On Tue, 29 May 2007 21:36:55 -0400
John Denker <sf@...> wrote:
> On 05/29/2007 08:06 PM, syd & sandy wrote:
> >> Well , Ive thought of that too .researching these things leads me to believe that in real life (I
> >> could be wrong),groundspeed is calculated using a nav signal as a reference point
> That's not right.
> Groundspeed is groundspeed. There's only one proper definition of
did you miss the (I could be wrong )?;)
> An _approximation_ to groundspeed in terms of the rate of slant range
> made good to/from a navaid is sometimes encountered, for example in a
> _DME_ unit. This is considered a nonideality of the DME system, not
> a redefinition of groundspeed.
> This nonideality is never AFAIK exhibited by GPS or RADAR units. Every
> GPS and every RADAR I've ever seen or heard of, when asked to report
> groundspeed, reports honest-to-goodness groundspeed, independent of any
> route, independent of the relationship between the ground track and
> this-or-that navaid.
> > > , so it is only
> > > accurate if you are flying directly toward that point... But a /velocities/groundspeed could be
> > > used as a starting point ...
> It takes only a couple of lines of nasal to calculate the groundspeed
> in terms of the already-available properties. Hint:
> Aircraft/A-10/Nasal/aar.nas line 261
> ... so I don't understand what the discussion is about.
Well I wasnt trying to start a war here ,simply trying to get my Primus 1000 system updated, but groundspeed is calculated in the source code , and since its been requested before , I thought it might be a good idea to show it in the property tree...
I just dont see a reason for redoing everything in nasal that's already done in the source code
> The Subject: line refers to groundspeed. If you want to ask about
> something else, perhaps about ETE or ETA at this-or-that station,
> then the answer might become route-dependent. (Different questions
> have different answers!)
> So: If there's a problem here that needs solving, please describe
> the problem more fully.
Like I said , it wasn't really a problem, it was a suggestion....
The only problem I see is the ai radar x-shift and y-shift that should REALLY be normalized to the radar range :)
Have a nice day ...
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syd & sandy <sydadams@...>