EXAMINATION OF DIFFERENT MODELS OF TROPOSPHERE DELAYS IN SBAS POSITIONING IN AERIAL NAVIGATION

This paper presents the results of a study on the use of different tropospheric correction models in SBAS positioning for air navigation. The paper, in particular, determines the influence of the Saastamoinen troposphere and RTCA-MOPS models on the determination of aircraft coordinates and mean coordinate errors in the SBAS positioning method. The study uses real kinematic data from a GPS navigation system recorded by an onboard GNSS satellite receiver as well as SBAS corrections. In the experiment, the authors include SBAS corrections from EGNOS and SDCM augmentation systems. The navigation calculations were performed using RTKLIB v.2.4.3 and Scilab 6.1.1 software. Based on the conducted research, it was found that the difference in aircraft coordinates using different troposphere models can reach up to ±2.14 m. Furthermore, the use of the RTCA-MOPS troposphere model improved the values of mean coordinate errors from 5 to 9% for the GPS+EGNOS solution and from 7 to 12% for the GPS+SDCM solution, respectively. The obtained computational findings confirm the validity of using the RTCA-MOPS troposphere model for SBAS positioning in aerial navigation

Zjawska burzowe w połnocno-zachodniej Polsce

Kirschenstein Malgorzata. Storm phenomena in northwestern Polan

Sumy opadów atmosferycznych w Polsce w latach 1951-1995

The aim of this article is the analysis of the seasonal and annual course of precipitation totals and their spatial distribution in Poland. T he basis for the analysis was mean daily precipitation totals for the 1951-199 5 period from 55 IMW M (Institute of Meteorology Wa - ter Management) stations and precipitation maps showing mean monthly, seasonal and annual rainfall distribution. The main part of the work is a description of spatial distribution of precipitation in Poland. Particularly winter a nd summer precipitation totals has been analyzed. In the article an annual period has been divided into four meteorological seasons: spring (whole months - III, IV, V), summer (VI, VII, VIII), autumn (IX, X, XI) and winter (XII, I, II). The research of rainfall variation in Poland in the seasonal and annual course has shown that: - summer precipitation totals are two times higher than in winter, - differences between spring and autumn precipitation totals are small, autumn slightly (1,1) exceed spring values, - quotient of winter/summer total precipitation decrease eastward showing gradual growth of continentality, - quotient of autumn/spring total precipitation diminishes from the north to the south of Poland; rather big quotients in the north are the result of the warming caused by the Baltic Sea during the autumn, - 62.9% of precipitation in Poland occur in the warm half-year

Integration the Meteorological Data for Monitoring the Troposphere Condition Over the Military Aerodrome in Dęblin

The integration of meteorological and tropospheric data is extremely important in precise monitoring of the atmosphere condition over a selected aerodrome. The paper presents the results of troposphere monitoring over the military aerodrome EPDE in Dęblin in Lubelskie Voivodeship in Poland. The three sources of meteorological data were applied for troposphere monitoring, namely: GNSS satellite technique, SYNOP data, TAF data. The troposphere empirical models within the GNSS satellite technique were utilized in the designation of the meteorological parameters, e. g. temperature, pressure and relative humidity. In paper, the meteorological parameters were estimated using three deterministic model, e.g.: SA model, RTCA-MOPS model and also GPT model

DESIGNATION OF METEOROLOGICAL PARAMETERS USING GPS SATELLITE TECHNIQUE IN A FLIGHT EXPERIMENT AT THE DĘBLIN MILITARY AERODROME

