Radar Tracking System Azimuthal Dithering Aperture Error Compensation
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Solution Overview
Problem
Single-channel receiver radars operating in the inverse synthetic aperture radar mode face challenges in producing images with adequate resolution due to inaccuracies in the electro-magnetic beam scanning, leading to limited image quality compared to multi-channel receivers.
Innovation Solution
A radar tracking system that includes a radar processing system capable of dithering images along their azimuthal extent and combining them to form enhanced images, using boresight correction factors derived from known terrain features to compensate for scanning inaccuracies and improve image resolution.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Device complexity
If single-channel receiver radars are used to reduce cost and complexity, then device complexity is reduced, but image resolution and measurement precision deteriorate due to inability to cancel noise through spatial separation
Solution Approach 1:
The patent applies dynamics by introducing dithering - a controlled dynamic modulation of the radar beam position during image acquisition. The beam is dynamically shifted by small amounts (dithered) during the scanning process, which introduces controlled variations that allow noise cancellation through signal processing. This dynamic approach enables a single-channel receiver to achieve noise cancellation capabilities typically requiring multiple spatially separated channels.
2Measurement precision
If multi-channel receivers are used to improve image quality and cancel noise, then measurement precision is improved, but device complexity and cost increase
Solution Approach 1:
The patent uses copying by creating multiple virtual channels through signal processing of the single physical channel. The dithered signal is captured and processed to generate multiple image components that are then combined. This copying approach in the signal domain replaces the need for multiple physical receiver channels, achieving the same noise cancellation effect through computational methods rather than hardware multiplication.
3Device complexity
If aperture errors are not compensated, then device complexity remains low, but manufacturing precision of image data deteriorates due to scanning inaccuracies
Solution Approach 1:
The patent implements feedback by using the dithering process itself to generate information about aperture errors. The known dither pattern is correlated with the received signal to detect and measure scanning inaccuracies and aperture errors. This feedback information is then used to correct the image data, creating a closed-loop system that automatically compensates for hardware imperfections without requiring complex external calibration systems.
Data Source
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AI summary
According to one embodiment, a radar tracking system includes a radar coupled to a radar processing system. Radar processing system receives images from the radar and that are each obtained at a differing angular orientation of the radar to a target. Radar processing system dithers each image along its azimuthal extent and then combines the dithered images to form an enhanced image of the target.