 1:
The patent applies dynamics by making the protection volume adaptive rather than static. The protection volume automatically adjusts based on the current speed of the aircraft and the calculated delay time, using dynamic parameters (speed, acceleration, time) to define its boundaries. This allows the system to maintain appropriate safety margins while minimizing unnecessary restrictions on aircraft operation.
Solution Approach 2:
The patent changes key parameters of the protection volume based on real-time conditions. Specifically, it modifies the temporal parameter (validity duration) and spatial parameters (dimensions) of the protection volume according to the aircraft's speed and acceleration characteristics. This parameter adaptation resolves the contradiction by tailoring the safety buffer to actual operational needs rather than applying a fixed conservative margin.
2Device complexity
If the protection volume is calculated with a delay to reduce computational load, then processing complexity is reduced, but the accuracy and validity of the protection limit deteriorates
Solution Approach 1:
The patent applies preliminary action by pre-calculating and storing the aircraft's acceleration characteristics and speed parameters before the protection volume calculation is needed. These pre-computed parameters are then used in the protection volume formula, eliminating the need for complex real-time differentiation and reducing computational load while maintaining accuracy.
Solution Approach 2:
The patent introduces intermediate parameters (pre-calculated speed and acceleration values) that serve as mediators between the raw sensor data and the final protection volume calculation. These intermediaries simplify the computational process by reducing the complexity of real-time calculations while preserving the essential dynamic characteristics needed for accurate protection limit determination.
3Productivity
If the protection volume is reduced to improve aircraft availability, then productivity is improved, but safety coverage may be insufficient
Solution Approach 1:
The protection volume uses dynamic parameters (current speed, pre-calculated acceleration) to adapt its size to the actual operational context. At lower speeds where less safety margin is needed, the volume is reduced to improve availability. At higher speeds where greater safety margin is required, the volume automatically increases to maintain safety coverage.
Solution Approach 2:
The patent changes the spatial and temporal parameters of the protection volume based on the aircraft's motion state. By using the current speed and pre-calculated acceleration to define the volume dimensions and validity duration, the system ensures that the protection volume is neither excessively large (reducing availability) nor too small (compromising safety).
Data Source
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AI summary
The method involves dividing a safety threshold between safety thresholds over position and speed of a movable body e.g. aircraft (1). A position and speed of the body at a present time t are determined. Static errors over the position and the speed at the present time are calculated. Protection limits PLpos (t) and PLvit (t) over the position and the speed at the present time are calculated from the errors and the thresholds. Another protection limit is calculated such that the latter limit is PLpos (t)+PLvit (t)x delta-t+gammax delta-t 2>/ 2, where gamma is maximum acceleration of the body.