Examination of Autonomous GPS and GPS/EGNOS Integrity and Accuracy for Aeronautical Applications

The Global Navigation Satellite System (GNSS) is increasinglyused in navigation and positioning in land, water and air applications.Although they are very useful and willingly employedin everyday live and commercial products, it must be stressedthat GNSS alone does not always provide adequate performance,particularly in demanding aeronautical applicationswhere high level of integrity is required. Integrity and accuracyof positioning are the key parameters in air navigation.The paper presents research on current values of GNSS accuracyand integrity in north-eastern Poland, the region whichuntil 2014 was out of official coverage of European GeostationaryNavigation Overlay Service (EGNOS) Open Service (OS).The integrity and accuracy of positioning of static point andflying aircraft was examined in order to check present usabilityof different GNSS techniques which can be deployed for enroute,approach and landing phase of a flight. Since the integritylevels in aviation are strictly dependent on the phase offlight and landing of an aircraft, the analyses were performedin two computational modes: positioning using GPS/EGNOSdata and using autonomous GPS. Both modes were calculatedin en-route variant and because with the use of EGNOS it ispossible to perform approach, GPS/EGNOS mode was alsoanalyzed in Precision Approach (PA) variant. Overall assessmentof the accuracy and integrity of positioning in the studiedvariants is at the satisfactory level, not exceeding the levelsdefined by official aviation regulations.