The error registration problem is the key problem to be solved in radar networking to accurately estimate and eliminate system errors.Dimensional expansion filtering can estimate the system error in real time, but the calculation amount increases with the increase of the dimension.The two-stage Kalman filter can greatly reduce the calculation amount, but it is prone to calculation error divergence.Based on the research of ASEKF and TSEKF algorithm, this paper combines the square root filtering with high numerical stability with the TSEKF algorithm, introduces the sequential idea, and proposes an error registration method based on SSR-TSEKF.The simulation shows that the new algorithm effectively improves the filtering stability on the basis of reducing the amount of calculation.