External Fuselage Altimeter with Modular Antenna
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Solution Overview
Problem
Existing altimeter systems for aircraft require complex installation and maintenance, with bonded antennas needing time to cure and requiring pressure testing, limiting quick access and replacement.
Innovation Solution
A low range altimeter (LRA) apparatus with a smart antenna system externally mounted on the aircraft fuselage, using a fractional-N synthesizer to reduce active electronics size, allowing for easy access and replacement without breaking the pressure seal, and featuring a radome cover to enclose the altimeter circuit and antennas.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If bonded antennas are used for altimeter installation, then reliable signal transmission is achieved, but installation time increases due to sealant curing requirements
Solution Approach 1:
The antenna system is divided into modular components that can be independently mounted and replaced. The antenna elements are segmented from the mounting structure, allowing each component to be installed separately without requiring full system disassembly or curing time for sealants across the entire assembly.
Solution Approach 2:
The patent replaces chemical bonding (sealant curing) with mechanical fastening systems. The antenna mounting structure uses mechanical fasteners and clips that provide immediate secure attachment without requiring chemical adhesives, thereby eliminating curing wait time while maintaining reliable signal transmission.
2Strength
If bonded antennas are used for altimeter installation, then secure mounting is achieved, but maintenance complexity increases due to pressure testing requirements
Solution Approach 1:
The mounting system transitions from a static bonded connection to a dynamic mechanically fastened system that can be easily assembled and disassembled. The mechanical fasteners allow the antenna to be securely mounted during operation but can be quickly removed for maintenance without requiring pressure testing or specialized bonding procedures.
Solution Approach 2:
The antenna system is extracted from the permanent bonded installation and converted into a removable module. This allows the antenna to be easily taken out for replacement or maintenance by simply unfastening mechanical connectors, eliminating the need for pressure testing that would be required with bonded installations.
3Ease of operation
If external fuselage mounting is used, then quick access and replacement is enabled, but pressure seal integrity must be maintained
Solution Approach 1:
The patent employs flexible sealing elements such as O-rings or gaskets that create pressure-tight seals at the fuselage mounting interface. These flexible membranes conform to the mounting surface and maintain pressure integrity while allowing the antenna assembly to be easily installed and removed through the fuselage opening.
Solution Approach 2:
A separate mounting plate or interface structure serves as an intermediary between the antenna system and the fuselage. This intermediate component provides the pressure seal function, allowing the main antenna assembly to be easily accessed and replaced while the mounting plate maintains the pressure barrier at the fuselage opening.
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
Enables quick and efficient installation, modification, or replacement of the altimeter system without the need for sealant curing or pressure testing, reducing downtime and improving maintenance efficiency while maintaining accurate altitude determination.
Implementation Method 1
A radar altimeter, also known as a low range altimeter (LRA), uses radio waves to determine an altitude above terrain for an aircraft
Data Source
AI summary
An altimeter apparatus for external fuselage mounting for an aircraft includes an altimeter circuit and a chassis. The altimeter circuit is coupled to an antenna system. The altimeter circuit is configured to generate a first signal and transmit the first signal via the antenna system, receive a second signal via the antenna system, wherein the second signal is a reflected version of the first signal, and determine an altitude based on the first and second signals. The chassis is configured to contain the altimeter circuit and the antenna system, wherein the chassis is connected to a fuselage of the aircraft and is located outside of the aircraft.