The EGNOS augmentation system can be used in air, sea, and road transport. In the case of the latter, an important aspect is its application in the field of car navigation. The main objective of this work is to develop an algorithm and computational strategy for determining the accuracy of a car's position based on a multi-receiver GPS solution with EGNOS corrections in navigation. In particular, the article proposes determining the coordinates of a car based on a mathematical equation of the center of the segment connecting two GNSS receivers placed on the roof of the car while driving. A total of four GNSS receivers were used for this purpose, two for each geometric segment. Thus, the center coordinates for two independent segments that intersected at a single point were finally determined, where a fifth GNSS receiver was installed to verify the coordinates obtained from the GPS/EGNOS solution. This made it possible to determine the center coordinates of the car while driving. The study used actual GPS/EGNOS kinematic data recorded by on-board GNSS receivers. The obtained results of the center coordinates of the geometric section were compared with the reference position of the movement for the purpose of calculating accuracy. Based on the tests performed, it was found that the average positioning accuracy is higher than 0.80 m for all BLh geodetic coordinates. The Kalman filter was also used in the study, reducing positioning errors by up to 40% for all BLh components. The developed methodology and calculation strategy can be used, for example, in air navigation for aircraft positioning.