Echo Model Analysis and Frequency-Domain Imaging Algorithm for Geosynchronous Spaceborne-Airborne FMCW Bistatic SAR...

Area of Science:

• Radar Systems Engineering
• Signal Processing
• Remote Sensing

Background:

• Geosynchronous spaceborne-airborne frequency-modulated continuous-wave bistatic synthetic aperture radar (GEO SA FMCW BiSAR) enables cost-effective, persistent target monitoring.
• Maneuvers of the receiver and continuous platform movement complicate echo signals, invalidating the traditional "stop-and-go" assumption.

Purpose of the Study:

• To develop an echo model that accounts for intra-pulse motion and accelerated motion of a high-maneuvering receiver in GEO SA FMCW BiSAR.
• To address the nonlinear range terms introduced by receiver acceleration that degrade image focusing.

Main Methods:

• A novel echo model is proposed, considering both intra-pulse and accelerated receiver motion.
• Receiver acceleration is approximated by segmenting the aperture and applying the "stop-and-go" assumption within sub-apertures.
• A two-dimensional (2-D) spectrum is derived using the principle of stationary phase and series reversion for azimuth stationary phase point determination.

Main Results:

• The proposed method effectively compensates for nonlinear range terms caused by receiver acceleration.
• The algorithm achieves well-focused images in the presence of complex platform dynamics.
• Simulation results confirm the algorithm's effectiveness and computational efficiency.

Conclusions:

• The developed echo model and imaging algorithm accurately process signals from GEO SA FMCW BiSAR systems with maneuvering receivers.
• This approach overcomes limitations of the "stop-and-go" assumption, improving image quality and maintaining efficiency for persistent monitoring applications.