电罗经航向的H ∞跟踪估计方法研究

为提高在风、流、摇摆等众多外界干扰下电罗经航向输出的精确度,提出 了基于H∞的航向跟踪估计方法。简要介绍了H∞估计理论,基于H∞估计理论对最速跟踪 微分器进行一步改进设计,构造误差反馈矩阵,实现最速跟踪微分器的在线反馈控制, 获得较为理想的效果,为减小电罗经航向误差及提高航行安全提供一种行之有效的方法。     

基于零点配置的BTT导弹逆控制研究

为实现BTT导弹准确快速跟踪指令的要求,采用能够提供品质良好的微分信号,并具有较强滤波能力的跟踪微分器设计了导弹控制器。该方法将跟踪微分器用于零点配置,构造了BTT导弹的逆系统,并与原系统串联构成伪线性系统,进而采用线性控制方法设计外环控制器,实现三通道的渐进无误差跟踪。仿真结果表明,所设计的控制器能很好地跟踪指令信号,且具有较强的鲁棒性。     

改进跟踪微分器设计

通过非线性和线性连续函数的恰当组合,使构造的奇次指数幂且连续的跟踪微分器函数的系统状态,无论在远离还是接近平衡点位置都能快速收敛。设计的跟踪微分器满足全局渐进稳定,仅收敛于一个平衡点。此外,由于未使用切换函数,也不存在抖振现象。计算机仿真表明,改进跟踪微分器跟踪效果优于经典的非线性跟踪微分器,且跟踪给定系统的状态变量与真实状态变量的响应高度吻合。     

一种基于非线性跟踪-微分器的角加速度估计方法

针对仅能获取角度信息的角加速度估计问题,基于卡尔曼滤波和非线性跟踪-微分器设计了一种角加速度估计算法。该算法利用卡尔曼滤波得到角速度的估计值,并以此为基础采用非线性跟踪-微分器对角加速度进行估计,通过对卡尔曼滤波与跟踪-微分器角加速度估计进行合理融合获得最终的角加速度输出。仿真结果表明,所设计的估计方法能满足视线角加速度的估计精度要求,具有一定的工程应用价值。     

水空跨介质航行器俯冲过程航迹角控制研究

基于神经网络自适应控制方法,研究了变体跨介质航行器俯冲过程航迹角控制问题。针对航迹角动态方程中出现的纯反馈形式,采用微分滤波的方法克服"代数环"问题;采用最小学习参数方法减少神经网络参数在线更新个数,降低计算载荷;采用动态面方法克服反步法虚拟控制的"微分爆炸"问题。仿真结果表明,所设计的控制器能够实现航行器在俯冲过程中对目标航迹角的跟踪,跟踪误差小于2°。     

离散跟踪微分器在着舰导引滤波中的应用

介绍了自动着舰导引系统的工作原理及其滤波问题。为了抑制着舰导引系统跟踪雷达的高频噪声,并且克服常用的滤波器采用有限差分法求微分估计的弊端,采用两个二阶离散跟踪微分器串联起来,对含有噪声的雷达测量值进行滤波,并且提取其一二阶微分信息。结果表明,在仿真中使用白噪声模拟雷达噪声,跟踪微分器的滤波效果令人满意。     

新型跟踪微分器在航空发动机磁悬浮轴承中的应用

为了实现航空发动机磁悬浮轴承的稳定悬浮，在磁悬浮轴承反馈控制器设计中获取光滑、精度高、相位滞后小的跟踪滤 波与微分信号等位移传感器信号，基于离散2阶串联型系统，提出了一种具有边界层函数、基于离散时间最优控制算法的新型跟 踪微分器。为减小算法在滤波与微分信号提取过程中的相位滞后，在所设计的跟踪微分器算法中引入相位调整因子对相位进行 实时有效地补偿。分别从时域与频域的角度进行仿真及试验验证，结果表明：所提出的新型跟踪微分器算法具有全程快速、无超 调、无颤振、相位滞后小、精度高等特点，与原基于离散时间最优控制的跟踪微分器算法相比，其平均相位滞后减小80~100个采样 周期，满足实际工程应用需求。     

