ILS-a safe bet for your future landings

An argument is presented in favor of the ILS (instrument landing system), the principal components of which are the localizer, which provides lateral guidance to the pilot, and the glide slope, which gives the vertical guidance. A pilot flying these signals precisely will end up over the hard surface runway with the ILS receiving antenna, wherever it is mounted on the aircraft, being about 20 ft above the touchdown point. The safety record and evolution of the ILS are examined, and a pilot's view of ILS (that of the author, an engineer who has worked with ILS since 1957 and a pilot who has used ILS safely for over 30 years) is given. System availability is discussed, and comments concerning future use are offered     

Improvement of Automatic Landing Through the Use of a Space Diversity ILS Receiving System

A space diversity method of receiving and processing ILS localizer information has been developed and flight tested. Multiple lateral ly separated antennas are used which sense the ILS signal on and around the approach path. Combining these signals suppresses ILS beam distortion produced by multipath signal interference and provides much improved guidance information to the landing aircraft control system.     

Design of an image radiation monitor for ILS glide slope

The design of a monitor that measures changes in ground reflected image radiation is presented. This monitor is shown to be theoretically capable of determining the effects of snow cover and standing water in the vicinity of an Instrument Landing System (ILS) image-type glide slope, thereby reducing the number and length of outages. A discussion of errors and calibration are presented, along with an example of a practical design     

Malfunction Detection System for Advanced Spacecraft

A design approach for a Malfunction Detection System (MDS) to beused on board a manned spacecraft is considered. This design is directed toward orbiting laboratory type vehicles, in which man will be subjected to hostile environments for extended periods of time. The prime purpose of the MDS will be to monitor and evaluate critical signals and display out-of-tolerance conditions. This paper initially discusses a mathematical model approach to a monitoring-system design. Another topic covered is the feasibility of using some value less than the specified tolerance as a signal ?test? limit. Finally, various design decisions and trade-offs involved in choosing a monitoring subsystem configuration are discussed, and the conclusion is that the approach is feasible and could be expanded to include other capabilities.     

Image quality issues for an enhanced vision head up display

A part task simulation study was performed to determine the ability of pilots to land an aircraft using head up display (HUD) guidance symbology overlaying an emulated millimeter wave imagery. The task was to land in Category IIIa weather at a Category I facility. Three image parameters were varied: image update rate, image processing latency, and the luminance contrast ratio of the runway image to the background noise. ILS beam bending that was representative of a Category I facility was randomly varied across the experimental runs. Nine pilots completed the test matrix. The only variable that made a significant difference was the runway to background contrast ratio     

Improved Antenna Systems for ILS Localizers

For many years Norwegian airports have been equipped with instrument landing system (ILS) localizers of conventional type. Most of the localizers, however, were found not to perform very well on these sites. The course bends were too large and even moderate amounts of snow and ice could cause the localizer to fall out of operation. To overcome these difficulties, the requirements for localizer operation at these airports were analyzed and a new and improved antenna system developed. After a long period of operational testing, during which it was made clear that a substantial improvement in performance had been achieved, the new localizer antenna system is now in operation at 13 Norwegian airports.     

ILS-past and present

Insight is provided into the evolution of VHF/UHF instrument landing system (ILS) equipment and the role of the US Civil Aeronautics and Federal Aviation Administrations in its development. The discussion covers the ILS localizer, glide slope (image arrays and nonimage arrays), marker beacon, reliability, and avionics     

民用飞机飞控系统传感器信号表决设计

电传飞控系统(Fly By Wire,简称FBW)通过传感器余度配置,提高了信号可用性和完整性。介绍了几类常见的传感器余度配置方案及其表决逻辑,设计了三余度传感器表决架构,对其中比较器、计数器进行了详细描述。最后通过一个仿真算例验证了表决器设计的正确性。对于国内民机传感器余度配置和表决管理具有指导意义。     

