摘要:

The mathematical techniquechosen to present targets from many radars on a single two–dimensional plane is discussed herein. The choice was based upon accuracy needed as well as computational simplicity.This presentation uses the simplest possible mathematics in order to make the technique understood by a diverse audience.Definitions and orientations with respect to longitudes, latitudes, and mathematical coordinate systems are contained in Section 2. Supporting diagrams are also included.The derivation of projection equations from earth points to coordinates in the stereographic plane is discussed in Section 3; while contained in Section 4 is the derivation of the tan ψ, which represents a rotation of radar azimuth into the systems plane to compensate for the varying orientation of North in different radar planes. The negative of ψ, the angle β, is then introduced. β appears in the equations of Section 5.Lastly, presented in Section 5, is the derivation of the equations for mapping a radar target from a radar plane to a systems

ISSN:0028-1522    

DOI:10.1002/j.2161-4296.1977.tb01271.x

出版商:Blackwell Publishing Ltd    

年代:1977

数据来源: WILEY

摘要:

Anew vor(vhf omni‐range) goniometer design which promises to improve the reliability and maintainability of the VOR ground station is described. The heart of the new concept is the use of two digital phase shifters to produce the rotating figure–of–eight pattern of conventional VOR. Using digital circuits, the goniometer adjustments and calibration reduce to timing adjustments of binary signals. A common clock used for timing the digital phase shifters also synchronizes the 30 Hz modulation of the 9.96 kHz refe

ISSN:0028-1522    

DOI:10.1002/j.2161-4296.1977.tb01272.x

出版商:Blackwell Publishing Ltd    

年代:1977

数据来源: WILEY

摘要:

Anew lunar methodof determining approximate longitude (and coincidentally latitude) without time is presented, explained and illustrated with an example. The method has been specifically designed for emergency use by the practicing marine celestial navigator who normally uses a chronometer and radio time checks but unexpectedly Has neither.The method is simple and does not require measuring the arc between two bodies; simultaneous sights; special tables; prior planning; lengthy or difficult computations; or unusual plotting. It utilizes conventional sextant altitude observations, sight reduction and plotting, and a minimum of additional computation. Accuracy of the method is discussed.

ISSN:0028-1522    

DOI:10.1002/j.2161-4296.1977.tb01273.x

出版商:Blackwell Publishing Ltd    

年代:1977

数据来源: WILEY

摘要:

the recent development of the microcomputerhas already significantly affected the electronics industry. It is expected to have an even more profound effect on many industries as its use proliferates. What will be its impact on Navigation Avionics?This paper reviews the development of the microcomputer and discusses the current state–of–the–microcomputer art. The capabilities and limitations of current microcomputers are summarized and expected future developments are identified. Several applications of microcomputers are discussed to illustrate the wide variety of applications which have already been realized. Using this information, including several current applications in navigation equipment, several predictions are advanced on the future impact of microcomputer use in navigation equipment. The mutual interdependence of common MUX communication and the use of local processors is highlighted.These developments are expected to have a significant effect on the cost and performance of future navigation systems and the source of these improvements is ident

ISSN:0028-1522    

DOI:10.1002/j.2161-4296.1977.tb01274.x

出版商:Blackwell Publishing Ltd    

年代:1977

数据来源: WILEY

摘要:

a method known as asymptotic singular decompositionfor compacting tabular data will be discussed. On considering a table as a matrix, the method proceeds to decompose the matrix into its associated singular values and singular vectors. Once decomposed, an element of the original matrix can be reconstructed to any degree of accuracy. Depending on accuracy requirements, most practical benefit of the method arises if the first–order solution is satisfactory. In this case, an M × N table can be decomposed into one of only M + N entries. The method can be applied to most any navigational table. In this paper, application of the method to the OMEGA Propagation Correction (PPC) Tables will be presented along with a discussion on the accuracy of the first order solution. The method should prove extremely useful in reducing the amount of memory needed to store a navigational table in either a mini– or micro–computer or possibly even in a hand–held ca

ISSN:0028-1522    

DOI:10.1002/j.2161-4296.1977.tb01275.x

出版商:Blackwell Publishing Ltd    

年代:1977

数据来源: WILEY

摘要:

The office of aeronauticalCharting 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.

