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The future applicability of the Global Positioning System (GPS) to the National Airspace System (NAS) for user navigation and landing support is discussed. Functional characteristics and performance estimates are presented for several GPS enhancements, including the use of a geostationary satellite L-band repeater, a CONUS calibration network, and pseudolites. Analysis results indicate that an enhanced GPS system can meet US Federal Aviation Administration (FAA) enroute/terminal area navigation and nonprecision approach requirements under conditions which include accuracy degradation due to worst-case satellite failure, selective availability, and signal integrity. Similarly, it is shown that a Category I precision approach and landing requirement is essentially met using two pseudolites per airport. Additional analysis and extensive testing are required to validate the Category I findings. >

Since the end of the second world war hyperbolic position-fixing systems have been available for use by merchant vessels. These systems originated in military requirements. Today for the navigation of merchant ships a number of existing systems can be used, such as Decca, Loran C, Omega, Transit and Cikada, the two latter being satellite navigation systems. Transit became operational in 1964 for military use and in 1967 the system was made available for use by merchant shipping.

As the marine sextant is only useful to low-flying aircraft because of its reliance on the sea horizon (see Section 1), many earlier pioneers descended almost to sea level to take their sights; but as Alcock and Brown were the first to discover, it is often necessary to climb above the cloud in order to see the sky. Some pioneers used the horizon of stratocumulus cloud below, among them K. M. Grieve who, with Hawker, would have been the first across the Atlantic if radiator trouble had not made them the first survivors of a mid-Atlantic aeroplane ditching. As Grieve was so happy with his cloud horizon, disbelief must be suspended. Indeed, what has been claimed to be ‘the first real aeronautical sextant’, designed in 1919 by the same ingenious Capt T. Y. Baker RN who invented the Baker Navigating Machine (see Section 4 5), used a reflecting prism as an index mirror and two horizon prisms giving a view of both the back and front horizons. Provided both cloud horizons were equally depressed below the true horizontal plane, the instrument gave the true altitude of the body observed.

A simple inexpensive optical projection map display is described which converts the range and bearing signals available from ground-based beacon aids such as TACAN or VOR/DME into a continuous map indication of present ground position without additional computing. This provides an area navigation system from such aids within their limits of accuracy, which increases with decreasing range from a beacon.The display, which is self-synchronous, employs a series of circular map micro-transparencies, each of which is centred on a TACAN or co-located VOR/DME beacon and which can be changed in flight. The transparencies are automatically orientated with reference to beacon magnetic north on insertion, by a notch in the rim. The transparency is rotated by the bearing signal and is translated radially by the range signal to give a continuous indication of present position.

Sixteen pilots of two widely different experience levels were flight tested in a Beechcraft Twin Bonanza on an area navigation task involving 3-D approaches having two levels of navigation procedural complexity. Two types of displays were used for level-ff at MDA, command leveloff and an altimeter. The four recorded performance measures were vertical steering, horizontal steering, airspeed control, and procedural accuracy. The less complex approach procedures (Simplified) resulted in better performance on all four recorded measures than the more complex procedures (Standard), However, no reliable performance differences were evident between levels of pilot experience and types of leveloff displays. In comparison with previously assumed values of flight technical error, Standard Procedures generally yielded larger errors, and Simplified Procedures generally smaller errors.

Airborne OMEGA navigation technology is now entering its third generation. The first generation “OMEGA” offered affordable, worldwide navigation, principally in the North Atlantic and other oceanic areas requiring Sole Means of navigation certification. The second generation “OMEGA/VLF” featured maturing software and improved signal reception and handling characteristics which enabled it to meet the more stringent RNAV certification requirements. The third generation “OMEGA/VLF NAVIGATION MANAGEMENT (NMS)” now combines OMEGA/VLF navigation information with a variety of position sensor inputs, including; VOR/DME, DME/DME and GPS. The combination of advanced technology, mature OMEGA software and multiple position inputs now offers a cost effective, reliable and exceptionally flexible navigation system which satisfies a wide range of current and future navigation needs.

