Radar Beacon Detection Using Azimuth and Elevation Scans
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Solution Overview
Problem
Current systems face challenges in precisely detecting and locating a stationary aircraft on a runway due to interference from other targets, low signal-to-noise ratio, and sensitivity to ground reflections, which complicates take-off and landing operations.
Innovation Solution
A method using a radar with a known beacon's elevation and transmission frequency to discriminate the aircraft from parasitic emissions by performing an azimuth scan followed by an elevation scan, leveraging interferometry or Doppler processing to confirm the target's position.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Area of stationary object
If a conventional radar is used to detect a stationary aircraft on the runway, then the detection coverage is broad, but the measurement precision deteriorates due to inability to discriminate between the aircraft and other targets at the same height using Doppler shift
Solution Approach 1:
The patent introduces elevation angle as an additional dimension to the traditional azimuth-elevation radar coordinate system. By scanning in the elevation dimension and comparing detected targets against a pre-stored three-dimensional map of the airport environment, the system achieves precise discrimination between the aircraft and other targets at the same height, resolving the contradiction between broad coverage and precise measurement.
2Measurement precision
If a millimeter wave radar with a narrow beam is used to achieve high distance resolution, then the measurement precision improves, but the device complexity and antenna dimension increase to prohibitive levels
Solution Approach 1:
The patent segments the detection process into multiple independent phases: azimuth scanning, elevation scanning, and position verification against a stored map. This segmentation allows the use of a standard wide-beam radar antenna while achieving precise measurement through algorithmic processing of returned signals across multiple dimensions, avoiding the need for complex high-resolution antennas.
Solution Approach 2:
The patent replaces the mechanical approach of using physically large high-resolution antennas with a computational approach. By processing signals through multi-phase scanning and comparing them against a digital three-dimensional map of the airport environment, the system achieves precise distance and position measurement using a standard radar antenna, substituting mechanical complexity with information processing.
3Measurement precision
If a laser beam system is used for precise targeting, then the measurement precision improves, but the reliability deteriorates in foggy weather conditions
Solution Approach 1:
The patent substitutes the optical laser beam system with an electromagnetic radar system that operates in the radio frequency spectrum. This substitution maintains precise target localization capability through multi-dimensional scanning and map comparison while eliminating the vulnerability to foggy weather conditions that plagues laser-based systems, thereby improving reliability without sacrificing precision.
4Ease of operation
If a GPS or DGPS positioning system is used to locate the aircraft, then the ease of operation improves, but the reliability deteriorates due to susceptibility to ground reflections and jamming
Solution Approach 1:
The patent introduces a three-dimensional map of the airport environment as an intermediary reference framework. Instead of relying directly on satellite signals that are susceptible to ground reflections and jamming, the system uses the stored spatial map as a mediator to verify and correct position measurements, thereby maintaining ease of operation while significantly improving reliability through cross-validation with the environmental model.
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 precise detection and localization of the aircraft using a low-cost, wide-beam radar with passive antennas, reducing maintenance costs and improving fault tolerance, while being insensitive to antenna positioning and weather conditions.
Implementation Method 1
A radar (1) is used to detect a beacon (2) emitted by an aircraft
Implementation Method 2
radars, whether millimetric or otherwise, are sensitive to reflections, in particular on the ground
Implementation Method 3
measuring the azimuth and the elevation in accordance with the French application for deposit number 0701926
Implementation Method 4
a conventional radar cannot exploit the Doppler shift to discriminate, in the same range resolution cell, echoes coming from the aircraft and spurious echoes coming from other targets
Data Source
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AI summary
The method involves detecting a target i.e. beacon (2), by carrying out azimuth scanning. The target is detected along an azimuth angle (theta-az) and along an elevation angle corresponding to an elevation angle of an object arranged at distance (Di) and specific height, when the target is detected at the distance along the azimuth angle. The target is reputedly detected, if the target is detected along the elevation angle at distance (D) that is equal to the distance (Di). An independent claim is also included for a method for locating a beacon with a radar.