Welcome to the Transionospheric Radio Link - Near-real-time Ionospheric Scintillation Maps service

Near-real-time local scintillation measurements from Neustrelitz station,
provided byIonosphere Monitoring and Prediction Center (IMPC), DLR.

Trans-ionospheric radio signals of global navigation satellite systems (GNSS) like GPS, GLONASS, and GALILEO may suffer from rapid and intensive fluctuations of their amplitude and phase caused by small-scale irregularities of the ionospheric plasma. This phenomenon, which is called radio scintillation, can strongly disturb or disrupt the signal transmission. For technical applications it is useful to derive and to provide the well accepted S4 and σ_Φ indices describing the amplitude/ intensity and the phase fluctuation of a received signal, respectively. For that purpose GNSS high-rate receivers in Europe provide necessary receiver-satellite-link specific amplitude and phase information.

This service provides near-real-time local scintillation data as well as regional and global maps. Additionally, solar and geomagnetic indices are provided, applicable for forecast or background models.

This service is implemented through a combination of products, tools and alerts which can be found through the following sections along with expert support provided by the teams constituting the SWE Network. Should you require further guidance in the use of this service, or have specific questions about any aspects of the service presented here, don’t hesitate to contact the Helpdesk.

The service is implemented through the following set of assets:

• Ionosphere Monitoring and Prediction Center (IMPC) provided by the German Aerospace Center (DLR);
• Real-Time Ionosphere Monitor (RTIM) provided by the Norwegian Mapping Authority (NMA);
• Ionospheric Scintillation Monitoring (ISM) developed by Collecte Localisation Satellites (CLS) and IEEA (currently under maintenance);

This service page is curated by the ESC Ionospheric Weather. For further information, please contact SSCC Helpdesk. 

Introduction

Radio wave scintillations are an indicator for ionospheric irregularities in the electron density.

There exist different indices, providing a measure of the intensity and phase scintillation. During their passage of the ionosphere, radiowaves get disturbed and phase and amplitude fluctuations are measured at the ground. These amplitude and phase fluctuations of the recorded signal are statistically characterised by two major parameters, amplitude and phase scintillation indices, denoted respectively by S4 and σ_Φ.

Scintillation recording systems can be distinguished by total power recording systems and phase and amplitude scintillation recording from stationary satellites. Also multi-frequency beacon transmission is capable of extracting scintillation information.

Often, scintillation causes a degradation of system performance due to interruption of communication links (e.g. for GNSS applications) or degradation of radar systems.

Scintillation indices

Scintillation Index S4:

The amplitude scintillation index S4 is defined as the ratio of the standard deviation of signal intensity and the average signal intensity. Amplitude scintillations are prominent near the geomagnetic equator. They almost regularly appear in the evening hours.

Scintillation Index σ_Φ

The phase scintillation index is defined as the standard deviation of a linearly detrended phase data segment. High rate (>1 Hz) GNSS receivers are necessary to estimate reliant σ_Φ. Phase scintillations are prominent in high latitudes. Their occurrence rate increases with geomagnetic activity.

Application

Since scintillations are an indicator for the presence of irregularities of electron density in the ionosphere, the scintillation measurements are used to determine the spatial and temporal distribution of the ionospheric irregularities. Furthermore, it supports the investigation of the physical processes that contribute to the formation of such irregularities. The phase scintillation index is more useful for the purpose of estimating electron density irregularities.

Multi-frequency scintillation studies have provided guidelines for the design of communication systems.

Key Products

S4 and σ_Φ maps for northern Europe provided by RTIM

S4 and σ_Φ maps for northern Europe provided by RTIM are based on GNSS measurements from a network of high rate (≥50 Hz) GNSS receivers.

Local S4 and σ_Φ measurements at different latitudes provided by IMPC

S4 and σ_Φ measurements based on several GNSS high rate (50 Hz) receivers in Europe operated by DLR. The data includes the necessary receiver-satellite-link specific amplitude and phase information.

Ionosphere Scintillation Service (ISM)

ISM provides global nowcast S4 and σ_Φ maps based on numerous GNSS receivers (1 Hz) and a few high rate GNSS receivers (50 Hz). Furthermore, it provides forecast of S4 and σ_Φ maps up to 6 hours ahead. The forecasts are most reliant near the equator and less reliant in polar regions.

Other Ionosphere Nowcast and Forecast

The ionosphere products provided in the TIO/tcr and TIO/tcf services also contribute to this service. It is used to discuss scintillations in combination with ionospheric disturbances.

Auxiliary Information

This section provides links to web pages or resources that are not part of the ESA Space Weather Network or esa.int domain. These sites are not under ESA control and therefore ESA is not responsible for any of the information or links that you may find there.

Other European Ionosphere Services

• Space Weather Application Service - Ionosphere (SWACI), one of the first prototypes for a near-real-time ionosphere data service in Europe, has been established in 2005 by the German Aerospace Center. It is currently transferred into the operational service Ionosphere Monitoring and Prediction Center (IMPC)

Reference documents

• ECSS-E-ST-10-04C Rev.1 Space environment (15 June 2020)
• N. Hlubek et al.(2014): Scintillations of the GPS, GLONASS, and Galileo signals at equatorial latitude, J. Space Weather Space Clim., vol. 4, A22, doi: 10.1051/swsc/2014020
• S. Basu and S. Basu (1989): Scintillation Techniques for probing ionospheric irregularities in World Ionosphere/ Thermosphere Study, WITS handbook edited by C. H. Liu, Vol. 2

Contact

For further information, please contact SSCC Helpdesk.