Aircraft position determination in sbas system in air transport

The article presents the results of GNSS satellite positioning in the SBAS support system in air transport. In accordance with ICAO recommendations, GNSS satellite technology may be implemented in air transport for GPS and GLONASS navigation systems as well as for their ABAS, SBAS and GBAS support segments. This academic article is intended to recreate the position of an aircraft using the SBAS support system, which is utilized in air transport. The position of the aircraft was determined using EGNOS differential corrections received from geostationary satellites, S120, S124, and S126. The mathematical model of the aircraft coordinate determination is based on absolute positioning (Single Point Positioning method - SPP). The research material comes from an in-flight experiment using a Cessna 172 aircraft, which was conducted at the military airfield in Dęblin, Poland. The computations of the Cessna 172 position were performed in the RTKLIB software (RTKPOST “Single” module). They were aimed at determining the coordinates of the Cessna 172 aircraft in the XYZ geocentric system. In order to analyze the test results obtained, a comparison was made with the coordinates of the Cessna 172 aircraft determined on basis of an EGNOS solution. The present work also specifies RMS errors of the Cessna 172 XYZ coordinates under comparison. The lowest dispersion for the difference in the XYZ coordinate values of the aircraft is based on the EGNOS S120 and S124 solutions. The greatest value of the RMS error for the X and Y aircraft coordinate difference occurs for the EGNOS S120 and S126 solutions. On the other hand, the greatest RMS error for the difference in the Z coordinate value of the aircraft may be seen for the comparison of the results of the EGNOS S124 and S126 solutions. Moreover, the article presents the verification and assessment of the ellipsoidal height h parameter for the Cessna 172 aircraft.