CAJ | 학술논문

为解决大带宽发射信号下的宽测绘带合成孔径声呐成像问题，提出了一种扩展的非线性线频调变标成像算法。算法通过将点目标响应的二维谱进行泰勒级数展开并保留至四阶项，有效提高了算法的宽带适应性；通过考虑等效调频斜率随时延差量的一阶线性及二次非线性变化特性，有效提高了算法的宽测绘带适应性；通过在推导由三次和四次相位滤波及非线性线频调变标操作时引入的相关参量的过程中，充分考虑等效调频斜率随时延差量的二阶非线性变化特性，精确补偿了距离向频率高阶相位项带来的误差，有效提高了成像质量。仿真试验结果验证了算法的有效性。
위해결대대관발사신호하적관측회대합성공경성눌성상문제，제출료일충확전적비선성선빈조변표성상산법。산법통과장점목표향응적이유보진행태륵급수전개병보류지사계항，유효제고료산법적관대괄응성；통과고필등효조빈사솔수시연차량적일계선성급이차비선성변화특성，유효제고료산법적관측회대괄응성；통과재추도유삼차화사차상위려파급비선성선빈조변표조작시인입적상관삼량적과정중，충분고필등효조빈사솔수시연차량적이계비선성변화특성，정학보상료거리향빈솔고계상위항대래적오차，유효제고료성상질량。방진시험결과험증료산법적유효성。
In order to solve the imaging problem of synthetic aperture sonar ( SAS) with wide swath under a wide-band transmission signal, an extended nonlinear chirp-scaling ( NCS) imaging algorithm is proposed.In the algo-rithm, by implementing Taylor series expansion for the two-dimensional spectrum with point target response and re-maining it to four-order terms, the broadband adaptation is effectively increased.However, by considering the prop-erties of the first-order linear change and the second-order nonlinear change of the equivalent slope of frequent mod-ulation following time delay difference, the adaptation to wide swath of the algorithm is effectively improved.The second-order nonlinear change properties of the equivalent slope of frequent modulation following time delay differ-ence in the process of deducing the relational parameters are introduced in operating the third and fourth order phase filtering and nonlinear chirp-scaling ( NCS) .The phase error due to the higher-order terms with respect to the range frequency is accurately correct and the image quality is improved apparently.The results of simulation showed the effectiveness of the proposed algorithm.