Hi,
I am using ROS Kinetic on a Linux 16.04 machine, Gazebo 7.0 and the simulated Kinect camera with the openni_kinect plugin on [Husky robot](https://github.com/husky/husky_simulator/tree/kinetic-devel). When starting the [ar_track_alvar pkg](http://wiki.ros.org/ar_track_alvar) to detect two markers in the environment (the precise position is known from my Gazebo world). I got the correct position of them,but detecting them from another position while driving gave other pose estimate value. The error is considerably high, around 30 cm, and gets worse the more I drive around.
I have two questions:
1. Am I seeing the correct behaviour from the ar_alvar package? I was especting to have much less error estimate from the actual marker's position. If yes how to reduce this error?
2. Is the simulated Kinect camera already calibrated to work with ar_track_alvar? I see (see file below) that distorsions parameter are all 0. I assume that being this a simulation, so "ideal" conditions, the Kinect does not have lens distorsion. Am I right? Should I do some calibration here?
Below on the left the correct detection, and on the right the faulty one.
Here the launch file for the ar_track package, the URDF Kinect code and the outputs of the markers' distance in both scenarios.
**Alvar launch file**
true 20.0 ${90.0*M_PI/180.0} R8G8B8 640 480 0.05 4.0 ${prefix} true 10 rgb/image_raw depth/image_raw depth/points rgb/camera_info depth/camera_info ${prefix}_frame_optical 0.1 0.0 0.0 0.0 0.0 0.0 0.4 ${robot_namespace}
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