For bigger drones this is quite common with the FFT because the first harmonic is often more energetic. The algorithm makes some attempt to figure out whether the highest peak is actually a harmonic, but it’s not perfect. You can play with FFT_HMNC_FIT to try and improve this. You can also set FFT_HMNC_PEAK to 2 to try and pick up the first harmonic - but you should check that it is being detected first.
so in this case I should try FFT_HMNC_FIT close to 50% to see if FFT realizes the central frequency is actually 60 Hz instead of the first harmonic?Sorry I am getting a little confused with this parameter
No, I think you should leave it as it is. The default is 10%, basically it says if there is a peak that is within 10% of being a multiple of the main peak then consider it a harmonic. If the lower peak is being tracked in FTN2[1] (say) then you can play with the other parameter. If its not being tracked then it won’t help.
why does the first harmonic is more energetic ?
No idea, physics innit
Hahaha
Ok, thank you for the Help
Is there no HITL simulator available? I would like to feed my px4 with log data from hovers. Then I could run multiple param sets for FFT to evaluate what works best on my platform. To get the best performance, while not encumbering my controller, I currently have to do multiple flights, vary one var at a time. Is there a way to simulate this that I am unaware of?
yes, you can do that. HITL is called replay in ArduPilot’s lingo.
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Forgot to add this earlier. I was having trouble changing any params other than EK3-related ones with replay. Replay worked well for some tests that I needed to run on EK3. Also, afaik, it is SITL; not HITL. If there is a guide on HITL I’ll read up on it.
We now have SITL running on the FC hardware, so it is much better than an HITL.
But you do need to use master to get that.