sensor accuracy


do anybody knows if their are sensors /mems so i can measure the height of the sensor or displacement with millimeter accuracy or how i can can get 2 UMI 9DOF sensors to tell me how many millimeters they shiftet from each other al though their distance between each other isn't changed only their position on their axis?? so if i can have the height at 1 or 2 mm accurate i can calculate the displacements with their angles yaw pitch roll

kind regards

Can you explain the geometry of your desired measurement better - sketch a diagram and photo it perhaps? Or try explaining in more but shorter sentences?