The Space Weather and Navigation Systems (SWANS) project Solar Terrestrial Centre of Excellence The Space Weather and Navigation Systems (SWANS) project René Warnant , Sandrine Lejeune , Gilles Wautelet , Justine Spits , Koen Stegen , and Stan Stankov Royal Meteorological Institute (RMI) Ringlaan 3, Avenue Circulaire B-1180 Brussels, Belgium Stan Stankov (S.Stankov@oma.be) for the RMI – Urania joint workshop, 14 Feb 2011, Dourbes

The SWANS project – intro, objectives Outline The SWANS project – intro, objectives K-LOGIC – Local Operational Geomagnetic Index K Calculation LIEDR – Local Ionospheric Electron Density Profile Reconstruction RTK status mapping SoDIPE - Software for Determining the Ionospheric Positioning Error Summary and Outlook http://swans.meteo.be/

SWANS - Objectives The Space Weather and Navigation Systems (SWANS) research and development project (http://swans.meteo.be) is an initiative of the Royal Meteorological Institute (RMI) under the auspices of the Belgian Government via the Solar-Terrestrial Centre of Excellence (STCE). Research on space weather and its effects on GNSS applications Permanent monitoring of the local/regional geomagnetic and ionospheric activity Development/operation of relevant nowcast, forecast, and alert services Consult professional GNSS/GALILEO users in mitigating space weather effects

K-LOGIC - Local Operational Geomagnetic Index K Calculation Motivation: The enhanced geomagnetic activity and especially the geomagnetic storms often lead to substantial ionospheric plasma fluctuations/disturbances among many other space weather effects. There is an ongoing demand for services that can provide real-time assessment of the (global and local) geomagnetic activity -- and being of importance to: - exploration geophysics, - radio communications and precise position/navigation practices, - space weather research and modelling, etc. Objective: To develop service/s that can promptly evaluate the current level of the local geomagnetic activity and to estimate in advance the activity index K. Stankov et al. (2010): On the local operational geomagnetic index K calculation. Geophysical Research Abstracts, Vol.12, EGU2010-7228, EGU General Assembly, 2-7 May 2010, Vienna.

K estimation space-based K estimation ground-based K-LOGIC - Local Operational Geomagnetic Index K Calculation Developments: Nowcast. The K nowcast system is based on a fully automated computer procedure for real-time digital magnetogram data acquisition, dataset screening, establishing the regular variation of the geomagnetic field, calculating the K index, and issuing an alert if storm-level activity is indicated. Forecast. A new hybrid model has been developed utilising space-based (solar wind) observations and local ground-based (magnetometer) measurements to predict (a proxy of) the K index. Solar Wind Parameters (ACE) K estimation space-based Ksw K hybrid K estimation ground-based Magnetometer Data (1 min, Dourbes) Kgnd Kutiev et al. (2009): Hybrid model for nowcasting and forecasting the K index. Journal of Atmospheric and Solar-Terrestrial Physics, 71, 589-596.

K-LOGIC - Local Operational Geomagnetic Index K Calculation Service Type: Nowcast: update – every 60 min, latency less than 3 min after the hour mark Forecast: update – every 60 min, forecast time horizon – up to 6 hours ahead Service Output: K index value - data files (ASCII), plots Quality Flag (QF) – data acquisition and processing quality assessment Alerts – web (verbose & colour code), email Registration Nowcast Forecast Service Selection K index value Alert (web based) Quality Flag Date Selection http://swans.meteo.be/geomagnetism

Ionospheric plasma density specification in real time LIEDR – Local Ionospheric Electron Density Reconstruction Objective: Development of operational procedure for reconstruction of the local ionospheric electron density distribution on a real-time basis using GNSS and vertical incidence sounding measurements. Ionospheric plasma density specification in real time Developments – procedure and service: Type – operational nowcast Output – ionospheric plasma density/frequency Altitude range – from 90 to 1100 km Time resolution – 15 min Latency – less then 3 min Applications: Research, verification of ionospheric models, ionospheric tomography, etc. Stankov et al. (2003): A new method for reconstruction of the vertical electron density distribution in the upper ionosphere and plasmasphere. Journal of Geophysical Research, 108(A5), 1164, doi:10.1029/2002JA009570.

Ionospheric plasma density specification in real time LIEDR – Local Ionospheric Electron Density Reconstruction Ionospheric plasma density specification in real time Development: Type – operational nowcast, Output – ionospheric plasma density/frequency, Altitude range – from 90 to 1100 km, Time resolution – 15 min, Latency – less then 3 min. enhanced density reduced density Ionosphere Plasma Frequency ionosphere storm Ionosphere Critical Frequencies (F2 layer - foF2 , E layer - foE) Ionosphere Total Electron Content (TEC) Ionosphere peak density altitude (hmF2) Ionosphere Peak Density (NmF2) http://swans.meteo.be/ionosphere/liedr

LIEDR – Local Ionospheric Electron Density Reconstruction http://swans.meteo.be/ionosphere/liedr