数字式跳频GPS/GLONASS接收机

在很多应用场合,对大量扩频导航卫星连续跟踪将获益匪浅。当接收机跟踪多于定位所需最小卫星数目时,通过优选卫星几何可提高卫星导航精度。动态定位可利用冗余卫星来实现更迅速的整周期判决和跳周修正。陆地导航利用额外的卫星可克服建筑物、树林和地形造成的遮挡。比较多个星座的测量值能获得有关导航稳妥性的度量。跟踪大量卫星的好处已引起人们研制能同时处理美国GPS和苏联GLONASS信号的接收机的兴趣。已经推出了几种接收机设计方案,但所有这些接收机中处理GLONASS信号的硬件都是与处理GPS信号硬件分开的。本文介绍一种高度综合的GPS/GLONASS接收机,接收机中的每一卫星跟踪通道都能随意指定它接收任一个GPS或GLONASS卫星。该接收机有一个模拟射频/中频(RP/IF)前端,用一个固定频率的本振(LO)。定制的数字专用集成电路(ASIC)跟踪选定的GPS/GLONASS卫星,并提供相关测量值送软件处理。本文介绍的GPS/GLONASS接收机利用了数字信号处理技术和有限脉冲响应(FIR)滤波器的新成果。该综合接收机的模拟RF/IF前端大大地简化了,然而其性能可与使用相当复杂模拟RF/IF电路的接收机相比拟。GPS和GLONASS之间的跳频完全在数字域中进行,不必象早期设计方案中那样用昂贵的跳频本振。深入利用数字处理技术,GPS/GLONASS接收机可采用大规模集成电路,将多个通道集成在一个芯片上。这样可大大减小体积,节省成本,不久即可推出商用多通道GPS/GLONASS接收机。     

跟踪微分器在某无人机定高控制律设计中的应用

首先论述了某型无人机本体特性和所用传感器精度。基于一个飞行试验平台,重点讨论用PD控制和跟踪微分器进行纵向定高控制律设计,分析比较了用这两种控制律设计的高度保持响应特性。研究表明,应用跟踪微分器设计定高控制律,高度稳态精度好、响应时间快。     

微分法在定位误差分析与计算中的应用

介绍了微分法分析计算定位误差的原理和适用范围,通过生产实例分析,证明了该方法在解决多误差因素定位误差分析与计算中的简便与快捷,从而有效简化了复杂定位方案定位误差的分析与计算,提高了夹具的设计效率。     

A GPS/GLONASS/INS test program

Under contract of different German Ministries a test program investigating the combinations of GPS, GLONASS, and Inertial Navigation has been carried out since 1991. Besides other goals, the aim of the project is to investigate the capabilities of GLONASS in comparison to GPS, to realize a combined GLONASS/INS solution and to perform joint processing of GPS and GLONASS raw data. The paper describes the test procedures and presents some of the results. This includes the comparison of DGPS with stand-alone GLONASS and GLONASS/INS under different dynamic situations, e.g., driving tests, flight tests, and also the presentation of results of combined GPS/GLONASS data processing, which was successfully achieved in March '93 for the first time. The results show the potential of the non-SA-degraded GLONASS and the advantage of using both, GPS and GLONASS for combined solutions     

GNSS receiver for GLONASS signal reception

This paper deals with the latest version of Experimental GNSS receiver built at the Czech Technical University and describes integration of GLONASS signal processing to the receiver. The new FPGA platform Virtex-D Pro by Xilinx is used and enables integration of whole digital signal processing of GNSS receiver into the single chip. The RE unit of the receiver is capable of processing all GLONASS frequency of the Li and L2 bands in two independent RE channels; each channel can process one band. The frequency selection of the appropriate satellite is accomplished in a digital correlator. The development flow of the GLONASS correlator is discussed herein. The complexity of the GLONASS correlator with complexity of GPS correlator is compared. The developed GLONASS correlator was tested in Simuelink tool during development. The next test was carried out using GLONASS simulator and real GLONASS satellite signal.     

