Research On Algorithms Of High-precision Underwater Positioning In Petroleum Exploration

With the rapid development of underwater positioning and petroleum exploration technologies, offshore oil exploration is moving in the fine. It requires high-precision positioning technology that the traditional exploration techniques cannot meet the requirements. Recently years, the shallow water OBC exploration techniques have achieved a certain economic benefits. Due to the complexity of marine environment, and the usage of average sound speed, the accuracy of targets will be restricted when the initial angles are large enough. Based on the above, the main researches of the paper are following aspects:1. Based on the principles of underwater acoustic positioning, several underwater positioning systems and acoustic secondary positioning system have been summarized. The influencing factors have been analyzed and some useful measures have been made.2. On the basis of exiting mathematical models of underwater positioning, the single and double differenced models have been established. The differential mathematical models based on ship and GPS buoy have been derived in detail, and confirmed the effectiveness of differential models by several examples.3. Research on underwater static positioning data processing method with Kalman filtering techniques. Effectiveness has been illustrated through simulations and real examples.4. Several sound speed correction methods have been summed up. The stratification gradient ray tracing algorithm has been improved, and the simulation and real examples demonstrate the effectiveness of the new method. The correction methods with differential operators have been proposed. The simulation results shown that the new methods could reach a high accuracy even in deep depth and large initial angle.5. This paper also implements the underwater differential program with GPS buoys by using MATLAB mixed with C# on VS2005 platform.