为确保通航船模的直航试验精度，以湘潭城际铁路特大桥桥区通航试验为背景，分析了船模直航精度对试验的影响，采用改进船模内部元件等方法提高了通航船模的直航精度，并用试验手段说明改进措施效果良好，能保证试验精度要求。

The direct navigation accuracy of ship model is an important factor which influences the test results. With the navigation test for the large bridge of intercity railway in Xiangtan as a case study, we analyzed the errors caused by inadequate direct navigation performance. It was found that electric motor system largely affected the direct navigation performance of ship model. Better synchronization performance of the motor system reduced the differences between two motors on parallel circuit and improved the direct navigation performance. By changing the motors of propulsion system and the materials and fixation of balances, together with improving the mode of transmission connection, the balance rudder angle decreased by 2°-3° compared with the original scheme. The direct navigation performance was improved, and the accuracy was guaranteed. The improvement measures could be referential for similar ship model tests. 