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The theory of linear statistical models is implemented to obtain an algorithm which accurately locates radar sites. True bearing and navigation data are used as input. The linear model developed is adaptable and allows removal of bearing errors that are nonrandom, or systematic. The model may be written in recursive form and used for real-time applications.

The evolution and state of development of the radars used in the Ground-Controlled Approach (GCA) systems of the U.S. Air Force is described. Emphasis is placed on the radar requirements of this application and the evolution made possible by the advances in component technology. We first review the concept of GCA operation and show how this leads to the requirements of the two radars in the system. Next we discuss the early history of GCA and the AN/MPN-1, the first operational system. The evolution of the GCA radars since the AN/MPN-1 is then summarized. Finally, we describe in more detail the AN/TPN-19. This is the most recent GCA system to be developed, and it makes effective use of array technology, frequency diversity, monopulse, pulse compression, and computer control.

This paper surveys the field of automotive radar and represents an expansion of a previous paper, "Automotive Radar-Problems and Promises" [1]. Both the roadside environment in which the car and driver operate and on-board physical environments in which the electronics must function are treated. Applications involving speed sensing, predictive crash sensing, obstacle detection, braking, and station keeping are addressed. Current radar system state of the art is reviewed. Considerations relating to target discrimination, weather penetration, and basic radar system parameters are covered. Modulation techniques for range determination are examined, and radar system configurations are discussed in an effort to identify the advantages and disadvantages of each. It is concluded that although considerable development work remains before radar becomes a practical automotive system, significant progress has been made.

This paper studies the application of Kalman filtering to single-target track systems in airborne radar. An angle channel Kalman filter is configured which incorporates measures of range, range rate, and on-board dynamics. Theoretical performance results are given and a discussion of methods for reducing the complexity of the Kalman gain computation is presented. A suboptimal antenna controller which operates on the outputs of the angle Kalman filter is also described. In addition, methodological improvements are shown to exist in the design of range and range-rate trackers using the Kalman filter configuration.

a unique aspect of the San Francisco Experimental Vessel Traffic System has been its extensive use of real time automatic processing technology. Automatic detection and tracking of vessels in radar coverage areas has successfully been accomplished even in the presence of clutter. Vessel movement information has been extracted, presented to operators on computer-animated displays, and traffic analyzed both automatically and at the request of operators. But these demonstrated capabilities should be employed only as a guide to the design of future systems and not interpreted as a literal prototype configuration. Future system designs should assume traffic will be controlled, rather than advised. Risk analysis based upon port geometry, traffic levels, and minimum turning radius can contribute to assessing deployment priorities. Vessel routing should be constrained to follow narrow tracks rather than broad lanes. A minimum configuration would be based upon a computerized Vessel Movement Reporting (VMR) system. Data entry and retrieval terminals could be available within the maritime community. Information, including guidance, could be selectively distributed to active ships via a novel multiplexed television transmission. All radar configurations would include automatic detection and tracking equipment. Finally, area navigation systems could be integrated with VTS. The opinions expressed in this document are those of the author, presented in the interest of stimulating discussion, and they do not necessarily reflect the views of either the Applied Physics Laboratory or the United States Coast Guard.

In radars that achieve a high subclutter visibility by coherent processing over several pulses, a serious problem appears in the form of blind Dopplers, or "speeds," at which target detection is impossible. Of the possible methods of eliminating these blind speeds, the most basic one that is employed when the performance requirements are high involves the use of several PRF's. These PRF's are chosen so that coverage is obtained at any Doppler with at least one PRF. The problem faced by the radar designer is to select the set of PRF's and the pulse numbers for each PRF so that the search frame time is minimized. This paper evolves a systematic method for the design of the blind-speed elimination scheme. A formalized approach is offered that shows the possible combinations of wavelength, PRF, and pulse number and the tradeoffs involved, without introducing the confusion ordinarily associated with multiparameter choices.

The developmental activities pertaining to the RF RATIOMETER was necessitated by the need for the continuous monitoring of VSWR in MEDIUM RANGE TRACKING RADAR being developed at Thumba Equatorial Rocket Launching Station, Trivandrum, and give warning when the VSWR reaches a value at which arcing is likely to occur. Since it is not possible to use the slotted line techniques at such a high power level as 1 MW, RF RATIOMETER becomes imperative.This equipment is coupled to the Tracking Radar in such a way as to trip it off when the VSWR exceeds a safe value. This equipment has the capability of measuring the VSWR over the complete frequency band of 10 MHz to 10 GHz.

