acoustic navigation造句

• In this paper , the main research works are as follows : 1 ) survey and analysis previous work in auv navigation and summarize : as the cumulate error , the dead - reckoning and inertial navigation systems ca n ' t be used without other modified system ; the acoustic navigation system is used only in small range , and is very expensive . 2 ) two important approaches in geophysical navigation techniques are summarized , one is terrain contour based navigation , this approach is investigated keystone today ; the other is image based navigation , due to no perfect image sensors and image seabed map , this approach has seldom been practised . 3 ) two important terrain contour based navigation algorithms has been applied to auv , one is match algorithm - based terrain contour match ( tercom ) ; the other is kalman filter - based sandia inertia terrain - aided navigation ( sitan )
  主要研究内容包括：一、总结分析了当前水下导航的常用方法和不足之处，指出基于航位推算的导航方法，存在着最大的问题就是导航误差的积累问题，如果没有修正系统，这种方法很难满足使用要求；其次指出基于声学的导航方法，造价昂贵，导航范围有限，难以满足自主水下航行器大范围导航的需求；二、总结了当前水下地形辅助导航的主要技术路线，一是基于地形高程的匹配方法，这是当前研究的重点；二是基于地形图像的匹配方法，由于缺乏良好的图像传感器，和可用的海底图像地图，目前这种方法还有待研究发展；三、将两种地形高程匹配的常用方法应用到自主水下航行器上：以相关算法为前提的地形轮廓匹配( tercom )方法和以卡尔曼滤波为基础的桑迪亚惯性地形辅助导航( sitan )方法，前者算法简单可靠，但是导航精度不高，后者虽然精度比较高，但存在着算法较为复杂、有可能发散和出现奇异值等问题。