摘要:

AbstractIt can be shownthat the geometry of the solution for orbital plane parameters is identical in part to that of the determination of a geographical fix from star altitude sightings. One standard technique used in air navigation has been adapted to the determination of orbital plane parameters. The sample tables prepared have been checked out using actual sextant sightings made aboard Gemini VII.

ISSN:0028-1522    

DOI:10.1002/j.2161-4296.1968.tb02233.x

出版商:Blackwell Publishing Ltd    

年代:1968

数据来源: WILEY

ISSN:0028-1522    

DOI:10.1002/j.2161-4296.1968.tb02234.x

出版商:Blackwell Publishing Ltd    

年代:1968

数据来源: WILEY

摘要:

AbstractThe irradiation phenomenonhas the effect of displacing the apparent edge between a bright area and a darker area toward the latter. One method of quantifying this effect is by determining the minimal angle of resolution (MAR) between a point source and an extended bright source. This paper presents the results of a series of investigations on the MAR between a point and an extended circular source and between a point source and a simulated horizon. The apparent angular diameter of an extended circular source is also quantified.A total of 11 highly trained male observers took part in the studies reported here. All had 20:20 distance acuity. Each observer moved a point source along various frontal plane meridians behind an extended source in order to determine at what position it became invisible due to the effects of irradiation. Results indicated that (1) the apparent edge of high luminance targets can be displaced as much as 15′ arc from the target's actual edge under some viewing conditions, (2) the MAR is a function of the contrast ratio between the target and background and the luminance of the point source, and (3) the detrimental effects of irradiation are not reduced by using optical filters across the entire field of view to reduce the luminance of the extended source. The findings are related to certain aspects of manual navigation presently in us

ISSN:0028-1522    

DOI:10.1002/j.2161-4296.1968.tb02235.x

出版商:Blackwell Publishing Ltd    

年代:1968

数据来源: WILEY

摘要:

AbstractThe equations for determiningrange from an object using altitude (angle) measured from horizon to the top of the object are derived and compared with those given in Bowditch for Table 9,Distance by Vertical Angle. It is shown that the geometric approximations in Bowditch are valid for small vertical angles but can introduce significant errors for long ranges and large vertical angles. Furthermore, it is shown that errors caused by non‐standard terrestrial refraction typically limit the accuracy over water to 0.1 nautical miles for long ranges. Finally, suitable tables equivalent to Bowditch's Table 9 are included with extensions to smaller angles and lower objects, having in mind the particular application of small craft pilotin

ISSN:0028-1522    

DOI:10.1002/j.2161-4296.1968.tb02236.x

出版商:Blackwell Publishing Ltd    

年代:1968

数据来源: WILEY

摘要:

AbstractSchuler tuned inertial datatracking OMEGA radio position data, with the difference applied to erect the inertial platform and damp Schuler oscillations, yields a Hybrid OMEGA‐INERTIAL system that follows vehicle maneuver without lag, with continuous correction of vertical and azimuth. Initial alignment prior to departure is not required. Position errors are bounded by radio data, so that inertial sensors of only moderate accuracy are sufficient. After signal acquisition, the radio data is tracked with zero error through all maneuver, including signal outages of moderate duration, so that OMEGA lane count is maintained. Azimuth and attitude are available for autopilot inputs, and the system provides a Universal Time scale to microsecond accurac

ISSN:0028-1522    

DOI:10.1002/j.2161-4296.1968.tb02237.x

出版商:Blackwell Publishing Ltd    

年代:1968

数据来源: WILEY

ISSN:0028-1522    

DOI:10.1002/j.2161-4296.1968.tb02238.x

出版商:Blackwell Publishing Ltd    

年代:1968

数据来源: WILEY

摘要:

AbstractThe ever increasingair traffic volume on high density international routes indicates the need for increased air space capacity. This involves reduction in air traffic separation standards. Consequently, improved navigation accuracy must be achieved. The examination of air carrier over‐ocean navigation practices discloses a wide variety of navigation concepts. For position fixing, general limitations of sensor data acquisition may be due to inadequate operator time availability, unfavorable environmental conditions, or by geographical limits of facility coverage. Techniques of sensor data acquisition and processing and the required levels of integration are discusse

ISSN:0028-1522    

DOI:10.1002/j.2161-4296.1968.tb02239.x

出版商:Blackwell Publishing Ltd    

年代:1968

数据来源: WILEY

摘要:

AbstractLatest studiesof navigation by satellite have emphasized the passive or one‐way approach, i.e., designing the satellite system so that a user may navigate without the requirement for a transmitter on‐board. Compared to a totally active or transponding system, this approach offers the advantages of increased numbers of potential users and increased resistance to interference. Independent measurements of position for North Atlantic ATC can be made simultaneously by incorporating transmitters in aircraft and relaying the position measurement data on ground command.The results of recent studies of hyperbolic ranging systems and long baseline interferometer approaches are presented. Spectrum occupancy, satellite power, lane ambiguities and computational procedures are discussed. Modes of operation which show promise for improving SST operation are descri

ISSN:0028-1522    

DOI:10.1002/j.2161-4296.1968.tb02240.x

出版商:Blackwell Publishing Ltd    

年代:1968

数据来源: WILEY

摘要:

AbstractPrecise measuresof position and velocity of an aircraft have important applications during the landing phase. Such measures can be obtained, in directions, normal to an instrument landing system (ILS) reference path, by suitably tying together an inertial navigation system and an instrument landing system. Operations performed on the difference between ILS position and inertially‐measured position yield corrections to the inertially‐measured position and velocity.An important facet of the fully automatic landing problem is the acquisition of the ILS localizer course. A considerable improvement in performance, compared with that of a conventional system, may be realized during this phase by applying optimal control theory with a minimal time‐to‐acquisition criterion. The second part of this paper presents a practicable realization of a minimal‐time controller which utilizes information derived from the ILS receiver and an on‐board inertial navigation system. Solution characteristics are presented for the Boei

ISSN:0028-1522    

DOI:10.1002/j.2161-4296.1968.tb02241.x

出版商:Blackwell Publishing Ltd    

年代:1968

数据来源: WILEY

摘要:

AbstractIn aie navigationno single method of choosing a MPP based upon one or two LOP's and a DR position has gained general acceptance. In this study the relative effect of the DR and celestial LOP errors on the accuracy of various methods of choosing a MPP are investigated. Two methods are found to have a probable error significantly less than the other methods examined.

ISSN:0028-1522    

DOI:10.1002/j.2161-4296.1968.tb02242.x

出版商:Blackwell Publishing Ltd    

年代:1968

数据来源: WILEY