The National Maritime Research Center, Kings Point, N.Y., is conducting projects dealing with the “new technology” in the field of navigation. This paper consists of a survey of this area of activity of the Center. The intent is not only to disseminate information to the wide community of navigators but also to structure a mutually beneficial communications link between the NMRC and the Institute of Navigation. The paper will cover the following projects, some innovative, others extensions of previous programs: —RAPS (Radar Automatic Plotting System) —MASS (MarAd Anti-Stranding Sonar) —TRANSIM (Simplified Transit) —MARINE RADAR TRANSPONDER —MARSCAN (Maritime Satellites Communication and Navigation System) —INTEGRATED CONNING SYSTEM

Advances in the design, development, and fabrication of key microwave components along with those in electronics have resulted in growing optimism about the application of radar technology to solving the automotive highway collision problem. However, before an automotive radar system can be fully realized, a major effort will be required to define the environment in which the system must operate, and to obtain a fundamental understanding of the influence of these RF parameters. One such parameter which will have a considerable effect on the design of automobile radars is that due to the presence of natural and man-made surfaces within the beamwidth of the antenna. Generally, the presence of such a surface will result in incident RF energy being reflected off the surface in a forward direction and some portion being scattered in a backward direction. This paper presents the results of a program which was designed to measure this type of reflectivity characteristic for common road surfaces. Measured data are presented along with a theoretical study demonstrating the influence that this phenomenon can have on highway collision radar systems.

The complex indicated angle technique, applicable to monopulse radars, is being investigated as a means of overcoming the serious degradation of elevation measurement caused by multipath when the target is within a beamwidth or so of the horizon. This technique makes use of the quadrature-phase component of the normalized difference signal, as well as the in-phase component. Results of analysis and computer simulation have been published previously. This paper reports results of a test program using a slightly modified AN/FPS-16 monopulse tracking radar and a simulated target. The results to date indicate a potential for high accuracy, though there are limitations as to the applications for which the technique appears feasible. A computer program has been developed to perform the elevation estimate and to resolve ambiguities.

Three microwave garnet phase-shifter designs are used in the AEGIS weapons system. The microwave design is straight-forward except that the toroid assembly is potted with silicone rubber to increase its power-handling capability and the magnetizing wires are shielded with a spiral-wrapped wire to prevent the propagation of higher order modes. The driver circuit uses a new "flux-feedback" concept for improved accuracy and employs monolithic circuits, hybrid circuits, and discrete components. Mechanical and electrical design of the interfaces with mating components are important cost considerations and the chosen designs are described in detail. Several techniques for improving production yield are discussed and a table of production statistics is provided. Performance histograms and data averages as a function of time and operating frequency are also presented.

The paper describes a special combination of high resolution, high accuracy, solid-state radar equipment with a sophisticated computer operated automatic acquisition automatic plot collision avoidance indicator. Technical characteristics and special features that make this equipment particularly suitable for the newer higher speed Merchant Marine vessels are described. A description is given of the separate displaying of high resolution radar and automatic navigational data. Information is also presented concerning application and performance features that make it particularly well suited for service aboard ships.

Solid-state array radar is of gyeat current interest because of the inherent reliability of solid-state devices and the concomitant promise for improvement in system reliability. However, no extensive reliability base has been established for solid-state devices employed under radar operating requirements. In this paper some of the important factors bearing a device reliability are treated. Accelerated life tests under RF conditions are presented for L-band power transistors. Preliminary life-test and failure-analysis data are also presented with recommendations on how the information can be used by the radar systems designer.

