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The Influence of Pressure in the Infusion Method Upon Mechanical Properties of Polymer Composites

Janiszewski Jacek, Komorek Andrzej, Bakuła Mieczysław, Bieńczak Rafał, Pękala Bartosz

Advances in Science and Technology. Research Journal

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2023

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Vol. 17, no 6

217--227

EN

In the modern aerospace industry, a steady increase in the share of composite materials is recorded every single year. Polymer layer composites seem to be the ones that are used most commonly in aviation. There are multiple methods of producing this type of materials, of which the most commonly used methods are as follows: the infusion method, the negative pressure bag method and the hydraulic press method. The infusion process makes it possible to obtain composites with the best mechanical properties. In the infusion process, the mould is pre-prepared (together with the reinforcement made of the material from which the composite is made, e.g. carbon fibre), which is tightly closed in a negative pressure bag, and the equipment supplying the previously mixed resin with hardener is connected to the injection points. The negative pressure generated by the negative pressure pump in the mould prepared in this way (negative pressure bag) makes the previously prepared resin seep through the reinforcement material. Various negative pressure levels can be used. This work describes the effect of the applied negative pressure level on the obtained mechanical properties of a composite reinforced with carbon fibres. It appears that the best visual properties of the composite material are obtained with the use of indirect (optimal) negative pressure but the best strength properties with the use of maximal negative pressure.

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

Mrozik Magda, Kozuba Jarosław, Krasuski Kamil, Ćwiklak Janusz, Bakuła Mieczysław, Ciećko Adam, Grunwald Grzegorz, Wierzbicki Damian

Archives of Transport

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2022

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Vol. 64, iss. 4

135--144

EN

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 positioning 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 navigation 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 arithmetic 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 navigation.

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Analysis of the determination of the accuracy parameter for dual receivers based on egnos solution in aerial navigation

Krasuski Kamil, Ćwiklak Janusz, Bakuła Mieczysław, Mrozik Magda

Acta Mechanica et Automatica

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2022

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Vol. 16, no. 4

365--372

EN

The paper presents the results of research on the determination of the accuracy parameter for European Geostationary Navigation Overlay System (EGNOS) positioning for a dual set of on-board global navigation satellite system (GNSS) receivers. The study focusses in particular on presenting a modified algorithm to determine the accuracy of EGNOS positioning for a mixed model with measurement weights. The mathematical algorithm considers the measurement weights as a function of the squared inverse and the inverse of the position dilution of precision (PDOP) geometrical coefficient. The research uses actual EGNOS measurement data recorded by two on-board GNSS receivers installed in a Diamond DA 20-C airplane. The calculations determined the accuracy of EGNOS positioning separately for each receiver and the resultant value for the set of two GNSS receivers. Based on the conducted tests, it was determined that the mixed model with measurement weights in the form of a function of the inverse square of the PDOP geometrical coefficient was the most efficient and that it improved the accuracy of EGNOS positioning by 37%–63% compared to the results of position errors calculated separately for each GNSS receiver.

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Operation and reliability of an onboard GNSS receiver during an in-flight test

Krasuski Kamil, Bakuła Mieczysław

Zeszyty Naukowe. Transport / Politechnika Śląska

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2021

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z. 111

75--88

EN

This article presents and describes the operational capabilities of an onboard GNSS receiver to determine the reliability of the in-flight navigation parameters. An analysis was made of the operation reliability of an autonomous single-frequency Thales Mobile Mapper receiver in air navigation as compared to the technical operation of a dual-frequency Topcon HiperPro receiver. To this end, this work contains a comparison of the aircraft flight navigation parameters based on readings obtained from the Thales Mobile Mapper and Topcon HiperPro receivers. In particular, the comparison concerned the reliability of coordinate determination and flight speed parameters of an aircraft. The research experiment was conducted using a Cessna 172 aircraft, a property of the Military University of Aviation in Dęblin, Poland. Technical operation of the GNSS satellite receivers was tested in the flights of the Cessna 172 aircraft around the EPDE military airport in Dęblin. Based on the results obtained from the tests, it was found that the operational reliability of the Thales Mobile Mapper in the operational phase of the in-flight test ranged from -3.8 to +6.9 m in the XYZ geocentric frame and from -2.2 to +8.1 m in the BLh ellipsoidal frame, respectively. On the other hand, the accuracy of the Cessna 172 aircraft positioning when using the Thales Mobile Mapper receiver was higher than 1.7 m in the XYZ geocentric frame and higher than 2 m in the BLh ellipsoidal frame, respectively. Furthermore, the reliability of the Cessna 172 flight speed determination was from -3.4 to +2.4 m/s.