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1

Galileo HAS - first performance tests during its initial phase of operation

Cydejko Jarosław

Aviation and Security Issues

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2023

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No. 1

265--286

EN

Galileo High Accuracy Service (HAS) became available in January 2023. As declared, in its final operational capability, it should be able to provide to users the Precise Point Positioning (PPP) at horizontal accuracy level better than 20 cm in real-time with 95% confidence globally. At the moment Galileo HAS works in its initial phase of operation with some limitations regarding its availability, convergence time and accuracy but gives the chance to observe the performance of positioning tool at the accuracy level which was available before by using differential measurement only. Galileo HAS PPP, free of charge and based only on satellite signals delivered by nominal Galileo constellation is unique in its kind between various GNSS positioning modes. This article presents the results of first, preliminary tests on Galileo HAS performance conducted in July 2023 in Gdynia, Poland. The field tests were conducted with Galileo HAS capable receiver in static conditions and focused on the verification the declared service performance in the real positioning scenarios. Additionally, the Galileo HAS PPP performance was compared with the simultaneous performance of other GNSS positioning methods such as EGNOS, DGPS, dual frequency GPS+Galileo or dual frequency GPS and dual frequency Galileo. This first experiences with Galileo HAS positioning should show all potential users what performance level can be achieved with this new, unique in its kind GNSS positioning method at the present state of its implementation.

PL

Galileo High Accuracy Service (HAS) stał się dostępny w styczniu roku 2023. Tak jak zadeklarowano, po osiągnięciu finalnej fazy operacyjnej serwisu powinien on zapewnić użytkownikom globalną możliwość realizacji trybu Precise Point Positioning (PPP) z dokładnością wyznaczania pozycji na płaszczyźnie na poziomie lepszym niż 20 cm w czasie rzeczywistym i na 95% poziomie ufności. Aktualnie serwis Galileo HAS pracuje w początkowej fazie operacyjnej z pewnymi ograniczeniami dotyczącymi dostępności, czasu inicjalizacji oraz dokładności, ale pozwala już na uzyskiwanie dokładności wyznaczeń pozycyjnych na poziomie dokładności, który wcześniej był osiągalny tylko z wykorzystaniem metod różnicowych GNSS. Ponadto, serwis Galileo HAS PPP jest serwisem ogólnodostępnym i wykorzystującym tylko nominalne satelity nawigacyjne systemu Galileo, co czyni go unikalnym wśród aktualnie dostępnych metod GNSS. W artykule zaprezentowano wyniki pierwszych, wstępnych eksperymentów oceniających parametry operacyjne serwisu Galileo HAS przeprowadzonych w Gdyni w lipcu 2023 r. Testy serwisu przeprowadzono w warunkach statycznych z wykorzystaniem odbiornika realizującego wyznaczenia pozycyjne z zastosowaniem sygnału Galileo HAS. Pomiary miały na celu weryfikację deklarowanych parametrów dokładnościowych i dostępnościowych serwisu w rzeczywistych warunkach pomiarowych. Dodatkowo, obserwowane parametry serwisu Galileo HAS PPP zostały porównane z rejestrowanymi równolegle wynikami wyznaczeń pozycyjnych uzyskiwanych innymi metodami GNSS, takimi jak: EGNOS, DGPS, dwuczęstotliwościowe pomiary GPS+Galileo oraz dwuczęstotliwościowy GPS i dwuczęstotliwościowy Galileo. Przedstawione w artykule wyniki pierwszych doświadczeń z wykorzystaniem serwisu Galileo HAS pokazują wszystkim potencjalnym użytkownikom, czego mogą się spodziewać, wykorzystując w procesie wyznaczania pozycji tę nową i unikalną w swoim rodzaju metodę pozycyjną GNSS na jej aktualnym etapie wdrażania.