基于成本效益分析的ILS/MLS过渡决策

本文在对民航几个具有代表性的机场和航空公司进行调研基础上，提出了ＩＬＳ／ＭＬＳ成本计算和未来机队预测方法，从我国目前应用ＩＬＳ现状出发，列举了由ＭＬＳ可能获得的效益。根据成本计算结果的比较和分析，提出了我国ＩＬＳ／ＭＬＳ过渡方案参考的结论和建议，供领导机关作决策选择。     

RF航段衔接ILS进近程序的最大下降角设计方法

RNP 程序的RF 航段与传统ILS 精密进近程序相结合能充分利用两类程序的优势,但两种程序的过渡阶段需要考虑最大下降角度的设计。本文分析过渡阶段程序的平面与剖面几何设计参数限制条件,以及从星基导航方式转为陆基无线电导航方式需要稳定截获航向信号与下滑台信号的运行限制条件;结合两种限制条件,设计一种可以从不同最后进近定位点（FAP）高度计算下滑道的偏离量与到最后航向截获点（FACF）的弧距离关系进行判断,从而确定最大下降角度的方法,并进行仿真验证。结果表明：该方法可以在不同过渡航渡长度与不同最后进近下降角度的限制下,根据给定最高程序假设温度计算得到符合两种限制条件的最大下降角,为RNP 程序与ILS 程序衔接过渡的下降剖面设计提供了一种基于理论基础且具有可行性的设计方法。     

Microwave Landing System

The National Microwave Landing Systems (MLS) program is a joint DOT/DOD/NASA effort to implement a common civil/military precision landing system to replace the current Instrument Landing System (ILS). The MLS will be capable of providing precision landing guidance down to Category III minimum while allowing for complex approach paths in both the horizontal and vertical planes. The system is based on the Time Reference Scanning Beam (TRSB) technique which was selected by the International Civil Aviation Organization (ICAO) in April 1978 as the new international landing system standard. MLS is less susceptible to interference from the surrounding area and provides a greater signal coverage area than ILS.     

High accuracy navigation and landing system using GPS/IMU systemintegration

In this paper, the accuracy, integrity and continuity of function requirements for automatic landing systems using satellite navigation systems are discussed. Such a landing system is the integrated navigation and landing system (INLS) developed by Deutsche Aerospace (DASA/Ulm, Germany). The system concepts of the INLS are presented. It is shown how an INLS, based on system integration of a satellite navigation system (e.g., GPS) in realtime differential mode with an inertial measurement unit (IMU) in the accuracy class of an attitude and heading reference system (AHRS), can meet the requirements: the results given are mainly devoted to the accuracy issues. Using Kalman filter techniques, an in-flight calibration of the IMU is performed. The advantage of system integration, especially in dynamic flight conditions and during phases of flight with satellite masking, is explained. The accuracy, integrity and continuity of function of the INLS were proven by means of flight tests in a commuter aircraft using a laser tracker as a reference. These flight tests have shown that the short-term accuracy (<60 seconds) of the AHRS used within the INLS has been improved from low cost sensor quality to the accuracy of a high quality laser inertial navigation system (LNIS). With the presented INLS, a landing at any airfield, not equipped with conventional Instrument Landing System (ILS) or Microwave Landing System (MLS), is possible by using a very cost effective system. The INLS is a high accuracy navigation and landing system designed to be used instead of conventional landing systems at small airfields and to fill operational gaps of conventional navigation and landing systems in cruise and approach on large airports     

基于VMD的自适应复合多尺度模糊熵及其在滚动轴承故障诊断中的应用

提出了一种基于自适应多尺度模糊熵、ILS（迭代拉普拉斯得分）特征选择和粒子群优化支持向量机(PSO-SVM)的滚动轴承故障诊断方法。该方法采用变分模态分解对振动信号进行分解和重构,并计算重构信号的复合多尺度模糊熵;同时采用迭代拉普拉斯得分选择敏感故障特征,并将特征选择结果输入到基于粒子群优化支持向量机的多故障分类器进行识别。将提出的方法应用于滚动轴承试验数据分析。结果表明:该方法对试验数据的故障识别率为100%。并将基于ILS特征选择方法与基于SFS（sequential forward selection）特征选择进行了对比,表明基于SFS特征选择的最高识别率为92.86%,而基于ILS特征选择的故障识别率达到100%。      

