Application the SBAS/EGNOS Corrections in UAV Positioning

Kamil Krasuski,Damian Wierzbicki

doi:10.3390/en14030739

Abstract

The paper presents a new concept of determining the resultant position of a UAV (Unmanned Aerial Vehicle) based on individual SBAS (Satellite-Based Augmentation System) determinations from all available EGNOS (European Geostationary Navigation Overlay Service) satellites for the SPP (Single Point Positioning) code method. To achieve this, the authors propose a weighted mean model to integrate EGNOS data. The weighted model was based on the inverse of the square of the mean position error along the component axes of the BLh ellipsoidal frame. The calculations included navigation data from the EGNOS S123, S126, S136 satellites. In turn, the resultant UAV position model was determined using the Scilab v.6.0.0 software. Based on the proposed computational strategy, the mean values of the UAV BLh coordinates’ standard deviation were better than 0.2 m (e.g., 0.0000018° = 0.01″ in angular measurement). Additionally, the numerical solution used made it possible to increase the UAV’s position accuracy by about 29% for Latitude, 46% for Longitude and 72% for ellipsoidal height compared to the standard SPP positioning in the GPS receiver. It is also worth noting that the standard deviation of the UAV position calculated from the weighted mean model improved by about 21 ÷ 50% compared to the arithmetic mean model’s solution. It can be concluded that the proposed research method allows for a significant improvement in the accuracy of UAV positioning with the use of EGNOS augmentation systems.

Highlights

The authors of the work pointed out that the corrections transmitted by the EGNOS satellites are different, which directly impacts the accuracy of the determined ellipsoidal BLh coordinates for the reference stations
Based on the performed tests, it was found that there are quite significant differences in the XYZ coordinates of the reference stations based on the EGNOS corrections applied from satellites S120, S124 and S126 and the catalogue position of the base stations
Based on the research results obtained, it can be seen that the quality of EGNOS corrections significantly influenced the position of the aircraft during the test flight

Summary

Introduction

The intensive development of unmanned aerial vehicle technologies has led to them being used in many modern technology areas. One such application is low-altitude imaging for photogrammetric and remote sensing studies. The SPP positioning mode is the basic solution in air navigation for low-cost UAVs. The SPP method uses the L1-C/A code measurements in conjunction with data provided in the navigation message broadcast. Ionosphere correction is evaluated using the Klobuchar model for broadcast data [7]. It is the low-cost method of determining the position in real-time with an accuracy limited to a few meters. A significant advantage of this method is that it is used in every GNSS

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