Study Of Frequency Scan SAR Echo Simulation Method

Synthetic aperture radar(SAR)has been widely used in the field of military and civilian reconnaissance and monitoring in recent years due to its all-day,all-weather advantages.The swath and resolution of the imaging scene are two important performance indicators of SAR imaging.High azimuth resolution helps us to obtain more target features,and wide mapping band enables simultaneous irradiation of larger scenes.The obtained data is highly timeeffective.In the traditional single-channel SAR system,the imaging performance of both high resolution and wide mapping band cannot be satisfied simultaneously,for example,the spotlight mode can achieve high resolution but not wide mapping band,while the scanning mode can achieve wide mapping band but cannot satisfy the azimuth high resolution at the same time.The existing high resolution wide swath imaging modes mainly rely on spatial filtering to achieve deblurring,which can reduce or avoid the contradiction between azimuth resolution and range-swath,but with the increase of imaging quality requirements,the number of channels required will increase,and the number of channels in practice will be limited by the engineering cost and equipment size,so there are limitations to improve the imaging performance by increasing the number of channels.Therefore,it becomes more meaningful to study a new high-resolution wide-swath imaging system.In this paper,we propose to apply the time-frequency-space coupling effect of frequency scanning arrays to azimuth frequency sacnning SAR systems to achieve high azimuth resolution while taking into account a wide mapping band.Compared with the traditional Stripmap SAR,the amount of simulation operation of azimuth frequency SAR increases dramatically,and it takes too long to use the traditional echo simulation method,this paper proposes a method of using GPU to complete the echo simulation,which improves the operation efficiency.The main research work of this article includes:1?The principle of intra-pulse frequency scanning array is studied and the waveform design guidelines of azimuth frequency scanning SAR are proposed,the echo signal model of azimuth frequency scanning SAR is constructed,the system parameter design constraints of azimuth dimensional frequency scanning SAR are given and suitable radar system parameters are designed,the computational power of the face target echo simulation is analyzed,and the method of using GPU to accelerate the echo simulation is proposed for the problem of long simulation time.2?The hardware architecture of GPU and CUDA is briefly introduced to prepare the ground for parallel design using GPU.The parallelization analysis of the azimuth frequency scanning SAR surface target echo simulation is carried out,and a parallel scheme of mixed programming with MATLAB and CUDA C is established.The analysis is optimized for the problems arising in the simulation process,and the time-consuming parts are modified and accelerated with the help of analysis tools to improve the computing efficiency of the program.3?Simulation experiments on azimuth frequency scanning SAR and processing of the echo data with a mature imaging algorithm are conducted to verify that it can achieve highresolution wide-format imaging.A comparative analysis of the echo results of face target CPU simulation and GPU simulation was conducted to verify the feasibility and correctness of GPU-based simulation of face target echoes,and the acceleration ratio was calculated,which has a large efficiency improvement compared with the traditional CPU simulation method.