Windmill-Mounted SAR Antenna for Vertical Cross-Range Resolution
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Solution Overview
Problem
Existing surveillance systems have low cross-range resolution, making it difficult to accurately estimate the distance between objects in large air/sea/ground areas, especially between objects separated in the vertical dimension, such as aircrafts, and are not adapted for permanent surveillance.
Innovation Solution
A Synthetic Aperture Radar (SAR) antenna is mounted on a windmill blade, utilizing its circular motion to create a vertical swath for improved cross-range resolution in azimuth and elevation, employing FMCW or pulse radar techniques and the ω-k algorithm with Fourier transform to estimate target positions.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If existing radar systems are used for surveillance, then large air/sea/ground areas can be covered, but cross-range resolution is low making it difficult to accurately estimate distance between objects
Solution Approach 1:
The patent transitions from traditional horizontal radar scanning to vertical plane imaging by mounting the radar antenna on a rotating windmill blade. This dimensional change enables the radar to illuminate and image targets in the vertical cross-range direction, achieving high cross-range resolution for objects at different altitudes while maintaining large area coverage through the windmill's rotational synthetic aperture.
Solution Approach 2:
The windmill structure serves multiple functions: it generates electricity for the surveillance system and simultaneously provides the rotational motion required to create the synthetic aperture. This multi-functionality reduces system complexity and enables permanent surveillance without requiring additional active components for rotation.
2Measurement precision
If helicopter-mounted rotating SAR is used, then cross-range imaging can be achieved, but it is difficult to fly a helicopter at a true stationary location
Solution Approach 1:
The windmill automatically provides the rotational motion needed for synthetic aperture radar imaging through wind-driven blade rotation. The system utilizes the natural environmental resource (wind) to perform the function of rotation, eliminating the need for complex flight control systems required to maintain stationary helicopter positions.
Solution Approach 2:
The patent extracts the rotation function from the aircraft platform (helicopter) and transfers it to the windmill structure. This separation allows the radar system to achieve stable synthetic aperture imaging without the operational difficulties of maintaining stationary aerial platforms.
3Area of stationary object
If airplane-mounted circular SAR is used, then ground area imaging can be achieved, but it is difficult to fly a true circle at constant altitude and speed
Solution Approach 1:
The windmill's blades naturally rotate in a circular path driven by wind force, automatically providing the circular motion required for circular SAR imaging. This eliminates the need for complex flight control systems to maintain constant altitude and speed along a circular trajectory.
Solution Approach 2:
Instead of moving the radar platform in a circle (airplane approach), the patent inverts the approach by keeping the platform stationary and rotating the antenna along a circular path using the windmill blades. This inversion simplifies the operational requirements while achieving the same imaging geometry.
4Duration of action of stationary object
If traditional radar systems are deployed, then surveillance can be performed, but the systems are not adapted for permanent surveillance
Solution Approach 1:
The windmill structure serves dual purposes: generating electrical power for the surveillance system and providing the rotational mechanism for synthetic aperture radar imaging. This multi-functionality enables permanent surveillance deployment without requiring separate power sources or rotation mechanisms, reducing overall system complexity.
Solution Approach 2:
The windmill automatically provides both power generation and rotational motion for permanent surveillance operation. The system utilizes environmental wind resources to sustain itself, enabling long-term permanent surveillance without requiring external intervention for power supply or motion actuation.
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 high-resolution cross-range estimation and target classification over large areas, facilitating permanent surveillance with a cost-effective and environmentally friendly solution that leverages existing windmill infrastructure.
Implementation Method 1
a radar antenna mounted on a blade of a windmill
Implementation Method 2
the phase of the received echo when the waveform is reflected by the targets
Implementation Method 3
mount a SAR antenna on a windmill blade... utilizing its circular motion to create a vertical swath
Implementation Method 4
the system comprising means to apply an ω-k algorithm with Fourier transform of the Green's function, so as to establish a cross-range image containing the targets and estimate azimuth and elevation
Data Source
AI summary
A surveillance system for detecting targets comprises a radar antenna mounted on a blade of a windmill.