Sunspots or Superstorm Sandy??

Went out yesterday and my GPS looked like it had been drinking strong coffee or something!! Same lake and waypoints as always, bluebird skies and track and speed was jumping several feet and several tenths of MPH. This is not typical behavior for my 788CI. I hope it was just halloween gremlins, but didn't make it out today to see if reception was better. Maybe sunspots or increased solar activity are affecting satellite signal strengh. Anyone else ever experience this? It didn't seem to bother the fish too much as I managed to catch several in spite of the jitters.