Bistatic SAR Echo Simulation and Imaging Processing

Bistatic SAR (Synthetic Aperture Radar) is a specialized radar system where transmitter and receiver antennas are located on separate platforms. Compared to monostatic SAR, it offers greater observation flexibility and enhanced stealth capabilities. Echo simulation and imaging represent critical stages in bistatic SAR data processing, where simulation generates simulated radar echo signals, while imaging processing converts them into recognizable images.

In bistatic SAR echo simulation, the entire process from signal transmission to reception must be modeled, including transmitted signal modeling, target scattering characteristics, propagation attenuation, and received signal acquisition. Due to the complex bistatic geometry, simulation must account for relative motion between transmitter and receiver, range history calculation, and Doppler frequency shift. Code implementation typically involves calculating two-way propagation paths using geometric transformations and applying appropriate signal modulation techniques to simulate realistic echo characteristics.

The imaging processing stage employs the nonlinear Chirp Scaling (CS) algorithm, a high-precision imaging method specifically suitable for bistatic SAR. Since bistatic SAR's slant range history is no longer a simple hyperbola, traditional monostatic SAR imaging algorithms (like Range-Doppler algorithm) cannot be directly applied. The nonlinear CS algorithm overcomes imaging distortions caused by bistatic geometry through phase compensation operations. Implementation involves cascaded phase multiplication steps in range and azimuth domains to correct range cell migration and achieve accurate azimuth focusing, ultimately producing high-quality SAR images.

This technology finds applications in military reconnaissance, topographic mapping, and disaster monitoring. Through precise echo simulation and efficient nonlinear CS imaging, bistatic SAR can provide high-resolution earth observation data suitable for target detection and analysis in complex scenarios.