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71.
非线性相对运动的飞行器碰撞概率研究 总被引:1,自引:0,他引:1
发展了一种非线性相对运动情况下的飞行器碰撞概率描述和计算方法。采用拟最大瞬时碰撞概率和总碰撞概率两个主要指标来定量描述飞行器碰撞的危险性,并针对这两个指标发展了相应的计算方法。对于拟最大瞬时碰撞概率的计算,首先需要在相对轨迹上寻找最小相对距离或最大概率密度的点,然后在这个点上计算拟最大瞬时碰撞概率。对于总碰撞概率的计算,由于总碰撞概率的增量可以表示成一个时间的函数,因此总碰撞概率的计算就是一个在时间域上的积分。所建立的这种描述和计算方法适用于相对速度和误差协方差矩阵随时间任意变化的情况。数值算例表明所提出的指标比单纯采用总碰撞概率能够更好的描述飞行器的碰撞危险性,并且碰撞概率的计算方法和线性相对运动情况下的计算方法是兼容的。 相似文献
72.
对作者此前推导出的一组误指令概率计算公式中的一个近似计算公式进行了反思,对文[1]最近提出的 新的近似计算公式进行了讨论。最后提出一个建立相应软件包的建议。 相似文献
73.
对现有的遥控指令错误概率的计算公式作进一步的分析。分析指出 ,现有的计算公式中的误指令概率计算公式难于成为好的工程近似计算公式 ,同时它还存在一种概念性缺陷。所以应该重新构建指令错误概率的计算方法。最后 ,给出此前推导出的一组能消除上述问题的计算公式 相似文献
74.
75.
A. Belov 《Advances in Space Research (includes Cospar's Information Bulletin, Space Research Today)》2009
X-ray flares and acceleration processes are in one complex of sporadic solar events (together with CMEs, radio bursts, magnetic field dissipation and reconnection). This supposes the connection (if not physical, but at least statistical) between characteristics of the solar energetic proton events and flares. The statistical analysis indicates that probability and magnitude of the near-Earth proton enhancement depends heavily on the flare importance and their heliolongitude. These relations may be used for elaboration of the forecasting models, which allow us to calculate probability of the solar proton events from the X-ray observations. 相似文献
76.
倪培溉 《中国民航学院学报》2009,27(2):57-59
数列xnm^(k)~rnm^(k)+q审敛原理是数列xnm~rnm+p审敛原理更加一般性的推广,进一步扩大了数列xnm~rnm+p审敛原理的适用范围;利用数列xnm~rnm+p印审敛原理还得到了判别数列收敛性的“子列~局部夹”准则。 相似文献
77.
Ankita Jain Dharmendra Singh 《Advances in Space Research (includes Cospar's Information Bulletin, Space Research Today)》2019,63(2):813-825
Different types of classification techniques are available in the literature for the classification of Synthetic Aperture Radar (SAR) data into various land cover classes. Various SAR images are available for land cover classification such as ALOS PALSAR (PALSAR-1, PALSAR-2), RADARSAT and ENVISAT. In this paper, we have attempted to explore probability distribution function (pdf) based land cover classification using PALSAR-2 data. Over 20 different statistical distribution functions are analyzed for different classes based on statistical parameters. Probability distribution functions are selected based on Chi-squared goodness of fit test for each individual class. A decision tree based classifier is developed for classification based on the selected pdf functions and its statistical parameters. The proposed classification approach has an accuracy of 83.93%. 相似文献
78.
79.
《中国航空学报》2016,(1):202-214
For the terminal guidance problem of missiles intercepting maneuvering targets in the three-dimensional space, the design of guidance laws for non-decoupling three-dimensional engage-ment geometry is studied. Firstly, by introducing a finite time integral sliding mode manifold, a novel guidance law based on the integral sliding mode control is presented with the target acceler-ation as a known bounded external disturbance. Then, an improved adaptive guidance law based on the integral sliding mode control without the information of the upper bound on the target accel-eration is developed, where the upper bound of the target acceleration is estimated online by a designed adaptive law. The both presented guidance laws can make sure that the elevation angular rate of the line-of-sight and the azimuth angular rate of the line-of-sight converge to zero in finite time. In the end, the results of the guidance performance for the proposed guidance laws are pre-sented by numerical simulations. Although the designed guidance laws are developed for the con-stant speed missiles, the simulation results for the time-varying speed missiles are also shown to further confirm the designed guidance laws. 相似文献
80.
The high level of safety demand of civil aviation requests local area augmentation system (LAAS) extremely high navigation integrity performance. A new LAAS pseudo-range error overbound method is proposed in this paper to improve the integrity of LAAS. Firstly, a more practical pseudo-range error distribution model is established. Then, by calculating the relationship between the statistical uncertainty of the model parameter and the integrity risk, a new method is proposed to calculate the pseudo-range error over-bound model. This method can effectively reduce the inflation factor and the resulting conservativeness of the over-bound model. Comparative experiments show that the method proposed in this paper performs better and satisfies the requirements of real applications. 相似文献