I am trying to use the Marvelmind ultrasonic system for indoor navigation and I am currently facing some issues.
There seem to be three ways to connect ArduPilot with the MM hedgehog:
NMEA protocol
ublox protocol
Marvelmind protocol
Please correct me if I’m wrong, but the first two seem to emulate a conventional GPS signal and pass it on to the FC, while the other one is more general and is processed in AP.
Now I managed to get the NMEA protocol running simply by hooking the MM hedgehog up and setting GPS_TYPE = 5 (NMEA). I put my GPS coordinates into MM Dashboard → Mode/Geofencing. I am getting a GPS 3D_FIX sometimes but not sufficiently often. Also there seems to be a lot of delay between the movement of the drone and the registered movement shown in MP. The delay is also way bigger than the one in the MM Dashboard.
Is there a way to make this NMEA signal more robust?
I could get any signal out of MM when changing GPS_TYPE = 2 (ublox) and changing to ublox in MM, respectively. When contacting the support, they immediately respond that the are only testing PX4 and not AP, and not much more. Has anyone here achieved a ublox signal with MM?
Finally the Marvelmind protocol which is also in the wiki Marvelmind for Non-GPS navigation — Copter documentation . I followed the instruction but couldn’t get it to work either. I saw some forum posts from 2018 but not a whole lot after that. Is this depricated?
I would appreciate any and all help I can get to have MM running the indoor GPS for AP.
Do you remember on what version of AP it was working back then? I would then try to work with the old firmware to see if it’s just my mistake or if it really is not supported anymore.
Do you know what has changed on the output of the MM system since back then and why it is no longer compatible?
And can you maybe briefly explain why the NMEA protocol is also working so poorly, although the tracking seems to be fine in the MM dashboard.
On our test NMEA never delivered accurate results in any of our multiple tests, so we decided not to use it.
We asked MM to gives us raw distance data so that we could feed that directly into our EKF and get very accurate noise filtering, and improve precision. They refused to do it for a year or so, because they had other priorities.
But they eventually did it. But they did not help us incorporate it in AP. And we gave up on it because It just had too many issues.
If you work on it, make sure to get MM involved. They should help out. After all you will be increasing their sales.
I had a couple of short conversations with MM and as soon as I mentioned AP they almost immediately responded that they are testing PX4 but not AP so they can’t give me information about compatibility with AP.
I have zero experience with PX4, but I always assumed that these systems are quiet similar.
Is this not the case? Do you have any experience with PX4 and do the developers in general have contact to PX4 devs?
If you experience any issues, you can always write to us via info@marvelmind.com. We have so much information that it is nearly impossible not to do basic tracking for drones: