用MLS引导飞机实现折线／曲线进场的研究

阐明了用ＭＬＳ（微波着陆系统）引导飞机实现折线／曲线进场着陆的基本思想，对折线／曲线进场所要解决的坐标变换，航线过渡方式和进场飞行评价三个问题作了论述，并剖析了一例飞机相对着陆点位置坐标的编程计算结果。     

联合战术微波着陆系统机载信号处理

本文描述了联合战术微波着陆系统(TTMLS)机载角度接收机中的信号处理技术,即如何利用综合化数字电子设备设计技术和与飞机结构有关的天线,实现全天候进场和着陆引导.综合化电子设备能在飞机所处的一个极宽范围内检测MLS信号并进行信号处理,为整个军用飞行控制系统和飞机座舱显示给出水平、垂直和航距引导信息.该系统能保证陆海空三军及民用导航的兼容性.     

基于倒谱的MLS抗多径干扰算法研究

机场周边复杂的电磁反射环境引起的多径效应降低了微波着陆系统的导航精度,严重影响飞机着陆安全。以往的抗多径干扰方法多是基于场地环境的电磁建模实现,存在计算量大、设计复杂等问题。为了有效抑制多径干扰的影响,提出了一种对机载导航设备接收的脉冲信号直接进行数字处理的方法,在倒谱域进行信号分析检测,直接抵消多径干扰的影响,估算出往、返扫描脉冲的时延差,从而实现进近飞机角度位置的精确计算。仿真结果表明,该方法能够有效抑制多径干扰引起的微波着陆系统的测角误差。     

基于DSP的微波着陆信号处理系统设计

由于仪表着陆系统(ILS)在使用中存在的局限性,微波着陆系统(MLS)能为任意起降飞机提供连续、精确的3维坐标信息、不受气候条件的限制,使得它在民航领域中产生了重要的应用价值.文中介绍了微波着陆系统的工作原理及相应信号处理系统的实现方案,并详细论述了基于DSP实现的DPSK自适应解调理论和硬件方案,为微波着陆信号处理提供了新的途径.     

微波着陆系统横向自动进近控制律设计

为更好地发挥微波着陆大范围着陆制导的优势,设计了一种新型的微波着陆横向轨迹自动生成控制律,可根据飞机初始位置和姿态生成一条进近轨迹并控制飞机沿此轨迹对准跑道中心线;提出了单圆、S型和直接指数进近3种进近模态,并分别对3种模态设计了控制律。仿真结果表明,所设计的控制律能够指引飞机在不同初始条件下对准跑道。     

微波着陆系统横向自动进近控制律设计

为更好地发挥微波着陆大范围着陆制导的优势,设计了一种新型的微波着陆横向轨迹自动生成控制律,可根据飞机初始位置和姿态生成一条进近轨迹并控制飞机沿此轨迹对准跑道中心线;提出了单圆、S型和直接指数进近3种进近模态,并分别对3种模态设计了控制律。仿真结果表明,所设计的控制律能够指引飞机在不同初始条件下对准跑道。     

基于光电经纬仪的飞机着陆下滑引导监视系统设计

基于飞机着陆下滑引导监视系统设计需求,针对现有光电经纬仪通信的缺陷,通过分析系统通信物理链路,突破了光电经纬仪之间通信转换协议设计、查表法CRC码校验快速计算、实测数据滤波模型构建等关键技术,以软件技术代替硬件板卡信号处理,实现了稳定可靠且成本低廉的飞机着陆下滑引导监视系统,实验部分验证了该方法的有效性。目前,该系统已成功应用到某型飞机灯光着陆系统试飞中。     

红外与激光技术在飞机着陆系统中的应用

据统计,飞机的大多数重大事故发生在进场阶段。进场和着陆制导系统对保证飞机安全、使其不受恶劣气象条件的影响是很重要的。因此,国内外军事和民用航空部门对研制全天候着陆系统都很重视。目前国际上自动着陆系统发展很快,先进的微波着陆系统逐渐取代仪表着陆系统,这种非自主式的着陆系统,需要地面上安装一套发射装置,机上安装一套接收设备,这就带来了不便。同时,在各种飞行阶段中,进场着陆时,飞机的操纵是困难的,尤其在能见度不良的情况下(阴天、夜间),操纵就更加困难了。为此,     

微波着陆系统中的相位干涉仪综述

<正> 引言四十年前所研制的超短波着陆系统(ILS)现时已经不能满足现代航空日益增长的要求。因此国际民航组织通过决议,决定建造新的微波着陆系统(MLS),并且在1980—1985年起用。在国际民航组织(ICAO)宣布的微波着陆系统设计竞争中有五国参加:美国、英国、法国、西德和澳大利亚。着陆系统的设计依据二个基本原理:     

低空风切变下飞机进场着陆自动改出控制研究

以微下击暴流为典型代表的低空风切变对飞机起飞着陆安全构成严重威胁。文中系统建立了典型商用飞机的动力学模型和微下击暴流风场模型。设计最优二次型调节器实现进场着陆的自动控制,并进行了仿真验证。在此基础上,进行飞机纵向改出风切变的控制策略及安全性研究。通过仿真结果与建模数据的对比表明,建立的动力学模型和控制律正确。通过不同改出控制策略的仿真,给出了飞机穿越风切变进场着陆的建议改出方法。     

