摘要:

Abstractthe effectivenessof the means employed in the search for THRESHER was related strongly to the quality of navigational control. Loran A, Loran C, Decca Navigator, reference buoys, radar, and navigation by echo‐sounding and acoustical ranging were all eventually available to the Research Vessel ATLANTIS II during the period April 11 to May 27, 1963. All navigational data were taken as frequently as possible (every one to five minutes), to provide enough samples for statistical treatment. Especially in the case of Loran A early in the search, this procedure provided closer navigational control than ordinarily would be estimated from the known characteristics of the system. Loran C provided but one good line of position. Combinations of lines of position from different systems were used repeatedly, but not generally successfully. Decca Navigator, buoys and radar, and soundings were the most effective of the tools used by ATLANTIS II. With their use, the positions of known fixed objects, such as contact Delta, could be reoccupied reliably. On the other hand, it was not equally possible to relate the positional data from several ships, probably because of differences in navigational technique. Determining the location of deeply towed search instruments in relation to one's ship was another navigation problem, of equal or greater magnitude, which was solved adequately by a method of acoustical positionin

ISSN:0028-1522    

DOI:10.1002/j.2161-4296.1965.tb01800.x

出版商:Blackwell Publishing Ltd    

年代:1965

数据来源: WILEY

ISSN:0028-1522    

DOI:10.1002/j.2161-4296.1965.tb01801.x

出版商:Blackwell Publishing Ltd    

年代:1965

数据来源: WILEY

摘要:

Abstractomega is a verylong‐range VLF navigation system generating hyperbolic lines‐of‐position by phase difference measurements of 10.2 kc/s time‐shared transmissions. A new multi‐frequency signal format is described which will increase the system utility. The background, theory, and results of a six‐year developmental effort on theomeganavigation system are presented. A worldwide system employing eight stations is feasible. Such a system would be straightforward in use and have an accuracy of one‐half to one mile. Operational results of twenty‐five shipboard installation

ISSN:0028-1522    

DOI:10.1002/j.2161-4296.1965.tb01802.x

出版商:Blackwell Publishing Ltd    

年代:1965

数据来源: WILEY

摘要:

Abstractconstant‐error isogramsapplicable to range‐range navigation aids, in which the distances to two fixed stations are determined, are well known. The error (actually precision) of a two LOP fix, for such systems, may be expressed statistically in terms of the precise bivariate equi‐probability error density ellipse or by the simpler, but conservatively approximate,drmscircle. This error is a function of the “angle of cut” of the two lines of position, the standard deviation of the errors in measuring the distances to the two stations, and the degree of correlation of these two measurement errors. Available error isograms are applicable to relatively short baseline systems and are based on a flat earth approximation. Proposed VLF systems would employ long baselines. When the baseline is several thousand miles in length the flat earth approximation is no longer valid. The magnitude of the discrepancies which are caused by the plane earth approximation are shown to be appreciable. The equations for the constant‐error contours are derived (based on a spherical earth) as a function of baseline length and the “angle of cut” of the two lines of position. Various error isograms were computed and plotted through the use of a digital computer. Several examples are presented. Area coverage is discussed as a function of baseline length, minimum and maximum reception distances, and the range of acceptable angles of cut between the two lines of position. The range of acceptable angles of cut is a function of the maximum acce

ISSN:0028-1522    

DOI:10.1002/j.2161-4296.1965.tb01803.x

出版商:Blackwell Publishing Ltd    

年代:1965

数据来源: WILEY

摘要:

Abstractthis paper containsa description of the Norden marine course computer and its sea evaluation aboard the S. S. Pioneer Ming. The computer provides a course control signal to a gyropilot as it estimates position and performs a number of other computations. It was designed to be a building block for partially automated ships and has been specified for AGS type ships. The device was successfully tested and found to be a reliable, accurate navigational aid. A standard error of only 4.5 miles results 12 hours after position fix—after 36 hours the error will be 7.8 mile

ISSN:0028-1522    

DOI:10.1002/j.2161-4296.1965.tb01804.x

出版商:Blackwell Publishing Ltd    

年代:1965

数据来源: WILEY

ISSN:0028-1522    

DOI:10.1002/j.2161-4296.1965.tb01805.x

出版商:Blackwell Publishing Ltd    

年代:1965

数据来源: WILEY

摘要:

Abstractthe importanceof the basic magnetic compass to the navigator of general aviation aircraft is discussed. An explanation is given for the various components of magnetic forces which cause deviation. It is suggested that a three‐component corrector system be used in such compasses, and that spherical compass bowls be employe

ISSN:0028-1522    

DOI:10.1002/j.2161-4296.1965.tb01806.x

出版商:Blackwell Publishing Ltd    

年代:1965

数据来源: WILEY

ISSN:0028-1522    

DOI:10.1002/j.2161-4296.1965.tb01807.x

出版商:Blackwell Publishing Ltd    

年代:1965

数据来源: WILEY

摘要:

Abstractthe dead‐reckoningnavigation system described, was designed to meet Canadian Army requirements for a navigation aid which would provide commanders of tracked or wheeled vehicles with continuous, accurate, positional and navigational information. The system permits vehicle movement about the battlefield under conditions of poor visibility such as in darkness, in fog or smoke and in country devoid of landmarks such as desert or arctic regions or in areas where reliable maps are not available. The, system continuously computes and displays the exact geographical location of the vehicle and the direction in which it is heading. The inputs to the land navigation system are: distance; travelled by the vehicle as measured by an odometer drive, and direction of travel obtained from a true north seeking gyro compass. The complete system consists of a Computer, Heading and Position Indicator, Vehicle Position Plotter, Heading Indicator, Gyro Compass and Power Supply.The Computer employs a unique and highly accurate mechanical analogue computing element (Ball Resolver) to convert inputs representing distance and direction of travel into electrical output pulses which represent the East/West and North/South movement of the vehicle. The commander's Heading and Position Indicator displays the computer outputs (vehicle position) as two four digit map references, and a 0–360° dial continuously indicates the grid heading of the vehicle. The Vehicle Position Plotter provides a continuous pictorial representation of the geographical location of the vehicle and the direction in which it is headed. An illuminated image of a positional dot and directional arrow is projected onto the underside of a standard military map attached to the top of the Plotter. This display enables the navigator to pictorially steer the vehicle along any prescribed course without manual plotting or mental calculations. The Heading Indicator, necessary only in vehicles where the driver is separated from the commander, continuously displays vehicle heading and can be used as a steering aid for a prescribed heading. The system operates from the vehicle battery and employs a static inverter to obtain the alternating current required by the Compass and other systems units. The land vehicle navigation meets the accuracy requirements of 1% of distance trave

ISSN:0028-1522    

DOI:10.1002/j.2161-4296.1965.tb01808.x

出版商:Blackwell Publishing Ltd    

年代:1965

数据来源: WILEY

ISSN:0028-1522    

DOI:10.1002/j.2161-4296.1965.tb01809.x

出版商:Blackwell Publishing Ltd    

年代:1965

数据来源: WILEY