摘要:

The Nimrod Airborne Early Warning aircraft will extend the surveillance radar coverage beyond that normally provided by surface radars. The paper discusses the Mission System Avionics part of the overall aircraft. The MSA undertakes the prime tasks of detection, classification, tracking and reporting. The system is capable of operation over land and sea surfaces and incorporates a very high level of automatic data handling. The paper reviews the radar, IFF interrogator, electronic-warfare support measures, communications, data handling, display and control and software aspects of the MSA.

DOI:10.1049/ip-f-1.1981.0069

出版商:IEE    

年代:1981

数据来源: IET

摘要:

It is extremely important that the management and direction of a large avionics project should be effective in ensuring that the cost and timescale performance is under control. The paper discusses the management of a major avionics project, using as an example the AEW Nimrod MSA project entrusted to Marconi Avionics by the UK Ministry of Defence. It outlines the formulation of a multilayer project family tree structure, which is the result of a predefinition of the hardware and software that has to be produced, and which identifies and relates the elemental tasks that go to make up the development of the whole equipment that has to be designed and built.

DOI:10.1049/ip-f-1.1981.0070

出版商:IEE    

年代:1981

数据来源: IET

摘要:

The paper discusses the design and manufacturing aspects of nose radomes for high-speed aircraft. Aircraft radomes are an acceptable comprise of the conflict between the electrical, structural, environmental and aerodynamic requirements. The paper reviews the requirements placed on the design and summarises the basic radome design and construction methods, as applied in current radome technology, concluding with an examination of the shortcomings of existing radomes and an indication of possible solutions to current problems. An Appendix is attached which includes a list of terms and their explanations.

DOI:10.1049/ip-f-1.1981.0071

出版商:IEE    

年代:1981

数据来源: IET

摘要:

The cockpit of any aircraft provides the man/machine interface by which the overall effectiveness of the system and aircraft combination may be accessed. One would assume therefore that this interface between the man and machine would be used to specify the control and functional attributes of the systems. This is often said to be the case in current aircraft. However, owing to inconsistences in system design, for example complex systems requiring little control and simple systems requiring extensive monitoring and control, many cockpits are criticised as cluttered and extremely difficult to operate. These initial problems are further compounded by improvements in aircraft equipments and changes in rôle during an aircraft life, requiring further controls and displays to be installed, these being in far from optimum locations owing to structural and other physical constraints. The paper illustrates how the progressive development of systems and changes in requirements over the last 20 years have affected the cockpit of one family of aircraft: the Harrier. The paper then describes those mature technologies and those which are likely to mature within the gestation period of the next fighter aircraft (approximately 10 years) and which may be used to radically redesign the cockpit while meeting the pilot's basic need to remain in overall control of the aircraft and its system. Finally, one of a number of cockpit designs presently being investigated, which integrates most of these technologies into an easily workable cockpit design, is described.

DOI:10.1049/ip-f-1.1981.0072

出版商:IEE    

年代:1981

数据来源: IET

摘要:

The paper describes three wire detection techniques. A millimetre-wave pulsed radar system operating on the grating returns from wires with a regular mechanical structure is discussed. Experimental evidence at 35 GHz proves the operational philosophy of the system and suggests that higher frequencies would produce more successful results. A passive 50 Hz system operating on the magnetic flux produced by live overhead power cables is shown to be capable of indicating the presence and direction of such wires at ranges in excess of 500 m. Finally, a CO2pulsed laser radar is discussed together with a processing algorithm to highlight wire presence. It is shown that identification of a 1/8 in diameter wire at 200 m range and in a visibility of 200 m is possible using only 4 W of laser power.

DOI:10.1049/ip-f-1.1981.0073

出版商:IEE    

年代:1981

数据来源: IET

摘要:

The paper reviews the procurement situation in respect of the reliability and maintainability aspects of the UK Ministry of Defence contracts prior to the introduction of the DCAD Technical Publication 1/77, discusses in general the content of the document and the translation of the document's principles into a form suitable for inclusion in contracts, reviews its application and gives some indications to the direction in which reliability and maintainability activities should proceed to meet the challenges of to morrow's systems.

DOI:10.1049/ip-f-1.1981.0074

出版商:IEE    

年代:1981

数据来源: IET

摘要:

Most single-pilot military aircraft are now being designed with head-up displays (HUD). The HUD has given the pilot a flight and weapon aiming display which has enhanced the safe operational flight envelope and the flexibility of weapons delivery. But has it benefited from the vigorous integrity analysis which has been given to other flight critical systems? The traditional pilot's instrument panel has both main and standby instruments laid out in a prescribed pattern for efficient scanning. The pilot has responsibility for crossmonitoring between these totally independent systems and for making a judgment in the event of deviance. Pilot monitoring, albeit over a much larger scan area, was also assumed when HUDs were introduced into the cockpit. This resulted in significant increases in physiological and psychological workload. This first generation of HUDs earned themselves a reputation for poor reliability and for a high occurrence of erroneous, but plausible, displays. This unsatisfactory performance has frustrated attempts to classify the HUD as the primary flight display and has forced responsibility for display monitoring onto the pilot. To improve this situation, the equipment manufacturers have made vigorous attempts to improve unit reliability and to extend the scope of their self-monitoring circuits. Is this the right approach? The paper is not directly concerned with reliability of these equipments but in examining how to ensure that specific flight critical data is always correctly displayed and that all failure conditions are ‘infallibly’ signalled to the pilot. The solutions to this problem can range from a reorganisation of the cockpit, thus reducing pilot workload to a level where cross monitoring is always possible, to the addition of redundant sensor and display systems with automatic crossmonitoring.

