Abstract: To solve the problem of lack of precision calibration target for survey vessel at sea，a research on the technology of course calibration identificationfor inertial navigation equipment by electro-optical theodolite from three aspects: selecting star，leading to star and calculating record data is conducted ． Combined with existing conditions and technologies，an algorithm for filtering and extrapolating the data of ship shaking with sine wave fitting method was proposed． This algorithm obtains the sine curve fitting parameters by the least square method after the parabolic difference subdivision of the ship shaking data． During the sea with “Yuan Wang”survey vessel，the method described was verified． The results show that the method can improve the isolation of ship shaking，the ability of tracking space targets and the accuracy and consistency while calculating the course error．

Key words: star calibration, survey vessel, system monitoring application, electro-optical theodolite, sine wave fitting