Increasing the synthetic aperture radar (SAR) imaging frame rate is vital for obtaining continuous SAR images and dynamic scene monitoring, which multistatic SAR can achieve. Multiple source synchronization errors in multistatic SAR enable the image to produce positional offset and target defocus, which deteriorate the image quality. In order to obtain highly precise multistatic SAR images, synchronization errors must be compensated for. However, geometry errors are unavoidable during platform movement, which introduce Doppler frequency errors and range cell migration just like synchronization errors. Therefore, these two errors will jointly affect the imaging quality when coupled together, which will increase the difficulty of compensation. Aiming to resolve the issue of obtaining imaging results when the two errors exist simultaneously, this article proposes a decoupled estimation and compensation method for geometry and synchronization error. At first, the coupling relationship between geometry error and synchronization error on echo delay and Doppler frequency is analyzed. Next, the decoupled estimation problem with geometry and synchronization error is transformed into a constrained optimization problem. Then, the differential evolutionary algorithm is employed to address the optimization problem. Finally, the estimated values are utilized to compensate for the echoes to obtain high-resolution imaging results, which are verified by the simulation results. The experimental results convincingly demonstrate the improvement of the proposed method in imaging frame rate and error decoupling ability.

Multi-core digital signal processor (DSP) is widely used in SAR real-time imaging system for its high-speed operation capacity and parallel working ability. The matching of the algorithm and the parallel architecture has great impact on imaging speed of SAR processing. This paper proposed an efficient imaging architecture based on multi-core DSP TMS320C6678. The system implements bistatic polar format algorithm (PFA), using two-dimensional Chirp-Z Transform and one-dimensional interpolation to realize two-dimensional resampling. The experimental results show that the proposed architecture can complete 1024×1024 points echo processing and output a 1024×1024 pixels image within 1.7 seconds.

Synthetic Aperture Radar (SAR), an all-weather microwave remote sensing technology, is widely used in environmental monitoring, earth resource surveys and other fields, especially in the military field to achieve monitoring purposes. In the monitoring process, it is crucial to achieve real-time imaging of the target scene. Therefore, in this paper, an efficient SAR real-time imaging system is designed to achieve timely parallel processing of the scene when the radar platform scans the target scene, so as to reduce the consecutive frame cycles of real-time imaging. In which, the signal processing board structure consists of two FPGAs and six DSPs is used to quickly implement high precision SAR real-time imaging for airborne radar, so that the radar system can display the target image in time with the platform moving and check whether the current echo is valid. In addition, the architecture proposed in this paper can be extended in case the continuous frame period for real-time imaging is short.