Abstract: BeiDou Navigation Satellite System is more and more applicated in the navigation and positioning around Asian area.On the basis of BDS tri-frequency carrier and the combination of MW,a carrier-phase combination detection method based on ultra-long wave without ionospheric effect is proposed,combined with the ionospheric segregation equations to detect the various combinations of small cycle slips in the carrier phase observations,which reduce the error and misjudgment of cycle slips detection effectively.In order to repair small cycle slips,on the basis of the spatial domain search method,the double image contrast method and the ionospheric segregation method are added,which improve the accuracy and correctness of the cycle repair effectively.The carrier phase observation data of MEO satellites,GEO satellites and IGSO satellites at sampling intervals 1,5 and 30 s are tested,which show that the cycle slip detection and repair method is feasible and effective,and all cycle slips under larger sampling interval can be detected and repaired accurately.

Key words: BeiDou Navigation Satellite System, cycle slips, detection and repair, space domain search method, double image contrast method, ionospheric segregation method