if you look at the GPA.Delta messages you will see the time in milliseconds between parsed positions. This should always be around 200 milliseconds +/- 20 milliseconds. If you see jumps on the order of 400 milliseconds this indicates an error.
if it drops the DOP messages/HW debug messages, but those are not that important. The main one it will let you know is if you miss a PVT message, which is very important.
https://discuss.ardupilot.org/t/bad-...k-fix/26532/50
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So I finally got this all hooked up and tested. ArduPilot checks for a location update every 20ms. So the GPA.Delta log shows that timing, and that is why it appears to be in 20ms intervals. These are on my test Solo sitting out on my deck using the brand new mRo M8N GPS. I had good reception and navigational use of all three systems.
The results confirm what I afraid of. I have not flown it to see if the results get event worse in flight, but they certainly may.
With the typical configuration of 2 systems enabled (GPS & Glonass), the location updates come in on time with a new location every 20ms or less, where you see them at 0 to 220. There are no errors, and everything is happy.
With the mRo configuration of 3 systems enabled (GPS, Glonass, & Galileo), location updates are consistently running late, and have quite a bit of jitter, where you see them spike up to 240. And there are numerous delayed updates in excess of the
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