Multi-spot ISAR Imaging via Dechirp Segmentation
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Solution Overview
Problem
Traditional ISAR systems are limited in their ability to generate multi-spot images within a single radar beamwidth, requiring increased dechirp bandwidth and complicating hardware implementation, which hinders the detection, identification, and tracking of multiple targets effectively.
Innovation Solution
The method involves generating multiple dechirp reference signals within a pulse repetition interval to demodulate return signals from multiple range intervals, allowing for independent processing and digitization of each range interval, thereby enabling multi-spot ISAR imaging without altering the chirp waveform or intermediate frequency bandwidth.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Productivity
If the dechirp bandwidth is increased to generate multi-spot images within a single radar beamwidth, then the detection and tracking capability of multiple targets is improved, but the hardware implementation complexity and system cost increase
Solution Approach 1:
The patent divides the single radar beamwidth into multiple range intervals (spots) by generating multiple dechirp reference signals at different time intervals within a pulse repetition interval. Each dechirp reference signal processes a specific range interval independently, enabling multi-spot imaging without requiring increased overall bandwidth. This segmentation approach allows parallel processing of multiple targets while maintaining manageable hardware complexity.
2Adaptability or versatility
If multiple dechirp reference signals are generated at different time intervals, then multiple range intervals can be processed independently, but the processing complexity and signal synchronization requirements increase
Solution Approach 1:
The patent employs periodic generation of multiple dechirp reference signals within each pulse repetition interval. These reference signals are generated at specific time intervals that correspond to the desired range intervals, creating a periodic processing pattern. This approach enables systematic handling of multiple range intervals while maintaining synchronization through the regular pulse repetition structure, reducing the overall processing complexity compared to arbitrary time sampling.
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
This approach enables the detection, identification, and tracking of multiple targets within a single radar beamwidth, improving discrimination and tracking capabilities while minimizing system hardware costs and maintaining compatibility with various antenna types.
Implementation Method 1
transmitting a chirp signal into a dwell surveyed by the antenna beamwidth
Implementation Method 2
Inverse Synthetic Aperture Radar (ISAR) is a technique used to generate two-dimensional resolutions (images) of an object or a target
Implementation Method 3
multiplying the received signal by a dechirp reference signal and then bandpass-filtering the resulting product. The mapping is controlled by the chirp rate and initiation time of the dechirp signal
Implementation Method 4
Pulse compression is achieved by performing a fast Fourier transform (FFT) on the range samples
Data Source
AI summary
Providing multi-spot inverse synthetic aperture radar (ISAR) imagery is disclosed. Embodiments of techniques in accordance with the present disclosure may advantageously improve multiple target discrimination, detection, identification, and tracking using ISAR imaging. In an embodiment, an inverse synthetic aperture radar (ISAR) method for producing multiple ISAR images from a single waveform includes transmitting a chirp signal into a dwell surveyed by the antenna beamwidth. Multiple dechirp reference signals may be generated to demodulate return signals from the dwell at multiple selected intervals within a pulse repetition interval (PRI) to create demodulated signals.