Telemeter Catenary Detection for Aircraft Filament Objects
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Solution Overview
Problem
Current methods for detecting suspended filamentary objects like cables near aircraft are unreliable, especially in bad weather and large sighting angles, leading to reduced operational range and safety due to inefficient computation and inaccurate detection.
Innovation Solution
A method using telemetry measurements to calculate terrestrial coordinates of echo points, identify straight line segments, and determine catenary parameters in vertical planes to detect suspended objects, employing a simplified catenary equation and iterative calculations for accurate parameter determination.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If a three-dimensional Hough transform is used to detect catenaries in each vertical plane, then detection accuracy is improved, but computation time increases very considerably
Solution Approach 1:
The patent divides the three-dimensional detection space into multiple two-dimensional vertical planes. Instead of performing a full 3D Hough transform, the method segments the problem into 2D slices where catenaries are detected independently in each vertical plane. This segmentation reduces computational complexity from O(n³) in 3D space to O(n²) in 2D planes while maintaining detection accuracy through systematic coverage of all possible cable positions.
Solution Approach 2:
The patent transforms the three-dimensional catenary detection problem into a series of two-dimensional problems by projecting the 3D space onto multiple 2D vertical planes. The Hough transform parameters are adapted from 3D (a, b, c) to 2D (a, b) for each plane, reducing the parameter space search dimensionality. This dimensional reduction enables real-time processing while preserving the ability to detect catenary curves through the accumulation of evidence across multiple planes.
2Productivity
If a specific accelerator card is used to reduce computation time, then productivity is improved, but device complexity increases
Solution Approach 1:
The patent replaces the need for specialized hardware accelerator cards with an optimized software implementation of the Hough transform algorithm. By reformulating the catenary detection mathematics and using efficient computational techniques (such as parameterization and iterative refinement), the method achieves high-speed processing using standard onboard computer hardware, thereby avoiding the complexity and cost of dedicated hardware while maintaining real-time performance.
3Productivity
If the digitization step is increased to reduce computation time, then computation speed is improved, but result accuracy deteriorates
Solution Approach 1:
The patent implements a dynamic, adaptive approach to the Hough transform where the parameter search ranges and resolution are adjusted based on the specific detection context. Rather than using a fixed coarse digitization step that sacrifices accuracy, the method dynamically refines the parameter space exploration, concentrating computational effort where catenaries are most likely to be found. This adaptive strategy maintains high detection accuracy while optimizing computation speed for each specific scenario.
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
This method significantly reduces computational complexity and improves detection accuracy, enabling reliable detection of cables under various conditions, including large angles and weather challenges, with enhanced performance and robustness.
Implementation Method 1
The Hough transform, which is described in U.S. Pat. No. 3,069,654, enables a set of aligned points to be detected in an image. Proposals are made in U.S. Pat. No. 5,296,909 to detect the presence of cables by means of a scanning laser telemeter (Lidar) that delivers echoes or plots, where each plot corresponds to a point in three-dimensional space that is characterized by its three coordinates in that space: the telemeter emits laser pulses that, by measuring their travel times, enable points to be obtained that are positioned in 3D space (3D plots).
Data Source
AI summary
A method of detecting the presence of a suspended filamentary object in view of a telemeter on an aircraft includes: i) calculating terrestrial coordinates of points corresponding to telemeter echoes, and selecting candidates; ii) searching a horizontal plane for straight line segments close to vertical projections of candidate points; and iii) searching each vertical plane containing one of the straight line segments for portions of catenaries close to candidate points. In step iii), for each considered vertical plane and each triplet of candidate points close to the considered vertical plane, calculating values of three parameters of a catenary containing the projections on the vertical plane of the three points of the considered triplet, and determining presence of at least one suspended filamentary object as a function of the distribution of values of catenary parameters calculated for all of the triplets of candidate points close to the vertical plane under consideration.