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Showing papers in "Ire Transactions on Aeronautical and Navigational Electronics in 1958"


Journal ArticleDOI
TL;DR: In this article, Stansfield's solution is extended to include the case of airborne direction finding, which introduces uncertainties in the locations of the direction-finding stations and increases the uncertainty of the fix, which is reflected in an increase in the variance of the solution.
Abstract: The situation where n stationary, accurately located, direction-finding stations fix the position of an unknown emitter by intersecting angular bearings has been previously investigated by Stansfield for the case where the angular bearings have small, normally distributed errors. The most probable location of the emitter and the surrounding confidence regions were determined. Stansfield's solution is here extended to include the case of airborne direction finding, which introduces uncertainties in the locations of the direction-finding stations. These uncertainties arise from navigation errors and increase the uncertainty of the fix, which is reflected in an increase in the variance of the solution. The increase in uncertainty is derived for celestial, dead reckoning, and direction-finding (Loran, Shoran, etc.) navigational procedures. Small, normally distributed navigation errors are assumed. In addition, a model in which celestial position fixes are taken between direction-finding cuts is investigated. The various procedures are compared.

37 citations


Journal ArticleDOI
M. Mark, M. Stephenson1, C. Goltsos1
TL;DR: In this article, the development and design of an evaporative system utilizing gravity return flow is discussed, and the test results of such a system are compared with those obtained utilizing a conventional metallic conductive paths technique.
Abstract: In airborne electronic packages, for either thermal or electrical reasons cooling air often is not ducted directly over the components but is passed through a heat exchanger. Consequently, the thermal path between the heat exchanger and the components must be of low impedance to result in efficient heat transfer. The high heat transfer coefficients obtainable as a liquid boils and condenses permit an effective reduction of the temperature drop between the electronic components and the heat exchanger. In this paper the development and design of an evaporative system utilizing gravity return flow is discussed, and the test results of such a system are compared with those obtained utilizing a conventional metallic conductive paths technique. Where heat dissipation or cooling air inlet temperature is high, the evaporative-gravity (ev-grav) system is shown to be the most effective.

9 citations


Journal ArticleDOI
TL;DR: The stellar inertial autonavigator (SINAV) as mentioned in this paper is a combination of photoelectric telescopes (star trackers) in combination with an inertial system to minimize or eliminate the cumulative effect of gyro drift.
Abstract: Automatic navigation of aircraft may be accomplished in a number of ways. Where radiative contact with the ground is satisfactory, systems such as the conventional radio ranges and the more recently developed hyperbolic grid techniques are economical and normally reliable. However, in some regions of the earth and under certain atmospheric conditions, these types of radio aids may not be reliable. Other systems that involve radiative contact with the ground include radio mapping techniques and Doppler navigation; these generally require more expensive airborne equipment, although they are less subject to atmospheric disturbances. But since in military applications radiation from an aircraft furnishes a potential means of enemy detection, such techniques are relatively undesirable. At the present time, Doppler systems are the least subject to this objection. Inertial navigation makes use of acceleration detection and integration for obtaining information on the progress of the aircraft over the surface of the earth. It is independent of radiative contacts, and therefore free from such detection. On the other hand, it is subject to errors resulting from instrumental imperfections. In particular, drift of the essential gyroscopes leads to cumulative errors in indicated position; consequently, pure inertial autonavigators are limited in the flight time over which their indications are satisfactorily accurate. Use of photoelectric telescopes (star trackers) in combination with an inertial system provides a tie to basic inertial space, such as to minimize or eliminate the cumulative effect of gyro drift. Such a combination is known as a stellar inertial autonavigator.

5 citations


Journal ArticleDOI
TL;DR: In attempting to gain some insight into the synthesis and analysis of a stable platform system the simple assumption that the platform can be analyzed on a single-axis basis is adopted.
Abstract: In attempting to gain some insight into the synthesis and analysis of a stable platform system the simple assumption that the platform can be analyzed on a single-axis basis is adopted. The single-axis analysis is then made applicable to the three-axis case by introducing a coupling factor. Of course, the shortcomings of this assumption, such as the omission of mechanical interactions, must be recognized. The inherently close association of the stability of the servo-system and the basis character of the input-output response will generally require that design requirements be compromised. The servosystem is essential to effect a suitable reduction in the influence of disturbances, and the factors involved in achieving stiffness must necessarily be considered. Finally, in discussing the design and features of the servoamplifiers it should be realized that the conditionally stable character of the system and the large attenuation involved in securing adequate phase lead create a difficult circuitry problem. In this regard, active research and development programs are under way toward the development of improved transistorized amplifiers.

