GPS fix oscillates on and off

Recently, we had a problem with a F550 frame hexacopter flying in loiter where the GPS fix started dropping out intermittently as shown here:

There was a GoPro onboard, but subsequent tests where the GoPro was placed near the GPS didn’t cause a complete loss of a fix. (Only 1-2 satellites were lost). We’ve flown with a GoPro many times in the past without any impact on the GPS as well.

Given the frequency of the GPS lock outage, it almost appears that a GPS update timeout is occurring.

Has anybody else seen this type of behavior before?

Have you tried to update your gps settings according to http://ardupilot.org/copter/docs/common-ublox-gps.html#common-ublox-gps ?

If so, what is your gps device?

I have had the same issues lately.

It seems to me a bad GPS cable…

The cable was checked and no problems were apparent.

Also, check this site