A technique to reduce radar pointing errors due to glint using frequency agility and amplitude weighting is presented. The reduction in rms tracking error is developed into an equation dependent upon the original glint tracking error, ?g, and the number of returns weighted, N. The rms tracking error is thereby reduced approximately by a factor of N. Finally, the equation formulated allows one to evaluate the reduction in glint error versus the number of frequencies chosen for frequency agility.

the vector analog computer (vac) is a new radio navigational instrument which enables a pilot (1) to fly a rectilinear course either on or off the Victor airways with no appreciable lateral displacement, (2) proceed directly to any given latitude and longitude with exact positional information at all times, (3) navigate directly to any specified holding point and then hold the pattern precisely, (4) make the transition to an ILS approach with extreme versatility, and (5) assist radar traffic controllers by providing more precise information about his aircratt's position in the traffic picture than radar can provide. VAC offers continuous readings of position, bearing, distance, and ground speed with signal reception from only one VORTAC station at a time. After proceeding beyond the range of the VORTAC transmitter it can still navigate for relatively long distances on mechanical memory. It is a superior anti-collision device, is readily adaptable to all aircraft from helicopters to jets, and is capable of directing an automatic pilot independently of the magnetic directional information normally required in beam guidance systems. This paper discusses the limitations of present radio navigation systems, offers a list of criteria for an airborne navigational director with the simplicity and accuracy of visual reference, and then explains the principles of design and operation of the Vector Analog Computer.

The measurement of the radar cross section of full-size targets in flight presents some unique problems. The techniques employed to maintain the dynamic range of the signal, facilitate data handling, and control the target aspect, all contribute to the efficiency with which the requisite data may be gathered and reduced. The approaches taken in solving these problems are discussed in connection with the U. S. Naval Research Laboratory (NRL) dynamic measurement radar. This system is specially designed for simultaneous pulse-by-pulse measurements at L, S, and X bands permitting a high degree of polarization flexibility. Data reduced from film records, when combined with program-derived aspect information, enables a graphical description of radar cross section to be plotted as a function of target aspect. Data from measurements of a C-54 aircraft have been plotted in this manner and show the variation of σVV, σHH at L and S bands, and σVV, σHH, σVH, σHV, σRR, σLL, σRL, σLR at X band. Operating experience with this system indicates the practicability of performing dynamic measurements.

This paper reports on progress in signal design that has led to improvedresolution capability in radar and communication systems without theuse of complicated signal-processing techniques.Two approaches to the problem of improving resolution capabilityare made. The first approach emphasizes the need to produce sharplypeaked autocorrelation functions. The optimum signal amplitude infrequency is specified to accomplish this, and the spectral density ofthe deterministic signal is shown to satisfy a homogeneous Wiener-Hopfequation. The second approach emphasizes the need to producelow and flattened cross-correlation functions, in order to distinguishthem (since they correspond to error outputs) from the sharply peakedautocorrelation functions. With the use of stationary phase integration,a detailed method for producing any desired cross-correlationamplitude is presented. In particular, the techniques necessary to producesinusoidally modulated cross-correlation functions are discussed.These tools are applied to a realistic N-signal processing system,and the resulting optimum signals are shown to be amplitude-modulatedchirped sinusoids. Detailed examples for physically justifiablesystem parameters are included.

Progress in coordinating the design of airborne radar equipment with the airframe is discussed, emphasizing such basic design characteristics as accessibility, form factor, heat dissipation, altitude, shock, vibration. R-F noise and primary power supply. A review of the scope of present-day installation problems follows, giving specific examples of coordinated design. Suggestions for improving current design practices include an early exchange of information among all agencies concerned, close liaison as the design unfolds, and throughout, an appreciative understanding of each others problems.

The development of an unambiguous unit-distance code configuration for automatic altitude reporting via the ATC Radar Beacon System is described. This code provides for compatible altitude reporting in increments of 100, 250, and 500 feet within one common system. The code is developed by using Karnaugh mapping techniques. Some assumptions and requirements are set forth to provide guidance for the determination of the most desirable code. A brief presentation of a developmental code in use in the United Kingdom is also given. It is concluded that the flexibility of the unit-distance code affords a satisfactory compromise which can satisfy the objectives of the various users.

An effective forward step in terminal area air traffic control has been accomplished by development and installation of Radar Approach Control (RAPCON) Center and control tower prototype facilities described. Esoteric complexes detailed provide airport and approach controllers with radar and communication implementation of manual aids to jet and propeller driven traffic control procedures and techniques. Equipment reported also serves as manual backup and override facilities capable of eventual expansion to fully automatic air traffic control system operation dictated by high-speed jet performance characteristics.