ISSN:0028-1522    

DOI:10.1002/j.2161-4296.1977.tb01276.x

出版商:Blackwell Publishing Ltd    

年代:1977

数据来源: WILEY

摘要:

the adp(advanced development program) described in this paper is an outgrowth of Navy exploratory development efforts in laser gyro technology together with the highly successful flight test demonstrations of two prototype laser gyro guidance/navigation systems: the Navy‐developed ATIGS (Advanced Tactical Inertial Guidance System) and the Honeywell LINS (Laser Inertial Navigation System) developed under internal development funds.The tests and evaluations completed on the ATIGS and LINS developmental hardware have demonstrated the ability of today's laser gyro strapdown technology to meet basic moderate quality inertial navigation system performance requirements. Under the RLGN Advanced Development Program, a single package laser gyro navigator (including laser gyro and accelerometers, computer and power supplies) is being developed to assess low life—cycle cost potential, reliability, maintainability, and performance factors in a full military environment. This not only includes land—based, fixed and rotary wing aircraft environments, but sea‐based aircraft environments as well, and the associated capability of the RLGN to align in the dynamic carrier motion environment. The data provided by the RLGN advanced development program will form the foundation for proceeding into the engineering and preproduction development program that will provide cost‐effective laser gyro inertial navigation system to meet a broad range of future weapon systems req

ISSN:0028-1522    

DOI:10.1002/j.2161-4296.1977.tb01277.x

出版商:Blackwell Publishing Ltd    

年代:1977

数据来源: WILEY

摘要:

TheDifferentialLaserGyro(dilag) is a significant advancement in strapdown inertial guidance. Its four simultaneously oscillating modes allow it to retain the advantages inherent in a laser gyro without many of the drawbacks found in present two mode units.The DILAG concept employs two complete laser gyros operating in the same optical cavity. The gyros are distinguished from each other by their polarization state; one is right circularly polarized (RCP), while the other is left circularly polarized (LCP). Both gyros are biased out of their respective dead‐band regions by the same Faraday cell. Because of their opposite polarization states, the gyros respond with equal but opposite frequency shifts to a given rotational input rate. When one gyro output is subtracted from the other, the result is a doubling of rate sensitivity combined with a cancellation of the common Faraday bias.Operated in this manner, the DILAG becomes insensitive to variations in the Faraday bias and thereby eliminates the usual requirements for Faraday cell stability. In addition the DILAG requires no dithering, either mechanical or electrical.This paper considers these points as well as a number of other special characteristics of the DILAG which offer significant improvements in gyro performance. Among those areas discussed are the reduction in shielding requirements, the elimination of all moving parts including those associated with cavity length control, and the advantages occurring in data collection and self check capabilit

ISSN:0028-1522    

DOI:10.1002/j.2161-4296.1977.tb01278.x

出版商:Blackwell Publishing Ltd    

年代:1977

数据来源: WILEY

摘要:

beginning januaey1, 1972, the standard time signal broadcasts no longer give directly the rotational position of the Earth to an accuracy of 1/10 of a second of time, as had been done previously. Instead the new UTC Time Signals may depart from the rotational position of the Earth by as much as 9/10 of a second. To retrieve the rotational position of the Earth to an accuracy of 1/10 of a second, it is necessary to apply a supplementary correction DUT1 which is coded into the time signal itself. Methods for using DUT1 in various applications are reviewed.

ISSN:0028-1522    

DOI:10.1002/j.2161-4296.1977.tb01279.x

出版商:Blackwell Publishing Ltd    

年代:1977

数据来源: WILEY

摘要:

the author believes that the literaturegives a misplaced emphasis, perhaps, to the problem of deciding on the form of error distributions in navigation. It is argued here that the crucial consideration is often the costs associated with the errors, which inevitably occur.

ISSN:0028-1522    

DOI:10.1002/j.2161-4296.1977.tb01280.x

出版商:Blackwell Publishing Ltd    

年代:1977

数据来源: WILEY