Application of the SBAS/EGNOS positioning method to determine UAV coordinates

Abstract: The article presents the results of research on determining the UAV (Unmanned Aerial Vehicle) position using the SBAS (Satellite Based Augmentation System) positioning method for the EGNOS (European Geostationary Navigation Overlay Service) support system. The experiment used a single-frequency AsteRx-m2 UAS receiver, which recorded GPS (Global Positioning System) satellite observations and EGNOS corrections. The test flight was performed in 2020 near Warsaw. Navigational calculations for determining the position of the UAV during the flight were made in the gLAB v.5.5.1 software. Based on the performed calculations, the following were determined: BSP coordinates in the ellipsoidal system BLh, mean errors of BSP coordinates, and values of DOP (Dilution of Precision) geometric coefficients. In addition, during the calculations, it was found that the mean error values of the determined BSP coordinates do not exceed 3.6 m, and the maximum value of the geometric coefficient GDOP (Geometric DOP) is less than 3.5. Keywords: SBAS, EGNOS, BSP, mean errors, DO

Analysis of the accuracy of EGNOS+SDCM positioning in aerial navigation

The article presents a modified scheme of determining the accuracy parameter of SBAS (Satellite Based Augmentation System) positioning with use of two supporting systems: EGNOS (European Geostationary Navigation Overlay Service) and SDCM (System of Differential Correction and Monitoring). The proposed scheme is based on the weighted mean model, which combines single solutions of EGNOS and SDCM positions in order to calculate the accuracy of position-ing of the aerial vehicle. The applied algorithm has been tested in a flight experiment conducted in 2020 in north-eastern Poland. The phase of approach to landing of a Diamond DA 20-C1 aircraft at the EPOD airport (European Poland Olsztyn Dajtki) was subjected to numerical analysis. The Septentrio AsterRx2i geodesic receiver was installed on board of the aircraft to collect and record GPS (Global Positioning System) observations to calculate the naviga-tion position of the aircraft. In addition, the EGNOS and SDCM corrections in the “*.ems” format were downloaded from the real time server data. The computations were realized in RTKPOST library of the RTKLIB v.2.4.3 software and also in Scilab application. Based on the conducted research, it was found that the accuracy of aircraft positioning from the EGNOS+SDCM solution ranged from -1.63 m to +3.35 m for the ellipsoidal coordinates BLh. Additionally, the accuracy of determination of the ellipsoidal height h was 1÷28% higher in the weighted mean model than in the arith-metic mean model. On the other hand, the accuracy of determination of the ellipsoidal height h was 1÷28% higher in the weighted mean model than for the single EGNOS solution. Additionally, the weighted mean model reduced the resultant error of the position RMS-3D by 1÷13% in comparison to the arithmetic mean model. The mathematical model used in this study proved to be effective in the analysis of the accuracy of SBAS positioning in aerial navigatio

Numerical Simulations of Bird Strikes with the Use of Various Equations of State

The paper presents results of numerical analyses of the collision of various bird models (dummies) with a helicopter windshield. Three different numerical bird models were elaborated. According to the subject literature, applying an appropriate equation of state has an influence on impact parameters. The author used the LS_DYNA software package. This is a computational code designed to analyse fast-changing phenomena by means of the finite-element method. SPH method has been used for bird strike simulations. In the research, three different equations of state have been used: Grüneisen's, polynomial and tabulated

Experimental and Numerical Investigations of Bird Models for Bird Strike Analysis

The article presents experimental and numerical studies of bird models during impacts with rigid and deformable targets. The main aim of the studies is the validation of bird models in order to prepare them for the numerical simulation of bird impact against aircraft windshields and other parts of aircraft, thus improving the air transportation safety by providing cost-effective solutions for designing bird strike-resistant aircraft. The experimental investigations were conducted with a special set-up of a gas gun equipped with high-speed cameras, tensiometers and force sensors. The simulations were developed on the basis of LS-DYNA software by means of the SPH method for the bird model shape of the cylinder with hemispherical endings at the speed of 116 m/s. The results of studies into such things as the impact force, pressure and bird model deformation were compared. Moreover, the authors’ and other researchers’ results were assessed. It can be noted that the curves of the impact force obtained as a result of the numerical analysis correlated well with the experimental ones

