Abstract: A federated version of spherical simplex unscented Kalman filter(SSUKF) waspresented for space-borne orbit debris surveillance mission.The nonlinear transformation filtering method brought the algorithm a high precision,while the reduced sigma point filtering technique endowed the algorithm with a high computing speed,and the decentralized structure ensured the algorithm a good capability of reconstruction in case of sensor fault or vision limit.A filtering system composed of gyroscopes,magnetometer,sun sensor and star tracker was designed using this algorithm,and was validated with numerical simulation.