I have a pose transformation code which is working but still I am unable to plan a reachable pose. I am following this moveit python tutorial. Here some default values have been given for x,y,z coordinates, my question is they are in which frame of PR2, is it base_link or is it world?

print "============ Generating plan 1"
pose_target = geometry_msgs.msg.Pose()
pose_target.orientation.w = 1.0
pose_target.position.x = 0.7
pose_target.position.y = -0.05
pose_target.position.z = 1.1
group.set_pose_target(pose_target)

I am asking this because when I will receive an object's pose from a sensor such as camera, I need to know the pose in camera sensor frame will be transformed to which frame for the arm to grip the object? I tried changing posetarget.position.x=0.75 instead of 0.7 and moveit could not make a motion plan but it was working till 0.74, so that slight change should not make the position unreachable, so I want to be sure about what is the target pose. Is it the arm of baselink?