为解决深中通道沉管隧道“水下整体推出式”最终接头在复杂水下环境中的毫米级实时定位难题，提出一种基于双目摄影视觉定位与水下拉线测角测距的组合定位方法。该方法通过双目摄影系统和水下拉线系统分别获取最终接头在推出过程中的姿态与位置数据，并结合管内贯通测量成果，实现最终接头高精度的水下实时定位。其中，双目摄影系统通过照相机实时捕捉特征点的三维位移，水下拉线系统通过激光测角与编码器测距，使用角度和距离实时解算特征点三维坐标。开发包含硬件、软件与协议的管节定位监测系统，其中，硬件集成摄影-拉线组合单元与同步控制器，软件构建三维可视化界面与数据管理平台，实现了半封闭空间内三维姿态的实时监测与冗余测量。经陆上推退试验、水下重载推出试验及现场应用，该系统定位精度在10 mm以内，满足最终接头安装的精度要求。该方法突破了传统GNSS-RTK测量塔定位系统在水下狭小半封闭受限空间难以应用的困境，同时打破了传统GNSS-RTK与声呐技术于此类空间的应用瓶颈，为水下环境中大吨位构件的安装提供了高精度动态定位可行方案。

To achieve millimeter-level real-time positioning of an "integral underwater thrust-type" closure joint in the Shenzhen-Zhongshan link immersed tunnel, which operates under complex subaqueous environments, the authors propose a hybrid positioning method that combines binocular camera vision with angle and distance measurements using a laser-wire system. The binocular camera system, in conjunction with the laser-wire system, facilitates the real-time acquisition of attitude and position data for the closure joint during the thrusting process. Integrating the results from in-tube surveys, high-precision underwater real-time positioning of the closure joint is achieved. The binocular camera vision system captures three-dimensional (3D) displacements of feature points, and the laser-wire system measures angles using a laser and distances using an encoder. These measurements allow for the real-time calculation of 3D coordinates for the feature points. In addition, a positioning and monitoring system is developed for the immersed tunnel, which includes hardware, software, and protocols. The hardware integrates the binocular camera-laser wire composite units with synchronous controllers, and the software creates a 3D visualization interface and data management platform. This system enables real-time monitoring and redundant measurement of the 3D attitude in a semi-enclosed space. Verification through onshore push-back tests, underwater heavy-load tests, and field installations demonstrates that the positioning accuracy of the system is within 10 mm, meeting the installation accuracy requirements for the closure joint. This approach addresses the challenges faced by traditional global navigation satellite system real-time kinematic (GNSS-RTK) survey tower positioning systems, which are difficult to apply in narrow, semi-enclosed, and restricted underwater spaces. It also overcomes the limitations of traditional GNSS-RTK and sonar technologies in these environments, providing a viable high-precision dynamic positioning solution for the installation of large-tonnage components underwater.