5 citations


Journal ArticleDOI
TL;DR: The historical behaviorial performance of the three major components of a Doppler navigation system the velocity sensor, the computer, and the heading reference are analyzed and presented graphically.
Abstract: A method of determining position error of Doppler navigation systems is discussed which is based on the component errors and on statistical considerations. Sample calculations for four typical systems are presented. The historical behaviorial performance of the three major components of a Doppler navigation system the velocity sensor, the computer, and the heading reference are analyzed and presented graphically. The weight trends of the components of Doppler navigation systems and of the complete systems are described. Possibilities of certain combinations of self-contained and ground-referenced navigation systems are discussed.

3 citations


Journal ArticleDOI
TL;DR: The data which have been processed so far indicate superior performance of the maximum likelihood method for azimuth estimation purposes, and a reliable indication was obtained of the detection efficiency, false alarm rate, and the obtainable azIMuth accuracy under a variety of conditions.
Abstract: In order to test and compare various azimuth estimating procedures, use was made of a search radar video simulator and a flexible high-speed digital video processor. The output of the video processor was recorded in digital form and analyzed on a general purpose digital computer. The azimuths of approximately 30,000 simulated targets at signal-to-noise ratios of 3, 6, 10, and 15 db were estimated by several methods. A reliable indication was obtained of the detection efficiency, false alarm rate, and the obtainable azimuth accuracy under a variety of conditions. The data which have been processed so far indicate superior performance of the maximum likelihood method for azimuth estimation purposes. The experimental results are presented in graphical form.

3 citations


Journal ArticleDOI
TL;DR: The general-purpose stored-program organization allows the C-1100 to be shared by various tasks during flight, and enables the same computer to execute a large variety of operations merely by changing the program.
Abstract: A pilot's job has become so complex that he must rely increasingly on support from automatic aids for such functions as aircraft stabilization, navigation, cruise control, and landing. The Transac® C-1100 series digital control computers are designed to handle these functions in a single computer for commercial and military aircraft. The C-1100 computers are entirely transistorized for small size and utmost reliability. While their modular structure allows variations in many features for different applications, the computers are characterized by high precision, typically one part in 106, and fast operation, typically 60,000 additions per second. The general-purpose stored-program organization allows the C-1100 to be shared by various tasks during flight, and enables the same computer to execute a large variety of operations merely by changing the program. A powerful system of internal and external decisions permits the computer to respond to both the en-route instructions by the pilot and to conditions of the system as sensed in one of the 64 data channels. A representative problem involving dead-reckoning and VOR-TAC navigation, automatic control of the aircraft, and fuel management illustrates how the computer is programmed. The functional and physical description should provide the reader with enough background to consider the computer in terms of his own application.

2 citations


Journal ArticleDOI
J. Kaye, H. Y. Choi1
TL;DR: In this paper, a brief introduction and review is presented of the problems of protecting and cooling airborne electronic equipment in present and future high-speed devices. But the authors focus on the thermal characteristics associated with high speed flight of manned and unmanned vehicles are related to the thermal problems of irreversible electrical and magnetic components.
Abstract: A brief introduction and review is presented of the problems of protecting and cooling airborne electronic equipment in present and future high-speed devices. The thermal characteristics associated with high-speed flight of manned and unmanned vehicles are related to the thermal problems of irreversible electrical and magnetic components which possess upper bounds of temperature for reliable operation. Various types of cooling devices, fluid flow processes, and techniques are presented and discussed, and the trends of future development are reviewed briefly.

2 citations



Journal ArticleDOI
TL;DR: In this article, interference blankers have been developed to give improvement ratio of 1000 in the presence of severe precipitation static of the order of 150,000 pulses per second for ADF receivers with the objectives of simplification, reduced size and weight, improved sensitivity, reduced intermodulation distortion, maintenance of the relative phases of the sense and loop signals.
Abstract: Interference blankers have been developed to give improvement ratios of the order of 1000 in the presence of severe precipitation static of the order of 150,000 pulses per second. Recently the blanking technique has been applied to ADF receivers with the objectives of simplification, reduced size and weight, improved sensitivity in the presence of interference, reduced intermodulation distortion, maintenance of the relative phases of the sense and loop signals, and general compatibility with ADF receiver operation.

2 citations


Journal ArticleDOI
TL;DR: In this article, the performance of an airborne moving-target indication (MTI) system, designed to detect moving ground targets, was shown to depend upon the video autocorrelation function of the ground return, both with and without a target.
Abstract: The performance of an airborne moving-target indication (MTI) system, designed to detect moving ground targets, is shown to depend upon the video autocorrelation function of the ground return, both with and without a target. The pulse-to-pulse video autocorrelation function is derived, and from it are obtained formulas for MTI cancellation and moving-target enhancement. Results are given only for a square-law detector.

