Aeronautical navigation is a scientific discipline that from a theoretical and practical point of view studies and applies methods of flight preparation, positioning and aircraft guidance during flight from one known position to another known position on the earth's surface in the space-time dimension. There are various navigation systems that make this possible, and among them are GPS and INS. From the very beginnings of aeronautical navigation, the aim is to improve the determination of the exact position of the aircraft in relation to the reference point and the reference coordinate system. In addition to the need to accurately determine the position of the aircraft, there are other conditions that need to be met: integrity, availability, continuity and functionality. There is no single navigation system that is perfect in all categories, but all navigation solutions are mostly trade-offs to meet criteria across all categories. Since no navigation system can be completely perfect, several navigation aids have been merged into one so that the best features are taken from each. Also, in addition to the constant demand to increase the accuracy of navigation systems, there is a need to use cheap sensors that would allow the most economical construction of navigation systems. An example of such a connection is the fusion of GPS and INS.