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

METHODS OF PRECISE AIRCRAFT POSITIONING IN THE GPS SYSTEM WITH AN APPLICATION OF THE TROPOSPHERE CORRECTION

This article presents the results of studies concerning the designation of accuracy in aircraft navigation positioning by means of the SPP and the SBAS code methods. The examination of the aircraft positioning accuracy was made in the aspect of the use of tropospheric correction in observation equations of the SPP and the SBAS positioning methods. The accuracy of the coordinates of the aircraft in the SPP and the SBAS solutions was referenced to the DGPS reference solution. The investigations were conducted on raw observation data and GPS navigation data in an air test in Dęblin. Based on the conducted calculations, it was proved that the lack of use of tropospheric correction in the SPP method causes an error in an aircraft position up to 18.5 m, and in the SBAS method up to 23.2 m. In addition, the statistical measure of RMS accuracy in the absence of applying the tropospheric correction in the SPP method results in an accuracy decrease to 8.6 m, and in the SBAS method to 12.2 m, accordingly

Monitoring the Vector Error Between a Reference Station and a GNSS on-Board Receiver in the GBAS System in the Polish Air Transport

The article presents research results concerning the determination of the vector error between a reference station and the GNSS on-board receiver in the GPS satellite measurements for GBAS system, taking into account the ZTD troposphere delay parameter. Based on the conducted studies, it was found that the highest value of the vector error between a reference station and the GNSS on-board receiver can exceed 0.18 m, for a distance of over 40 km and the ZTD value equalling to 2428.1 mm. The error results of vector measurement can be used in the RTK-OFT differential technique in the GBAS system

DESIGNATING THE ERROR OF VERTICAL COORDINATE OF AIRCRAFT POSITION IN THE GPS SYSTEM

This article presents the results of research concerning the determination of an error of the vertical position of an aircraft during a flight, taking into account, the flight altitude and the values of the ZTD tropospheric product. In particular, this work focuses on the impact of an error in designating the ZTD tropospheric product on the correct determination of a flight altitude. The authors of this work performed a scientific experiment for research data of two flights made by a Cessna 172 around the aerodrome in Dęblin. This article shows the findings of the tropospheric ZTD product specified for the single-frequency SPP positioning method and dual-frequency PPP positioning method. Based on the obtained results, it was discovered that the error of the ZTD tropospheric delay causes an altitude error from 0.08 m at the zenith angle equal to 80o even to 0.79 m at the zenith angle equal to 85o

Accuracy analysis of aircraft positioning using real radar and GPS data

This paper presents an analysis of the accuracy of aircraft positioning using radar and GPS satellite data. In particular, this study shows the results of research on determining the position of an aircraft, as well as the range and azimuth parameters for the GCA-2000 radar to the GPS solution. The research used measurement data from the GCA-2000 radar and the Thales MobileMapper Pro receiver placed onboard a Diamond DA-40NG aircraft. The flight experiment was carried out at the EPDE military airport in Dęblin. It was found that the average error in determining the position of the aircraft for the GCA-2000 radar was 295.57 m. Moreover, the average error in determining the range for the GCA-2000 radar is 138.12 m. Additionally, the average error in determining the azimuth for the GCA-2000 radar is equal to 0.408°