Radar Reflectors for Runway Light Detection in Fog
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Solution Overview
Problem
Current radar systems face challenges in accurately identifying runway structures and providing visual approach slope indications (VASI) or precision approach path indications (PAPI) in low visibility conditions, especially in heavy fog, and there is a need for cost-effective solutions that do not rely on lighting.
Innovation Solution
The implementation of an image processing system with enhanced angular and range resolution using X-band or C-band airborne weather radar systems, combined with radar reflectors integrated into runway light structures, allows for real-time detection and visualization of approach paths and lighting systems, enabling accurate identification of runway features and providing VASI/PAPI indications without the need for visible lighting.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Illumination intensity
If passive sensors (infrared or visible light cameras) are used to acquire runway environment data, then video image quality is improved, but the system fails to identify required visual references in heavy fog conditions
Solution Approach 1:
The patent introduces radar reflectors as intermediary objects attached to runway lighting structures. These reflectors act as mediators between the radar system and the runway environment, enabling radar detection of lighting structures that would otherwise be invisible in heavy fog. The reflectors bounce radar energy back to the aircraft, providing reliable detection capability independent of weather conditions.
Solution Approach 2:
The patent replaces the optical-based passive sensing system with a radar-based active sensing system. Instead of relying on visible light or infrared cameras that fail in heavy fog, the system uses electromagnetic radiation in the radar frequency range to detect runway structures. This substitution enables operation in all weather conditions including heavy fog.
2Reliability
If active sensing systems (radar) are used to detect runway structures, then detection capability in heavy fog is improved, but the ability to accurately identify runway structures and their positions deteriorates
Solution Approach 1:
The patent applies the concept of changing radar cross-section characteristics by attaching reflectors with specific geometric shapes and orientations to runway lighting structures. These reflectors are designed to return radar energy in characteristic patterns that allow the radar system to distinguish between different types of structures (e.g., approach lights, runway edge lights, centerline lights) and accurately determine their positions.
Solution Approach 2:
The patent modifies the radar cross-section parameters of runway lighting structures by attaching reflectors. This changes how the structures interact with radar energy, creating distinct return signatures that improve the radar system's ability to identify and locate different types of runway structures with greater precision.
3Ease of operation
If traditional lighting infrastructure is used to provide VASI/PAPI indications, then visual approach slope indication is achieved, but operational costs and infrastructure complexity increase
Solution Approach 1:
The patent makes the radar reflectors serve multiple functions: they enhance the radar detectability of runway lighting structures while simultaneously providing visual approach slope indications (VASI/PAPI). Instead of requiring separate lighting systems for these functions, the same reflector structures that make the lights visible to radar also provide the slope guidance information, eliminating redundant infrastructure.
Solution Approach 2:
The radar system provides its own illumination function by transmitting radar energy that reflects off the reflectors attached to the runway lighting structures. The system uses its own electromagnetic energy to both detect and characterize the structures, eliminating the need for separate active lighting systems to provide visual cues during approach.
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 solution enhances the ability of radar systems to detect runway structures and provide accurate visual approach slope and precision approach path indications in challenging weather conditions, allowing for lower landing minima and reducing operational costs by eliminating the need for lighting infrastructure.
Implementation Method 1
Active sensing systems, such as, millimeter wavelength (MMW) (e.g., 94 GHz) and weather radar systems (e.g., X-band or C-band), transmit electromagnetic energy into the environment and receive return electromagnetic energy reflected from the environment.
Implementation Method 2
receive return electromagnetic energy reflected from the environment
Implementation Method 3
receiving radar returns from an X-band or C-band airborne weather radar system from a radar reflector associated with an approach lighting system
Data Source
AI summary
An apparatus interfaces with a light stanchion associated with a runway. The apparatus can include a first interface for attaching to the light stanchion, second interface for attaching to runway light, and a radar reflective member. The radar reflective member can be a corner reflector. The radar reflector can be part of set of reflectors arranged in accordance with visual approach slope indications or precision approach path indications.