Simplertk2b heading shown but not used

Good afternoon,

I’m using an old pixhawk 2.4.8 to test an ardusimple simplertk2b heading kit and I’ve been having problem that I’ve had no success trying to work out, and i was hoping someone could offer some advice?

I’m following this guide: https://www.ardusimple.com/ardupilot-simplertk2bheading-configuration/
everything appears to have worked up until the check in step 18, however the check in step 19 works.

I have the yaw data present in GPS_RAW_2 however the pixhawk is making no use of it, just the position data.
Presumably I have a setting wrong somewhere, but I’ve had no success trying to work out what or where I’ve gone wrong.

I’ve attached some images and the param file, hopefully it helps illustrate whats wrong.

I’m reasonably confident I’ve ruled out the basics (not that that’s a guarantee of anything):

• the pixhawk was updated and had all its parameters reset prior to starting
• both GPS modules spit back their respective config file after a power cycle (perfect match to that uploaded), so I’m reasonably confident they’re configured correctly.
• The GPS is the only peripheral connected, The wiring is very basic, and I’m getting data so I’d assuming its not an electrical issue.
• Mission planner and u-center both report ‘RTK fixed’ and the position is stable so I should have good signal.
• The antenna spacing is 848mm which u-center is reporting accurately, well with the 20% tolerance of that set in ardupilot.
• the gps and ardupilot are on a flat level surface (no specified tolerance for that but within a few degrees)

thanks for taking the time to read this. hopefully its a quick fix.



pixhawkParam24_10_27.param (14.5 KB)

I’ve encountered this issue on firmware after 4.3. After 4.3, the ublox driver added checks to assume that you are connecting one ardusimple to each of the gps inputs and passing data between them, and throws away data if it is not configured correctly. They’ve matured the gps “auto config” code to assume that this is the physical configuration.

In my case, I am using a stacked set of ardusimples and don’t need any of the driver’s config smarts, but I was not able to work around the checks and couldn’t get the driver to accept the gps heading message even though I know it was being sent. For fun, try making sure that gps autoconfig is off, and flashing 4.3 for your system and see if it “just works”

It’s on my list to circle back to fix this issue, but for now I’m running 4.3

Thanks for the reply, I gave it a try on 4.3.0 but I unfortunately get the same results. (I also gave it a try with 4.3.8 just in case it was a bug that was fixed)

but it was certainly worth a go.

Do you know if there’s any advantage to having them stacked vs routing via the ardupilot? I only went for the stacked option to simply wiring and to keep the footprint smaller.

So far I think you just save a telem port, which is why we do it, but I know others on this forum swear by the autoconfig code of later firmware versions. I haven’t had a chance to try it and on our systems that extra telem port is spoken for. I will report back someday if I find something definitive