This paper presents a high-precision underwater depth measurement system based on multi-sensor data fusion and the Kalman filter algorithm to effectively improve the accuracy and reliability of underwater depth measurement. The system is controlled by PID controller and Kalman filter algorithm to reduce the depth difference of four corners during the platform diving process. To accurately measure the depth value of the platform at the final position, the Kalman filter algorithm is used to reduce the error caused by the sensor and environmental factors. Based on the data measured by the depth meter and the inclinometer, the depth of the platform center position is calculated by a spline curve to improve the calculation accuracy. Through a large number of simulation experiments, the proposed measurement system has good stability and measured depth accuracy in the diving process. Meanwhile, the measurement system can also enable the platform to predict an accurate depth value in the case that a depth sensor is damaged.
With the continuous progress of social industrialization, the gradual depletion of land resources and the increasing demand for marine resources in the world, the development and utilization of marine resources will have important strategic significance to alleviate the shortage of human resources (Yu et al., 2019). Marine exploration has been a major subject in the past two decades. However, due to the complex underwater environment and the lack of necessary means of observation and communication, it still faces huge challenges. Fortunately, underwater equipment can significantly reduce the costs and risks associated with various underwater missions (You et al., 2012), which leads to an increase in the demand for underwater capabilities to perform high-precision missions. In recent years, stretch-leg platforms have been widely used in marine exploration. The unique structure of the tension leg platform makes it superior to similar products. For example, it is better than semi-submersible platform in terms of anti-interference capability and is more convenient and economical than a fixed platform. (Xia et al., 2015) The attitude measurement technology of underwater vehicles is a prerequisite for stable underwater operations, and the accuracy of motion attitude measurement will directly affect the stability of underwater vehicle control. Therefore, the accuracy and stability of attitude measurement (Wang et al., 2012) is particularly important for the stability control of underwater vehicles. Therefore, this paper not only deals with the measurement accuracy of underwater depth but also ensures the stable attitude of the platform.
