OK, moving here from the FSX forum.Maybe we should forget what GPS is providing the signal...I've got a "Brand X" GPS that provides vertical glideslope guidance.It shows up in a gauge if I display(A:HSI GSI Needle,number)My question is: Is there a way to change an XML autopilot to use thissignal for an Approach?My autopilot just uses <Click> 0 (>K:AP_APR_HOLD) </Click>which feeds off the NAV signal, as best I can tell and ignores the GSI signalthat is driving the HSI..I've read through all the Key Commands in the SDK, but I do not see where tofeed the signal to the autopilot.Help!

As far as I'm aware there is no GPS for FS that provides any vertical guidance. Period.All HSI's are display devices only. If there is no valid signal to the GS needle, it should either be "parked" or in the case of an EHSI, not displayed at all.

Maybe a naive question but are there actually any differences in your situation between(A:HSI GSI Needle,number)and(A:NAV GSI, number)Both of whose values represent needle deflection and are +119.

As far as I'm aware there is no GPS for FS that provides any vertical guidance. Period.All HSI's are display devices only. If there is no valid signal to the GS needle, it should either be "parked" or in the case of an EHSI, not displayed at all.

Bill, this Brand X GPS provides the signal... I have a simple gauge that displays the HSI GSI needleand it activates nicely when LPV comes on and the HSI does the same.I can fly the approach by hand and the glideslope needle will guide me all the way with the GPS providing the guidance.So, the signal is there... now the question is whether I can use this signal to guide the autopilot!

It shows up in a gauge if I display(A:HSI GSI Needle,number)

HSI GSI Needle is a non-settable value... as in it can not legitimately be changed by another application. Thus that would mean that RXP has hacked FS to be able to change it.I can't really provide details on how I drive the vertical component in FS... sorry, after all I use it in commercial products.I'll simply state that you're thinking "inside the box" and need to get outside... the answer isn't in the direction you're currently thinking. :(

Maybe a naive question but are there actually any differences in your situation between(A:HSI GSI Needle,number)and(A:NAV GSI, number)Both of whose values represent needle deflection and are +119.

Yes, there is a difference, the NAV GSI variable gives me no reading.

Maybe a naive question but are there actually any differences in your situation between(A:HSI GSI Needle,number)and(A:NAV GSI, number)Both of whose values represent needle deflection and are +119.

There is a difference in that the RXP GNS can only override (A:HSI GSI Needle, number) with its LPV glide slope error

So, the signal is there... now the question is whether I can use this signal to guide the autopilot!

If the person who coded this "Brand X" GPS cannot do so, and furthermore can't provide the information you seek, then it seems rather obvious that the answer is no...

I'm getting a lot of: "I know how to do this, but I am not going to tell you"here... this is somewhat of a new experience for me... not quite sure what to think :(

Now, any real life AP simply works with that error alone

Hi Bert, the AP isn

I'll simply state that you're thinking "inside the box" and need to get outside... the answer isn't in the direction you're currently thinking. :(

OK, I'm now outside the box and feeding an error signal to the Elevator trim.This works, but in it's simplest form is unstable, as control theory would predict.Since you guys do not want to reveal proprietary information, which I respect,for an unsophisticated controller, what is the simplest way to add damping to thecontrol loop? I was thinking that simply limiting the trim excursion to a few degreesmight actually do the trick, but that could cause never ending oscillations.

Hi!Controling the arcraft trough the elevator trim is kind of difficult and it can even upset it. May I suggest you a different approach?, excuse the pun. You cannot overwrite the flight director while APP is activated, but you can use another pitch mode and your G/S parameter to fly the approach. You got to translate your L:var into FD like instructions and write to another L:var (that now has a pitch command) and Hold ATT not APP for the FD to follow a custom approach. ;).Just a few ideas, thinking about it, I can use this for my HUD's AIII mode.RegardsJavier

Javier,That

Hi Danny!You got it, I haven't test it yet but the basic idea is the translation of the custom G/S to an angle the FD can understand. I've been using ATT hold whit the CWS P of my 737 and have no problem, the only thing is that there is no Roll angle hold for the FS A/P so I can not use it for my HUD :(, I'm not using FSX so I'm not sure if there could be a problem about the ATT hold, I don't think so. Javier