# Designation of the Quality of EGNOS+SDCM Satellite Positioning in the Approach to Landing Procedure
###### Abstract
As far as these two procedures are concerned, the quality parameters of SBAS positioning are characterised by the following values [2]:  
The accuracy parameter for navigation in the horizontal plane should not exceed 16 m for the SBAS APV-I and SBAS APV-II procedures;  
The accuracy parameter for vertical navigation should not exceed 20 m for the SBAS APV-I procedure and 8 m for the SBAS APV-II procedure;  
The maximum time-to-alert should not exceed 10 a for the SBAS APV-I procedure and 6 s for the SBAS APV-II procedure;  
The positioning continuity must not be lower than \(1\div 8\times 10^{-6}/3600\) s for a minimum of 15 s for the approach procedures SBAS APV-I and SBAS APV-II;  
The availability of positioning should fall into the range from 0.99 to 1 for the approach procedures SBAS APV-I and SBAS APV-II;  
The integrity parameter HPL (Horizontal Protection Level) for navigation in the horizontal plane should not exceed 40 m for the SBAS APV-I and SBAS APV-II procedures;  
The integrity parameter VPL (Vertical Protection Level) for vertical navigation should not exceed 50 m for the SBAS APV-I approach procedure and 20 m for the SBAS APV-II procedure. The research problem defined in the title of this paper refers mainly to the aviation aspect of the use of SBAS supporting systems, i.e., to the determination of the accuracy, continuity, availability, and integrity of SBAS positioning in aviation. In the territory of Poland, the EGNOS (European Geostationary Navigation Overlay Service) supporting system has been used for many years to improve GNSS positioning [4]. Apart from that, the Russian SDCM (System of Differential Correction and Monitoring) has also been used for several years [5]. Both these SBAS systems share a common coverage of the positioning range in the area of Poland and thus they may also be used in the realisation of aviation experiments and analysing the SBAS positioning quality in this part of Europe. The EGNOS and SDCM systems have been used multiple times in academic publications related to the subject literature. Research projects where all the quality parameters of EGNOS positioning in aviation were determined may be found in publications [6; 7; 8; 9; 10; 11; 12; 13; 14; 15; 16; 17]. On the other hand, the accuracy parameter alone was calculated and discussed in publications [4; 18; 19; 20; 21; 22; 23; 24; 25; 26], while the integrity parameter was determined and presented in publications [3; 27; 28; 29; 30; 31]. It is worth adding that the referenced research projects were conducted in Poland and, in one case, in Slovakia. It should also be noted that the scope of research referred either to conducting an aviation experiment or a static GNSS measurement with use of EGNOS corrections. Kinematic flight tests were performed mainly in eastern Poland, i.e., at the border of the range of availability of EGNOS system corrections in Eastern Europe. At least one and sometimes more GNSS receivers with the function of EGNOS tracking and measurement were always installed in the aerial vehicles. On the other hand, static GNSS measurements were conducted in the vicinity of airports and landing areas at various latitudes. This allowed for analysing the SBAS signal quality and verifying its potential usefulness in aviation applications. The EGNOS system is also used in Europe and northern Africa to improve GNSS positioning quality for the purposes of air transport. Publications [32; 33; 34] present the positioning quality results for the territory of Algeria. On the other hand, in Europe [35; 36; 37; 38; 39; 40; 41; 42; 43; 44; 45; 46] various aspects of analysing the GNSS positioning quality in aviation were also presented. What is worth noting is that the publications referenced above very often emphasised the fact that the task of EGNOS is to correct the code positioning of the GPS s part of the SPP (Single Point Positioning) method. On the other hand, the SDCM system was far less frequently used in aviation applications.