一种基于时延估计的双辅助声源阵形校准方法

布放柔性水平阵列时,各阵元的相对位置很难精确知道,为了解决这一问题,提出了一种阵形校准方法。首先布设两个成一定张角的校准声源,利用它们估计各阵元信号的时延关系,利用声源和接收阵的GPS位置,确定各阵元的相对位置。得到的位置估计是无偏估计,给出了位置估计标准差的数值模拟结果,得出了两校准声源的最佳角度关系。利用2001年亚洲海国际实验的数据对该方法进行了验证,用校准后的阵形得到的测量声源方位角和实际角度一致,实测的阵增益也和理论值相符合。理论及实验分析结果表明,该方法能够准确定出各阵元的相对位置。

Claris Home Page——用Home Page创建网点轻松方便

所见即所得的网点编辑器市场已经很拥挤了,Microsoft、Symantec和NetObjects都推出了具有丰富功能的编辑器,用户无需直接编辑HTML代码即可方便地为自己的网点生成页面。现在,Claris凭借其Home Page 2也闯入了这一竞争激烈的领域。 面向初级和中级Web用户的这一版本提供了大量新特性,其中包括指导用户完成一个完整的网点构建过程的Assistant(助手)。Home Page还包含页面模板和网点样式,它们具有协调一致的观感。

Method of array shape calibration based on time delay estimation using two auxiliary sources

As for a flexible horizontal array deployed in the sea, it is difficult to obtain each sensor＇s precise relative position. Therefore a method of array shape calibration is proposed. The method is described as follows. Firstly two separate auxiliary sources are deployed. Secondly time delay of each sensor＇s received signal is estimated. Finally, with the aid of GPS location of the sources and the horizontal array, relative sensor positions of the horizontal array can be determined. The estimation of relative sensor positions is unbiased. Simultaneously, simulation analysis has been done to estimate its standard variance, and the optimal flare angle of the two sources has been derived. Data of 2001 Asian Sea International Experiment have been used to validate the method. After array calibration, measured source azimuth angle agrees with the real one, and measured array gain agrees with the theoretical gain. In conclusion, the theoretical and experimental results both show that the method can determine each sensor＇s relative position precisely.