Changed default settings for fixed wing throttle smoothing in navigation modes

[Airwide]

This pull request contains a proposal of changed default settings for the new throttle smoothing feature introduced in pull request #6104. The change is a result of the testing performed by me and @avsaase, and will let all fixed wing pilots take advantage of this feature by default in the next release.

The proposed defaults:
nav_fw_pitch2thr_smoothing = 6 which equals a low pass filter cutoff frequency of 0.14 Hz.
nav_fw_pitch2thr_threshold = 50 which equals +/- 5 degrees deadband around the filtered pitch angle.

[avsaase]

I have not tested this yet with nav_fw_pitch2thr_smoothing = 6 so maybe it works well, but intuitively a cutoff frequency of 0.14Hz seems very low to me. I don't have much experience with low-pass filters so I could be wrong. Maybe this is asking too much, but could you maybe apply this filter to a simulated time series so it becomes clear how this filter behaves in this application?

[Airwide]

I have not tested this yet with nav_fw_pitch2thr_smoothing = 6 so maybe it works well, but intuitively a cutoff frequency of 0.14Hz seems very low to me. I don't have much experience with low-pass filters so I could be wrong. Maybe this is asking too much, but could you maybe apply this filter to a simulated time series so it becomes clear how this filter behaves in this application?

@avsaase I tested it with a cutoff frequency of 0.1 Hz in this post. As you can see in the first screenshot, the 10 degree pitch change was outside of the 5 degree deadband for only 1 second before the filtered average caught up the 5 degree difference.

The cutoff frequency for a low pass filter is defined as the frequency where changes of the input signal is transfered to the output signal by 50% (-3 dB).

I figured 0.14 Hz is a bit more conservative than the tested 0.1 Hz which didn't feel slow at all.

WDYT?

[avsaase]

I could be wrong, but shouldn't the defaults be changed here as well?

inav/src/main/navigation/navigation.c

Lines 160 to 161 in b5c332d

	.pitch_to_throttle_smooth = 0,
	.pitch_to_throttle_thresh = 0,

[Airwide]

I could be wrong, but shouldn't the defaults be changed here as well?

inav/src/main/navigation/navigation.c

Lines 160 to 161 in b5c332d

	.pitch_to_throttle_smooth = 0,
	.pitch_to_throttle_thresh = 0,

Good catch! I’ll fix it when I get home tonight. Thanks!