O Level - Weather & Climate - Factors Affecting Air Pressure and Wind
The Analysis of Solar Radio Weather Events Affecting Radio Communications: Key Issues
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Transcript of The Analysis of Solar Radio Weather Events Affecting Radio Communications: Key Issues
SESSION 6SESSION 6
5th ESWW, 21 November 2008, Bruxelles
M. Messerotti1,2, M. Molinaro1
1INAF-Astronomical Observatory of Trieste, IT2Department of Physics, University of Trieste, IT
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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
Conclusions5th ESWW, 21 November 2008, Bruxelles 2
PROXIES OF SOLAR DRIVERSPROXIES OF SOLAR DRIVERS Type I Bursts (magnetic topology changes) Type II Bursts (propagating shocks; particle beams) Type III Bursts (particle acceleration; particle beams) Type IV Bursts (magnetic reconnection;
acceleration) Spikes (energy release fragmentation; acceleration) Precursors (radio signatures preceding flares)
DIRECT SOURCE OF GEOEFFECTSDIRECT SOURCE OF GEOEFFECTS Radio Flares (Very Intense Broad Band Radio Noise)
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The Sun is a radio sourceThe Sun is a radio source non-directional broad band
Solar radio noise canSolar radio noise can increase by several orders of magnitude during
outbursts persist at high levels for minutes to hours
Enhanced solar radio noise can perturbEnhanced solar radio noise can perturb HF communications (MIL!MIL!) Mobile communications (GSM, UMTSUMTS) Global Navigation Satellite Systems (GPS, GNSS)
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SOLARSOLARRADIORADIO
PHENOMENAPHENOMENA
SOLARSOLARRADIORADIO
PHENOMENAPHENOMENA
MULTI-FREQUENCYRADIOMETRY
MULTI-FREQUENCYRADIOMETRY
RADIOSPECTROGRAPHY
RADIOSPECTROGRAPHY
RADIOHELIOGRAPHY
RADIOHELIOGRAPHY
LOCALLOCALDIAGNOSTICSDIAGNOSTICS
LOCALLOCALDIAGNOSTICSDIAGNOSTICS
GLOBALGLOBALDIAGNOSTICSDIAGNOSTICS
GLOBALGLOBALDIAGNOSTICSDIAGNOSTICS
LOWLOWTIMETIME
RESOLUTIONRESOLUTION
LOWLOWTIMETIME
RESOLUTIONRESOLUTION
FULL-DISKFULL-DISKSPATIALSPATIAL
RESOLUTIONRESOLUTION
FULL-DISKFULL-DISKSPATIALSPATIAL
RESOLUTIONRESOLUTION
SOURCESOURCESPATIALSPATIAL
RESOLUTIONRESOLUTION
SOURCESOURCESPATIALSPATIAL
RESOLUTIONRESOLUTION
MULTI-FREQUENCY
INTERFEROMETRY
MULTI-FREQUENCY
INTERFEROMETRY
HIGHHIGHTIMETIME
RESOLUTIONRESOLUTION
HIGHHIGHTIMETIME
RESOLUTIONRESOLUTION
INDICESINDICESINDICESINDICES
TIMINGSTIMINGSTIMINGSTIMINGS
COMPLEMENTARYCOMPLEMENTARYFOR SPW APPLICATIONSFOR SPW APPLICATIONS
COMPLEMENTARYCOMPLEMENTARYFOR SPW APPLICATIONSFOR SPW APPLICATIONS
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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 6
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)
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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)
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[see Cerruti et al., 2006] Source: GPS Daily (http://www.gpsdaily.com)Source: GPS Daily (http://www.gpsdaily.com)
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5th ESWW, 21 November 2008, Bruxelles
Multichannel Synoptic Graph - 1 s downsampled data - updated every 10 minutes
Solar Radio Indices Graphs - 1-min-average values - 1-min-max values - 1-min-ahead forecast - updated every 10 minutes
Solar Radio Indices Files - ASCII - Binary - FITS
Multichannel Synoptic Graph - 1 s downsampled data - updated every 10 minutes
Solar Radio Indices Graphs - 1-min-average values - 1-min-max values - 1-min-ahead forecast - updated every 10 minutes
Solar Radio Indices Files - ASCII - Binary - FITS
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5th ESWW, 21 November 2008, Bruxelles
1-min-average and 1-min-max radio indices1-min-average and 1-min-max radio indices
237, 327, 408, 610, 1420, 2695 MHz237, 327, 408, 610, 1420, 2695 MHz
FLUX DENSITY & CIRCULAR POLARIZATIONFLUX DENSITY & CIRCULAR POLARIZATION
[ W / m[ W / m2 2 / Hz ] & [ dBm / Hz ]/ Hz ] & [ dBm / Hz ]
Observed and 1-min-ahead Predicted ValuesObserved and 1-min-ahead Predicted Values
Single polarization channelsSingle polarization channels & sum of & sum of channelschannels
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Intense SRBs are a direct source of interference Intense SRBs are a direct source of interference for wireless communications and GPS systemsfor wireless communications and GPS systems
Published radio indices are not appropriate Published radio indices are not appropriate descriptors as they provide incomplete descriptors as they provide incomplete informationinformation
1-min radio indices are inadequate as well 1-min radio indices are inadequate as well → → wrong estimate of time over the threshold and polarizationwrong estimate of time over the threshold and polarization
Circular Polarization information is needed due Circular Polarization information is needed due to the characteristics of radio systemsto the characteristics of radio systems
Real-time high time resolution analysis is a must Real-time high time resolution analysis is a must for properly evaluating the interfering effect on for properly evaluating the interfering effect on radio systemsradio systems
TSRS has the required features for this purposeTSRS has the required features for this purpose5th ESWW, 21 November 2008, Bruxelles 24