SAR Image Artifact Reduction via Subaperture Signal Extraction
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Solution Overview
Problem
Synthetic aperture radar (SAR) image quality is compromised by radio frequency (RF) interference from communication signals, leading to artifacts that hinder target identification and image clarity.
Innovation Solution
A signal detection system identifies and extracts communication signals from radar returns, deramping and sampling the data to separate radar clutter and communication signals into subapertures, allowing for the reapplication of the communication signal to reduce artifacts while maintaining desired radar returns in the SAR image, using spectral estimation and linear predictive coefficients for filtering.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Adaptability or versatility
If communication signals are transmitted simultaneously with radar signaling, then RF communication capability is enabled, but artifacts are generated in SAR images reducing image quality
Solution Approach 1:
The received signal is divided into multiple subapertures based on range gate positions. Subapertures containing communication signals are identified and segmented from those containing only radar clutter, enabling selective processing to remove artifacts while preserving communication signals
Solution Approach 2:
Communication signals are extracted from the received signal by identifying subapertures where communication signals are present and separating them from radar clutter. This extraction allows the communication signals to be removed or attenuated from the final SAR image while maintaining their integrity for communication purposes
2Manufacturing precision
If communication signals are removed from radar returns, then SAR image quality is improved, but communication signal strength is reduced
Solution Approach 1:
A spectral estimation filter is introduced as an intermediary processing step between signal reception and SAR image formation. This filter selectively attenuates communication signal components in the frequency domain while preserving radar clutter and target signals, thereby removing artifacts without completely eliminating communication signals
Data Source
AI summary
The various technologies presented herein relate to reducing and/or filtering undesired artifacts in a SAR image, wherein the artifacts are generated by RF interference resulting from a communication signal being included in a radar return which also comprises radar clutter. The radar return is separated into two subapertures, a first subaperture comprising radar clutter only, and a second subaperture comprising radar clutter and the communication signal. The communication signal is extracted from the second subaperture and reapplied to the initially received radar return. Reapplication of the communication signal to the radar return enables any undesired artifacts arising from the communication signal to have their return strength reduced or minimized, while maintaining any desired radar returns in the SAR image.