The following paper was presented at an Ordinary Meeting of the Institute held in London on 21 March 1979 with Mr S. S. D. Jones in the Chair.This paper is not so much a forecast of future navigation systems as a personal view of the philosophy of the increased use of micro-processors. Digital computers were first introduced into airborne systems in the late 1950s to meet the demands of new sensors such as inertial navigators and star trackers for which analog computation methods proved inadequate and inaccurate, but their cost restricted their application to specialized high accuracy systems.

On October 9, 1981, a Supplemental Type Certificate for airborne, en route, IFR use of Loran-C was awarded to the State of Vermont following completion of a flight test program by the Transportation Systems Center, Research and Special Programs Administration of the U.S. Department of Transportation. The certification of a Beechcraft E50 aircraft equipped with a Loran-C navigator, is the first ever granted for use of Loran-C in the National Airspace System and culminates a four-year federal-state evaluation program. This paper describes the systematic approach leading to the award. It includes a thorough examination of the certification process, the accuracy requirements described in the Federal Aviation Administration's Advisory Circular 90–45A “Approval of Area Navigation Systems for Use in the U.S. National Aerospace System,” the organization of the program, the preparation of a flight test plan, the collection of the data base, the analysis of the data, and resulting conclusions.

The office of aeronautical Charting and Cartography (NOS, NOAA) is responsible for the production and maintenance of aeronautical charts and chart related products. The maintenance of visual aeronautical charts is assisted by airborne surveys of charted areas within the United States. These surveys permit current inspection and editing of data portrayed on the charts. This paper describes the theory, development, and use of a Computer Generated Area Navigation (RNAV) Waypoint Grid System for airborne surveys. Control for these surveys is provided by aircraft equipment utilizing the VOR/DME navigation facilities of the National Airspace System. Bearings and distances (waypoints) from existing facilities are fed into RNAV equipment to create the survey grid. These waypoints are generated by a computer program using coordinate search and geodetic computation techniques from a navigation facility data base. The resultant waypoint grid data, in a form easily used in the aircraft's RNAV equipment, provides accurate position and guidance information for the survey. This method may fulfill the control requirements for other airborne surveys.

Many of the tasks which have occupied the navigator ever since measurement and calculation were first applied to the subject are now being carried out or aided by technical devices. This has been going on for a long time, and I would like to consider how far we have got, and what will remain for the concern and interest of our Institute when this technical growth has fully matured.

Statistical and operational results of extensive government field-testing of the Rockwell-Collins Global Positioning System (GPS) units are summarized. The equipment has exhibited better than 16-m spherical-error probable-position accuracy in over 6300 hours of testing conducted during the past two years. One-channel, two-channel, and five-channel receivers were subjected to thorough evaluation. Their respective signal-processing and data-processing architectures are described. Data highlighting dynamic position accuracy, static position accuracy, acquisition times, and field reliability are presented. GPS equipment integration and operation with nine different host vehicles is described. The results of mission scenarios, such as area navigation, rendezvous, and weapon delivery, are presented. >

A method of determining an observer's terrestrial latitude and longitude is proposed which, once the altitude observations are made and corrected to true altitudes, can be performed entirely on a mini-computer.

An examination is made of old and new navigation technology that considers most factors affecting this technology, including cost, accuracy, autonomy, time-delay, global coverage, and the human interface. The author reviews cartography and the navigation of land, ship, air, and space vehicles, concluding with a forecast of navigation in the twenty-first century. An extensive annotated bibliography is included. >

The stringent maintenance requirements that apply to North Sea structures make the cost of inspection a significant factor in North Sea operations. A failure on a large production platform necessitating its shut down would result in a loss of revenue of between half and three-quarters of a million pounds per day. Current practice is such that the whole inspection process is very weather-dependent, and only a portion of a large structure can be examined during the ‘weather window’ (roughly speaking, the period between April and October). The area to be inspected has to be planned in advance, acoustic nets have t o be laid down and calibrated, a range of sophisticated equipment has to be deployed; divers also require relatively long lead times prior to the operation and considerable time for decompressing after the operation. The use of divers will, it is hoped, diminish. It is now general practice to use Remotely Controlled Vehicles (RCV) and television for sub-sea inspection.

