Yo Luke!
I dont bother to respond to whinging. If you can boil that down to
a few answers to questions I asked, or a few technical questions,
then I'll look at what you write.
I have enough yak to shear without more bikehsedding to do.
OK, so here it is, boiled down.
Please download the two attachments attached to this email. They are the exact same ones I sent two messages prior (which you chose to ignore).
The only difference between them is that "binary.log" was captured with the device setting "native":1, and nmea.log was captured with "native":0. Interpret the effect of the "native" setting however that is supposed to be interpreted. That is the only important variable here. It either causes or stops the anomalous behavior.
Now replay each of those two logs, using `gpsfake -c 0.5 -P 4001 <logfilename>`, as I described two messages prior. Meanwhile, view the behavior of each of the logs using `cpgs localhost:4001` each time. (Or use xgps, if you would prefer -- it does the same thing.)
Watch the "Altitude" display in cgps (or xgps). I am using the word "Altitude" even though you banned me from doing it, because gpsd's own clients use that exact word.
You will see that these two logfiles, captured a minute or two apart, have very different behavior from the point of view of the client. nmea.log shows updates every second that look pretty normal, e.g. Altitude updates at 1Hz. However binary.log shows Altitude switching back and forth between two values, twice within each 1Hz window. And the Latitude and Longitude fields also switch back and forth within each 1Hz window, albeit to a smaller degree.
You now have everything you need. Please go replay those logs and help me understand what's wrong.
Thank you.
nmea.log