How to pass Authentication from ipvs.informatik.uni-stuttgart.de?

edit

I follow roboearth doc.

I have already created an account sam. I can login on website.

But I failed to login in terminal:

  sam@sam:~/code/ros/cram$ svn info http://ipvs.informatik.uni-stuttgart.de/roboearth/repos/public/tags/latest
  Authentication realm: <http://ipvs.informatik.uni-stuttgart.de:80> RoboEarth Repository (BV)
  Password for 'sam': 
  Authentication realm: <http://ipvs.informatik.uni-stuttgart.de:80> RoboEarth Repository (BV)
  Username: sam
  Password for 'sam': 
  Authentication realm: <http://ipvs.informatik.uni-stuttgart.de:80> RoboEarth Repository (BV)
  Username: sam
  Password for 'sam': 
  svn: OPTIONS of 'http://ipvs.informatik.uni-stuttgart.de/roboearth/repos/public/tags/latest': authorization failed: Could not authenticate to server: rejected Basic challenge (http://ipvs.informatik.uni-stuttgart.de)
  sam@sam:~/code/ros/cram$

How to solve it?

Thank you~