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)

5th ESWW, 21 November 2008, Bruxelles 3

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)



SOLARSOLARRADIORADIO

PHENOMENAPHENOMENA

SOLARSOLARRADIORADIO

PHENOMENAPHENOMENA

MULTI-FREQUENCYRADIOMETRY

MULTI-FREQUENCYRADIOMETRY

RADIOSPECTROGRAPHY

RADIOSPECTROGRAPHY

RADIOHELIOGRAPHY

RADIOHELIOGRAPHY

LOCALLOCALDIAGNOSTICSDIAGNOSTICS

LOCALLOCALDIAGNOSTICSDIAGNOSTICS

GLOBALGLOBALDIAGNOSTICSDIAGNOSTICS

GLOBALGLOBALDIAGNOSTICSDIAGNOSTICS

LOWLOWTIMETIME

RESOLUTIONRESOLUTION

LOWLOWTIMETIME


FULL-DISKFULL-DISKSPATIALSPATIAL


FULL-DISKFULL-DISKSPATIALSPATIAL


SOURCESOURCESPATIALSPATIAL


SOURCESOURCESPATIALSPATIAL


MULTI-FREQUENCY

INTERFEROMETRY

MULTI-FREQUENCY

INTERFEROMETRY

HIGHHIGHTIMETIME


HIGHHIGHTIMETIME


INDICESINDICESINDICESINDICES

TIMINGSTIMINGSTIMINGSTIMINGS

COMPLEMENTARYCOMPLEMENTARYFOR SPW APPLICATIONSFOR SPW APPLICATIONS

COMPLEMENTARYCOMPLEMENTARYFOR SPW APPLICATIONSFOR SPW APPLICATIONS

5

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)


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)Source: GPS Daily (http://www.gpsdaily.com)

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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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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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C

M

X

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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

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

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