I also am trying to use the hydra for spatial location and am having similar issues. The attachment below is a test I did to see how much spatial distortion there is as you move away from the hydra. The hydra was located just below this grid and in the middle. The black triangles are the real points and the green circles are the hydra readings. Each point is 10 cm away from each other making the grid 120 cm wide and 110 cm tall. I tried to hold the controller in the same orientation to negate the location of the sensor in the controller.