Abstract: n this paper,the author presents a nonlinear estimation method of theconstant systematic errors and orbit parameters of continuous wave radar systems.This method processes data in a long time interval altogether,using splines to describeorbit parameters,thus establishing a high precision nonlinear model with fewerparameters.The systematic errors and orbit parameters are thus estimated byapplying this model.Compared with the traditional EMBET method,this method hasthe advantages of much fewer parameters,small model errors, and high accuracy.