Radio Altimeter Interference Mitigation via Dynamic Modulation

Resolve Bottlenecks,
Find Innovative SolutionsGenerate Solutions

Solution Overview

Problem

Existing radio altimetry systems in multiple installations face interference issues during critical flight phases, leading to measurement errors due to synchronization of radio waves, which is exacerbated by the need for differentiated manufacturing for each configuration, increasing costs.

Innovation Solution

A radio altimetry system with a frequency-modulated radioelectric wave generator featuring variable duration waiting stages, utilizing pseudo-random number generators to dynamically select configuration based on system identifiers, ensuring non-synchronization of ramps and reducing manufacturing costs by allowing identical production for multiple installations.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Reliability

If several radio altimeters are positioned on an aircraft to ensure safety, then operational safety is improved, but interference between systems increases causing measurement errors

Engineering Contradiction:

Improveoperational safetyVSAvoidinterference between radio altimeters

Core Design Contradiction:

ReliabilityVSObject-affected harmful factors

Solution Approach 1:

The patent applies parameter changes by varying the modulation signal characteristics (ramp repetition frequency and/or ramp duration) for each radio altimeter system. This allows differentiating the emission patterns of multiple radio altimeters to prevent synchronization interference while maintaining their individual safety functions.

Inventive Principle:

Principle #35Parameter changes

Solution Approach 2:

The patent implements dynamics by making the modulation signal configuration adaptable rather than fixed. The system can dynamically adjust ramp repetition frequency and duration based on operational requirements, allowing flexible differentiation between multiple radio altimeter systems without requiring fixed differentiated hardware configurations.

Inventive Principle:

Principle #15Dynamics

2Ease of manufacture

If radio altimetry systems use fixed modulation signal configuration, then manufacturing is simplified, but interference elimination is incomplete and additional manufacturing costs are required for different configurations

Engineering Contradiction:

Improvemanufacturing simplicityVSAvoidinterference elimination

Core Design Contradiction:

Ease of manufactureVSReliability

Solution Approach 1:

The patent applies universality by designing a single radio altimeter system that can function in multiple configurations through software-controlled modulation parameter adjustment. One hardware design can serve multiple installation scenarios (single or multiple radio altimeters) by dynamically changing operational parameters, eliminating the need for differentiated manufacturing while maintaining reliable interference avoidance.

Inventive Principle:

Principle #6Universality (Multi-functionality)

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 effectively minimizes synchronization interference and ensures operational safety in multiple radio altimetry installations while maintaining performance and reducing manufacturing costs by allowing dynamic configuration based on system identifiers.

Implementation Method 1

a radioelectric wave generator frequency modulated by a modulation signal comprising a repetition of frequency variation sequences

Methodology Applied

Scientific EffectFrequency modulation: Phase Modulation

Implementation Method 2

measure height by measuring the propagation time of radio signals transmitted and received after reflection on the ground

Methodology Applied

Scientific EffectReflection: Reflection

Implementation Method 3

measure height by measuring the propagation time of radio signals transmitted and received after reflection on the ground

Methodology Applied

Scientific EffectTime of flight: Time of Flight

Implementation Method 4

utilizing pseudo-random number generators to dynamically select configuration based on system identifiers

Methodology Applied

Scientific EffectPseudo-random number generation:

Data Source

PatentEP2653887B1Radio system capable of operating in a multiple radio altimeter system

Publication Date: 2016.05.18 THALES SA

Figure 1~2
Figure 3
Figure 4

AI summary

The invention relates to a radio altimetry system capable of being attached to an aircraft and providing a distance from said aircraft to a surface, adapted for operation in a multiple radio altimetry installation comprising at least two such radio altimetry systems. Each radio altimetry system comprises a frequency-modulated radio wave generator using a modulation signal consisting of repeated frequency-variation sequences, two successive sequences being separated by a waiting period of variable duration. The radio altimetry system of the invention includes means (26) for obtaining an identifier enabling the radio altimetry system to be distinguished from any other radio altimetry system in said multiple installation, and means (30) for selecting a configuration of the waiting periods for said modulation signal based on the identifier obtained.The invention also relates to a multiple radio altimetry installation comprising at least two such radio altimetry systems.