1. Irregularities and Scintillation Measurements and Effects

Chairs: Keith Groves, Iurii Cherniak and Andrzej Krankowski

The occurrence of amplitude and phase scintillations on transionospheric radio wave signals due to scattering by ionospheric irregularities is an important aspect of space weather that affects space-based communications and navigation systems in different ways. Advances and research in irregularities and scintillation measurements and effects are discussed in this section. Relevant topics include the characterization of irregularities focused on their climatology and morphology, spatial and temporal correlations and occurrence patterns, and their associated scintillation effects on radio wave propagation including the relationship between different scintillation indexes, effects of amplitude and phase scintillation on new GPS signals (L2C and L5) and spatial/temporal/spectral characteristics and correlations. This section also targets the influence of irregularities and scintillation on GNSS positioning and the potential for threat reduction relative to GPS-only applications. Studies of irregularities effects on GNSS users are solicited, especially for space-and ground-based augmentation and aviation users, and discussion of important results, outstanding problems and challenges related to GNSS systems is welcome. New measurement techniques and comparisons of scintillation observations with other sensor data are of particular interest.

2. Theory and Modeling of Ionospheric Scintillation and Irregularities

Chairs: Chuck Rino and Biagio Forte

Radio propagation disturbances regularly observed on low earth-orbiting and GNSS satellites are attributed to intermediate-scale structure (tens of kilometers to hundreds of meters). This scintillation phenomenon is of practical concern because it can degrade satellite communication, navigation, and surveillance operations. The global monitoring capability of the GNSS has stimulated significant advances in our understanding of large-scale ionospheric structure. However, commensurate progress in reconciling scintillation observations with hypothesized and/or measured power-law structure characteristics has been limited. This session seeks multi-frequency scintillation data analyses that attempt to reconcile observations with theoretical predictions based on definitive power-law structure and/or in-situ structure measurements.

3. Data Assimilation Modeling

Chairs: Bruno Nava and Matthew Angling

Many models have been developed to capture different aspects of the ionosphere: median empirical models capture the ionospheric climatology, whilst first principle models can represent many of the physical processes in the ionosphere. However, in order to represent ionospheric weather (i.e. processes and structures occurring over periods of hours and over medium spatial scales) it is necessary to move towards data assimilation (DA). DA can exploit diverse data types such as ground and space-based GNSS derived TEC, in situ electron density measurements, and ionosonde derived plasma frequency. Furthermore, a wide variety of DA methods have been applied to the ionosphere in recent years. These include Kalman Filters, 3 or 4-dimensional variational methods and tomographic techniques. Papers on the assimilation of ionospheric data into empirical or first-principle models are solicited for this session. Of particular interest are papers describing new assimilation methods, methods that exploit multi-sensor observations, and methods that exploit more than one model such as multi-model ensembles.

4. Modeling and Validation

Chairs: Manuel Hernandez-Pajares and Maxim Klimenko

Advances in observations have revealed anomalies and structure in the ionosphere previously unmodeled. For instance, ground-based GNSS networks and radio occultation have revealed three or four peaks in the F-region plasma density latitude structure, rather than the typical two peaks associated with the traditional equatorial ionization anomalies (EIAs). In addition, during strong geomagnetic activity, storm-enhanced densities at mid-latitudes can dominate the global structure and create steep gradients in plasma density. Furthermore, new ionosonde and digisonde observations, as well as the GNSS observations, have enabled visualization of the complex high-resolution ionospheric wave structure seen as TIDs and MSTIDs, driven by waves from the lower atmosphere and from the auroral sources propagating through the thermosphere. This session targets new modeling capabilities, including thermosphere-ionosphere, whole atmosphere-ionosphere, and magnetosphere-ionosphere-thermosphere models, that are able to capture these anomalies, structure, and features. This session also targets the challenge of developing appropriate metrics to validate the existing and new modeling capabilities. Note that this session does not specifically target new data assimilation techniques, or ionospheric structure associated with equatorial irregularities, which are covered by other sessions.

