| Popis: |
The novel celestial navigation method based on starlight refraction has attracted widespread attention in the aerospace field due to its strong autonomy and high navigation accuracy. However, aero-optical effect occurs when starlight passes through the complex flow field outside hypersonic aircraft, resulting in deflection of the starlight propagation direction. This deflection causes measurement errors in starlight vectors and subsequently affects the accuracy of celestial navigation. The traditional starlight deviation prediction method based on fitting models uses data to fit the starlight deviation model for prediction. This method ignores the physical process of starlight deviation, and thus requires high accuracy and data volume for fitting, resulting in limited prediction accuracy. Aiming at this problem, a high precision aero-optical starlight deviation prediction method based on analytical computation results is proposed. By analyzing the flow characteristics of gas passing through the conical shock wave, a density proxy model of the flow field is constructed based on the PSO-BP network. By analyzing the mechanism of starlight deflection in the flow field and considering the influences of shock wave and the flow field after shock wave on starlight propagation, an accurate model of starlight deflection angle is established. Furthermore, in order to achieve high precision prediction and compensation of starlight deflection, an aero-optical starlight deflection prediction method based on density proxy model and starlight deflection model is proposed. Simulation results demonstrate that compared to the traditional data fitting model prediction method, the proposed method can achieve higher accuracy of starlight deflection angle at the sub angular second level, compensate for over 80% of starlight deviation caused by aero-optical effects, and significantly simplifies the construction process of the prediction model, thereby exhibiting high applicability and engineering value. |