Air traffic information collected by long range radars is available to the CAA at the radar sites. This information will be remoted to the air route traffic control center. A theoretical study is made here of resolving power and the information rate inherent in the air traffic, radar video signals, displays, and various transmission techniques. Air traffic provides the basic information and radar video establishes the maximum information rate for the system. On the other hand, a display can show only a limited amount of this information. But if the display magnifies a small area, it can show all the information the radar collects. Between the radar and the presentation, the information may be transmitted by a wide band communication channel that transmits all the radar video information or it may be compressed by analog, digital or manual methods so that it can be transmitted over a much narrower communication channel. The final choice of system components will be decided by the requirements of the basic problem for resolution, off-centered displays and the needs of the traffic controller.

This paper describes some preliminary results in a study of a twin-channel frequency-modulated radar which is capable of measuring both the range and bearing of a target from a stationary aerial system consisting only of one transmitter and two receiving elements. The basic operation of the system is described along with some experimental results for range measurement. Also the proposed extension of the work to examine the bearing resolution of the system is outlined.

Techniques are presented for the approximate calculation of optimum midcourse fixed- and variable-time-of-arrival velocity-correction schedules. The theoretical results are compared to those of a simulation program which utilizes Earth-based radar and onboard sextant tracking data processed with a Kalman filter for two typical interplanetary transfets. It is shown that the agreement between theory and simulation improves as the amount of radar data processed is increased and that the theoretical optimum timing equations provide an accurate first estimate for generating interplanetary midcourse velocity-correction schedules.

In the foreseeable future, a radar system immune to clutter through use of a special reflecting tag could aid the the driver to maintain a safe distance between the cars, the closing rate, and the driver's ground speed. To eliminate the clutter and blinding problems, a system has been designed that uses an harmonic radar concept. An experimental harmonic radar collision avoidance system has been built using an RCA transferred electron oscillator power source. The measurement of distance was quite repeatable and of adequate accuracy for highway use. In the automatic braking system once the alarm is given, the brake pedal is automatically depressed by a force that increases linearly with time up to maximum pressure until the alarm is removed. The force is then removed linearly with time. The harmonic radar system will reject all blinding signals that it receives other than the second harmonic of its transmitted frequency. The possibility of a false alarm from crosstalk interference is reduced with harmonic radar. The system is adaptable to integrated and printed-circuit techniques. It operates in regions of the frequency spectrum which are still underutilized and spectrum space can be set aside for its future use. The average power density in the immediate vicinity of the antenna is 0.2 mW/cm2. When a dangerous driving situation is detected, an audible warning is sounded and a warning light is flashed. The harmonic radar system provides protection from certain types of rear-end collisions; those where the car in front is in line with the following car. Vehicles that are stopped, but not parallel to the center line, will not be "seen" by the following car because of the purposefully narrow beam of the passive reflector./SRIS/

This paper describes the use of frequency-modulated radar techniques for accurate location of faults on power transmission lines. It includes the design of a prototype frequency-modulated fault location system. Test results of this system operating on a simulated transmission line are also included.

This paper covers several of the significant "inservice improvements," including the introduction of simulation study techniques, new displays, and automatic data processing that have been taken to meet the air traffic control requirements. A review of the three basic simulation methods: graphical, dynamic, and fast time is provided together with a description of the dynamic simulation facilities at the Technical Development Center of the Federal Aviation Agency (FAA), Indianapolis, Ind. The requirements for daylight viewing displays and the programns conducted to obtain TV types of radar displays are included. The report concludes with the introduction of digital computers to perform certain data processing functions.

The problem of designing finite-pulse-train radar signals and receivers to maximize the detectability of targets masked by thermal noise and clutter returns is considered in this paper. A practical constraint is introduced: the amplitude of each subpulse in the transmit waveform is taken to be fixed. The need for such a constraint is dictated in most radar applications, because the transmitter is most efficiently utilized by saturating its amplifying tube. An algorithm for generating optimal waveforms subject to this new constraint is presented, and the performance of the resulting waveforms is compared with those obtained using existing optimization techniques.

This paper describes a test method which enables one to locate reflections on traveling-wave tube helices and to measure the return loss of each reflection. This information is needed for traveling-wave tubes used in pulse code transmission since "echo" pulses arising from reflections can distort the meaning of the code. This test method employs millimicrosecond pulses in a radar circuit with a stroboscopic viewing system. The sensitivity of the system permits easy observation of reflections having return losses as high as 40 db. Using this method we have been able to identify two previously unsuspected sources of helix reflections.