5. Space and Ground-based TEC Techniques and Measurements

Chairs: Sandro Radicella, Babatunde Rabiu and Irina Zakharenkova

Critical to ionospheric modeling efforts and data assimilative processes are ground and space-based TEC measurements availability and quality. A number of recent initiatives have led to deployment of ground networks capable of measuring TEC in regions hitherto dearth of TEC data. The increasing amount of available GNSS constellations, ground networks of receiving stations and altimetry missions able to increase the number of accessible measurements is an important contribution to the data availability. Space based TEC data are being used more and more to characterize the ionosphere under different solar-geomagnetic conditions mainly through radio-occultation techniques. Differences in performance of different TEC calibration techniques remain a problem particularly when data are used for model validation or assimilation. The session conveners aim to get an updated vision of the availability of ground and space based high quality TEC data and their use to advanced characterization of ionospheric conditions. Authors are encouraged to present their results obtained using TEC ground and space measurements with special attention to multi-station or regional coverage and estimate of data retrieval accuracy.

6. Radio Occultation Techniques and Measurements

Chairs: Ron Caton and Jann-Yeng Liu

A number of radio occultation (RO) techniques have been exploited to study the structure and properties of the atmospheres of Earth as well as many outer planets and moons. By measuring phase delay of radio waves from GNSS satellites as they are occulated by the Earth’s atmosphere, vertical density profiles of the bending angles of radio wave trajectories can be estimated using measurements onboard LEO satellites. By examining amplitude and phase fluctuations on long slant paths through the ionosphere, researchers have mapped the global climatology of scintillation patterns. A number of recent missions, inspired by the successful GPS/MET experiment, have produced fruitful radio occultation data sets including the CHAMP, GRACE, SAC-C, FORMOSAT-3/COSMIC, Metop-A/B, C/NOFS satellite, and FORMOSAT-7/COSMIC-2. Advanced technology including the proliferation of CubeSat missions and ability to simultaneously record signals from multiple GNSS sources promises to exponentially expand the coverage of radio occultation sensing in the very near term. With this abundance of data comes a need for advanced processing techniques to enhance the reliability and accuracy for use in data assimilation. In this session, we welcome contributions from techniques that advance and improve the application of RO for space environment models. Innovative methodologies addressing current problems with RO inversion techniques or geolocating ionospheric irregularities along RO slant paths are invited along with descriptions of improved solutions for identifying and mapping the occurrence of sporadic-E.

7. Polar (high-latitude) Effects on GNSS

Chairs: Nicolas Bergeot and Pierre Cilliers

This session solicits contributions on GNSS-based research and applications at high latitudes. Studies dealing with ionospheric irregularities, scintillation and total electron content (TEC) gradients are of interest. Papers dealing with GNSS data collection, data sets, model and processing developments and infrastructure available to support investigations are also welcome, as are those where GNSS is one part of a multi-instrument approach in particular in conjunction with incoherent scatter radars. Finally, papers highlighting and contrasting the differences and similarities at high and low latitudes and bi-polar comparisons are of interest. Impacts of research results on different applications such as positioning, space weather, solid Earth, cryosphere research and remote sensing are also highly encouraged.

8. Space Weather Effects

Chairs: Iwona Stanislawska and Endawoke Yizengaw

Space weather events become noticeable in the geospace system either by the direct action of solar flares onto the atmosphere or through the coupling of the solar wind into the magnetosphere and ionosphere via the geomagnetic field. The resulting effects can impact positioning, navigation, and communications. The best way to prepare for near-and long-term space-weather impacts on modern society is to improve our ability to understand the physics and forecast space weather events and to fully realize what the impacts are on our technological infrastructure. The goal of this session is to provide a forum for discussing space weather driven ionospheric dynamics in the context of applications utilizing space-based radio systems. The following questions should be addressed:

• How can ionospheric monitoring and modelling be utilized to further our understanding of space weather in its complexity?
• How are ionospheric dynamics impacted by energy inputs, either directly from the sun or indirectly via coupling processes with other geospheres such as the thermosphere and magnetosphere?
• How can ionospheric dynamics be described, benchmarked and forecasted effectively to correct and mitigate the ionospheric impact on applications utilizing trans-ionospheric radio signals?
• How can this information be provided to customers in an appropriate form according to their needs, e.g. considering latency, temporal and spatial resolution, and reliability, taking into account international perspectives on observations, modeling and forecasting?

