I believe the problem is that the VRPN server is sending the InterSense data in a different coordinate frame than Vizard's coordinate frame. You can use the
swapQuat command on the VRPN tracker object to modify its coordinate system. I'm not sure what exact values you will need to correct the VRPN data, but here is how Vizard's built-in InterSense plugin swaps the quaternion data:
Code:
tracker.swapQuat([-3,4,-2,1])
Add this code after you create the VRPN tracker object and see if it helps. If it doesn't then you might need to modify the swap values.