The most accurate instrument for satellite attitude determination is star tracker now

in which the key problem is the identification of star map. In this paper

cluster match is performed only with the observed star position information and using the star angular distance between observed star map and guide star catalog

then match identification is made with respect to the connection of the observed star map

at last

utilizing the computer(main frequency 120M)simulation the effects of threshold and position noise on identification and identification time are analyzed. When the threshold is 0.05°

position noise δ is less than 0.02°

in any areas

the identification efficiency is 100%

and the average identification time is less than 0.2s.