Solar flares will disrupt GPS in 2011

Navigation, power and communications systems that rely on GPS
satellite navigation will be disrupted by violent solar activity
in 2011, research shows.

A study reveals Global Positioning System receivers to be
unexpectedly vulnerable to bursts of radio noise produced by
solar flares, created by explosions in the Sun's atmosphere.

When solar activity peaks in 2011 and 2012, it could cause
widespread disruption to aircraft navigation and emergency
location systems that rely heavily on satellite navigation data.

Full story at:
http://www.newscientisttech.com/channel/tech/dn10189-solar-flares-will-disrupt-gps-in-2011.html/article/dn9751

Hans-Georg

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No mail, please.

Hans-Georg Michna wrote:
http://www.newscientisttech.com/channel/tech/dn10189-solar-flares-will-disrupt-gps-in-2011.html/article/dn9751

Abstract from ION GNSS 2006 (Sept. 26-29)

Observed GPS and WAAS Signal-to-Noise Degradation Due to Solar Radio Bursts
A. Cerruti, Cornell University

GPS signals, systems, and navigation accuracy are vulnerable to a
variety of space weather effects that are caused mostly by the
ionosphere. However, the sun, which is sometimes a strong radio source,
is the cause of GPS signal interference presented here. The first
direct observations of GPS L1 (1.57542 GHz) signal-to-noise ratio
degradation on two different models of GPS receivers due to the solar
radio burst associated with the 7 September 2005 solar flare are
presented.

Signal-to-noise ratio data from three identical, collocated receivers
at Arecibo Observatory and also from four identical receivers of a
different model located in Brazil, were available at the time of the
solar radio burst. These receivers were all in the sun-lit hemisphere
and all were affected similarly. The maximum solar radio burst power
associated with the 7 September 2005 flare had a peak intensity of
about 8,700 solar flux units (1 SFU = 10-22 W/m2-Hz) RHCP at 1,600 MHz,
which caused a corresponding decrease in the signal-to-noise ratio of
about 2.3 dB across all visible satellites. Only the right-hand,
circularly polarized (RHCP) emissions affected the GPS signals.

To confirm the effect, the solar radio burst associated with the 28
October 2003 flare was investigated. Although polarization data were
not available for this event, the maximum degradation at GPS L1 was
about 3.0 dB, and a degradation of 10 dB was observed on the
semi-codeless L2 signal for a solar radio burst of 13,600 SFU.

The event analyzed herein can be used to scale historical solar radio
bursts of 80,000 SFU. Decreases of 12 dB (21 dB) in the L1 (L2,
semi-codeless) signal-to-noise ratio are implied along with loss of
tracking for inadequately designed GPS receivers. Since solar radio
bursts affect all satellites in view of a receiver, all receivers in
the sun-lit hemisphere, the new Galileo navigation system, and all
space-based augmentation systems such as WAAS and EGNOS, they are a
potential threat to life-critical systems.

On Wed, 04 Oct 2006 18:23:37 GMT, Sam Wormley wrote:


Sam,

thanks, interesting! Still not quite sure whether my handheld
receivers will be totally useless at the predicted time or
whether they will continue to work, albeit with less accuracy
and less reliability.

Hans-Georg

--
No mail, please.

Hans-Georg Michna wrote:


The solar activity cycle has a period of 22 years with peaks of
opposite polarity every 11 years. My eMap and GPS12 worked fine during
the last maximum in 2000 with only a few days where reception was
somewhat degraded. I expect that my eMap (or whatever successor I get
by then) will also function adequately during the next one.

peter wrote:


Same here .. I noticed no problems in 2000 and was
using an eMap and a GPS-III as best I recall.
Perhaps it is just an issue for precision users.

Phil