Rapid identification of time-varying aerodynamic parameters for aeroassisted vehicle via asynchronous iterative filtering

Aeroassisted maneuver represents a promising low-energy and high-efficiency maneuvering mode for orbital operations. Nonetheless, this maneuver necessitates that the vehicle traverse through unstable atmospheric conditions within a short timeframe to achieve orbital energy modulation. Such conditions imply that precise and time-varying aerodynamic parameters are critical to the accuracy of the dynamic model, and consequently, the safety of the flight. This paper proposes a methodology for identifying time-varying aerodynamic parameters through asynchronous iterative filtering. The effectiveness of this approach is demonstrated under various initial states and aerodynamic parameters, validating both its speed and robustness. Initially, to swiftly and accurately ascertain the initial values of aerodynamic parameters and state quantities in situations where these parameters are unknown and the vehicle state has an initial error, a time-synchronized initial value determination strategy is designed for the flight's beginning phase. Following this, an asynchronous iterative filter is developed by incorporating time delay characteristics from dynamic system theory, enabling rapid and accurate tracking of the time-varying aerodynamic parameters throughout the subsequent flight process. Finally, Monte Carlo simulation analyses are conducted across multiple typical aeroassisted maneuver scenarios. These simulations illustrate the identification effectiveness of the proposed method under various initial states and aerodynamic parameters, thereby confirming its speed and robustness.