Work on integrated navigation for aircraft started at RAF Farnborough at least as early as the mid 1950s. At that time the Inertial Navigator (IN) for a guided bomb was being developed and the navigation of the aircraft to the target used a combination of the weapon IN, Doppler radar and position fixing. An output of the navigation process was a calibration of the weapon IN. The operational concept was interesting in that after weapon release the aircraft had to return home using Doppler and compass.Development of this system included flight trials in raf and a & aee aircraft using the Decca Navigator chains in Southern England for position reference. The same method was used in the development of the FSP 100 IN intended for the TSR 2 which took place in 1960/63. On these trials an early airborne digital computer on board the trials aircraft enabled Decca, Doppler and the IN information to be recorded and processed in-flight in a form suitable for post-flight analysis using a ground digital computer. This technique formed the basis for producing the reference navigation system which has been used for all our subsequent trials. The production of a position, velocity and attitude reference system for trials of inertial and other navigation systems has formed a major objective for RAE work on integrated navigation since that time.

Since the large-scale development of offshore oil installations started in the 1970s the requirements for navigating men and machines around structures and on the sea bed have increased dramatically.The earliest forms of navigation were by tracking with fish-finding sonar, either directly or with the aid of an acoustic transponder. The sonar would usually be fitted to a surface craft, whose position was found by using one of the commercial navigation systems such as HIFIX. The range and bearing of the object being tracked was then applied to this position. Most of this work was done by hand and the position up-date rate was of the order of minutes. The error of position was the sum of the surface system and tracking system errors and was of the order of at least 10 m.

Systematic and economic design and evaluation strategies were applied to a computer-generated 4-D aerial navigation system. During the evaluation each of 24 experienced instrument pilots received training in a PLATO-based digital flight simulator using either a keyboard entry/static map, keyboard entry/dynamic map, or touch entry/dynamic map system. Tasks performed during the execution of an area navigation course included continuous flight control, navigation data updating, digital data entry, and amended course plotting. Digital data entry training time was comparable for all three systems but the touch-map proved superior for the plotting tasks, greatly reducing training and task execution times while virtually eliminating errors. Subsequent performance evaluation showed that the touch-map reduced flight path tracking error, increased processing rates on a digit-cancelling secondary task, and increased the accuracy of manual plotting operations. It was concluded that a touch entry system could significantly reduce cockpit workload across a wide range of operational environments.

As a general rule the navigational function is aimed at determining the position of the aircraft in order to resolve three types of problem:(1) To subject the aircraft's flight path to an optimum trajectory calculated before departure or progressively adapted in course of flight to the circumstances encountered.(2) To choose at each point of the selected flight path the flight system best adapted to the safety and economy of the flight.(3) Taking into account the presence of other aircraft in the airspace, to know and make known the actual position and the information allowing provision to be made for future positions, so as to permit effective air traffic control.Departures of the actual from the chosen flight path penalize the flight by a lowering of economy (in flying time or fuel consumption). It does not seem, however, that the problems raised from this point of view by S.S.T. are by nature or in difficulty any different from those which affect conventional aircraft. Taking into account the present-day precision of navigational aids there is every reason to believe that departures of the actual flight path from the optimum flight path will introduce a penalization which it is possible to ignore when compared with the penalization due to the inaccuracy of the knowledge of the elements (winds, temperatures, pressures) which have, in fact, served to determine this optimum flight path.

Navigational accuracy improvement by combining VOR/DME information with airspeed and heading data via maximum likelihood filter, using small airborne computer

In 1972 an atomic time standard based on the fundamental properties of the caesium atom is being substituted for Greenwich Universal Time, based on the rotation of the Earth on its axis, as the ultimate control for international time signals. Greenwich Time and longitude are inseparable, so that any necessary correction to the time signals he receives will be of vital importance to the navigator.This paper was presented at a meeting of the Institute in London on 27 January 1970 with the Hydrographer of the Navy, Rear-Admiral G. S. Ritchie, C.B., D.S.C., in the Chair. Mr. Humphry Smith, head of the Time Department at the Royal Greenwich Observatory and Chairman of the Directing Board of the Bureau International de l'Heure, reviews the relationship of uniform time systems to the precise astronomical observations that determine the irregularities of the Earth's rotation. He outlines the current proposals for time signals, their correction to Universal Time and the implications for the navigator.

