Determination of aerodynamic coefficients for a re-entry body by means of an extended Kalman filter

An extended Kalman filter is used to determine the major aerodynamic coefficients of a reentry body. The emphasis is on estimating the states and parameters only on the basis of the reentry on-board measurement data in the absence of trajectory observation data. The measured data include angular rates and acceleration obtained from the rate gyros and accelerometers installed in the vehicle. A mathematical model presented is based upon the six-degree-of-freedom motion equations. Both ballistic and maneuvering reentries are considered. The numerical simulation and real data extraction show that the method can provide satisfactory results.