Convert tracking system position to unity world position/"Calibrate" tracking system

hi guys,

We have a tracking system set up here which gives you the position and orientation in their system. I want to move and rotate the camera based on the users movement, which is being tracked through a sensor. So the sensor gives out some data, say (1 5 3) for (x,y,z) position and (30,90,20) for rotation in euler angles. what I've to do is to place the user at a desired unity world location, and when the user moves the camera moves accordingly. Usually in other languages/SDKs we do it this way, find four corresponding points from both the tracking system and the unity world system (these are known points). With these four points, find the transformation matrix. Then use the transformation matrix to do any future transformation from one system to other. But in Unity, the transformation matrix is not exposed, so there is no apparent "direct" way to calculate it. Can anyone guide me how I should approach this problem in Unity?