IN DESCRIBING the projected ground based navigation environment for the period 1965 to 1975 expected to exist within the United States, not very much of a crystal ball is needed. For a variety of reasons, some good, and some open to criticism, ground based navaids in use by aviation today appear to have changed slowly. After all, it. is now the 34th anniversary of the four-course range, and it is still with us. It is simple to take this situation and consider it a horrible example of FAA backwardness. But this is an oversimplification of the grossest sort. Although we have been labeled backward in some respects, there are other reasons why navigation aids suitable for use in civil operations change slowly. This is not the time to explore these reasons with you detail, although I can touch upon them briefly. They involve the very nature and role of aviation in our economy. The fact that our system of air navigation and traffic control must satisfy the needs of many diverse elements is a factor, as is the conservative approach associated with the desire for tried and proven techniques to achieve a high order of operational reliability on a dayto- day basis. This factor is one which the airline passenger at least is willing to welcome.

In 1969, by specifically including 'pilotage error' in the error budget for area navigation system certification, the Federal Aviation Administration legally attached economic premiums and penalties to human as well as equipment performance in man-machine system design. To establish the accuracy of use and freedom from pilot blunders associated with systems employing various configurations of displays and controls requires both simulator and flight experimentation. An automatically adaptive cockpit side task provides a saturating level of pilot workload and allows the sensitive, orderly, and statistically reliable measurement of a pilot's residual attention as a common metric for navigation and control system assessment. A simulation experiment employing this measurement system compared pilot performances as a function of the number of waypoints that could be stored in an airborne area navigation (RNAV) computer (1, 2, 4, or 8) and the type of manual flight control system used (normal flight control versus maneuvering performance control). (Author Modified Abstract)

The accurate, continuous determination of position, heading and course at all times, under all normal operational conditions, would be very desirable. This ideal has not been achieved for flights or voyages of long duration, but the many developments of recent years begin to give some promise that it may be possible. For high altitude aircraft the continuous optical observation of celestial bodies offers an evident solution, and doppler systems can give continuous speed over ground. For ships, however, the attainment of such an ideal navigation system is difficult. The various shore-based radio navigation systems have made important contributions, as have the development of inertial techniques. In addition, automatic optical sextants have been developed which can be used in clear weather.

In this note, we propose to enquire into how far it may in principle be possible to employ zenith-photography for astro-navigation in the air, also to touch on the question of whether the mechanical difficulties can be adequately overcome. The question of principle seems in fact quite clear, but the practical side will undoubtedly demand much care and study by engineers and by practical navigators if the method is ever in fact to be adopted; we hope to show that the method has advantages sufficient to make the problem worthy of attention.

General aviation has become the major user of the airspace in the United States, and will continue as an increasingly predominant airspace user as time goes on. Thus future programming must take into consideration more and more the impact of general aviation on the control of air traffic, and in particular its inherent need for flexible flight routes between many points on the surface. A significant requirement for aircraft flying over multiple routes connecting virtually unlimited combinations of departure and destination points and for the efficient control of high density traffic is that pilots can perform area navigation. Airborne equipment is now available which provides accurate area, multiple track, navigational flexibility. During the remainder of this Century, probably the most acceptable equipment with this capability for the majority of general aviation aircraft—from both an operational and economic viewpoint—will involve the introduction of airborne computers for use with conventional VOR/DME receivers, coupled with suitable read-outs giving continuous position information. Aircraft so equipped also will be able to provide data link reporting of position information derived from the airborne navigation system, which will constitute an important contribution to future automation in the control of air traffic.

Rihans is a multi-phase development program initiated by the Coast Guard's Office of Research and Development. It addresses the need for an all-weather precision navigation system in harbors and their entrances. System requirements have been developed, and solutions solicited from industry. The first phase objective is a refinement analysis of the technical approach and detailed definition of the system. Contracts have been awarded for three competing concepts.