Enhanced vision for adverse weather aircraft landing

Landing in poor weather is a crucial problem for the air transportation system of the future. To aid the pilots for these conditions several solutions have been suggested and/or implemented including instrument landing system(ILS) and microwave landing system(MLS) that put the responsibility of the landing to a large extent in the hands of the airport facilities. These systems even though useful are not available due to their high costs except in few major metropolitan airports. This shortcoming has generated interest in providing all weather capabilities not on the landing facility but on the vehicle itself. The Synthetic Vision System Technology Demonstration sponsored by the United States Federal Aviation Administration(FAA) and the US Air Force represents an effort to respond to the above needs[1,2]. In this paper we present a summary of a typical synthetic vision system. This system consists of a scanning 35GHz radar a scanning antenna, a signal/image processor and a head up display(HUD). The pilot is presented a final perspective image of the scene sensed by the radar with associated flight guidance symbology. This systems is implemented in real time hardware and has been under going tower and flight testing under a variety of weather conditions since early 1992.     

航天飞机自动进场着陆引导系统

本文通过对航天机自动进场着陆过程特点和着陆引导系统的介绍,认为采用新一代标准微波着陆系统(MLS)作为航天飞机自动进场着陆的传感器是最佳选择.     

Scanning-beam microwave landing system--Multipath-errors and antenna-design philosophy

Multipath reception can cause guidance-angle errors in a microwave landing system (MLS). The antenna radiation-control problem for a scanning-beam MLS is defined and analyzed. "Centerline emphasis" is presented as a helpful design philosophy for the ground antennas. It is shown that the maximum guidance-angle error is proportional to 1) the amplitude of the indirect signal, 2) the antenna beamwidth, and 3) the time derivative of the indirect signal as the direct beam-peak scans by the receiver. This result is used in developing a rationale for the selection of the antenna beamwidth and sidelobe level (aperture size and excitation) for the azimuth and elevation guidance functions.     

Design considerations for achieving MLS Category III requirements

The authors examine microwave landing system (MLS) ground equipment design considerations for achieving the requirements for Category III landing operations. Specifically addressed are accuracy, continuity of service, and integrity requirements. Accuracy near the touchdown region is achieved by providing adequate transmitter power, sufficiently small antenna beamwidth, low effective sidelobes (e.g. by introducing a degree of randomness in the dynamic sidelobes and by using a directive element pattern), and, in the azimuth antenna, by shaping the vertical pattern. High continuity of service is achieved by using a high-reliability design, through redundancy of critical elements, by providing an uninterruptible power supply, and by incorporating prealarm warnings. High integrity is achieved by providing an appropriate configuration of redundant monitors, a capability to verify monitor performance periodically, a high-reliability control circuit, and sufficiently independent implementation of transmitter, monitor, and control functions     

微波着陆系统与自动驾驶仪耦合技术探讨

微波着陆系统（MLS）作为新一代标准进场与着陆系统已在我国军用飞机上领先使用。本文从微波着陆系统性能特点出发给出了从一般无线电导航过渡到微波着陆系统引导过程中的三种修正航线的算法，使自动驾驶仪能够平稳转换，这在民用飞机上是必不可少的。     

微波着陆系统模拟试验电磁相似性分析

根据微波着陆系统的技术体制和导航原理,应用电磁相似理论,将机场微缩到室内,微波波段微缩到光波段,建立基于缩比模型的微波着陆系统机场场地多径效应的半实物仿真系统,利用激光在缩比模型下的传播模拟微波载波在实际机场场地环境下的辐射.鉴于模型系统中电磁波频率不能精确相似,提出了双尺度的缩比实验方法.以雷达散射系数为依据,对原型...     

Monitoring techniques for phased-array antennas

The problem of monitoring phased-array antennas in general and microwave landing system (MLS) in particular is considered. Various methods of monitoring phased-array antennas are suggested. One is based on changes in the far-field radiation pattern arising from defects in the array. Another method uses the near-field to far-field transformation, based on the concept of the plane-wave spectrum, for the detection of defects in the antenna. A third method is based on near-field measurements and uses the properties of the Fresnel integral. The methods were simulated on the computer and, where possible, were tested by experiment. A comparative assessment of the methods is given, and an operational monitoring system is suggested for the MLS phased army.     

Antenna radiation modeling for microwave landing system

Geometric optics and diffraction techniques are used to develop radiation models of antennas mounted on an aircraft structure. Measurements at 35 GHz on a 1/35 scale model space shuttle and 1/11 scale Boeing 737 are used for comparison with computed patterns and are in very good agreement. Radiation coverage in the elevation plane on full scale Boeing 737 and Boeing 747 at 5.1 GHz, as applied to the microwave landing system (MLS), is examined for vertically- and horizontally-polarized antennas mounted at different locations on the aircraft.