This paper describes the design and development of a double-ridge waveguide designed to propagate both C-band and X-band (5,400 and 9,300 mc) so as to allow for a common waveguide installation in commercial airliners which could use either a C-band or an X-band weather penetration radar. This double-ridge waveguide is capable of propagating over the desired frequency range with single mode operation only; it yields attenuation at C-band which is only slightly higher than that of normal C-band waveguide and has somewhat reduced attenuation at X-band compared to standard 1 X 1/2 rectangular waveguide. This double-ridge guide has been adopted by Aeronautical Radio, Inc. and is specified in their Characteristic No. 529 entitled "5.7 Cm Weather Penetration Airborne Radar." This paper also gives an analysis of the calculated guide wavelength in this double-ridge guide, attenuation, and peak power-handling capabilities; and compares the results of these calculations with measured data. Peak power-handling capability for this double-ridge guide is well within the requirements of this application. The testing procedures used for high-power breakdown measurements are described. This paper also covers the development of double-ridge waveguide flanges, elbows, bends, twists, transitions, and flexible waveguide for use over this extremely broad band.

In many maintenance situations for certain weapon systems, such as anti-aircraft systems, the problems confronted are: 1) which priority for repair is to be assigned, and 2) which type of component should be assigned priority for repair. This can be done on the basis of mean time to system failure. This paper discusses the reliability characteristics of a system of two paralleled radars working in conjunction with two paralleled computers. The system is in up stage even if one computer and/or one radar fails. The system failure takes place only when both the computers or both the radars are in failed condition. The distribution of time to system failure and its expectation have been derived assuming that the failures occur following Poisson distribution and the repair times follow the negative exponential distribution for these two types of subsystems imposing head-of-the-line priority and preemptive resume priority for the repair process. The results are discussed with reference to numerical examples. It has been observed that the mean time to system failure is higher when the head-of-the-line priority discipline is adopted for repair of components, especially when the repair times are shorter.

The Dynamic Target and Countermeasures Simulator described herein was developed at the U. S. Army Signal Missile Support Agency Laboratories, White Sands Missile Range, Las Cruces, N. M., by a group of Signal Corps engineers and technicians, utilizing components from scrapped radars and standard RF test equipment. This versatile simulator can be used to test existing radars for signal saturation and electronic counter-countermeasures techniques, such as regulating RF and video gain, contrast, etc. Provision is made to simulate antenna patterns and to vary the size of the target from 0.1 to 100 square meters. The expense involved in training radar operators to cope with raids involving hundreds of aircraft has led to the development of various target simulators. As the state-of-the-art in electronic countermeasures (ECM) improved, it became apparent that ECM simulation was also necessary to train radar operators under the conditions that would prevail when aircraft would be radiating thousands of watts of jamming power. Most of the simulators developed used IF or video injection of target signals in the simulator and did not provide the realism desired or allow the radar operator to exercise electronic counter-countermeasures (ECCM) techniques effectively. The problem then became one of realistic simulation of both target and jamming signals. Field experience at White Sands Missile Range (WSMR) had demonstrated that simulation could be accomplished most effectively at the RF level. This finding, by WSMR engineers, led to the design and development of the Dynamic Target and Countermeasures Simulator.

Uniform coherent pulse trains offer a practical solution to the problem of designing a radar signal possessing both high range and range-rate resolution. The Doppler sensitivity provides some rejection of off-Doppler (clutter) returns in the matched filter receiver. This paper considers the use of a processor in which members of the received pulse train are selectively weighted in amplitude and phase to improve clutter suppression. The techniques described are particularly suitable for rejecting interference entering the processor through ambiguous responses (range sidelobes) of the signal. The complex weights which are derived are optimum in the sense that they produce the maximum clutter suppression for a given detection efficiency. In determining these weights, it is assumed that the distribution of clutter in range and range rate relative to targets of interest is known. Thus, clutter suppression is achieved by reducing the sidelobe levels in specified regions of the receiver response. These techniques are directly applicable to array antennas; the analogous antenna problem would be to reduce sidelobe levels in a particular sector while preserving gain. Complex weighting is most successful when the clutter is limited in both range and velocity.

