基元扰动对三维前视声纳测向性能的影响分析

Influence of Sensor Uncertainty on the Direction Estimation of 3D Forward-looking Sonar

提出了多层圆弧阵三维前视声纳的几何设计,利用圆弧波束形成和旋转不变子空间算法,分析了基元幅相扰动下声纳的方位估计性能。首先建立了多层圆弧阵三维前视声纳的阵列结构模型,利用远场阵列模型和海底混响扰动叠加定理,依次推导了基元幅相扰动下,水平向圆弧波束输出和垂直向波束内方位估计结果的理论表达式,并得到了垂直方位估计误差的理论结果。然后仿真分析了基元幅相扰动下三维前视声纳的垂直方位估计误差和空间分辨能力,并与理论结果进行了对比。理论分析与数值仿真表明,相同的基元幅相扰动下,多层圆弧阵三维前视声纳垂直角度估计均方误差约为半波长基元对应的单通道估计结果的1/(2M 0)(M 0为圆弧波束形成基元数)。此外,在假定基元幅相误差为互相独立的随机变量且均满足高斯分布时,当幅度误差标准差小于0.1、相位误差标准差小于10°的条件下,三维前视声纳的实际空间分辨能力与理论分辨率吻合。

In this paper,the design of 3D forward-looking sonar with multi-layer arc array is proposed.Taking advantage of the arc beamforming and estimation of signal parameters via rotational in variance techniques(ESPRIT),the direction estimation property of the sonar proposed formerly is discussed under the influences of the random sensor distribution.Firstly,the sensor distribution model of the sonar is established,together with the far-field array model and seafloor reverberation superposition theorem,the theoretical expression of the output of horizontal arc beam and vertical angle estimation results are obtained,and then the estimation error of the vertical angle results.Secondly,under random sensor uncertainties,the experimental results of vertical estimation error and spatial resolution are compared with the theoretical results through simulation analysis.The comparison results under the same condition show that the mean square error of the angle estimation through the processing flow in this paper is 1/2M 0(M 0 is the sensor number of arc beamforming)of the standard ESPRIT’s.In addition,when the random sensor errors are modeled as uncorrelated,zero-mean Gaussian distributed and the sensors’standard deviation of altitude below 0.1 and of phase below 10°,the actual spatial resolution of 3D forward-looking sonar is consistent with theoretical resolving power.