Development of a remote controlled low light level TV (LLLTV) camera-television sextant navigation system which the operator within the ship can operate to obtain celestial body altitude sightings.

In order to find out what type of doppler navigation equipment would be most suitable for the S.A.S. fleet of DC-8s it was decided to start a programme of doppler evaluation in Spring 1958. The doppler evaluation programme included evaluation of doppler equipment from Canadian Marconi, General Precision Laboratory (G.P.L.) and Collins Radio Company.The programme started in April 1958 with evaluation of Canadian Marconi doppler equipment. The evaluation period lasted six months. In April 1959 evaluation of Collins and G.P.L. doppler equipment started and lasted for eight months. In March 1960 evaluation of Collins and Canadian Marconi doppler equipment started and is still in progress. And finally by the middle of May 1960 evaluation of G.P.L. Radan 500 was in progress.

The effect of the geometrical relationship between course-line and ground stations on area navigation errors is analyzed. The analysis is applied to both the RHO/THETA and the RHO/RHO systems. Graphs for determining the along-course and cross-course error standard deviations for both systems are presented. The concepts of trading off along-course precision for cross-course precision and the selection of geometrically optimal ground station configurations are discussed and illustrated. The results of this paper are of operational value since they can be used to sequence ground station selections and determine the feasibility of existing ground stations to provide area navigation for the traffic patterns of a given geographical region.

Installation and operation of satellite navigation equipment is described, including what the user should expect during a satellite pass. Characteristics of the new short Doppler computer program which promote better and more consistent accuracy are given, including documentation of 150 ft. RMS fix results. Approaches to an integrated navigation system are reviewed.

Inertial navigation systems are being adopted by air carriers for application on long-range oceanic routes and their existence in cockpits in increasing numbers warrants attention to their possible application during enroute and terminal, domestic operations. This paper discusses performance requirements for airborne area navigation systems as proposed in FAA Advisory Circular 90–45 and projects these performance requirements through 1995. The application of an INS with position updating from conventional ground referenced navigation aids to meet these present and forecasted performance requirements are assessed and the effects on pilot workload are discussed. Also included in this paper is a brief description of a planned flight evaluation to assess the effects of an integrated Inertial/DME-DME/Map Display area navigation system on aircraft navigation performance and pilot workload.

The contribution of an inertial Navigation System (INS) combined with present and projected VOR/DME to the accuracy and efficiency of area navigation is evaluated by comparing system performance with and without INS aiding. Sensitivity to INS quality is described by showing area navigation performance using high and medium accuracy production INS. The increased accuracy of the INS aided area navigation system is evaluated with respect to its impact on decreasing the protective airspace requirements, greater waypoint location flexibility, and increased accuracy of vertical navigation between waypoints. To complete the description of an inertially aided AREA-NAV system, the basic computational techniques and trade-offs for optimally mixing sensor information are presented.

Recently, with the increasing frequency ship-wrecks by the driftice on the North Pacific Ocean contained the Okhotsk Sea and the adjacent sea of Kurile Islands, the establishment of ice-area navigation has become a matter of urgent necessity.For purpose to preserve these wrecks, it is intended in the present study to details a practical method to passage through ice-area over this sea-region, based on the lessons brought those shipwrecks and the experimences for many years of the navigators.In chapter 2 details of the methods to foretell an existance of ice-area at outside of the field of vision, make use of the atmospheric phenomena (ice-blink, water-sky and mirrage of drift-ice, etc.), sea state, distribution of sea surface temperature and radar, etc.…The practical method of ice-area navigation breaking through the ice-strips lied between the open waters, and the requisite measures in the case of beseted into very close ice-area (for example, quotating the exploding technics of hummocked ice-floes carried out at the entrance of Abashiri harbor in 1956) are discussed in chapter 3.In chapter 4 mentions the counter-measures ought to take for ice-area navigation before the departure.Finally, it is explained that the adoption of reconnaissance flight is very efficacy to ice-area navigation. (chapter 5)

A computer known as the Radio Track Guide, of which both air and ground trials have been held, is described. As a system it can provide accurate automatic guidance for all anticipated operational conditions in a manner which is of value for both navigational and movement-control purposes. Mr. Britnell's paper was presented at the Paris convention on automatic navigation.The criterion for assessing the efficiency of a navigational aid must include a reference to the ease and precision with which it enables a vehicle to maintain a specified track. In aircraft navigation the most accurate tracks are, of necessity, those made in the vicinity of the runway during the landing and take-off phases. At such times the errors must be limited to a few feet and such small values are a result of the pilot using an ideal reference frame for lateral guidance purposes. This is centred upon the runway and within it he is able to detect, with a high degree of accuracy, the two quantities necessary for precise track keeping. These two quantities are the displacement and rate of displacement from the required track.

