ILS Glide Signal Capture Inhibition for Replica Axis Avoidance
Find Innovative SolutionsGenerate Solutions
Solution Overview
Problem
Instrument Landing Systems (ILS) face challenges in accurately guiding aircraft during landing due to signal replication, which can result in false Glide axes being detected, leading to incorrect guidance and potentially requiring go-around maneuvers.
Innovation Solution
A landing aid system comprising an ILS signals receiver, information sources, and a processing unit that determines a protection volume where replica Glide signals are not detected, inhibiting the capture of the Glide signal and alerting the pilot when above this volume to prevent incorrect guidance.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If the ILS system emits Glide signals with multiple lobes for longitudinal guidance, then the aircraft can be guided along the approach axis, but replica Glide axes with false slopes are generated that can be mistakenly detected by the receiver
Solution Approach 1:
The system determines a protection volume before Glide signal capture is attempted. This protection volume is calculated based on the aircraft's current position and the known geometry of replica signals. By establishing this protective boundary in advance, the system prevents the aircraft from entering regions where replica signals could be mistakenly captured, thus resolving the contradiction between providing guidance and avoiding false signal detection.
Solution Approach 2:
The processing unit acts as an intermediary between the ILS signals receiver and the replica Glide signals. It monitors the aircraft position relative to the protection volume and selectively inhibits signal capture when the aircraft is in dangerous proximity to replica axes. This intermediary control mechanism allows the system to benefit from the Glide signal guidance while filtering out harmful replica signal interference.
2Reliability
If the aircraft operates above the protection volume to avoid replica signals, then false Glide axis capture is prevented, but the aircraft cannot capture the legitimate Glide signal for guidance
Solution Approach 1:
The Glide signal capture inhibition is not static but dynamically adjusted based on the aircraft's real-time position relative to the protection volume. When the aircraft is above the protection volume, capture is inhibited to ensure reliability. When the aircraft descends into the protection volume, the inhibition is lifted to enable normal guidance operation. This dynamic control resolves the contradiction by adapting the capture capability to the aircraft's operational context.
Solution Approach 2:
The system changes the operational parameter of signal capture based on the aircraft's vertical position. Above the protection volume, the capture function is disabled; within the protection volume, it is enabled. This parameter change approach allows the system to maintain high reliability when needed while preserving ease of operation when safe, thus resolving the contradiction between these two features.
3Adaptability or versatility
If the ILS system uses a fixed Glide axis slope for all approaches, then the system is simple to implement, but it cannot accommodate different approach slopes required by various runways and conditions
Solution Approach 1:
The processing unit is designed to handle multiple approach slopes by calculating protection volumes for different Glide axis slopes. Instead of requiring separate systems for each slope, a single universal processing unit adapts its calculations based on the selected approach parameters. This multi-functionality allows the system to accommodate different runways and approach conditions while maintaining relatively simple architecture.
Solution Approach 2:
The system changes the protection volume calculation parameters based on the selected approach slope. When different Glide axis slopes are required, the processing unit adjusts its internal parameters and recalculation logic accordingly. This parameter adaptability enables the system to support multiple approach configurations without requiring fundamentally different hardware or complex multi-system architectures.
Data Source
AI summary
The system for aiding the landing of an aircraft on a landing runway of an airport equipped with an Instrument Landing System (“ILS”) corresponding to an axis of a predetermined approach, includes: an ILS signals receiver and a processing unit. The processing unit is configured to, when the ILS signals receiver) has not yet captured a Glide signal corresponding to a Glide axis of the approach as a function of items of information relating to the predetermined approach, acquired from a database, determine a protection volume in which there is no risk of the ILS signals receiver detecting a replica of the Glide signal; and when a current position of the aircraft is above the protection volume, inhibit the capture of the Glide signal by the ILS signals receiver and instruct the emission of an alert item of information in the cockpit of the aircraft.