This paper presents research results on the determination of meteorological parameters utilising the GPS satellite technique. The meteorological parameters were designated using Standard Atmosphere (SA) and UNB3m empirical models. The research experiment was realised during a flight test at the Dęblin military aerodrome. In the flight test, the Cessna 172 plane was used. The values of meteorological parameters (for example, temperature, pressure and relative humidity) from the troposphere empirical models were presented and compared in the paper. In addition, the values of the meteorological parameters were estimated at flight attitude. The range of the flight attitude was between 150 and 700 m. The precision position of the aircraft in vertical frame was determinated using the RTK-OTF differential technique. The mean difference of temperature between the SA and UNB3m models is equal to -5.7°C with the RMS bias approximately 0.2°C. The mean difference of pressure between the SA and UNB3m models equals -1.0 hPa with the RMS bias of approximately 0.3 hPa. The mean difference of relative humidity between the SA and UNB3m models equals 25.5%, with the RMS bias approximately 0.6%. On paper, the values of meteorological data from the SA and UNB3m models were compared with true results interpolated from SYNOP message. In research, the three SYNOP stations, that is, Kozienice, Deblin/Irena and Lublin Radawiec were used for interpolation of the real meteorological data. The difference between empirical and interpolated meteorological data were presented in this paper. The accuracy of the designation of temperature is better in the SA model rather than the UNB3m model. The accuracy of the designation of pressure was relatively low in both models, SA and UNB3m. On the other hand, the accuracy of the designation of relative humidity was better in the UNB3m model than the SA model

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

Assessment of the Variability of Many Years of Thunderstorm Activity in the Aspect of Potential Threats to Aircraft at Selected Airports in Poland

The article presents an assessment of the long-term variability of storm activity in the aspect of potential threats to aircraft. The analysis of data from the period 1970–2018 was conducted for selected airports in Poland: Gdańsk Lech Wałęsa Airport, IATA code: GDN, ICAO code: EPGD (54°22′39″N 18°27′59″E, altitude above sea level 149 m above sea level); Solidarity Szczecin- Goleniow Airport, IATA code: SZZ, ICAO code: EPSC (53°35′05″ N 14°54′08″ E, altitude above sea level 47 m above sea level); Poznań-Ławica Henryk Wieniawski Airport, IATA code: POZ, ICAO code: EPPO (52°25′16″ N 16°49′35″ E, altitude above sea level 94 m above sea level); Warsaw Chopin Airport, IATA code: WAW, ICAO code: EPWA (52°09′57″ N 20°58′02″ E, altitude above sea level 110 m above sea level); Copernicus Airport Wrocław, IATA code: WRO, ICAO code: EPWR (51°06′10″ N 16°53′10″ E, altitude above sea level 123 m above sea level); John Paul II International Airport Kraków-Balice, IATA code: KRK, ICAO code: EPKK (50°04′40″ N 19°47′06″ E, altitude above sea level 241 m above sea level). The purpose of this paper is to assess the long-term variability of storm activity in the aspect of potential threats to air operations in Poland with the examples of six selected airports. In order to achieve the goal, an analysis of the frequency of storm phenomena in Poland was carried out both in annual and long- term terms. The analysis will allow the assessment of the geographical diversity of the distribution of storm phenomena and their variability in the years 1970–2018. The next stage of the work will be to determine the climatic conditions that exert the greatest impact on the formation of storms. The important factors include atmospheric circulation, which, over the Polish territory, is shaped by the influence of air masses from the Atlantic Ocean, the Baltic Sea and in addition, from the vast continental area. All these air masses clash over the area of Poland causing large variability in the frequency of occurrence of hazardous atmospheric phenomena. For this reason, the Polish climate is defined as a moderate warm climate with transitory features. The important factors affecting regional diversity are local conditions, such as terrain, nature of the land, and distance from water reservoirs. The thermal, humidity and aerodynamic properties of the substrate, which are components of radiation processes, determine the exchange of energy at the interface between the atmosphere and the earth, and largely determine the intensity of selected hazardous atmospheric phenomena. Each occurrence of a storm is a potentially dangerous meteorological event that threatens the environment and human activities, including all types of transport. The studied phenomenon of storms is particularly dangerous for air transport. Literature shows that storm phenomena in Poland are characterized by a large regional diversity, both during the year and over many years. The greatest threat of storm phenomena occurs in the warm period of the year—spring and summer