精确星光大气折射导航观测模型的研究

高精度星光折射间接敏感地平的自主导航方法,目前被国内外广泛关注,由于大气参数变化的不确定性,国内外现用星光折射模型有一定局限性,使得利用星光折射导航定位精度大打折扣.根据大气密度随高度、纬度、季节等变化规律,有效改进现有固定高度(25km)的观测模型,可从整体上提高自主导航精度及可靠性.并通过对大气折射原理、平流层大气数据、大气模型以及影响星光折射观测模型的诸多因素的深入研究,建立了自适应连续高度(20~50km)的星光折射观测模型,同时建立带摄动的系统方程,利用Unscented卡尔曼滤波算法进行了计算机仿真研究,并对仿真结果进行了误差分析.

Precise research on stellar horizon atmospheric refraction model

The concept of stellar horizon atmospheric refraction is considered to be one of the most promising concepts for satellite autonomous navigation. However, the precision of the method is limited due to the uncertainty of the stellar horizon atmospheric refraction model. According to the rule that atmospheric density would vary with altitude, latitude, season and so on, the fixed altitude measurement model (25km) can be availably modified. Consequently, the navigation precision and dependability can be effectively improved. By thoroughly studying on the principle of the atmospheric refraction, the stratospheric atmosphere data, the atmospheric model and other factors related to the precision of the measurement model, a self-adapted continuous altitude (20~50km) measurement model was established, and then the system model with the orbit perturbation was established as well. Finally, a simulation experiment was performed by using the Unscented Kalman Filter programme, and an error analysis was achieved.