Fix Static Notches

[andyp1per]

Bug introduced in #25442
I will note in passing that my review indicated this shouldn't be removed.
I have added a test to make sure this can't regress

[IamPete1]

I think we should still remove the check here:

ardupilot/libraries/AP_InertialSensor/AP_InertialSensor.cpp

Line 1871 in 3dd44dd

if (params.tracking_mode() != HarmonicNotchDynamicMode::Fixed) {

It will allow runtime param changes to take affect for static notch as they do for the others.

[andyp1per]

It will allow runtime param changes to take affect for static notch as they do for the others

This was/is covered by the init() above. The reason not to do it here is the cost of updating the static notch all the time when it doesn't need it.

[IamPete1]

This was/is covered by the init() above.

The init allows runtime change in frequency/bandwidth/attenuation but not runtime change in harmonics or double/triple notch.

The reason not to do it here is the cost of updating the static notch all the time when it doesn't need it.

I guess I don't really understand why we carefully check if we should re-init due to param change. It seems to be the update is the costly one we just do that all the time (except static). Why don't we check for a change in options or harmonic too and then call init and update at once?

[andyp1per]

The init allows runtime change in frequency/bandwidth/attenuation but not runtime change in harmonics or double/triple notch.

I mean this is true, but I don't think what you are suggesting fixes this does it? I agree that allowing runtime changes to these properties would be convenient.

I guess I don't really understand why we carefully check if we should re-init due to param change. It seems to be the update is the costly one we just do that all the time (except static). Why don't we check for a change in options or harmonic too and then call init and update at once?

Really just copying the pattern that was there for the LPF. It is true that calculating A&Q is expensive, so avoiding doing that all the time makes sense. However, we have made a lot of effort into making update cheap, so it may be that simply removing the check is not such a big deal anymore.

[tridge]

good find, thanks!

[andyp1per]

Thanks @tridge I've pulled in the change

[IamPete1]

I think this is correct.