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Re: [Orekit Developers] Problem with getPVCoordinates?


If you use the following line instead do you still see the problem?

Frame earthFrame = FramesFactory.getITRF(IERSConventions.IERS_2010, false);

My guess is that the difference has to do with how Orekit caches and interpolates EOP data to speed computation. Using simple EOP is roughly equivalent to cm level accuracy in LEO. Hopefully Luc can chime in with error levels introduced by interpolating and shifting the frame transformations, but in one case I only noticed differences at the mm level.

Best Regards,

On 01/26/2017 07:54 AM, alessandro.vananti@aiub.unibe.ch wrote:
I have a problem with the following code.

Frame inertialFrame = FramesFactory.getEME2000();
GeodeticPoint station = new GeodeticPoint(Math.toRadians(40),
Math.toRadians(0), 0);
Frame earthFrame = FramesFactory.getITRF(IERSConventions.IERS_2010, true);
BodyShape earth = new
Constants.WGS84_EARTH_FLATTENING, earthFrame);
TopocentricFrame staF = new TopocentricFrame(earth, station, "station");

staF.getPVCoordinates(AbsoluteDate.J2000_EPOCH, inertialFrame);   // line to
comment out


When I run it I get as a result: 866163.3982467309
If I comment out the line "staF.getPVCoordinates(AbsoluteDate.J2000_EPOCH,
inertialFrame);" then I get as a result 866163.3982467302.
So the last digit is different. How is it possible?