9. Ionospheric Effects on Satellite Based Navigation Systems

Chairs: Patricia Doherty and Ashik Paul

This session will address ionospheric effects on Satellite Navigation Systems and their users including aviation, maritime and land users. These systems may include regional augmentation systems such as Satellite-Based Augmentation Systems (SBAS), Ground-Based Augmentation Systems (GBAS), and the Global satellite systems including GPS,GLONASS, Galileo and Compass. The FAA’s WAAS system was the first SBAS system deemed operational in July 2003. Since that time, the greatest impacts to WAAS availability have been extreme solar storm events. Other systems like EGNOS, started operations during solar minimum and they have experienced impacts on performance from the ionosphere during the current Solar Cycle 24. Navigation users in the polar regions will be challenged by solar storms with degraded availability due to geomagnetic disturbances. Augmentation and aircraft systems planned to operate in the low latitude regions will experience availability issues imposed by the extreme ionospheric dynamics of the equatorial ionosphere. These challenges have already been observed by air, land and maritime users in those areas. Solar Cycle 24 is now near its minimum phase and it will go down in history as one of the least active lowest solar cycles in over 100 years. However, satellite navigation systems have continued to develop with new services, applications and new frequencies. This session invites abstracts related to system performance assessments due to ionospheric effects, mitigation techniques, effects on users and program status for all navigation systems.

10. Monitoring Natural Hazards: Signatures of Earth-Ocean Coupling to the Ionosphere

Chairs: Attila Komjathy and Elvira Astafyeva

Natural hazards, including earthquakes, volcanic eruptions, and tsunamis have been significant threats to humans throughout recorded history. The Global Navigation Satellite System (GNSS) satellites including GPS, GLONASS, Galileo, BeiDou and others have become primary sensors to measure signatures associated with such natural hazards. These signatures typically include GNSS-derived seismic deformation measurements, co-seismic vertical displacements, and real-time GNSS-measured ocean buoy positioning estimates. Another way to use GNSS observables is to compute the ionospheric total electron content (TEC) monitor post-seismic and pre-seismic ionospheric disturbances caused by earthquakes, volcanic eruptions, and tsunamis. These measurements provide new scientific insight into the geophysical source phenomenology, wave propagation physics, and electromagnetic coupling processes. We solicit observational, theoretical and modeling contributions that specifically address the societal benefits that can be realized through the routine monitoring of atmospheric and ionospheric disturbances. Innovative concepts for the monitoring of seismic and tsunami hazards that make use of Earth to ionosphere coupling via acoustic gravity waves are particularly welcome. Precursory signals and perturbations consecutive to recent earthquakes are also pertinent. With improved knowledge of the various geophysical processes involved, these means have the potential to enhance natural hazards warning systems in order to save human life and mitigate economic damage.

11. Emerging Topics of Interest to the Beacon Satellite Studies

Chairs: Patricia Doherty, Andrzej Krankowski and Bruno Nava

This session welcomes papers on emergent topics relevant to the Beacon Satellite Community. These papers can focus on new missions, new techniques and innovative applications of interest to the Beacon Satellite Community. The Beacon Satellite Symposia is historically meaningful as it has been a forum to present and discuss innovative topics relevant to radio propagation in our international community of radio scientists since the 1970s.

12. Poster Session

Chair: Bartosz Dabrowski

This session will accommodate all topics listed above in a poster session format. If you prefer a poster presentation, please submit your abstract to this session. Other accepted papers, which cannot be accommodated in an oral session, will be offered an opportunity to present the paper in a poster format.