Sat-nav systems under growing threats

Technology that depends on satellite-navigation signals (GPS/Glonass/Compass) is increasingly threatened by :

• attack from widely available equipment : while "jamming" sat-nav equipment with noise signals is on the rise, more sophisticated methods allow hackers even to program what receivers display (see BBC News / Financial Times / NZ Master Mariners articles)
  

• solar activity rising : GPS systems are particularly sensitive to major electric activity in the ionosphere, which interferes with satellite signals. The Northern Lights (or Aurora Borealis) could be messing with GPS satellite navigation systems when the satellite signal passes through the phenomena (see Telegraph article). The Sun is on its way to another solar maximum, which could generate large and unpredictable sat-nav errors (see BBC News other article)
  

Some more reasons to not rely too heavily on an GPS chart plotter which can be inaccurate sometimes (see the recent story occured in Australia : "Fatal yacht crash inquiry blames GPS")