针对移动机器人在水下完成核反应堆堆内构件检修时的无人自主定位任务，提出了一种结合惯性测量单元（inertial measurement unit, IMU）与单目视觉测距的机器人水下几何定位方法。结合实际环境需求，简述了单目相机测距原理；针对水下核辐射环境对传感器使用的限制，提出了基于单目视觉校正惯性测量单元位姿估计积分误差和几何定位方法，模拟实验验证表明该定位方法能够有效地校正机器人利用惯性测量单元定位过程中产生的累积误差，提高了机器人的水下运动定位精度。

Aiming at the unmanned autonomous positioning task of mobile robot during the maintenance of nuclear reactor internals, an underwater geometric positioning method combining inertial measurement unit(IMU) and monocular visual distance measurement was proposed. Combining with the actual environment demand, the principle of distance measurement with monocular camera was described briefly. Aiming at the limitation of the underwater nuclear radiation environment on the use of sensors, a method based on monocular vision correction of inertial measurement unit position estimation integral error and geometric positioning was proposed. Simulation experiments show that the positioning method can effectively correct the accumulated error generated in the positioning process of the inertial measurement unit, and improve the positioning accuracy of the robot in underwater motion.