New Insights Into Alternating Transmitting Mode (ATM) for Bistatic Multichannel SAR

The bistatic synthetic aperture radar (BiSAR) employs the alternating transmitting mode (ATM) to capture multidimensional scattering information of the target. However, the drawback of the ATM lies in doubling the pulse repetition frequency (PRF) and reducing the echo window (i.e., swath width), consequently limiting the high-resolution and wide-swath (HRWS) imaging capabilities of BiSAR. To achieve HRWS imaging, the article proposes new insights into the ATM of bistatic multichannel synthetic aperture radar (SAR). First, multichannel signal models containing time and phase synchronization deviations are established for BiSAR. Then, the imaging mode, clock synchronization scheme, and imaging method to achieve HRWS imaging are detailed. Finally, a group of system parameters for the HRWS imaging of the ATM is designed based on the LuTan-1 (LT-1) BiSAR system, and the synchronization and imaging simulations of the ATM are conducted using the data of the LT-1. Simulation results demonstrate that the ATM can achieve the HRWS imaging mode of 3 m/60 km. In short, these new insights pave the way for the HRWS imaging of distributed SAR.