The evolution of radar technique is traced and the radar-development program of the United States Army Signal Corps at the Signal Corps Laboratories, Fort Monmouth, New Jersey, described from its inception to America's entry in the War. Two radars developed by the Signal Corps Laboratories during this period, SCR-268 and SCR-270, are described in detail.

This paper describes the design, construction, and performance of an experimental radar, in which an electronically scanned X-band array is employed as the receiving antenna. Backscatter from targets uniformly illuminated from a separate transmitting antenna is intercepted by 128 horn antennas, unequally spaced over a nine-foot circular aperture. The received signals are processed electronically to provide a complete scan of a 30X30 degree field every ten milliseconds. Resulting target images were displayed on a cathode ray tube and recorded on 16-mm motion picture film, for varying conditions of target motion using monochromatic and frequency-modulated X-band illumination. Sequences of motion picture frames obtained from a rotating copper cone are presented, which demonstrate significant changes in the image and side-lobe interference patterns for small changes in target aspect angle. Side-lobe interference effects were reduced by integrating many antenna scans as the target rotated; a clear image of a foil letter R is presented that demonstrated this result. The main objective of this work was to test this radar technique as an approach to target recognition.

This paper outlines the work currently being carried out at the Royal Radar Establishment (RRE) in the RF and Microwave National Standards Division of the British Calibration Service, on both hot and cold noise standards and comparator systems. The design of three cryogenic noise sources for use in WG15 are described in detail along with the theoretical calculation of their output noise power spectral density. A noise-adding radiometer is analyzed, and finally the sources of uncertainty involved in a recent calibration are discussed.

The elementary electronics circuits familiar to radar men are not limited to one field, as is shown by this description of a typical industrial electronics application. Ultrahigh frequency techniques are described as used for register control in the printing and paper industries.

This paper contains a brief summary of the Signal Corps' contribution to the antenna art. Emphasis is on the post World War II period and on microwave antennas. Only developments which have had reasonably wide application are discussed.

Needs for nondispersive microwave variable delay devices exist in RADAR, communication, ECM, and test systems. Methods which have been investigated to satisfy these needs are reviewed in this paper. Techniques that employ solid-state microwave acoustic interactions and that have promise of satisfying some of the microwave variable delay requirements are described in detail, and their present capabilities and potential capabilities are discussed. One technique employing magnetoelastic waves is particularly promising and the state of the art of this technique is analyzed thoroughly.

General considerations pertaining to the parameters of a tracking radar are discussed and an optimum set of the system parameters for long range capability are arrived at. A concise description of the radar microwave transmit/receive chains designed and developed here and the measured performance on various subsystems are given and this data is then compared with the requirements arrived at in the above context.

The 120-foot diameter Haystack antenna operates at X-band and is used for satellite communications, radio astronomy, and radar astronomy. Haystack is used to study stars, planets, the sun, the moon, and earth satellites. In order to point the antenna to within 1/10 beamwidth (22 seconds of arc) and to provide flexible control and data processing for diverse users, a digital computer is tightly integrated into the control system. The parameters of an experiment and computer control are arranged via simple operator discourse through a keyboard/printer. The computer system can simultaneously direct the antenna, process receiver signal data, drive convenient operator displays, and permit operator discourse. Thus, processed signal data can be observed in real time, and experiment modifications rapidly implemented. The computer control system is in full operation.

Ground-Controlled Approach (GCA) was developed to meet military requirements for a "universal" blind-landing system, needing no additional airborne equipment or pilot indoctrination beyond short-range voice radio and basic instrument training. The talk-down principle, previously discredited in favor of beam-approach systems, was proved feasible when accurate information was available. The requirements of rapid radar scanning, at low angles to the horizon, with a high degree of accuracy at short range, were met by linear dipole arrays at 3-cm wavelength, with mechanical variation of waveguide width varying the angle of radiated power to the array. Half-power beamwidth for the elevation antenna was 0.1°; for the azimuth antenna, 0.8°. To translate range/angle data into a linear relationship of range vs deviation in feet from a selected approach path, a new type of indication was developed, i.e., Expanded Partial PPI Indicator (EPI). This permitted direct interpretation and immediate transmission of the data to the pilot by the controller. GCA's wartime service record, beginning late in 1944, proved its effectiveness under all conditions and led to further modifications and simplification for postwar commercial as well as military use.

