Abstract: The present thesis centers on the signal processing methods of quadrant photodetector. Analyzing the current methods of obtaining facula parameters in quadrant photodetectors and the sources of their indices and errors

the author of the thesis proposes a method of calculation on obtaining the facula parameters of quadrant photodetector by means of fretting. In comparison to the traditional or current methods

the method of fretting can obtain not only the light spot centroid

but also the spot radius

which is beyond the means of any traditional method

and more relevant information. In addition

this method has the advantage over the traditional method in that the errors are unrelated to the light spot centroid and the spot radius. Theoretical analysis and simulation experiments have proved that obtaining the facula parameters of quadrant photodetector by means of fretting has considerable advantages. Field tests in the atmospheric laser photoelectric precision positioning system of inter-vehicle communications

show that this method is advantageous in speed

accuracy and convergence. Using this method Parameters obtained from 2 to 3

the use of 30mm of GaAs-PIN four-quadrant detector

the maximum error decreases from 18% to 1.2% .