If it helps, when building Flightgear, I get compile warnings saying
that there's a narrowing conversion from double to float in some YASim
methods:
|flightgear/src/FDM/YASim/YASim.cxx:261:30: warning: narrowing
conversion of
‘((YASim*)this)-YASim::anonymous.FGInterface::get_uBody()’ from
‘double’
How far off is the aircraft placement - how much is the jump? Is it
many hundreds of meters, or on the order a meter or two, or just
centimeters?
Jon
Several meters!
Or more precise:
first: lat= 47.306263 lon= 11.379070
jump to: lat= 47.3062060567 lon= 11.3790703145
It really smells like a double - float conversion somewhere in the
pipeline (more than a geocentric / geodetic conversion or something like
that).
Curt.
On Tue, Jun 25, 2013 at 2:01 PM, D-NXKT d_n...@yahoo.de wrote:
How far off is the aircraft placement - how much is the jump? Is it
many
Date: Tuesday, June 25, 2013 12:05 PM
To: FlightGear developers discussions
flightgear-devel@lists.sourceforge.netmailto:flightgear-devel@lists.sourceforge.net
Subject: Re: [Flightgear-devel] Positioning Aircraft: accuracy
It really smells like a double - float conversion somewhere
The hang glider is using the UIUC fdm, right? Perhaps that is using a
float (6-7 digits of precision) to represent it's initial
conditions ... or somewhere in the startup pipeline or the flightgear
interface to the uiuc
model, the initial lon/lat is stored as a float?
Curt, you pointed
It seems that we have a problem with the FG/JSBSim-interface or it's a
rounding error during JSBSim-initialisation?!
Summarizing my observations:
- immediately after FG is started the property browser shows the
correct values
- this values hold true as long as the splash-screen appears
-
Hello,
I noticed that positioning an aircraft at FG startup with --lon= and
lat= has only a limited accuracy. It seems that only the first 7 digits
are read. This leads to an uncertainty of several meters/feet!
For example lon=11.379070 --lat=47.306263 is needed to place our hang
glider directly
Hi,
Am 2013-06-23 22:27, schrieb D-NXKT:
I noticed that positioning an aircraft at FG startup with --lon= and
lat= has only a limited accuracy. It seems that only the first 7
digits are read. This leads to an uncertainty of several
meters/feet! For example lon=11.379070 --lat=47.306263 is
Hi Tom,
How have you checked these values? I've just tried it myself and in
the property browser exactly the same values appear.
I started FG with
--lon=11.379070
--lat=47.306263
--heading=155
--units-meters
--on-ground
and found me at --lon=11.3791
Hmm, everything is fine if I use a different plane. Seems to be a hang
glider specific problem.
Monitoring the latitude and longitude variabel from the very beginning
shows, that both variables have at first indeed the correct values. Then
the latitude value suddenly jumps from 47.306263 to
The hang glider is using the UIUC fdm, right? Perhaps that is using a
float (6-7 digits of precision) to represent it's initial conditions ... or
somewhere in the startup pipeline or the flightgear interface to the uiuc
model, the initial lon/lat is stored as a float?
On Sun, Jun 23, 2013 at
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