Ionospheric slab thickness monitoring LIEDR – Local Ionospheric Electron Density Reconstruction Objective: Explore the capability of this key ionosphere parameter for monitoring and estimating the level of ionosphere disturbances. Ionospheric slab thickness monitoring Developments (service): Type – operational nowcast Output - slab thickness [km] - relative deviation [%] from monthly medians Update rate – 15 min Latency – less then 3 min The ionospheric slab thickness (τ) is the depth of an idealized ionosphere which has the same electron content (TEC) as the actual ionosphere but uniform electron density equal to the maximum electron density (NmF2), τ =TEC/NmF2. Applications: - Research - Modelling Monitoring the local ionosphere disturbance, etc. Stankov et al. (2008): Ionospheric slab thickness – analysis and monitoring applications. Proc. Ionospheric Effects Symposium (IES), May 13-15, 2008, Alexandria, VA, USA, pp.159-164.

LIEDR – Local Ionospheric Electron Density Reconstruction slab thickness relative deviation from non-disturbed behaviour Ionospheric slab thickness behaviour during geomagnetically disturbed conditions τ rel disturbed & depleted ionosphere τ Ionospheric slab thickness Geomagnetic activity indices Kp and Dst Geomagnetically disturbed conditions Stankov et al. (2009): Ionospheric slab thickness – analysis, modelling, and monitoring. Advances in Space Research, 44, 1295–1303.

LIEDR – Local Ionospheric Electron Density Reconstruction http://swans.meteo.be/ionosphere/slabthickness

A (colour) code assigned to each station, code ranging from RTK status mapping Provides a quick look at the small-scale ionospheric effects on the RTK precision for several GPS stations in Belgium Assesses the effect of small-scale ionospheric irregularities by monitoring the high-frequency rate of TEC (ROT, TECU/min) at a given station ROT calculated using ‘geometric-free’ combination of GPS dual frequency measurements (no ambiguity resolution) A (colour) code assigned to each station, code ranging from “quiet” (green) to “extreme” (red) and referring to the local ionospheric conditions. Alerts dispatched via e-mail to subscribed users when disturbed conditions are observed. Warnant et al. (2007): Monitoring variability in TEC which degrades the accuracy of Real Time Kinematic GPS application, Advances in Space Research, 39(5), 875-880. http://swans.meteo.be/GNSS/RTK_map

SoDIPE – Determining the Ionospheric Positioning Error Development of software (SoDIPE-RTK) allowing to monitor the effect of the ionosphere on high precision real time positioning (RTK targeted in particular) 13 May 2007 20 Nov 2003 SoDIPE output (positioning error) in 2 cases (quiet day, storm day) Method: Geometric-Free combination of double-differenced (DD) phase measurements used Compute the ambiguity term considering the whole DD observation period Isolate the ionospheric residual term on each carrier Compute IPE, the positioning error (on L1) due to the ionosphere only (least-squares adjustment applied, in topocentric coordinates) IPE mean and standard deviation computed (each baseline, 15 min time resolution) A (colour) code assigned to each baseline, range from “nominal” (green) to “extreme” (red) error level Wautelet et al. (2010): Monitoring the ionospheric postioning error with a GNSS dense network. Geophysical Research Abstracts, Vol.12, EGU General Assembly, 2-7 May 2010, Vienna.

SoDIPE – Determining the Ionospheric Positioning Error Positioning error is “translated” onto a map where the colors (from green to red) give the magnitude of the ionospheric error depending on the region Yellow, Orange, Red Iono disturbance (small / strong / severe accuracy degradation) Belgian Active Geodetic Network 66 stations 160 base lines 05 Mar 2010 05 Mar 2010 Green  No iono disturbance (no degradation) http://swans.meteo.be/ionosphere/SoDIPE/image

SoDIPE – Determining the Ionospheric Positioning Error Positioning error is “translated” onto a map where the colors (from green to red) give the magnitude of the ionospheric error depending on the region Yellow, Orange, Red Iono disturbance (small / strong / severe accuracy degradation) Belgian Active Geodetic Network 66 stations 160 base lines 20 Nov 2003 20 Nov 2003 Green  No iono disturbance (no degradation) http://swans.meteo.be/ionosphere/SoDIPE/image

SoDIPE – Determining the Ionospheric Positioning Error Belgian Active Geodetic Network 66 stations 160 base lines 20 Nov 2003 20 Nov 2003 © RMI http://swans.meteo.be/ionosphere/SoDIPE/image

Summary and Outlook Modern GNSS-based applications demand high precision -- simultaneous real-time observation of several characteristics plus the solar/geomagnetic background is essential. Operational applications range from ionospheric/space weather monitoring, research & modelling (further understanding the ionospheric morphology, validating existing ionospheric models) -- to improving comm/nav systems performance (incl. HF propagation and ray tracing, adverse ionospheric effects warnings/mitigation) Further work: Improve ionospheric storm onset determination procedure/s Develop Dst nowcast and forecast Develop TEC nowcast and forecast Development of an empirical model to forecast the occurrence of ionospheric disturbances which pose a threat for GNSS positioning (TIDs, noise-like structures, …)