Aircraft Approach Determination Using Radio and Barometric Altimeters
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Solution Overview
Problem
Current aircraft approach determination systems face challenges in accurately determining the approach phase without increasing aircraft weight, as they rely on multiple altimeters, which can lead to weight increases and reliability issues due to the inability to precisely define approaching states using flap and slat positions alone.
Innovation Solution
A computer system that uses a combination of a radio altimeter and a barometric altimeter to determine approach by establishing conditions based on absolute altitudes, with redundancy provided by different measurement principles, allowing for reliable approach determination without additional weight, even in case of altimeter failure.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If multiple altimeters are used to improve reliability of approach determination, then reliability is improved, but weight of the aircraft increases
Solution Approach 1:
The patent combines the radio altimeter and barometric altimeter into a unified approach determination system. The computer system integrates data from both altimeters to determine approach conditions, achieving reliable determination without requiring multiple radio altimeters. This merging of measurement sources resolves the contradiction by maintaining reliability while avoiding additional weight.
Solution Approach 2:
The barometric altimeter, which is already an essential device for aircraft flight, is utilized for approach determination in addition to its conventional function. This multi-functionality allows the system to improve approach determination reliability without adding dedicated measurement devices, thereby avoiding weight increase.
2Device complexity
If flap and slat positions are used as the sole index for approach determination, then device complexity is reduced, but measurement precision deteriorates
Solution Approach 1:
The approach determination is divided into multiple independent conditions: first condition based on radio altimeter measurement and second condition based on barometric altimeter measurement. Each condition can be evaluated separately, and the overall determination is made when at least one condition is satisfied. This segmentation allows precise determination while keeping each individual condition simple.
Solution Approach 2:
The system transitions from using only configuration parameters (flap and slat positions) to incorporating altitude measurements from two different sources (radio altimeter and barometric altimeter). This adds a new dimension of measurement that significantly improves precision in determining approach phase without excessively increasing complexity.
3Weight of moving object
If a single radio altimeter is used to reduce weight, then weight is reduced, but reliability deteriorates due to potential measurement failure
Solution Approach 1:
The barometric altimeter acts as an intermediary measurement source that complements the radio altimeter. When the radio altimeter is available, it provides primary measurement; when it fails or provides unreliable data, the barometric altimeter serves as a backup. This intermediary approach maintains reliability while using only one radio altimeter to minimize weight.
Solution Approach 2:
The system prepares for potential radio altimeter failure by having the barometric altimeter ready as a backup measurement source. The computer system is configured to switch between measurement sources or use both simultaneously, cushioning against the risk of single-point failure without requiring duplicate critical components.
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 system effectively determines aircraft approach while minimizing weight increase and ensuring reliability by using redundant altitude measurements from a radio altimeter and a barometric altimeter, reducing the risk of measurement failures and improving overall approach determination accuracy.
Implementation Method 1
a first absolute altitude determined by a radio altimeter mounted on the aircraft
Implementation Method 2
a second absolute altitude that is obtained by subtracting an altitude of the landing site from a pressure altitude determined by a barometric altimeter mounted on the aircraft
Data Source
AI summary
A computer system 20 provided in an aircraft 1 includes, as a module of a computer program to be executed, an approach determination section 31 configured to determine whether the aircraft 1 is approaching a landing site. The approach determination section 31 includes, as a condition for determination of approaching, establishment (C1) of one or both of a condition (C11) that a first absolute altitude A1 obtained by an radio altimeter 21 mounted on the aircraft 1 is low relative to a first approach altitude AA1, and a condition (C12) that a second absolute altitude A2 that is obtained by subtracting an altitude AL of the landing site from a pressure altitude Ap determined by a barometric altimeter 22 mounted on the aircraft 1 is low relative to a predetermined second approach altitude AA2.