gillesbdx

LPV on V2.4.4

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Hello everyone
I just installed the 2.440 update.
it was hopeless to have LPV management in Europe and this because  the garmin 530 trainer application that was at fault (too old and abandoned by Garmin).
also it's magic and it works now, thanks to RXP developper.
now we have a precise glide in LPV for RNAV Gnss procedure in EUROPE.
My question is: is it possible to couple the autopilot in GPS mode on this glide and if so how? (APR does not work nor NAV, only LOC is followed)

Thanks and best regard

Gilles from LFBD

 

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Bonjour Gilles,

Thank you for your kind words!

I'd suggest you search this forum, or the RXP GNS X-Plane one, there has been a long discussion about how this works with LPV approaches a few weeks around the time we've released the v2.4.4 update.

update: here is one of these a few discussions below this one:

 

Edited by RXP
link to LPV discussion

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Hi Jean-Luc,

Thank's for this repply. i had allready read this topic .

but 

concretely, under p3d v4, how to take the glide by the AP while it is already active on the NAV mode.
before no glide in LPV ok the question did not arise but now ...?
I tested the APPR mode is no effect and the plane does not go down.
unless I am mistaken, I have not seen any information that deals with that.
good Sunday

gilles

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Bonjour Gilles,

Maybe it is just related to the autopilot the aircraft you are flying with.

This has been documented in the forum as well maybe a year ago (roughly), but to sum up:

Most aircraft vendors assume there is no vertical guidance from the GPS because the default doesn't have vertical guidance. Therefore, they code their A/P with the following logic:

  1. Is the NAV source a LOC/VOR? Don't use vertical deviation as a signal to the A/P.
  2. Is the NAV source a GPS? Idem as 1)
  3. Is the NAV source an ILS? Do use the vertical deviation as a signal to the A/P.

Whereas it should be:

  1. Is the lateral deviation flagged? Don't drive lateral A/P, otherwise, use LCDI as A/P input, use NAV source as sensitivity factor.
  2. Is the vertical deviation flagged? Don't drive vertical A/P, otherwise use VCDI as A/P input.

As a matter of fact, any custom made autopilot in third party aircraft vendors are capable of both lateral and vertical coupling when used with an ILS nav source. It is just a matter they review their code to use the very same coupling regardless it is a GPS or not, i.e., like in the real world, the GPS 'bakes' ILS-like signals to feed the A/P, and the A/P doesn't bother whether it is a real ILS or a faked one.

Having said this, can you try out with a default aircraft like the Baron 58?

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9 minutes ago, gillesbdx said:

i use classic  fsuipc offset to activat AP in GPS mode.

Maybe this is the reason. Can you try out with just the default A/P controls to see if this makes a difference?

Edited by RXP

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hi Jean-Luc

i 've tested and it's ok when i used the mouse clic on AP button of kingair 350 panel and APPR .

i use this fsuipc offset witch are ok for an ILS approch:

Var 2544, name AP_APPR_fs, Link FSUIPC_INOUT, Offset $0800, Length 4 // Commande PA mode APPR
Var 2545, name AP_GS_CAPT, Link FSUIPC_INOUT, Offset $07FC, Length 4, Value 0 // Commande capture du Glide  

i 'm going to look for 0ther  offset, i hope find it.

if you know a good one ... thank's in advance..

best regard

 

gilles

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Why not just ditching 'custom' FSUIPC commands, and use FltSim stock commands instead?

Otherwise, we interface the A/P only when these conditions are met:

  • GTN in GPS mode with active leg.
  • NAV/GPS switch in GPS mode.
  • Either or both "AUTOPILOT NAV1 LOCK" and "AUTOPILOT APPROACH HOLD" are set (these are default FltSim simvars).

Whenever the above is met, the GTN uses both lateral and vertical coupling.

I'd suggest you review the commands you are sending, and whether the APPROACH HOLD is armed so that the FltSim autopilot guides the aircraft vertically too.

[update] quick google search first link:

https://forum.simflight.com/topic/68915-capturing-glideslope-via-0x0800/

Edited by RXP

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Hi JL,

it's royal why make it simple when you can make it complicated!
so I used for those who are interested:
in my Sioc code:

Var 2546, name AP_APPR_sw, Link IOCARD_SW, Input 63, Type P // Poussoir PA mode APPR
{
    If &AP_APPR_sw = 1
    {
         &joy64 = SETBIT 3
    }
     ELSE
    {
        &joy64 = CLEARBIT 3
    }
}

var 2631 , name joy64, link FSUIPC_INOUT, Offset $3340, Length 4

this triggers a button via virtual joystick fonction of fsuipc.

then in FS/P3D addon menu fsuipc, button+switch, I press the APPR button of my AP and I assign the command fs AP APPR HOLD on when pressed and ....off when released.

thanks again for the suggestion Jean-Luc, the fact is that my AP works very well in ILS has blocked me to imagine that the problem comes from my code.

 

kind regards

 

gilles

  • Upvote 1

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