Journal ArticleDOI
TL;DR: In this paper, the authors outline the flow of heat within, through, and from heat producing electronic parts in terms of internal thermal limitations, part surface and environmental ratings, and cooling indices.
Abstract: The results of adequate cooling of electronic parts are gains in part life and reliability. An engineering compromise between ideal electronic part temperature and the thermal point of diminishing return must be evaluated not only with respect to desired life, but also in terms of the electronic circuit and cooling efficiencies. This paper outlines the flow of heat within, through, and from heat producing electronic parts in terms of internal thermal limitations, part surface and environmental ratings, and cooling indices. Natural heat flow design data pertinent to conduction cooling of heat sources, tube shields, the placement and mounting of parts, and ?sink connectors? are presented.

Journal ArticleDOI
TL;DR: In this paper, the authors developed equations for cold plates and the effect of variations in fin configuration on performance are discussed. And the application of the cold-plate technique is illustrated for power transistors.
Abstract: A solution to the problem of cooling certain types of high heat-dissipating airborne electronic equipment is the modification of the equipment chassis to incorporate a simple plate-fin heat exchanger, sometimes called a ?cold plate.? In this paper equations for cold plates are developed and the effect of variations in fin configuration on performance are discussed. Theoretical and experimental results based on tubes mounted on a cold plate are found to compare very favorably. The application of the cold-plate technique is illustrated for power transistors. This method of cooling is shown to be useful and efficient.

Journal ArticleDOI
TL;DR: A proposal is offered by which cooling provisions may be standardized for airplanes of widely varying performance, and basic design parameters for the development of such a system are outlined, as are the economic factors involved.
Abstract: High-speed aircraft require the successful operation of large quantities of electronic equipment. The problem of providing a suitable environment for such equipment is of interest to both airplane and electronic designers. A proposal is offered by which cooling provisions may be standardized for airplanes of widely varying performance. Basic design parameters for the development of such a system are outlined, as are the economic factors involved.

Journal ArticleDOI
TL;DR: In this article, a comprehensive review of the problem of indicating the vertical from moving bases and methods for its solution, both theoretical and practical, is made, based on research work carried out at the Instrumentation Laboratory of the Massachusetts Institute of Technology.
Abstract: A comprehensive review is made of the problem of indicating the vertical from moving bases and methods for its solution, both theoretical and practical. This is based on research work carried out at the Instrumentation Laboratory of the Massachusetts Institute of Technology. The concept of Schuler tuning for precise vertical indication is shown to be a particular application of aided-tracking feedback systems in which proper use of the effect of vehicle acceleration can be made to cancel the dynamic tracking error that otherwise would exist. The 84-minute natural period resulting requires accurate instrumentation. A discussion of equipment suitable for this work concludes the paper.


Journal ArticleDOI
TL;DR: The body of this paper deals with the plans of Airways Modernization Board for applying computers to air traffic control in its five-year Phase II program.
Abstract: The present manual system of air traffic control is described briefly to provide background material for the reader who is not familiar with existing practice. Then follows an outline of the plans for modernization of our national airways system as set forth in the Curtis Report. The body of this paper deals with the plans of Airways Modernization Board for applying computers to air traffic control in its five-year Phase II program.


Journal ArticleDOI
TL;DR: In this article, it was shown that radar target detectability is determined by the spot intensity rather than by the radar spot brightness, which is not a linear function of the radar parameters.
Abstract: Some factors that influence radar target detectability on a cathode-ray tube at high ambient light levels, such as occur in fighter airplanes, have been investigated. The signals considered are those that are intensity-modulated, as in B scopes and PPI. The problem is considered to consist of three parts that should be investigated separately: 1) the ambient brightness at which the indicator shall produce detectable signals, 2) the target spot brightness or intensity required for detection in this surround, and 3) the conversion of electrical signals into visual signals in the CRT. In this paper only 2) and 3) are discussed. It is found that with an intensity-modulated display, target detectability is determined by the spot intensity rather than by the spot brightness. The brightness of a conventional CRT shows an early saturation, but the intensity increases uniformly. Neither brightness nor intensity is a linear function of the radar parameters.

Journal ArticleDOI
TL;DR: In this paper, the U.S. Flag Air Carriers now arrive at procurement specifications, and how they determine their current operational needs, and the responsibilities and activities of ATA, ARINC, AEEC and RTCA are described and related to the development and coordination of such specifications.
Abstract: This paper reviews some of the earlier developments of civil avionic equipment design specifications, and describes how the U.S. Flag Air Carriers now arrive at procurement specifications, and how they determine their current operational needs. The responsibilities and activities of ATA, ARINC, AEEC, and RTCA are described and related to the development and coordination of such specifications.