Patent ID: 7933181

Claim:
A method of adjusting a tilt of an optical detection unit (ODU) with multiple detection areas on opposite sides of an axis, the method comprising: receiving a first set of signal components (A 1 , B 1 , C 1 , and D 1 ) at respective detection areas of the ODU; generating a first signal (RF 1 ) equal to x 1 *A 1 +x 2 *B 1 +x 3 *C 1 +x 4 *D 1 , wherein x 1 , x 2 , x 3 , and x 4 are weighting factors greater than zero; measuring a first value for a signal characteristic of RF 1 ; receiving a second set of signal components (A 2 , B 2 , C 2 , D 2 ) at respective detection areas of the ODU; generating a second signal (RF 2 ) equal to y 1 *A 2 +y 2 *B 2 +y 3 *C 2 y 4 *D 2 , wherein y 1 , y 2 , y 3 , and y 4 are weighting factors greater than zero; measuring a second value for the signal characteristic of RF 2 ; calculating an amount of tilt adjustment as a function of the first value and the second value; and, adjusting the tilt of the ODU based on the amount of tilt adjustment.