一种波导不变量的被动定位方法

A Passive Positioning Method Using Waveguide Invariant

波导不变量β是用来刻画由于不同简正波间相互干涉形成声场强度在距离-频率的干涉条纹图案的一个标量。通过β定义式可以利用干涉条纹图案斜率、频率来实现目标被动定位。基于此,本文提出了一种利用Sobel锐化算子来进行图案边缘检测得到干涉条纹图案斜率的方法:分割图案,确保各个小窗口中条纹斜率基本相同,利用Sobel锐化算子进行边缘检测得到斜率,再利用β定义式估计距离,最后综合各个小窗口的估计即可得到更加稳健的距离估计。通过对干涉条纹图案斜率进行计算可以实现目标的被动定位。计算机仿真得出距离估计良好,最大误差在10%以内。湖上试验也验证了采用该方法获得的目标距离估计最大误差在25 m以内,表明该方法简单、有效,具有良好的应用前景。

Waveguide invariant β is a scalar for characterizing the distance-frequency interference stripes, which is formed by the acoustic field due to mutual interference between different normal wave modes. Target can be passively positioned by the slope of the interference stripes and the frequency based on the definition of β. In this paper, a method for calculating the slope of the interference stripes is presented by taking advantage of Sobel sharpening operator to detect pattern edge. First, the pattern of the interference stripes is divided into smaller parts to keep the slope of stripes in each part approximately constant. Then, the Sobel edge detection method is employed to select the intermediate value and calculate the slope in the frequency range of the smaller part, further to obtain estimation value of distance by using the formula of β. Finally, the same on a different frequency range smaller pattern estimated value to the average to a more accurate estimation can be obtained by integrating the distance estimations of all smaller parts. Passive positioning of target can be realized by calculating the slope of interference stripes. Simulation result shows that the proposed method possesses a good performance in distance estimation, and the maximum relative error of target distance estimation is smaller than 10%. Lake trial indicates that the maximum error of its target distance estimation is smaller than 25 m.