Bistatic ISAR Synchronization via Direct Path Signal
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Solution Overview
Problem
Bistatic inverse synthetic aperture radar (ISAR) systems face challenges in synchronization due to the asynchronous operation between the transmitter and receiver, which hinders coherent processing and image formation.
Innovation Solution
The use of the direct path signal from the transmitter to the receiver for timing and phase synchronization, allowing the system to operate in a quasi-monostatic mode and enabling traditional ISAR processing techniques by detecting and extracting the direct path signal for synchronization.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Adaptability or versatility
If bistatic ISAR systems operate with asynchronous transmitter and receiver, then the system can be configured flexibly with separate transmit and receive platforms, but synchronization between transmitted and received signals deteriorates, hindering coherent processing and image formation
Solution Approach 1:
The patent introduces a direct path signal as an intermediary element that mediates between the transmitter and receiver. This direct path signal, which travels directly from transmitter to receiver without reflecting off the target, serves as a reference signal to establish timing and phase relationships. By using this intermediary signal, the system achieves synchronization between the asynchronous transmitter and receiver while maintaining the flexibility of separate platforms.
2Reliability
If conventional monostatic ISAR processing is used, then coherent processing and image formation are achieved, but the system requires a single platform performing both transmission and reception, reducing operational flexibility
Solution Approach 1:
The patent segments the monostatic radar system into separate bistatic components - an independent transmitter platform and an independent receiver platform. By dividing the single monostatic system into two separate platforms, the system gains operational flexibility and adaptability while maintaining coherent processing capabilities through the direct path signal synchronization method.
3Measurement precision
If direct path signal is extracted and used for synchronization, then timing and phase alignment between transmitted and received signals is achieved, but the complexity of signal processing increases due to the need to separate direct path signal from target signal
Solution Approach 1:
The patent extracts the direct path signal from the total received signal by exploiting its distinct characteristics. The direct path signal is separated from the target reflected signal through signal processing techniques that identify and isolate the direct path component based on its known transmission timing and propagation characteristics. This extracted direct path signal is then used as a reference for synchronization, achieving precise timing and phase alignment.
Data Source
AI summary
Systems and methods are provided for synchronizing a bistatic inverse synthetic aperture radar (ISAR) imaging radar system using only the signal that travels directly between the transmitter and receiver. In an embodiment, an extracted direct path signal is used as a matched filter reference function. In an embodiment, full pulse compression is used for a matched filter implementation. Embodiments of the present disclosure provide systems and methods for detecting and extracting the direct path signal and using this direct path signal to synchronize the received signal stream in a bistatic ISAR system.