On 14 Sep 2009, at 23:31, James Turner wrote: > At EGPH, at about 200ft above the > runway, the navradio suddenly picks the 'other' end, with, as they > say, hilarious consequences. Actually the GS angle jumps from 3.0 > degrees to 177 degrees, instantaneously. > > I suspect penaltyForNav is broken, probably by me - so that's where I > shall look next. > > Torsten, it would be good if you could confirm my analysis, by trying > some approaches in runways where the ends do not share an ILS > frequency, and report on what you see.
This is 'fixed' now - except it's not. penaltyForNav is basically broken - we all know it's broken conceptually, but it's also broken in practice, because it doesn't even do what it claims (and never has, that I can see) - bias to directional transmitters based on aircraft *heading*. The problem is it's biasing based on *bearing* from the aircraft to the transmitter. The fix is sort of a work-around (but also a correctness improvement); in the problem cases, we're picking the 'opposite' end LOC, but still getting the correct GS. Eg at EGPH, as you pass over the Rwy 06 LOC (ident=IVG), while flying the rwy 24 (ident ITH) ILS, the navradio switches to the 06/IVG LOC - but we're still using the ITH GS. What I've done is adjust the navradio to handle this case (mismatched LOC and GS) sanely, and hence avoid the bizarre angles being generated. The CDI needle still jumps when the LOC switches, but since it jumps onto the back course lobe, that's much more tolerable. As ever, please test and let me know what you think. All of this is short-term fixes until we properly model active/inactive ILS installations; which I'm going to be working on 'soon'. Regards, James ------------------------------------------------------------------------------ Come build with us! The BlackBerry® Developer Conference in SF, CA is the only developer event you need to attend this year. Jumpstart your developing skills, take BlackBerry mobile applications to market and stay ahead of the curve. Join us from November 9-12, 2009. Register now! http://p.sf.net/sfu/devconf _______________________________________________ Flightgear-devel mailing list Flightgear-devel@lists.sourceforge.net https://lists.sourceforge.net/lists/listinfo/flightgear-devel