Accuracy analysis of aircraft position at departure phase using dgps method

The aim of this paper is to present the problem of implementation of the Differential Global Positioning System (DGPS) tech-nique in positioning of the aircraft in air navigation. The aircraft coordinates were obtained based on Global Positioning System (GPS) code observations for DGPS method. The DGPS differential corrections were transmitted from reference station REF1 to airborne receiver using Ultra High Frequency (UHF) radio modem. The airborne Thales Mobile Mapper receiver was mounted in the cabin in Cessna 172 aircraft. The research test was conducted around the military aerodrome EPDE in Dęblin in Poland. In paper, the accuracy of aircraft positioning using DGPS technique is better than 1.5 m in geocentric XYZ frame and ellipsoidal BLh frame, respectively. In addition, the obtained accu-racy of aircraft positioning is in agreement with International Civil Aviation Organization (ICAO) Required Navigation Performance (RNP) technical standards for departure phase of aircraft. The presented research method can be utilised in Ground-Based Augmentation System (GBAS) in air transport. In paper, also the accuracy results of DGPS method from flight test in Chełm are presented. The mean values of accuracy amount to ±1÷2 m for horizontal plane and ±4÷5 m for vertical plane

Accuracy Analysis of Aircraft Position at Departure Phase Using DGPS Method

The aim of this paper is to present the problem of implementation of the Differential Global Positioning System (DGPS) technique in positioning of the aircraft in air navigation. The aircraft coordinates were obtained based on Global Positioning System (GPS) code observations for DGPS method. The DGPS differential corrections were transmitted from reference station REF1 to airborne receiver using Ultra High Frequency (UHF) radio modem. The airborne Thales Mobile Mapper receiver was mounted in the cabin in Cessna 172 aircraft. The research test was conducted around the military aerodrome EPDE in Dęblin in Poland. In paper, the accuracy of aircraft positioning using DGPS technique is better than 1.5 m in geocentric XYZ frame and ellipsoidal BLh frame, respectively. In addition, the obtained accuracy of aircraft positioning is in agreement with International Civil Aviation Organization (ICAO) Required Navigation Performance (RNP) technical standards for departure phase of aircraft. The presented research method can be utilised in Ground-Based Augmentation System (GBAS) in air transport. In paper, also the accuracy results of DGPS method from flight test in Chełm are presented. The mean values of accuracy amount to ±1÷2 m for horizontal plane and ±4÷5 m for vertical plane

APPLICATION OF THE GLONASS CODE OBSERVATIONS FOR THE DESIGNATION OF COORDINATES OF AN AIRCRAFT IN FLIGHT TEST MODE: A CASE STUDY

The aim of this article is to present the results of GLONASS positioning in kinematic mode in air navigation. The flight experiment was conducted at Dęblin Airfield on a Cessna 172 aircraft. The aircraft position was recovered on the basis of the single-point positioning (SPP) method of the GLONASS code observations. The numerical computations of aircraft coordinates were executed in the RTKPOST library of the RTKLIB software. The standard deviations in aircraft position in a BLh geodetic frame were checked with the ICAO standards on civil aviation for the GLONASS system. The typical accuracy of aircraft positioning on the horizontal plane is better than 12 m, whereas, on a vertical plane, it is better than 17 m. In this paper, standard. deviations in aircraft position were also compared with the theoretical accuracy of the non-precision approach (NPA) landing procedure for the GNSS system. In this paper, the MRSE parameter was also calculated during the flight test

APPLICATION OF THE DGPS METHOD FOR THE PRECISE POSITIONING OF AN AIRCRAFT IN AIR TRANSPORT

This article presents research results concerning the determination of the position of a Cessna 172 aircraft by means of the DGPS positioning method. The position of the aircraft was recovered on the basis of P1/P2 code observations in the GPS navigation system. The coordinates of the aircraft were designated due to the application of the Kalman forward-filtering method. The numerical calculations were conducted using RTKLIB software in the RTKPOST module. In the scientific experiment, the authors used research materials from the test flight conducted by a Cessna 172 aircraft in the area of Dęblin in the Lublin Voivodeship in south-eastern Poland. The research experiment exploited navigation data and GPS observation data recorded by the geodetic Topcon Hiper Pro receiver mounted in the cockpit of the Cessna 172 and installed on the REF1 reference station. The typical accuracy for recovering the position of the Cessna 172 with the DGPS method exceeds in the region of 2 m. In addition, the authors specify the parameters of availability, integrity and continuity of GNSS satellite positioning in air navigation. The obtained findings of the scientific experiment were compared with the International Civil Aviation Organization’s (ICAO’s) technical standards