针对目前常用的电阻式地形仪存在的问题，介绍了一种新型的河床模型三维全自动地形仪。该仪器采用超声测量原理实现了水下地形的无接触快速扫描测量，采用阻抗原理实现了洲滩、边滩、浅滩的地形测量，有效提高了测量速度，并减小了对河床的扰动影响。系统采用灵巧纵向行走机构和适当的计算机控制方式，使测桥纵向行走自如。系统能自动完成三维地形测量、断面图形显示、等高图和三维地形图的绘制 。

A kind of automatic measuring instrument for 3-D river bed model topography is introduced.The instrument adopts the theory of ultrasonic echo for quickly scanning river bed topography under water and employs the principle of resistance for measuring river bed topography upon water and shallow beach topography, which increases the measuring speed effectively and decreases the disturbing influence on river bed. Because of using moving framework facility and proper computer controlling method, the testing bridge can move freely lengthways. The instrument can automatically accomplish the measurement of 3-D river bed topography,the display of three dimension topography and the drawing of contour map.