Measurement of Drag Coefficient and Estimation of Aerodynamic Coefficients Using Nonlinear Least Square Method on Simulated Aeroballistic Tests Considering Experimental Errors

Accurate aerodynamic coefficients and stability derivatives estimation is one of the feature of aeroballistic tests. This can be done by measuring the linear and angular coordinates, velocities and other relevant parameters from different sensors. The important question is the accuracy of the results, the method correctness and the coefficients estimation algorithm. Therefore, the effect of any measured parameters error on the estimated aerodynamic coefficients should be considered and analyzed.In addition, in order to investigate the effect of errors on the estimation of aerodynamic coefficients, a set of aeroballistic tests for measuring the sphere drag coefficient with error of less than 3% in this study. This shows the capability of high precision coefficient measurements in such tests. The errors involved in aeroballistic tests are mainly due to sensors, model manufacturing, data collection and the estimation algorithm. By modelling the error origins, the final error of the system can be predicted and analyzed. This investigation shows effect of each sensor error on the modelled collected data plus other flight simulation data that would help in designing the actual experiments.