In recent years, the typhoon happens frequently. When typhoon suddenly arrives, the only way to rescue the ship which calls for help in time is to locate the position of the ship in the sea quickly and exactly. But in the ocean, due to the non-ideal channel environment, multipath propagation between accident vessels and monitor stations. All these factors will make the detection of error in measurement of signal characteristics, thus affecting the positioning accuracy. In order to improve the location accuracy of accident vessel in the ocean, two kinds of methods are used. One is to search for realistic channel environmental models for the line-of-sight and the non-line-of-sight propagations to study the characteristics of signal measurements error with good robustness of high-precision positioning algorithms.The other is to analyze the main cause of the different kinds of the measurement errors to find their solutions to decrease the errors.