DOI:10.1049/ip-f-1.1981.0075

出版商:IEE    

年代:1981

数据来源: IET

摘要:

The VHF omnirange radial system (VOR) is used extensively as an aircraft navigational aid, and the need for greater utility of VOR has led to a requirement for greatly improved standards and traceable calibration facilities in this parameter. The paper presents the development and assessment of two standard VOR waveform synthesisers and a VOR waveform decoder. The synthesiser designs use the technique of regeneration of a wave shape which has been ‘fixed’ by digital methods in an addressable memory. The technique has been refined and brought to a state of high precision. One synthesiser is a complex desk-top computer-controlled system which, as well as being a standard, is excellent for producing imperfect waveforms. The second synthesiser standard is a compact portable unit suitable for field system testing and standards dissemination. The decoder design is based on digital sampling and storage of one cycle of the composite ‘audio’ waveform: this data is then Fourier transformed and analysed to determine the FM modulation depth and the differential phase of the two 30Hz modulating signals—the VOR bearing angle. The standard synthesiser and decoder standards have demonstrated uncertainties not exceeding ± 0.03° (95% confidence level). An extensive and detailed analysis of the sources of uncertainty is presented, particularly with regard to a ‘digital’ decoder operating with a signal produced by a ‘digital’ synthesiser. The uncertainties are tackled on two fronts: first by computer simulation not involving any hardware or genuine data transfer, and secondly by analysing data transferred from synthesiser to decoder. By these means, various sources of uncertainty are identified and assigned. The sensitivity of the detection method to digitisation uncertainties, asynchronism between decoder and generator, anharmonic 9.96 kHz subcarriers and random amplitude and phase noise was investigated. Measurements are also made on transmissions from local VOR beacons.

DOI:10.1049/ip-f-1.1981.0076

出版商:IEE    

年代:1981

数据来源: IET

摘要:

The ever increasing demands on the performance of airborne antennas place comparable demands on the design of the enclosing randome to ensure minimal degradation of the antenna radiation pattern. Radomes for airborne application can be separated into three main categories: large aircraft radomes of either the nose-cone or under-fuselage type, small aircraft radomes often flush mounted to the airframe and missile radomes. The geometry of the radome, being largely determined by aerodynamic considerations, often leads to severe degradation of the electrical performance of any enclosed antenna. Rain erosion and heating of the radome surface also constrain the electrical design by limiting the choice of material and builds. For large airborne radomes, the enclosed antenna may be required to exhibit both low angular aberrations and small sidelobe degradations. Radomes for these applications may also be required to operate in either a dual-, broad- or multiband role. Metallic or dielectric bodies, such as lightning conductors, the pitot tube and pitot-static pressure tubes, either within or on the radome surface, also present potential sources of electromagnetic degradation. Missile radomes share most of these effects, but to varying degrees because of their relatively smaller size and different operational constraints. The paper reviews the electromagnetic design and analysis of such radomes, examines the sources of degradation of the enclosed-antenna radiation pattern and discusses the design requirements with reference to the operational environment.

DOI:10.1049/ip-f-1.1981.0077

出版商:IEE    

年代:1981

数据来源: IET

摘要:

Electronic displays are being increasingly used in aircraft for the presentation of information to aircrew. This trend is due to two principal reasons, the steady improvements in the technology of electronic displays which are finding growing use in a wide range of markets, and the radical changes to the methods of distributing and processing data on board both military and civil aircraft. However, the peculiar environmental and other factors which constrain the design of airborne displays have caused the aircraft world to lag behind other markets in the use of new types of electronic display. It is the aim of the paper to review both the available and potentially promising display technologies, the human factors and environmental constraints, and the integration of the display devices into the total avionic systems, in order to present a balanced view of both the advantages and the problems associated with the use of airborne electronic displays. The design of the aircraft cockpit and the wide range of ambient light levels impose particular problems, and these are considered in relation to the characteristics of the human eye to provide some overall guidelines for display design. The types of information which are typically presented and the design of symbology are reviewed. Electronic display devices described include monochrome and colour CRTs, which are coming into use in the new generation of civil aircraft after many years of use in military aircraft, digitally-addressed CRTs, and a range of solid-state matrix and alphanumeric displays, both emissive and reflective. Image intensifiers for use in night operation are discussed. Some types of display, particularly for military aircraft, incorporate optical elements for magnification, collimation and image combination, and the use of both refractive and diffractive optical techniques is reviewed. The design of complete display systems to provide multifunction capability and protection against component failure is seen as one of the greatest potential advantages of integrating electronic displays with digital data highways.

DOI:10.1049/ip-f-1.1981.0078

出版商:IEE    

年代:1981

数据来源: IET