With a couple of aircraft we are getting the “Bad GPS Health” warning. I know that this comes from a less the 5Hz update rate (specifically a delta of greater the 250ms between messages) as the flight controller sees them.
I have identified two different symptoms which may or may not be related.
The delta raises above the 250ms limit if the satellite count on said GPS is above 18. Scoped the data lines when we have had this happening and the bus isn’t anywhere near full.
(from a bench test unit with a GPS that was showing the same issue in the aircraft)
And this odd occurrence where the message freq simply just halves.
Both the cable and the GPS unit has been replaced in the aircraft with the same results.
That GPS unit has shown the same slow message freq on a bench test cube that had a clean install of latest stable on it.
Message freq has been upped from the default 5Hz to 10Hz and once the sat count was over 18 there again was delays in the message freq over the threshold.
This has all been captured when not in flight. To continue with other testing we have relied on the second (CAN) GPS only.
I have run some more bench tests with a brand new HERE and a HERE2, the HERE shows the same halving in freq symptom but the HERE2 does not.