Concept for Ionospheric Scintillation Mitigation for Professional GNSS in Latin America

“When the solar winds come around, you’d better hang onto your GNSS receiver, not your hat. That’s because satellite signals propagating through the Earth’s atmosphere can be profoundly affected when the Sun acts up, as it does periodically in 11-year cycles – the upward trajectory of which is just beginning.”

J. Kunches, NOAA, in Inside GNSS

Background

Objectives of CIGALA

Description of Work

Expected Results

The Team

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Background

Solar induced drifting ionospheric electron density irregularities may lead to the scintillation of transionospheric radio waves, as in the case of signals broadcast from GNSS satellites. Scintillations can not only degrade signal quality but also cause GNSS signal loss-of-lock, therefore posing a major threat to GNSS based applications demanding high levels of accuracy, availability and integrity. The problem is particularly acute in low latitude areas and will be exacerbated with the next solar maximum, predicted for 2013. Latin America, which rely in a greater extend to GNSS in activities such as land and offshore surveying, is particularly exposed. This was demonstrated during latest major solar storm in 2003, which led to delay or cancellation of major surveying and drilling operations as well as serious perturbations of the WAAS system in those areas with, as consequence significant economical loss.

Objectives of CIGALA

CIGALA aims to develop and test ionospheric scintillation mitigation approaches to be implemented in professional multi-frequency GNSS receivers from European manufacturers, providing a timely competitive advantage in the Latin American market. In order to achieve this, the project will leverage research and development activities coordinated between leading European and Brazilian experts and will set up a wide-scale measurement and test campaign at several locations in Brazil during the period of increasing solar activity. Most affected local GNSS users will be involved in the assessment of the threat and countermeasures in order to promote greater awareness of the problem and solutions proposed by European Manufacturers.

Description of Work

The challenge to achieve the CIGALA objectives is to understand the causes of ionospheric disturbances and model their effects in order to develop novel countermeasure techniques.

The project will achieve this goal by:

• Studying the market needs and end user requirements locally in one of the regions most affected by ionospheric scintillation, addressing the whole spectrum of GNSS users, in particular safety critical and high accuracy applications;
• Researching deedly into the underlying causes of ionospheric scintillation and developing state-of-the-art models capable of predicting signal propagation and tracking perturbations related to this phenomenon;
• Carrying out field measurement campaigns through the deployment in close collaboration with local academic and industrial partners of multi-frequency Galileo-capable receivers, in the area of interest, in order to collect data to support model development;
• Completing these measurements through access to archive as well as simulated data;
• Designing and implementing newly developed scintillation countermeasures or mitigation techniques;
• Field testing those newly developed techniques, leveraging the same partnership and measurement; infrastructure as during the measurement campaign.

The project will selectively and effectively exploit the varied expertise of the different partners covering: space weather and signal perturbation prediction and modeling; receiver architecture and signal processing design and implementation; high precision application design, implementation and deployment. 
The project will strongly foster international activities in Latin America, with two partners out of six being located in Brazil. Both the initial phase of the measurement campaign and the final field testing and demonstration of the newly developed scintillation mitigation techniques will be held across different field of GNSS applications highly relevant in the geographic area. This will be done in close collaboration with the local partners, notably with the complimentary support of Petrobras’ survey department, and in full synergy with on-going European GNSS activity and projects.

Expected Results

At first, CIGALA technical results is expected to significantly advance the state-of-the-art in understanding climatologic, signal perturbation and tracking dynamical aspects of strong ionospheric scintillation events. Existing climatologic (WBMOD, GISM and WAM) and classical receiver tracking loops models will be further developed and validated by field measurements. Secondly, a repository of scintillation event records will be established, providing data as well for GPS legacy signals in L1 band as for newly available modernized GPS (L2C, L5) and Galileo signals (E1, E5a, E5b, E5 AltBOC).

Leveraging both modeling and field measurement efforts, receiver-level countermeasures will be made available in Septentrio’s receiver products, strengthening their capability to track GNSS signals and deliver the required accuracy even in presence of moderated to strong scintillation, which will provide Europe with a strong competitive advantage in the high potential Latin American market.

Finally, a targeted dissemination effort will ensure visibility and awareness about the incoming solar thread and the developed countermeasures as well in the GNSS and Space Weather research communities as with key industrial stakeholders in Latin America.

The Team

Acknowledgement

the CIGALA project has received Community research funding under the EU Seventh Framework Program, and is carried out in the context of the Galileo FP7 R&D program supervised by the GSA.