The signal simulator is an important semi-physical simulation equipment, which is often used to test the performance of the Synthetic Aperture Radar (SAR) fully in a lab environment. Two issues need to be focused on, one is the synchronization between the SAR and the simulator, the other is the application range of the simulator. In this paper, the impact of the synchronization errors on the test is analyzed, the corresponding mathematical models are derived, and the indicator of phase synchronization is presented. Then a scheme of high-accuracy SAR signal simulator based on adaptive synchronization technology is proposed. By recognizing and processing the input frequency from different SAR systems based on coherent methods, the frequency signal can be converted into an important reference clock that the simulator can adopt directly, so the simulator can be adaptive to different frequencies covering almost all kinds of SAR systems. Furthermore, by means of analyzing the difference between the input frequency and the inner reference clock of the simulator, digital phase processing unit integrated in the simulator can obtain the phase synchronization of the SAR system. The experimental results show that the method is reasonable and effective in the end.
For the purpose of improving the range resolution of SAR system under the existing technical conditions, multi-channel synthesis is one of the main technical approaches. However, this method can bring the problems of amplitude-phase distortion and channel synchronization among different channels. In this paper the structure of multi-channel signal synthesis is built, the error characteristics of synthetic wideband signal and the errors’ influence on the synthesis are analyzed, and a mathematical model of channel errors is established. Then an adaptive channel error correction method, which is based on the improved internal calibration method, is proposed. By adjusting the input power of the exciting signal, the low-power transmitting signal is made to work in a stable saturation area, where the amplitude-frequency and phase-frequency characteristics of the signal are constant. By means of pre-distortion technology, the transmission characteristics of the channels can be obtained, and the phase-mplitude error in the multi-channel can be eliminated and corrected.The experimental results show that the method is reasonable and effective in the end.