2

A combined iCEEMDAN and VMD method for mitigating the impact of ionospheric scintillation on GNSS signals

Dey Abhijit, Chhibba Rohan, Ratnam Devananboyina Venkata, Sharma Nitin

Acta Geophysica

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2021

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Vol. 69, no. 5

1933--1948

EN

Severe amplitude and phase scintillation induced by the ionospheric plasma density irregularities degrades the performance of global navigation satellite system (GNSS) receivers. Scintillation typically has adverse effects at the tracking process and thus adversely affects the raw GNSS measurements used in a number of applications. Hence, it is important to develop robust methodologies for detecting and mitigating ionospheric effects on the GNSS signals. In this paper, we propose a novel method based on the combination of improved complete ensemble empirical mode decomposition with adaptive noise (iCEEMDAN) and variational mode decomposition (VMD) methods. The proposed method employs a detrended fuctuation analysis (DFA)-based metric for robust thresholding between the scintillation-free and amplitude scintillated GNSS signals. The major contribution of the proposed method is development of novel approaches for selection of intrinsic mode functions (IMFs) based on DFA and optimised selection of [K, 훼] parameters of the VMD. The performance of the proposed method was evaluated and was observed that it is better than existing ionospheric scintillation effects mitigation algorithms for both simulated and real-time GPS scintillation datasets. The proposed method can denoise approximately 9.23–15.30 dB scintillation noise from the synthetic and 0.2–0.48 from the real scintillation index (S4) values. Therefore, the proposed (iCEEMDAN-VMD) method is appropriate for mitigating the ionospheric scintillation effects on the GNSS signals.

3

Comparative analysis of three ionospheric broadcast models for global navigation satellite systems

Li S., Li L., Wang S., Peng J., Xu Y., Zhao Y.

Acta Geophysica

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2017

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Vol. 65, no. 2

395--410

EN

An ionospheric model and corresponding coefficients broadcasted via GNSS navigation message are generally used to estimate the time delay for single-frequency GNSS users. In this article, the capabilities of three ionospheric models, namely, Klobuchar model, NeQuick Galileo version (NeQuick G), and Neustrelitz TEC broadcast model (NTCM-BC), were assessed. The models were examined in two aspects: total electron content (TEC) prediction and ionospheric delay correction effects in single-point positioning. Results show that both NeQuick G and NTCM-BC models outperformed Klobuchar model for predicting global TEC values during all the test days. Compared with Slant TEC (STEC) along the receiver-to-satellite ray path derived from IGS global ionosphere map (GIMs), STEC from NeQuick G and NTCM-BC models tend to have less bias than those from Klobuchar model in most situations. The point positioning results were improved by applying ionospheric broadcast models especially at the mid- and low-latitude stations.

4

Transport safety : the GNSS spoofing detecting using two navigators

Dobryakova L., Lemieszewski Ł., Ochin E.

Logistyka

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2014

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nr 3

1328--1331

EN

The purpose of this paper is to introduce the principles of GNSS spoofing detection theory using two navigators. With that in mind, some of the theoretical treatment has been simplified to provide a starting point for a mathematically literate user of GNSS who wishes to understand how GNSS spoofing detection theory using two navigators works, and to get a basic grasp of GNSS spoofing detection theory and terminology.

PL

Celem tego artykułu jest przedstawienie zasad teorii detekcji GNSS spoofingu za pomocą dwóch nawigatorów. Mając to na uwadze, niektórzy z leczenia teoretyczne zostałi uproszczony, aby stanowić punkt wyjścia dla matematycznie literat użytkownika GNSS, który chce zrozumieć, jak działa teoria wykrywania GNSS spoofingu za pomocą dwóch nawigatorów i uzyskać podstawowe zrozumienie teorii wykrywania GNSS spoofingu.

5

e-Navigation and Future Trend in Navigation

Amato F., Fiorini M., Gallone S., Golino G.

TransNav : International Journal on Marine Navigation and Safety of Sea Transportation

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2011

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Vol. 5, no. 1

11--14

EN

The International Maritime Organization (IMO) adopted the following definition of e-Navigation: “e-Navigation is the harmonised collection, integration, exchange, presentation and analysis of maritime information onboard and ashore by electronic means to enhance berth to berth navigation and relat-ed services, for safety and security at sea and protection of the marine environment”. A pre-requisite for the e-Navigation is a robust electronic positioning system, possibly with redundancy. A new radar technology emerged from the last IALA-AISM conference held in Cape Town, March 2010, where almost all the manu-factures companies involved on navigation surveillance market presented –at various state of development- solid state products for VTS and Aids to Navigation indicating a new trend for this application. The paper present an overview of the systems for global navigation and new trend for navigation aids. The expected de-velopments in this field will also be briefly presented.

