On Montag, 5. April 2004 11:05, Erik Hofman wrote:
> Prior to takeoff you have to sync "your" altitude with the ones provided
> by ATC. But in fact you synchronize the altitude of the sensor with the
> one provided by ATC.
>
> So if ATC says you're at 120 foot, you set the altitude of the sensor to
> report 120 foot and you're all set.
Ok, you are talking about a sensor in my way of thinking.
When an aircraft is placed in the world, this is completly sensor independent.
You can even place a peace of wood in the world, a peace of wood without any
sensor.
Also this sensor value is not sufficient to place the aircraft in the world.
You need to know many things from the environment to place something
according to a sensor value.
That's the reason I wanted to distinguish between hard and soft values.
And the problem here is that JSBSim at the moment initializes the position of
the aircraft to match the dynamic center of gravity to be at a given set of
hard values. But we want later to report only the VRP to flightgear.
This is for the first cut just inconsistent. Even if this is fixed, which
needs to be, this reported reference point in the aircraft is not the correct
one for the altitude value you are interrested in. Ok you can match this
reference point to the position of the altimeter. But then your radar sensor
is most propably off. And so on, for every possible reference point you will
find an argument that this one is not useful. I just think of the VRP
discussion ...
So the question is what to do?
My answer to this would be that we do not need to agree which reference point
is best (please do *NOT* restart that VRP discussion). We need a hard
referrence point which is used to exchange the position between a FDM and
Flightgear. This is just the physical location of a given reference point
fixed in the aircraft relative to the globe. The VRP *can* do this job.
And we need a bunch of soft 'sensor values' usually required. But they don't
make any sense to be set by flightgear. They are a result of the hard
position combined with some aircraft internal knowledge.
That's my way of thinking.
Greetings
Mathias
--
Mathias Fr�hlich, email: [EMAIL PROTECTED]
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