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The Analysis of Solar Radio Weather Events Affecting Radio Communications: Key Issues

SESSION 6. The Analysis of Solar Radio Weather Events Affecting Radio Communications: Key Issues. M. Messerotti 1,2 , M. Molinaro 1 1 INAF-Astronomical Observatory of Trieste, IT 2 Department of Physics, University of Trieste, IT. Outline of the Talk. The Sun as a radio noise source

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The Analysis of Solar Radio Weather Events Affecting Radio Communications: Key Issues

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  1. SESSION 6 The Analysis of Solar Radio Weather Events Affecting Radio Communications:Key Issues M. Messerotti1,2, M. Molinaro1 1INAF-Astronomical Observatory of Trieste, IT 2Department of Physics, University of Trieste, IT 5th ESWW, 21 November 2008, Bruxelles

  2. Outlineof the Talk • The Sun as a radio noise source • Effects of SRBs on Wireless Systems and GPSs • TSRS and solar radio indices • Multi-timescale analysis of the 5 Dec. 2006 SRB • Conclusions 5th ESWW, 21 November 2008, Bruxelles

  3. RelevanceofSolar Radio BurststoSpaceWeather • PROXIES OF SOLAR DRIVERS • Type I Bursts (magnetictopologychanges) • Type II Bursts (propagatingshocks; particlebeams) • Type III Bursts (particleacceleration; particlebeams) • Type IV Bursts (magneticreconnection; acceleration) • Spikes (energyreleasefragmentation; acceleration) • Precursors (radio signaturesprecedingflares) • DIRECT SOURCE OF GEOEFFECTS • Radio Flares (Very Intense Broad Band Radio Noise) 5th ESWW, 21 November 2008, Bruxelles

  4. The Sunas a Radio Noise Source • The Sunis a radio source • non-directional • broad band • Solar radio noise can • increasebyseveralordersofmagnitudeduringoutbursts • persist at high levelsforminutestohours • Enhancedsolar radio noise can perturb • HF communications (MIL!) • Mobile communications (GSM, UMTS) • Global Navigation Satellite Systems (GPS, GNSS) 5th ESWW, 21 November 2008, Bruxelles

  5. Radio DiagnosticsRelevanttoSpwApplications LOW TIME RESOLUTION GLOBAL DIAGNOSTICS MULTI- FREQUENCY RADIOMETRY FULL-DISK SPATIAL RESOLUTION INDICES RADIO SPECTROGRAPHY SOLAR RADIO PHENOMENA HIGH TIME RESOLUTION LOCAL DIAGNOSTICS MULTI- FREQUENCY INTERFEROMETRY TIMINGS SOURCE SPATIAL RESOLUTION COMPLEMENTARY FOR SPW APPLICATIONS RADIO HELIOGRAPHY 5th ESWW, 21 November 2008, Bruxelles

  6. EffectsofSRBson Wireless Systems • Bala et al. (2002): • For a cellular base station operating at 900 MHz , the equivalent solar flux (thermal noise=solar noise level) Feq 960 SFU  more than twice the thermal noise power. • For a base station operating at 2.4 GHz, Feq 6,000 SFU. • The bit error rate (ber) changes rapidly with the S/N power ratio. (0.75 dB change  10x in ber). • Assuming an SRB effectivity threshold of 1,000 SFU, the statistics over 4 decades indicates a probability of interference every 10-20 days on average per year, modulated by the solar cycle. • Lanzerotti et al. (2002); Nita et al. (2004) 5th ESWW, 21 November 2008, Bruxelles

  7. EffectsofSRBson GPS Systems • Cerruti et al. (2006): • Observed reduced carrier-to-noise ratio in sunlit GPS receivers over the duration of SRB (8,700 SFU RHCP  2.3 dB loss; 2005.09.07) • Estimated L1 C/N0 fade of 3 dB and L2 C/N0 fade of 5.2 dB for commonly used GPS antennas with a gain of 4 dBic, from a SRB of 10,000 SFU • SRB are a potential threat to life-critical systems based on a Global Navigation Satellite System (GNSS): a 80,000 SFU SRB can determine a 12 dB fade at L1 and a 26.2 dB fade on the L2 channel  loss of lock in semi-codeless receivers. • Possibly 4,000-12,000 SFU Chen et al. (2005) 5th ESWW, 21 November 2008, Bruxelles

  8. EffectsofSRBson 5-6 December 2006 • P. Kintner (Cornell University): • Large number of receivers stopped tracking GPS signal over the entire sunlit side of the Earth • First quantitative measurement of the effect • P. Doherty (Boston College): • The 6 Dec SRB was the first one ever detected on the civil air navigation system (WAAS, Wide Area Augmentation System) [see Cerruti et al., 2006] Source: GPS Daily (http://www.gpsdaily.com) 5th ESWW, 21 November 2008, Bruxelles

  9. The Trieste Solar Radio System (TSRS) Data ProductsforSpW • MultichannelSynopticGraph • - 1 s downsampled data • - updatedevery 10 minutes • Solar Radio IndicesGraphs • - 1-min-average values • - 1-min-max values • - 1-min-ahead forecast • - updatedevery 10 minutes • Solar Radio IndicesFiles • - ASCII • - Binary • - FITS 5th ESWW, 21 November 2008, Bruxelles

  10. TSRS Data Productsfor SWENET • 1-min-average and 1-min-max radio indices • 237, 327, 408, 610, 1420, 2695 MHz • FLUX DENSITY & CIRCULAR POLARIZATION • [ W / m2 / Hz ] & [ dBm / Hz ] • Observed and 1-min-ahead PredictedValues • Single polarizationchannels & sum ofchannels 5th ESWW, 21 November 2008, Bruxelles

  11. GOES SXR Lightcurve 2006.12.05 X M C 5th ESWW, 21 November 2008, Bruxelles

  12. TSRS MultichannelSynopticGraph 5th ESWW, 21 November 2008, Bruxelles

  13. TSRS Radio Indices 5th ESWW, 21 November 2008, Bruxelles

  14. TSRS 1420 MHz 1-min Radio Index TSRS observedmaximum radio flux density significantlyexceedreportedlevels: S2695max = 10,391 SFU S1420max = 4,870 SFU 5th ESWW, 21 November 2008, Bruxelles

  15. TSRS 1420 and 2695 MHz CP Graph 5th ESWW, 21 November 2008, Bruxelles

  16. Timing of SRB withrespectto SXR 5th ESWW, 21 November 2008, Bruxelles

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  24. Conclusions • Intense SRBs are a direct source ofinterferencefor wireless communications and GPS systems • Published radio indices are not appropriate descriptorsastheyprovide incomplete information • 1-min radio indices are inadequateaswell → wrong estimate oftimeover the threshold and polarization • CircularPolarization information isneeded due to the characteristicsof radio systems • Real-time high timeresolutionanalysisis a mustforproperlyevaluating the interferingeffect on radio systems • TSRS has the requiredfeaturesforthispurpose 5th ESWW, 21 November 2008, Bruxelles

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