6

The Implementation of the EGNOS System to APV-I Precision Approach Operations

Fellner A., Banaszek K., Tromiński P.

TransNav : International Journal on Marine Navigation and Safety of Sea Transportation

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2010

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Vol. 4, no. 1

41--46

EN

First in the Poland tests of the EGNOS SIS (Signal in Space) were conducted on 5th October 2007 on the flight inspection with SPAN (The Synchronized Position Attitude Navigation) technology at the Mielec airfield. This was an introduction to a test campaign of the EGNOS-based satellite navigation system for air traffic. The advanced studies will be performed within the framework of the EGNOS-APV project in 2009. The implementation of the EGNOS system to APV-I precision approach operations, is conducted ac-cording to ICAO requirements in Annex 10. Definition of usefulness and certification of EGNOS as SBAS (Satellite Based Augmentation System) in aviation requires thorough analyses of accuracy, integrity, continui-ty and availability of SIS (Signal in Space). Also, the project will try to exploit the excellent accuracy perfor-mance of EGNOS to analyze the implementation of GLS (GNSS Landing System) approaches (Cat I-like ap-proached using SBAS, with a decision height of 200 ft). Location of the EGNOS monitoring station Chelm, located near Polish-Ukrainian border, being also at the east border of planned EGNOS coverage for ECAC states is very useful for SIS tests in this area. According to current EGNOS programmed schedule, the project activities will be carried out with EGNOS system v2.2, which is the version released for civil aviation certification. Therefore, the project will allow demonstrating the feasibility of the EGNOS certifiable version for civil applications.

7

Galileo AltBOC E5 Signal Characteristics for Optimal Tracking Algorithms

Vejrazka F., Kovar P., Kacmarik P.

TransNav : International Journal on Marine Navigation and Safety of Sea Transportation

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2010

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Vol. 4, no. 1

37--40

EN

The paper deals with an optimal processing of a Galileo E5 signal. A proposed correlator struc-ture was developed on a base of a deep study of an E5 signal cross correlation function. Due to the non linear-ity of the E5 AltBOC modulation the proposed correlator calculates the cross correlation function between a received signal and a signal replica for all possible hypotheses of the navigation message bits. A correct peak tracking verification is realized by implementation of a single side band correlator, which also serves for course signal acquisition and secondary ranging code synchronization. The signal processing was verified on the Galileo Giove A and Giove B satellites with very positive preliminary results.

8

Wykorzystanie symulatora GNSS w procesach dydaktycznych oraz badawczych

Mielnik P.

Zeszyty Naukowe Politechniki Rzeszowskiej. Mechanika

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2004

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z. 63 [213], t.2

489--496

PL

Współczesna nawigacja opierająca się na systemach radiotechnicznych wykorzystuje w coraz szerszym aspekcie sygnały satelitarnych systemów nawigacji (GNSS - Global Navigation Satellite System). Równolegle spotykane są w życiu codziennym aplikacje, w których stosowane są odbiorniki systemów GNSS. Znajomość możliwości urządzeń odbiorczych czy systemów jest warunkiem koniecznym w przypadku adaptacji określonych rozwiązań dla danego zastosowania. Dotyczy to zwlaszcza aplikacji lotniczych, gdzie wymagane jest spełnienie wielu kryteriów determinujących możliwość zastosowania danego urządzenia. W Instytucie Radiolokacji WAT podejmowanych jest szereg zagadnień zakresu nawigacji satelitarnej. Większość z nich realizowanych jest w oparciu o posiadany symulator systemu GPS oraz systemów SBAS (WAAS, MSAS i EGNOS). W artykule scharakteryzowano zagadnienia dydaktyczne oraz badawcze realizowane w oparciu o symulator GNSS.

EN

Contemporary radio navigation is based mainly on GNSS signals. Simultaneously, the GNSS receivers are present in many fields of our live. The knowledge of receiver performance can help to the choice of right receiver to specific application. This is especially important for aircraft applications. There are some of works realized in the Institute of Radar Technology connected with satellite navigation. A few of them are being made using GPS / SBAS simulator. The aim of article is to show some of works from teaching and research domain where the GNSS simulator is used.