On Mon, 2009-09-14 at 10:38 +0100, James Turner wrote: > Two (unrelated) glideslope things: > > 1) I tested making the has-gs property be based upon the GS range > check (leaving aside any discussion of how GS reception range should > be calculated). This is good, because existing panels generally use > has-gs as a 'valid GS signal being received', to un-park / show the > needle/pointer. > > The catch is, most of the flightdirector / autopilot scripts have been > written assuming that when approach mode is *armed*, has-gs is already > true. I.e they don't arm GS holding, if no valid GS is being received > at that point. It feels like this is a genuine problem - depending on > how far out the localiser is captured, and given that you could be > intercepting the localiser from an angle, I *guess* the real-life > equipment wouldn't assume a valid GS signal was being received at that > time. > > What do the real world pilots say? The 'fix' would be to remove the > 'has-gs' flag checks from the various autopilot/flight-director Nasal > scripts, which I'm not exactly thrilled at the prospect of - but it > would make the GS needle/pointer behaviour more correct 'for free'.
I have always assumed and used the "has-gs" to identify a valid ILS frequency instead of a VOR frequency. This flag is needed so every instrument doesn't have to implement the rather arcane rules for determining whether or not a tuned frequency is ILS or VOR. "The localizer is a VHF radio transmitter and antenna system using the same general range as VOR transmitters (between 108.10 MHz and 111.95 MHz). Localizer frequencies, however, are only on odd-tenths, with 50 kHz spacing between each frequency." http://www.allstar.fiu.edu/aero/ILS.htm Or the chart here: http://en.wikipedia.org/wiki/Instrument_landing_system#Frequency_list Thanks, Ron ------------------------------------------------------------------------------ Let Crystal Reports handle the reporting - Free Crystal Reports 2008 30-Day trial. Simplify your report design, integration and deployment - and focus on what you do best, core application coding. Discover what's new with Crystal Reports now. http://p.sf.net/sfu/bobj-july _______________________________________________ Flightgear-devel mailing list Flightgear-devel@lists.sourceforge.net https://lists.sourceforge.net/lists/listinfo/flightgear-devel
