An Improved Omega-K Algorithm for Squinted SAR With Curved Trajectory

The omega-K algorithm (
$\omega $
KA) is an accurate imaging method for squinted synthetic aperture radar (SAR) with linear trajectory. However, for SARs with curved trajectory, since it does not allow the radar velocity to vary with range, the imaging quality would degrade severely. To address this issue, an improved
$\omega $
KA is proposed in this letter. We design a special Stolt mapping to avoid the complex additional range cell migration (RCM) and the skew of the data support region. Then, the RCM correction (RCMC) and azimuth compression are operated in the range Doppler domain. With these improvements, the radar velocity is allowed to vary with range, which greatly reduces the phase error in the case of large range swaths. Numerical results validate the proposed algorithm.