基于宽带模糊函数的线性调频信号速度分辨力分析(英文)

Resolution ability analysis of linear frequency modulated signal based on wideband ambiguity function

速度分辨力是线性调频信号(LFM)的关键特性之一,其和LFM参数的现有定量关系是在窄带近似条件下基于窄带模糊函数的分析结果.在宽带声纳或者超宽带雷达应用中,窄带近似条件往往难以满足,现有速度分辨力和LFM参数的定量关系不再成立,而应在宽带条件下重新分析.本文在宽带条件下利用宽带模糊函数工具,建立了关于LFM参数的速度分辨力隐函数方程.由于该隐函数方程不能直接反映速度分辨力和LFM参数的定量关系,文中采用了一种数值分析方法.该方法将速度分辨力表示成各单参数函数的连乘形式,综合运用方程求根和曲线拟合方法,求出单参数函数关系,进而综合出速度分辨力的表达式.本文应用该方法分析给出了宽带条件下的速度分辨力和LFM参数的定量关系式.结果表明速度分辨力不仅和LFM的脉冲宽度以及中心频率参数有关,还与LFM的相对带宽参数有关.验证实验表明,与通常结论相比,本文给出的结论可准确表达宽带条件下的速度分辨力和LFM参数的定量关系.该定量关系为宽带条件下LFM的参数设计和性能分析建立了基础.

Velocity resolution is one of key characteristics of linear-frequency modulated（LFM） signal.The existing quantitative relation between velocity resolution and LFM parameters is the analysis result based on narrowband ambiguity function in approximate narrowband condition.In wideband sonar or ultra wideband radar applications,approximate narrowband condition is usually not satisfied.The existing quantitative relation of velocity resolution and LFM parameters is not applicable,and should be re-analyzed in wideband condition.In this paper,the implicit function between velocity resolution and LFM＇s parameters is established using wideband ambiguity function in wideband condition.Because the implicit equation cannot directly reflect the quantitative relation between velocity resolution and LFM parameters,a numerical analysis method for solving the implicit equation is employed in the paper.By this method,velocity resolution is expressed as a multiplicative form of each single-parameter function,and figure out the expression of single-parameter function with a combination of employing equation extracting and curve fitting methods so as to integrate for the expression of velocity resolution.Applying this method,the quantitative relation between velocity resolution and LFM parameters is analyzed and revealed.The result shows that velocity resolution is not only decided by LFM＇s pulse width and central frequency,but also decided by LFM＇s relative bandwidth.Verification experiment indicates that comparing with the usual conclusion,the result of this paper can exactly express the quantitative relation between velocity resolution and LFM parameters in wideband condition.This quantitative relation lays the foundation for parameters design and performance analysis of LFM under wideband signal model.