组合GPS和GLONASS在民航中应用的研究

研究了ＧＰＳ和ＧＬＯＮＡＳＳ在民用航空中的应用前景。分析了组合ＧＰＳ和ＧＬＯＮＡＳＳ所具备的可用性、精确性和完整性潜力。组合ＧＰＳ／ＧＬＯＮＡＳＳ在我国民航中具有重要的技术与战略意义。提出了一种集成１２通道ＧＰＳ／ＧＬＯＮＡＳＳ接收机的结构与实现。射频前端部分采用３级变频将ＧＰＳ和ＧＬＯＮＡＳＳ信号变至中频并采样为同相与正交样本。数字处理部分对各样本加以积累与处理,解调卫星的导航电文。在导航解算中结合了ＷＧＳ－８４和ＰＺ－９０坐标系之间的转换。     

GPS／GLONASS共用PDOP研究

对全球卫星定位系统的DOP因子进行了分析。对GPS/GLONASS共用系统的可用性和PDOP因子进行了理论分析和软件仿真,对星座的定位特性进行了评估。分析结果表明,GPS/GLONASS共用系统相对于单一的GPS系统在可用性和PDOP因子方面都有很大的改善,从而可以进一步改善定位精度,这就为GPS/GLONASS组合导航的进一步研究和应用奠定了基础。     

The Soviet Union's GLONASS Navigation Satellites

GLONASS (Global Orbiting Navigation Satellite System) is the most recent satellite navigation system developed by the Soviet Union and currently in the pre-operational stage. Obvious parallels exist between GLONASS and the NAVSTAR Global Positioning System (GPS) developed in the United States and also, at present, in a pre-operational phase. In the progress towards operational status, the launch capability for NAVSTAR satellites has been seriously affected by the recent failure of the Space Shuttle Challenger, clearly increasing the prospects of GLONASS reaching operational status first. It is therefore the main purpose of this paper to discuss certain aspects of the GLONASS satellite navigation system, in particular its orbital features and radio-frequency signal characteristics. Comparisons with NAVSTAR are inevitable and for this reason, the paper begins with a brief resume of relevant features of the NAVSTAR GPS system for later reference. The main section of the paper then deals with orbital behaviour, radio frequency signal structure and channelisation using NAVSTAR as a reference point for discussion.     

卫星导航系统发展动态

卫星导航系统是20世纪60年代中期发展起来的一种新型导航系统，90年代，卫星导航时入全运行和盛行时期，除了用于陆上，海上和空中的航行引导外，几乎扩展到军事和经济的各个方面，目前，除了已经运行的美国的GPS（全球定位系统）和俄罗斯的GLONASS（全球导航卫星系统）外，欧盟也正在积极开发伽利略系统。本文分别介绍GPS、GLONASS和伽利略系统的发展状况。     

二阶滑模跟踪微分器与带通滤波器频域分析

简要介绍了二阶滑模跟踪微分器的基本原理,应用描述函数法对其频率特性进行了分析。在此基础上设计了带通滤波器并对其频率特性进行了分析,给出了二阶滑模跟踪微分器及由其所构成带通滤波器的参数选择和调试方法。仿真结果表明,通过适当选取有关设计参数,带通滤波器能够从几种频率合成信号中提取出特定频率的信号。     

Characterization of NAVSTAR GPS and GLONASS on-board clocks

Investigation into navigation satellite on board clock frequency references and performance are reported. The focus is on the stability of the clocks aboard the NAVSTAR GPS (Global Positioning System) and GLONASS satellites as well as those used by their respective maser control stations and associated time scales. Allan-variance techniques have been applied to determine the long-term time-domain behavior of satellite clocks in an attempt to identify different regions of power spectral density. Coupled with analysis of relative-frequency drift over a period of many weeks, this behavior allows the type of satellite onboard standard to be tentatively identified. The known nature of the GPS clocks has shown that the different types of clocks aboard the satellites (crystal, rubidium, and cesium) are distinguishable given a sufficient sample time. The same approach has been applied to the GLONASS satellites, and a comparison of the results obtained from GPS has allowed conjecture on the type of clock used by the GLONASS satellites. It appears that GLONASS has used clocks of the quality of rubidium atomic oscillators since at least 1986, and that the quality and performance of onboard standards have increased steadily with time. Some current satellites perform well enough in terms of frequency drift, flicker FM noise floor, and long-term stability to compare favorably with the cesium beam standards carried on NAVSTAR GPS satellites launched in 1983-84