推力矢量和二元喷管

推力矢量是第四代战斗机获得过失速机动性的必要条件,而二元喷管又是推力矢量控制中性能较为优越的一类喷管。本文较全面地阐述了目前世界上推力矢量和二元喷管的发展和现况、二元喷管的构造和性能、二元喷管对改进飞机升阻特性和机动的作用。推力矢量能显著提高飞机在空战中的作战效率以及推力矢量控制所需的效能也在文中作了介绍。     

利用双目标优化寻求颤振抑制控制律

本文对一个三角机翼/外挂系统的颤振主动抑制进行了系统的研究。在理论上,对如何应用现代控制理论设计优化控制律进行了探讨;对非定常气动力拟合的Pade矩阵近似作了改进;提出了用理想极点和二次型性能指标进行双目标优化来确定加权矩阵的思想;在实现上,用状态观测器和单秩法极点配置两种方法设计了输出反馈控制律。风洞实验结果表明:用本文的方法所综合的控制律是合适有效的,成功地使机翼/外挂系统的颤振速度提高了15.7％,与理论计算结果吻合良好。     

Precise line-of-sight modelling for angles-only relative navigation

This work presents a precise analytical model to reconstruct the line-of-sight vector to a target satellite over time, as required by angles-only relative navigation systems for application to rendezvous missions. The model includes the effects of the geopotential, featuring: the analytical propagation in the mean relative orbital elements (up to second-order expansion), the analytical two-way osculating/mean orbital elements’ conversion (second-order in $J_2$ and up to a given degree and order of the geopotential), and a second-order mapping from the perturbed osculating elements’ set to the local orbital frame. Performances are assessed against the line-of-sight reconstructed out of the precise GPS-based positioning products of the PRISMA mission. The line-of-sight modelled over a far-range one day long scenario can be fitted against the true one presenting residuals of the order of ten arc-seconds, which is below the typical sensor noise at far-range.     

Study of GNSS-measured ionospheric total electron content variations generated by powerful HF-heating

The purpose of this work is to report the experimental evidences for the influence of perturbations in the electron density in the dayside mid-latitude ionosphere, that are caused by high-frequency heating of the F2 layer, on the GNSS signals. The experiments were carried out at the Sura heater (Radio Physical Research Institute, N. Novgorod). During the sessions of ionospheric heating with different time modulations of the radiated power the rays linking the navigational satellites with the ground receiver intersected the heated region. Variations in the total electron content (TEC) were studied; these variations are proportional to the reduced phases of navigational signals. It is shown that with the square-wave modulation of the radiated power (with periods of 1, 6, 10 and 15 min), perturbations with periods of the main modulation of heating and its harmonics appear in the spectrum of TEC variations. Examples are presented of identification of the heating-induced variations in TEC, including determination of the amplitudes and time characteristics of these variations.     

The verification of GNSS tropospheric tomography model in a mountainous area

The GNSS (Global Navigation Satellite System) has not been developed as a meteorological data source provider, but with a careful and sophisticated processing strategy it might be used as one. The term GNSS tomography refers to the usage of the ray traced GNSS signal as scanning rays in the tomographic model input. The model is divided into a number of voxels. The system is inverted and value of refractivity is obtained. Typically, as in the most of the inverse processing, there is a problem of the undetermined system and as a consequence the cofactor matrix is close to singular. To avoid singularity additional conditions or constrains should be added to the system. Here, additional parameters are derived with the help of the air flow analysis in the Sudety mountains (south-west region of Poland), and special Slant Wet Delay (SWD) trimming procedure. The flow’s synthetic parameters like the Bruint-Väisälä frequency and the Froude number are determined. This way the type of the flow is recognized and the analysis of the impact of orographic barrier has been quantified. The SWDs from the GNSS observations were tested against, SWD from raytracing through the COAMPS model field. The modified GNSS tomography model was tested for the real GNSS observations delivered from the GNSS network Karkonosze located in the Sudety mountains and compared with the COAMPS model. The solution shows a considerable improvement in comparison with plain tomographic model results.     

支线飞机综合飞行仿真平台设计

针对支线飞机机械操纵系统的特点,设计了由模块化的功能单元组成的综合飞行仿真平台,可以实现机械操纵系统数字仿真,在支线飞机的设计与制造中有着重要的应用价值,此平台通过改进还可用于支线飞机的试飞科目训练,从而降低试飞风险并缩短研制周期。     

基于总线式集成框架的本体构建及映射研究

通过本体的构建及相应的本体映射策略,可以很好地解决信息集成过程中出现的语义异构问题。是实现异构数据源语义解析的基础。在已有研究成果总线式信息集成框架的基础上,针对目前本体构建过程存在的不足,提出了基于共享词汇表的全局本体构建技术和基于UML的局部本体构建技术,使所构建的本体元素间关系更加准确完备,具有良好的一致性。提出了基于综合相似度的本体映射策略,大大提高了本体映射的精度。     

基于网络的GPS时钟信号发布系统

从空管的实际应用出发,本次研究尝试以TCP Server/Client的模式进行GPS时钟信号的网络发布,通过这种方式实现多套系统灵活的时钟信号引接。     

基于B/S的空管自动化综合航迹显示系统的设计与实现

提出一种基于B/S的综合航迹显示系统,该系统通过解析空管自动化系统的综合航迹实现了在IE浏览器上对区域内的航迹的监视。系统实现主要包括三部分:一是综合航迹的接收,主要通过对同步串口卡的数据读取;二是对数据的数据库处理;三是对综合航迹的显示。系统实现了对MH4008003类数据的解析以及对空管自动化系统的地图解析,并且在IE界面上提供了航迹态势显示以及用户交互接口。     

基于T-S模糊模型的模糊大系统的混合滤波

针对非线性大系统内部过程参数的检测估计,采用连续模糊大系统模型,利用lyapunov定理和分布式处理方法,给出了模糊大系统的H2/H∞混合滤波器设计方法。该方法在保证滤波误差系统全局稳定的同时,具备了H2/H∞性能。通过求解线性矩阵不等式,可以得到滤波器参数。最后,用一个数值例子验证了该方法的正确性和有效性。