Back Projection Processor Radar Imaging Limited Access
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Solution Overview
Problem
Synthetic aperture radar techniques require access to targets from multiple orthogonal viewing angles to generate detailed imagery, which is challenging for structures with limited access, such as buildings, due to the large size of radar systems typically mounted on stationary or large mobile platforms.
Innovation Solution
A radar image generation system that uses a back projection processor to combine multiple return signals and adjust the squint angle of the radiation pattern, allowing for the generation of dynamic images of internal features by narrowing and updating the beamwidth of the radiation pattern, enabling imagery acquisition with limited access using a mobile platform like a truck.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If synthetic aperture radar techniques are used to generate detailed imagery, then measurement precision of internal characteristics is improved, but device complexity and difficulty of access to targets worsen
Solution Approach 1:
The patent divides the radar system into a mobile platform (truck) and a processing system that performs synthetic aperture radar functions through signal processing rather than requiring a large physical aperture. The back projection processor segments the imaging function across multiple return signals and processes them to generate detailed imagery.
Solution Approach 2:
The patent replaces the mechanical requirement for large physical aperture or multiple orthogonal viewing angles with electronic signal processing. The back projection processor uses computational methods to synthesize the aperture and generate detailed imagery from signals collected by a smaller mobile radar system.
2Measurement precision
If access to targets from multiple orthogonal viewing angles is provided, then measurement precision of internal characteristics is improved, but ease of operation and access to targets worsen
Solution Approach 1:
The patent transitions from requiring physical access to multiple orthogonal viewing angles (three-dimensional spatial access) to achieving multi-angle information through signal processing dimensions. The back projection processor analyzes return signals at different squint angles and combines them to create detailed imagery of internal features.
Solution Approach 2:
The patent changes the parameter of beamwidth from a fixed physical characteristic to an adjustable processing parameter. By dynamically modifying the beamwidth and squint angle parameters in the back projection processing, the system can extract detailed information about internal features without physically repositioning the radar system.
3Measurement precision
If beamwidth is narrowed to update imagery portions, then measurement precision of specific features is improved, but loss of information from other areas increases
Solution Approach 1:
The patent employs periodic scanning of the radar beam across different squint angles and positions. The back projection processor systematically varies the beam parameters to periodically sample different portions of the target, building up comprehensive imagery through multiple periodic passes that cover both detailed feature extraction and overall coverage.
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 the generation of detailed imagery of internal characteristics of buildings and other structures with limited access, providing useful information about structural features like orthogonal walls by adjusting the beamwidth and filtering levels, facilitating covert data acquisition.
Implementation Method 1
Radar transmits electro-magnetic radiation toward a building and receives reflected electro-magnetic radiation to generate return signals
Data Source
AI summary
According to one embodiment, a synthetic aperture radar includes a back projection processor that is configured to receive multiple return signals from the radar as the radar is moved with respect to an object, wherein the return signals are representative of electro-magnetic radiation reflected from the object. The back projection processor generates a dynamic image of one or more internal features of the object from the return signals by varying a squint angle of the plurality of return signals in which the squint angle varied by modifying a back projection filter. Once generated, the back projection processor displays the dynamic image on a display.