Evaluation of the accuracy of the ship location determined by GPS global positioning system on a given sea area

Abstract The current location of navigation and navigation depends heavily on global satellite navigation systems, mainly GPS (Global Position System). In actual maritime practice, the position of the ship is determined to be the most probable position and will be the center of the circle of probability containing the ship’s position. However, this is not entirely accurate because the exact position on the chart depends on many factors such as deviation of the geodetic system, the accuracy of the chart, etc. On the other hand, the probability circle contains the location. The ship is scalar, the radius of error of the probability circle depends on many factors, etc. Therefore, determining the probability location with the highest accuracy is a rather complex problem. In particular, in the waters where the safety system is not complete, the level of survey is not good: Solomon Islands, Papua New Guinea, Indonesia, Cambodia, Vietnam, etc. actual errors of GPS location operating above. The chart is much larger than the error recommended by the manufacturer. In the context of the article, the author proposes a method for determining the probability area containing the actual ship position and its orientation to improve high safety in manoeuvring and navigating vessels at sea, testing on coastal Vung Tau - Vietnam.