The Council's report, our increasing membership, the eminence and wide range of activity of the new Fellows and the growing status and rising circulation of theJournalshow that the Institute is making very good progress. I felt, nevertheless, as former Presidents have, that I should attempt some kind of reckoning and try to make some useful suggestions. I soon found that I could not improve on what Sir Robert Watson Watt said when he addressed us in 1950 and 1951, what he said seems all the more appropriate now. When he spoke, this country had the world's largest shipping and shipbuilding industries and a lead in the design and manufacture of the most advanced types of civil aircraft. He was concerned that we should do all we could to maintain and increase such dearly bought greatness. We could no longer afford, he said, to concentrate almost exclusive attention on the big 10 to 20 per cent factors which govern overall efficiency in such industries, and must give a greater share than before to the small 1 to 5 per cent factors. These, he pointed out, were mainly advances in the arts and sciences on which navigation depends for its full usefulness, and on which navigators depend more or less consciously in making their decisions. They generally advance with the help of new methods and practices which, though at first too novel or too elaborate for ordinary use, become commonplace before long.

Modern navigation might be dated from the invention of the marine sextant in 1734, followed by the invention of the marine chronometer in 1766. These developments made it possible to determine longitude as well as latitude at sea. The steady developments of nautical tables, almanacs, and the further refinements of sextants and timepieces gave an accuracy of position under good conditions at the turn of this century within two miles and this with a speed of solution based on four stars, of about half an hour.

The paper discusses the way in which the accuracy provided by different navigation systems can best be presented diagrammatically, and it is concluded that contours of constant 95% radial error give the best general picture of a system. Where a more detailed picture is required error ellipses can be added at suitable points in the system. The 95% radial error of fixing is calculated for radial, rθ, azimuthal and different hyperbolic systems, and graphical methods are developed for drawing contours along which the 95% error is constant, and also for drawing 95% ellipses. Diagrams show typical results for the different systems.

Before considering what animals can do, without conscious thought, in the way of navigation, it would be useful briefly to review their ability to pilot themselves, to find their way around an area in which they have already had experience. Here landmarks play an obviously vital role, and in many cases they are visual landmarks which we can appreciate ourselves. But often the characteristics of the environment to which the animal reacts are non-visual, detected by senses similar to ours but of much higher acuity. The sense of smell is of dominating importance among the mammals, which will go so far as to provide their own ‘scent flags’ along the boundaries of their private preserves. Sounds are often used to guide animals, particularly to another member of their species or to their prey. The bats have gone further and rely on a form of echo-location for guidance of their fast erratic flight through the darkness. They emit high-pitched, if not supersonic squeaks and detect and analyse the reflections back from obstacles even so slight as a piano-wire stretched across their path. Animal ‘sonar’ of this kind has also been demonstrated in a bird and probably is also to be found in fish and porpoises. Certain snakes are believed to detect their warm-blooded prey by special heat-receptors in the head. Many other examples could be cited and our knowledge of the means by which animals can determine their course in familiar territory is probably not yet exhaustive. We are only just beginning to appreciate and understand what they can do when they are in completely unfamiliar areas or when, known landmarks are present but cannot be used.

Satellite navigation aid for marine craft, objectives of ATS and ATS-A, -B and -C spacecraft

The NASA, working with American Airlines, has completed the first phase of research to evaluate the operational feasibility of two-segment approaches for noise abatement. For these tests, area navigation was used to establish the upper glide slope and an ILS was used to establish the lower. The flight director was modified to provide command information during the entire approach. Twenty-eight pilots representing the airlines, professional pilot associations, FAA, and NASA participated. With an ILS approach for comparison, the procedure gave a noise reduction of 18 EPNdB at the outer marker and 8 EPNdB 1.1 n. mi. from touchdown.

