| With the increasing function of synthetic aperture radar(SAR)and the complexity of electromagnetic environment,the SAR signal appears intentional and unintentional interruption.The SAR system achieves radar versatility through intentional discontinuity in time or frequency domain,which is mainly caused by equipment failure,electromagnetic interference and other factors.Interrupted SAR signals will lead to interrupted in time domain or frequency domain,resulting in a large number of false targets in SAR images,which seriously affects subsequent SAR image interpretation and related applications.This paper mainly focuses on the design of the interrupted SAR system and the method of processing the interrupted signal.The main work and innovation of this paper include the following aspects.1.Firstly,the causes and characteristics of SAR interrupted signal are analyzed.According to the characteristics of unintentional and intentional interruption,several different SAR interruption cases are studied,and different solutions are studied according to different SAR interruption cases.For a small amount of interruption missing data in SAR,the missing part of the signal can be recovered by interpolation to obtain a complete SAR signal.For the large amount of interrupted data missing in SAR,the signal recovery cannot be realized through interpolation.Linear prediction method is introduced to predict and estimate the signal,and then the complete SAR signal is obtained.Point target simulation verifies the effectiveness of different SAR interruption modes.2.Aiming at the urgent application demand of radar communication integration in the future,a radar communication integration design scheme based on communication information adaptive adjustment of interrupted mode is proposed.In this scheme,the communication bandwidth and communication timing sequence are designed according to the required information and communication rate requirements.When the communication rate requirements are high,the time-domain discontinuous mode is adopted;when the communication information is large but the speed requirements are not high,the frequency domain discontinuous mode is adopted,so as to avoid the mutual interference between radar and communication.The linear prediction method is used to recover the interrupted part of SAR signal loss,so as to obtain the complete SAR imaging echo data and realize the integration of SAR communication.Finally,the effectiveness of SAR communication integration based on the interruption mechanism is verified by the imaging simulation experiment of point target.3.In order to solve the problem that the single antenna of Frequency Modulation Continuous Wave(FMCW)radar cannot work properly,the Interruption Continuous Wave(ICW)working system in frequency domain and time domain is studied,so as to realize the multiplexing of transceiver antenna.According to the characteristics of interrupted echo signals in time domain and frequency domain,the corresponding ICW-SAR signal processing method is studied,and the quality of SAR imaging is improved by predicting and estimating the interrupted signal.The effectiveness of SAR interrupted frequency modulation continuous wave working system is verified by point-target imaging simulation. |