ILS下滑道结构改善思路及措施

通过对ILS下滑道形成的理论分析，阐述了各种因素对下滑道结构的影响．提出了改善下滑道结构的思路和方法，在近几年广汉机场ILS飞行校验中得到了验证．下滑道结构有了明显的改善。     

军用飞机推行综合保障工程的研究

阐述了ILS的涵义及ILS在军用飞机形成战斗力中的重要作用,结合军用飞机实施ILS的现状,对大力推行军用飞机ILS的实施提出了几点建议。     

Evaluation of image-type glide slope performance in the presence ofsnow cover

A formulation for the effects that the ground-reflected signal has on the far-field performance of image-type glide slope is developed using geometrical optics. The effects of snow cover are then related to the formulation and analyzed. Results indicate that it is possible for certain types of dry snow to cause glide slope system performance to exceed U.S. Flight Inspection Manual (USFIM) tolerances at depths below existing Federal Aviation Administration (FAA) plowing criteria     

某型发动机新件涡轮叶片叶冠掉块故障分析

为排除某型发动机新件涡轮叶片叶冠掉块故障,对故障件进行尺寸检测、加工制造工艺复查、断口分析、结构和强度分析等,认为:引发故障的主要原因是叶冠转接R不圆滑、存在尖角,造成应力集中;而相邻原机件叶片弦宽尺寸超差,锯齿形工作接触面积小,以及非工作面局部碰磨,是引发故障的次要因素。采取并验证了有针对性的排故措施。     

Disturbance of ILS Localizer Signals by Reflections from Large Hangers

An equation giving the disturbance of ILS localizer signals by reflections from a flat hangar wall is derived, and a computer program for performing the required calculations is discussed. Results calculated for a hypothetical case are presented.     

Hybridizing contemporary glide slopes to provide vertical guidancefor GPS approaches

Vertical guidance for an instrument approach to landing during conditions of reduced visibility is a crucial element with respect to safety of flight. It is noteworthy that this vertical component-to be most useful and safe-must desirably provide the pilot with no more than several feet of uncertainty. Unfortunately, with GPS the vertical portion of the position information supplied the pilot by GPS signals is the least precise because of geometries involved. Augmentation for enhancement of accuracy is quite important and the assertion is that it is necessary for totally safe vertical guidance. Evidence from approximately 60 years of experience with electronic landing systems serving the public is that there has been no aircraft accident due to a defective vertical guidance signal. Visibilities as low as 600 feet horizontally can exist at certain airports and landings can still be accomplished. These landings, while not common, are being accomplished flawlessly by contemporary aircraft and equipment. Many aspects of the contemporary UHF glide slope have been studied during its half-century of use. This paper reports on advances, some of them quite recent, that make it realistic to claim that a glide slope can be sited for Category I operation at any runway that meets the physical requirements for this type of operation. For the UHF glide slope, siting imperfections are accommodated by using one of five available types of contemporary glide slope systems or derivatives thereof. This paper reviews how accommodations are achieved in practical cases. Results from earlier tests are identified which show hybridizing of UHF glide slopes and GPS can be used to provide good approach guidance to aircraft making fully automatic approaches to touchdown     

The ILS Glidepath: New Designs for Severe Sites

A fundamental new theory for the operation of the instrument landing system (ILS) glidepath is presented. Simple new image array designs for use on severe sites are developed from this theory. The new arrays have been thoroughly tested at model scale and on a particularly severe site at Sydney airport. The approach also leads to a simpler setting up procedure which substantially improves performance.