It seems appropriate first to define and explain the term Area Navigation that lately has almost become a slogan in discussions on short-range radio navigation aids. The term itself does not convey much because virtually any radio navigation system permits navigation in the area of coverage of the associated ground stations; for a systematic classification of navigation systems, the term Area Navigation (herein called ANAV) is unsatisfactory. It can be understood only in the context of air traffic control requirements. For a long while the requirements of short-range navigation systems were almost exclusively governed by the needs of air traffic control systems based on an airways concept. When during recent years A.T.C. methods became less associated with a fixed route structure, especially in the terminal area, the requirements to be met by a navigation system changed accordingly. There now appears to be a general trend for area navigation capability to become available as a substitute for a point-to-point navigation system.

In many critical areas today navigation is more concerned with maintaining the flow of traffic than with finding the way. In his Presidential Address, which was presented at the Annual General Meeting of the Institute in London on 14 October 1970, Mr. Stratton discusses some of the characteristics of sea and air traffic systems and how they interact with the costs and benefits to the community as a whole.In my previous address I concentrated on the way in which new scientific principles have been applied to determining the basic quantities of position, course and speed as inputs to the navigation process and with some of the technological problems encountered. The science and technology of navigation, however, are but the means by which navigation fulfils an operational task which itself is directed at the safe and expeditious movement of passengers and goods or to some military ends. In this address I will concentrate on some of the current and future operational tasks for navigation on the sea and in the air in fulfilment of the commercial need to transport goods and passengers and of the personal use of the vehicle for transport and leisure.

The difficulties of determining latitude and longitude under adverse weather conditions, when neither the Sun nor stars can be sighted, are well-known, and the advantages of a non-visual system of position finding which could operate through clouds or fog are too obvious to require emphasis.A Radio Sextant, which detects and locks-on to 8 mm. radiation from the Sun, has already been made and tested in America with reputedly excellent results. An analysis of both the theoretical and the practical design factors is given in the present paper, together with the results of successful experiments made in Great Britain.

(1947). A Navigation Computer. The American Mathematical Monthly: Vol. 54, No. 8, pp. 453-458.

This paper describes the characteristics of the common system navigational aids, VOR and DME, as an area navigation system, and discusses methods for using them other than by flying along radials to or from the station. The use of pictorial displays and course line computers, either separtely or in combination, to achieve area navigation capability is distinctly possible. The choice of pictorial display or of the computer or of both will be made on considerations other than accuracy. Justification will have to be based on operational benefits such as least time and distance tracks, altitude availability or on air traffic control benefits. Cockpit space and chart provisioning are major problems in connection with pictorial displays, but can be overcome if cost benefits are sufficient. Flight evaluation in a live-traffic environment of the Bendix-modified Alternate Track VORTAC Computer in a united Air Lines DC-8F Cargoliner is described. Modification consisted of an additional function permitting operation parallel to radiais, in addition to phantom station mode of operation. Results were promising and indicate the track-keeping ability of a parallel course computer is consistent with existing airway criteria with little increase in pilot workload. Significant increases in traffic capacity of the existing airway system is possible with no required increase in number of VOR/DME facilities presently available.

This paper will discuss application of the microwave landing system as a terminal area navigation tool, as an aid to vehicle guidance, and as a position control feedback element. Navigation in this context is used to mean velocity and position determination together with a description of desired velocity and position. Guidance relates to the usage of velocity and position information to describe progress along the desired path and specifically to describe changes required to maintain that path. Control relates to manipulation of the vehicle to satisfactorily achieve the guidance commands. These aspects of the general problem of terminal area navigation using the microwave landing system as a ground based aid will be discussed from a flight control engineer's viewpoint with the emphasis on subtleties of the system characteristics that can greatly impact its eventual usefulness. Safety in flight will be discussed with respect to guidance requirements for separation, control requirements for monitoring, and integrity of the ground station itself.