Warning on GPS accuracy
GPS accuracy to be affected in months ahead
Yacht and boat users should be aware that the summers months may bring a reduction in the accuracy of GPS systems.
The summer sun be welcome after an unpredictable winter and spring, but there is the possibility that the sun itself may be responsible for GPS performing below par or not working at all.
As part of an 11-year solar cycle, the sun will be entering its most active period over the coming months. Now here’s the science bit – this activity can create solar flare and sunspots which will can drive up something called ionising solar radiation. This in turn creates a greater number of free electron in the ionosphere.
Abrupt changes in the ionosphere’s density can lead to delay in the sending of GPS signal and an inconsistency in those signals.
Experts believes these effect could last well into 2014 and could even stop some GPS systems from linking up with satellites.
Boat and yacht owners beware
Boat and yacht owners should note that that GPS difficulties like these are more likely to occur during the day than at night time with the greatest chance of disruption likely to take place just after sunset.
Latitudes around the equator are likely to be the most adversely affected with travelers in the polar cap regions also highly likely to experience difficulties.
GPS units could be out by more than 10m with differential GPS likely to be affected, but no to the same degree according to experts.
The General Lighthouse Authority has also warned that boat and yacht users may also outages in the coverage of their GPS systems.
“GPS is far from robust. Although reliable and accurate for long periods, it can suddenly and unexpectedly fail. In recent years such failures have been due to a range of vulnerabilities: solar disturbances, space-vehicle failures, unintentional radio interference and, increasingly, deliberate jamming,” a report by the GLA stated.
“The consequences have included not only the loss of GPS service but, more seriously, positions and velocities shown on ship’s displays that without warning became incorrect, yet remained plausible.”
There is also concern that outages to GPS coverage may not even alert the yacht or boat owner as an alarm won’t necessarily go off.
The advice they give is for seagoing folk to familiarise themselves with older navigation methods, saying that these anticipated GPS problems would: “force the mariner to revert to increasingly unfamiliar fallback navigation methods such as chart, compass and visual bearings.”
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