Welcome to the Transionospheric Radio Link - Quality Assessment of Ionospheric Correction service

Vertical Total Electron Content (VTEC) map for Northern Europe,
provided byReal-Time Ionosphere Monitoring (RTIM), NMA.

The service "Transionospheric Radio Link - Quality Assessment of Ionospheric Correction" aims to provide information on whether standard corrections to GNSS signal are applicable, including for the TEC core products a-posteriori and estimated parameters and near-real-time alarms to indicate the level of degradation of ionospheric correction models with respect to the actual state of the ionosphere. This latter assessment shall be established by considering the update rate for the different service users among the following:

• Users of GNSS Single frequency services with average accuracy, no integrity (e.g. typical GNSS mass market user)
• Users of GNSS Single frequency services with average accuracy, using integrity (e.g. EGNOS user)
• Users or multi-frequency GNSS systems with very high accuracy (e.g. GNSS geodetic users, RTK).

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);
• European Ionosonde Service (EIS) provided by National Observatory of Athens (NOA);
• Nowcasting of TEC over Italy provided by Istituto Nazionale di Geofisica e Vulcanologia (INGV);
• Ionospheric Scintillation Monitoring (ISM) developed by Collecte Localisation Satellites (CLS) and IEEA (currently under maintenance);
• Swarm Utilisation Analysis Ionosphere (SUA I) provided by the German Research Centre for Geosciences (GFZ).
• Swarm Utilisation Analysis Geomagnetic conditions (SUA G) provided by the German Research Centre for Geosciences (GFZ).
• ESA/ESOC Ionosphere Monitoring Facility, IONMON;
• UPC-IonSAT service provided by the Universitat Politècnica de Catalunya (UPC);
• Nowcast and geomagnetic indices provided by the British Geological Survey (BGS).

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

Introduction

Many applications use ionospheric correction models to estimate the ionospheric dependencies. The accuracy of this estimation depends on the actual state of the ionosphere. Degradation of the accuracy occurs during perturbed conditions, e.g. ionospheric storms or scintillations. Therefore, this service provides TEC core products a-posteriori and estimated parameters and near-real-time alarms to indicate the level of degradation of ionospheric correction models with respect to the actual state of the ionosphere.

Application

This service will allow users using ionospheric correction models in their applications, to judge the performance at any time. This includes the following types of users:

• Users of GNSS Single frequency services with average accuracy, no integrity (e.g. typical GNSS mass market user)
• Users of GNSS Single frequency services with average accuracy, using integrity (e.g. EGNOS user)
• Users or multi-frequency GNSS systems with very high accuracy (e.g. GNSS geodetic users, RTK)

Key Products

Near-real-time TEC maps

• IMPC - Near-real-time TEC maps are provided with global coverage and for the European region. They are provided with 5 minutes latency and 15 minutes temporal resolution. Both products differ in the applied background model. A dedicated European TEC background model allows a higher quality TEC product for the European region. Each TEC map is provided along with a TEC error map.
• RTIM - Near-real-time TEC maps are high resolution TEC maps for the high-latitude region around the Scandinavian countries (50°N – 80°N, 10°W – 40°E). Since the data coverage is high, no TEC background model is necessary. The temporal resolution is 5 minutes and the spatial resolution is 1° x 1° in latitude and longitude. The quality of the RTIM - TEC maps is presented by the Grid Ionospheric Vertical Error (GIVE) values. The GIVE is an upper bound on 99% of the TEC error.
• ISM - Near-real-time TEC maps have a global coverage. Their temporal resolution is 1 hour.
• EIS - Near-real-time TEC maps are derived from ionosonde measurements. Four different maps are produced for the European region each 15 min of the hour: the map of the integrated electron density from 90km to hmF2 (bottomside TEC), the map of the integrated electron density from hmF2 to the transition height (topside TEC), the map of the integrated electron density from the transition height to 20,000km (Plasmaspheric TEC) and the map of the integrated electron density from 90km to 20,000 km (TEC). The mapped area extends from -10 °W to 40 °E in longitude and from 34 °N to 60 °N in latitude, and the spatial resolution of the maps is 1°x1°. The product is based on the 3D electron density grids that are calculated using TaD model in DIAS system. The maps are made available with a latency of 30 min in both ASCII and PNG formats.
• IONMON - The Ionosphere Monitoring Facility IONMON delivers animated maps of the global distribution of the Total Electron Content (TEC) & the TEC Root Mean Square errors (RMS). The animations cover 24 hours with an 1-hour time resolution. Both TEC and RMS levels are displayed in TEC units (1 TECU = 10^16 el/m^2) on the colour maps. The range of values, displayed on the colour bars underneath the maps, is fixed from 0 to 60 TECU for TEC and from 0 to 10 TECU for RMS. In case TEC and RMS values exceed the aforementioned fixed limits, the maximum value will be shown next to the colour bar. The maps are provided by the ESA/ESOC Navigation Support Office (OPS-GN).

TEC and local electron density from Swarm satellites

Valuable data for validation is provided by SUA in form of TEC measurements along the line of sight between Swarm satellites and GNSS satellites. Swarm satellites also deliver the local electron density along the flight paths' of the satellites.

Scintillation measurements

Degradation of ionospheric models and performance of GNSS applications often suffer degradation during ionospheric scintillations. Local scintillation measurements and maps of scintillation parameters are provided in near-real-time as follows:

• 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.
• 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.
• 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.

EIS - URSI parameters

URSI parameters are derived from ionosonde observations. They help interpreting the ionospheric conditions. URSI parameters are currently provided by the EIS service.

Solar and geomagnetic indices and measurements

Solar and geomagnetic indices and measurements provide indicators for the source of ionospheric perturbations and performance degradation of ionospheric models.

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)
• To better classify the ionosphere and forecast its disturbances over Europe, a data collection endeavour called the European Digital Upper Atmosphere Server (DIAS) was initiated in 2004 by a consortium formed around several European ionospheric stations that transmit in real-time ionospheric parameters automatically scaled. The DIAS project is a collaborative venture of eight institutions funded by the European Commission eContent Programme.

Reference documents

• ECSS-E-ST-10-04C Rev.1 Space environment (15 June 2020)

Contact

For further information, please contact SSCC Helpdesk.