James Turner wrote: > It adds false LOC and GS signals, a better GS deviation computation, > and LOC sensitivity based on the runway dimensions. The last part I'm > not totally sure about - it makes localizers *very* sensitive - maybe > I've adapted the code incorrectly, but this doc: > > http://www.allstar.fiu.edu/aerojava/ILS.htm > > indicates that at 10nm, the beam should be approx 1m (statue or > nautical, I don't know) wide (with some variation for the runway > aspect formula) - and it feels much, much narrower than that to me, > though I haven't tested this rigourously. > > Comments awaited with interest :) > As a sanity check, I used the rule of thumb of 0.5 deg per dot => CDI pegs at 2.5 deg each side and x/10 = sin(2.5 deg) .
So LOC full width at 10 nm from LOC antenna = 20*sin(2.5 deg) = 0.872 . Since this is approximate (i.e. from the rule of thumb), the statement in the link /"The width of the navigational beam may/ be varied from approximately 3º to 6º, with 5º being normal. It is adjusted to provide a track signal approximately 700 ft wide at the runway threshold. The width of the beam increases so that at 10 NM from the transmitter, the beam is approximately one mile wide." passes this sanity check. I have not flown the patch yet. In this patch, does the region of reliable signal satisfy Figure 1-1-6 on page 503 of the 2008 AIM? That figure shows valid signals for two over lapped archs. Arch 1: +\-35 deg out to 10 nm. Arch 2: +\- 10 deg out to 18 nm. In real IFR flying, you are always looking for two events as you are intercepting the LOC. #1: the needle to "come live" with a valid morris code for the LOC, and #2 the needle to break away from the case (i.e.un-peg). #1 occurs well before #2 and relates to the AIM figure 1-1-6. #2 relates to the beam width. It would be great to have both well modelled. Dave P ------------------------------------------------------------------------------ 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
