With a lot of help from Drotek’s excellent customer support, the only solution to my GNSS problem may be to move south to 37km SE of Toulouse in France where Drotek are based 🙂
They sent me the following results yesterday from the uCenter ublox app showing the satellites detected by the NEO-M8T I’d sent back to them. This shows 15 satellites, all but one over 30dB signal strength.
This is what I got yesterday indoors: 9 satellites all of whose signal strengths were under 20dB:
The plot on the left shows the variance of the fixed location of NEO-M8T sat in my office. It drifts north / south by nearly 20 meters. I think this corresponds to the top right locations of satellites: east / west is covered well, but there’s a gaping hole north of me, leading to the north / south drift.
So I went to the field next door…
and scanned GNSS for several minutes…
which above is showing 9 satellites available which are all in use; occasionally 10 were available but still only 9 were used. Graphing the logs from these nine minutes’ samples (10:47:14 – 10:56:16) shows…
…roughly 1m east / west and 1.8m north / south uncertainty. That’s more than good enough for my GNSS piDrone project to proceded, but with 2 critical dependencies::
- I get permission from the farmer to use his field for flying.
- the DroTek NEO-M8T EMI shielding works well when the GNSS is running on Hermione when she’s flying.
I suspect #2 will just work. However I have not idea how to address #1!
P.S. Anyone recognise the painting the GNSS graph portrays? Adam (as in “and Eve”), Isaac Newton or Leonardo da Vinci? I’m sure there is a classical painting out there, but hours of googling has failed so far.