Journal of Astronautics ›› 2021, Vol. 42 ›› Issue (9): 1139-1149.

### Modified Aerodynamic Coefficient Fitting Models of Hypersonic Gliding Vehicle in Reentry Phase

XU Hui, CAI Guang bin, ZHANG Sheng xiu

1. College of Missile Engineering, Rocket Force University of Engineering, Xi ’an 710025, China
• Received:2020-10-12 Revised:2021-01-22 Online:2021-09-15 Published:2021-09-15

Abstract: In order to improve the characterization accuracy of the reentry aerodynamic coefficients of a hypersonic glide vehicle, based on the published CAV H aerodynamic coefficient data, an improved fitting model is proposed for the reentry aerodynamic coefficients of a hypersonic glide vehicle in this paper. Firstly, a fitting model of aerodynamic coefficients combining the quadratic term of the angle of attack and the negative exponential term of the velocity is established. Secondly, the multivariable nonlinear least squares method is used to identify the parameters of the model, and the goodness of fit is used to evaluate the degree of interpretation of the aerodynamic coefficient data. Then, according to the model, the flight characteristics of the aerodynamic model are analyzed from the perspective of lift to drag ratio. Finally, data fitting simulation is performed on the model, the lift to drag ratio characteristics of the model are analyzed, and the reentry trajectory optimization task simulation is performed. The aerodynamic data fitting experiment shows that compared with the existing typical models, the fitting error is greatly reduced, and the goodness of fit is greatly improved. The flight simulation experiments with different constant lift drag ratios fully demonstrate the characteristics of re entry gliding flight using this model. The simulation results of the reentry gliding mission show that the reentry trajectory obtained by the model in this paper is more stable than the comparison model.

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