What is the input data for the los.py program?

[EricDaJiang]

I'm not clear on what the difference is between data rospy.Subscriber("/vectornav/ins_2d/NED_pose", Pose2D, self.gps_callback) and rospy.Subscriber("/vectornav/ins_2d/ins_ref", Pose2D, self.gpsref_callback)?
Do ros::Subscriber ins_pose_sub = n.subscribe("/vectornav/ins_2d/ins_pose", 1000, ins_callback); and ros::Subscriber local_vel_sub = n.subscribe("/vectornav/ins_2d/local_vel", 1000, vel_callback); in asmc.cpp refer to odometry information?