Autopilot fine tuning

[ptr.dvorak]

Hello,
I would like to ask whether it is possible to set a "waypoint radius" or a similar variable that would define how strictly should the autopilot overfly a waypoint...i.e. at what distance from the actual waypoint should it consider it "overflown".

I have understood that this should be influenced by the "toggle overfly" option, however I was not able to observe any difference between the overfly and flyby modes.

Similarly, it would be greatly appreciated if an analogical variable could be adjusted for "cross-track error tolerance" - i.e. how far from the actual track should the autopilot stop trying to approach it.

Thank you very much and have a nice day,

Kind Regards,

Petr Dvorak.

 

[Dynon]

There isn't currently a way to adjust these parameters. When you're in overfly mode, the flight plan will simply connect the dots. When the AP flies that path, it will fly exactly to the waypoint, at which moment the flight plan leg will sequence, and then the autopilot will go after the next leg subject to its bank angle and other tuned limits. For bigger than "small" angles between legs, you'll track slightly off-course as the autopilot gets back on track after the leg transition.

When you use flyby, the autopilot connects the two legs with a curved transition that attempts to make a standard rate turn from leg to leg. Depending on the radius of the turn required, you'll the aircraft will turn sometime before the programmed waypoint to make the turn at standard rate without giving up any cross-track error on the next leg. This has its limits, of course: turns that are too tight, or legs that form a very acute angle aren't possible, and very shallow legs with almost no turning end up being about the same whether you choose the flyover or flyby option.

 

[ptr.dvorak]

Thank you. The described behavior is what I would expect based on the manual etc.
However, even when I fly to an "overfly" waypoint, the active leg is switched to the next one prior to actually reaching the waypoint. The difference is hundreds of meters, which I guess is not significant for the standard use of autopilot, however in my application I need to fly over the waypoint with accuracy of tens of meters ... that is why I was asking for an adjustable "waypoint tolerance". This behavior is most articulated when there is a sharp angle between the two consecutive steps.
Do you plan to implement (or "enable" ... while I believe there has to be such a constant in the code) this feature in the future?

Thanks,

Petr.