A brief discussion of several types of CW radar will be given. Emphasis will be directed toward the function of the tube in each of the various radar systems. A detailed discussion of the requirements placed on the CW oscillator for each of the radar systems will be made. Tube characteristics which limit radar performance will be discussed. Some measuring techniques for evaluating magnetrons and klystrons will be discussed.

The errors in beam rider system are largely due to lags in the tracker and missile servos. To a certain extent it is possible to reduce these errors by increasing the stiffness of the servo system, but this would demand larger band-widths and hence increased response to noise. There is therefore an optimum bandwidth giving the minimum possible miss-distance. In his approach to the design problem, Whitfield3 assumes the target flying directly towards the radar set and accelerating perpendicular to the radius vector. This is a hypothetical trajectory, and the design approach has therefore to be modified to suit a particular tactical situation that the beam rider system is most likely to face during its operation. The present paper attempts to present this modified design philosophy.

A seven-hop 295-mile combined microwave and tropospheric forward-scatter communications system is being installed for carrying voice, timing, telemetering, radar data, and controls for the Eglin Gulf Testing Range. System design of the frequency-diversity 7000-mc microwave system is reviewed, as well as the design of the four-fold diversity 2000-mc scatter system. Problems of special interest on transmission of timing signals, telemetry, and radar digital data are discussed and solutions indicated. Considerations for reliability, flexibility and ease of maintenance are indicated. Integration of the range operations by use of the commnnications system is described.

The objective of this paper is to identify problem areas in the use of radar and to show the implication of these problems to those involved in ship operations and radar development. The discussion includes the operating procedure for radar, the philosophy of radar use in the merchant service and the modification thereto required by increased speeds and traffic, the relevance of basic operator capabilities, and operator information requirements versus current display capabilities. These problem areas and requirements were identified as one aspect of a study of “Human Factors in Ship Control” conducted for the Maritime Administration (MA-4221). The paper emphasizes the need for research designed to develop a radar system which meets the deck officer's requirements yet which is compatible with his capabilities and the cost constraints of the merchant service.

The communications capacity required of the Common System for the year 1965 is projected from figures of fix postings for 1946 and 1954. In 1946, 8,800,000 fixes were reported; in 1954, 16,900,000 fixes were recorded. If this trend continues, the forecast for 1965 is 1,100,000 instrument approaches, and 32 million fix postings! Additionally, there are new requirements to be considered for the 1965 communications system. These are Airport Surface Detection Equipment and expanded helicopter service making short distance flights between cities and from airports to urban heliports, plus the ever increasing tendency for all flights to be controlled similarly to IFR flights. Studies on improving communications, conducted in the Boston area, have indicated the pattern for future work to be undertaken. One finding was the excessive amount of time spent by the controller communicating rather than controlling. The possibility of using codes for routine communications to eliminate repetition of messages between pilot and controller was suggested by this study. The Common System Beacon, under development primarily for radar reinforcement and flight identity, with the addition of altitude information would lend itself well to coding, with a subsequent saving in voice communications time. In the investigation of a communications system for the Common System of Air Navigation and Traffic Control, the goal should be for one of limitless communications capacity. This is the challenge for the communications engineer.

I have now had the privilege of sailing in the Peninsular and Oriental Company’s liner Canberra for nearly two years, originally as Senior Watchkeeping Officer and for the last year as Navigating Officer, and I am now even mow convinced that the bridge design in Canberra is the only workable one in fast passenger liners on world routes. All officers who have had the privilege of sailing her are agreed that with the increase in the numbers of ships fitted with radar our system and layout are essential for safe navigation where a quick reliable radar plot is required and where all the navigational equipment is at one's finger tips and not buried in obscure corners, as is the practive of most merchant ships.

Radio frequency interference has been a particularly difficult area for achieving effective standardization, principally because of technical considerations, but also because it is of concern to so many interests and activities. Prior to World War II, standardization efforts were mainly confined to the medium-frequency broadcast band. During the war it became evident that the problem must be considered on a much broader basis. More recently, highly critical systems being used in space research have placed additional requirements on system engineering for interference-free operation. Radio frequency interference can mean the difference between success and failure of a costly space project. There are four general categories in which standardization efforts are required: 1) terms and definitions, 2) measurement methods, 3) instrument characteristics, and 4) interference limits. Various professional, industrial, and governmental organizations are working at both national and international levels on standards in these areas.