摘要:

AbstractAperfected sextantwith artificial horizon for air navigation does not seem to have existed before the 1940's. Yet the history of attempts at developing an artificial horizon for celestial navigation can be traced back more than two centuries. In this study some of the early 18th century attempts to modify the old Davis quadrant and the new Hadley quadrant are described. Henry Serson's “whirling speculum”, apparently the first successful vertical gyro is discussed in some detail. Lastly, the age of air navigation is introduced by means of a study of the Willson, the Pioneer MK III, and the Kollsman pendulous mirror and bubble sextants. Note is made of parallel efforts in Portugal and Great Britain during the same per

ISSN:0028-1522    

DOI:10.1002/j.2161-4296.1973.tb01149.x

出版商:Blackwell Publishing Ltd    

年代:1973

数据来源: WILEY

摘要:

AbstractIn1970–71a studyof Loran‐C reception and stability characteristics was carried out along the Lower Great Lakes. By setting up calibration stations for periods from 1 hour to 18 days between Eastern Lake Ontario and Western Lake Erie, measures were obtained of chain variability, instrument variability, signal strength and certain other effects. Calibration curves were obtained which permit correction of Loran data over Lake Ontario and Lake Erie. Monitor stations were used to determine the advantage resulting from use of the differential mode of operation. Results indicated that any propagation variability was small as compared to instrumental and chain variability. In the differential mode, overall system accuracies, geometry and signal strength appear to be attractive for precise navigation or for a large area survey operation in the Lower Lakes. The study was sponsored by the Canadian Hydrographic Serv

ISSN:0028-1522    

DOI:10.1002/j.2161-4296.1973.tb01150.x

出版商:Blackwell Publishing Ltd    

年代:1973

数据来源: WILEY

摘要:

AbstractAschemefor estimating aircraft velocity directly from airborne air‐to‐ground range measurements is discussed. The idea is based on the premise that the motion of an aircraft can be represented by a polynomial in time, having stationary coefficients over intervals relatively long compared to the measurement sampling interval. The coefficients of the polynomial are estimated by processing range measurements. Radial velocities to two known radio stations at a given location of the aircraft are sufficient to determine aircraft velocity in the plane containing the aircraft and the two radio stations.The results of a study showed that with favorable data rates, a worst case trajectory can be fitted very accurately by a series of connected third order polynomials in time.A proposed two‐stage Kalman‐Bucy filter implementation for estimating the ground speed vector from aircraft heading information and data from two VOR/DME stations, is de

ISSN:0028-1522    

DOI:10.1002/j.2161-4296.1973.tb01151.x

出版商:Blackwell Publishing Ltd    

年代:1973

数据来源: WILEY

摘要:

AbstractThe need forthree‐dimensional diagrams for the display and illustration of long‐range navigation problems is discussed, and the adequacy of the spherical earth model pointed out. Formulas by which three‐dimensional problems in navigation, adequately represented by points and arcs on the surface of a sphere, can be reduced to the two dimensions of a plane are derived. Use of these formulas yields a scaled illustration of any three‐dimensional problem as viewed from any direction normal to the earth's surface from an infinite distance. Computational problems are discussed and sample illustrations are i

ISSN:0028-1522    

DOI:10.1002/j.2161-4296.1973.tb01152.x

出版商:Blackwell Publishing Ltd    

年代:1973

数据来源: WILEY

摘要:

AbstractAfamily ofdigital attitude reference systems (DARS) is developed for three‐axis‐stabilized, earth‐oriented satellites. It includes the complete DARS configuration, which utilizes measurements from a sun sensor in addition to the horizon sensors and gyros in use on conventional analog gyrocompassing‐type attitude reference systems (CARS). The complete configuration also utilizes statistically optimal (Kalman) filtering to process these measurements to estimate and compensate for important measurement errors as well as to estimate the spacecraft attitude. Various suboptimal configurations of DARS are also studied. Based on simulation results, the attitude accuracies of the two most promising DARS configurations are approximately 0.03 and 0.04 deg (1σ), respectively, and the convergence time of both systems is less than 20 sec. Thus, DARS is shown to fill the important gap between low‐accuracy gyrocompassing systems (using horizon sensors and gyros) and high‐accuracy systems (requiring star sensors or trackers) by achieving intermediate attitude accuracy at the expense of low‐to‐m

ISSN:0028-1522    

DOI:10.1002/j.2161-4296.1973.tb01153.x

出版商:Blackwell Publishing Ltd    

年代:1973

数据来源: WILEY

摘要:

AbstractAsummaryof a technical evaluation of the Decca, Differential Omega and Loran‐C systems' capabilities to fulfill the navigation requirements of mariners in the U. S. Coastal Confluence Region is presented.This paper includes a summary of marine operational requirements, system evaluation criteria and system performance comparisons. The results of the evaluation lead to the recommendation of a system for implementation to satisfy the marine navigation needs in the U. S. Coastal Confluence Region.The work was completed by Polhemus Navigation Sciences, Inc., under contract to the U. S. Coast Guar

ISSN:0028-1522    

DOI:10.1002/j.2161-4296.1973.tb01154.x

出版商:Blackwell Publishing Ltd    

年代:1973

数据来源: WILEY

摘要:

AbstractRihansis a multi‐phase development program initiated by the Coast Guard's Office of Research and Development. It addresses the need for an all‐weather precision navigation system in harbors and their entrances. System requirements have been developed, and solutions solicited from industry. The first phase objective is a refinement analysis of the technical approach and detailed definition of the system. Contracts have been awarded for three competing conce

ISSN:0028-1522    

DOI:10.1002/j.2161-4296.1973.tb01155.x

出版商:Blackwell Publishing Ltd    

年代:1973

数据来源: WILEY

摘要:

AbstractTheOMEGA NavigationSystem, consisting of eight transmitting stations operating in the 10–14 kHz frequency spectrum, is scheduled to be completed by the end of 1974. When fully operational, navigation using relatively simple equipment will be possible at essentially any point on the globe. To improve positioning accuracy, a technique of differential OMEGA can be employed to remove propagation errors introduced by diurnal height shifts of the ionosphere and other causes.This paper discusses some possible limitations to the differential technique and presents a sample of data obtained during an experiment performed during the period January to April 1972 for the U. S. Coast Guard. Also discussed are the effects on accuracy of power line harmonic interference on short term phase stabilit

ISSN:0028-1522    

DOI:10.1002/j.2161-4296.1973.tb01156.x

出版商:Blackwell Publishing Ltd    

年代:1973

数据来源: WILEY

ISSN:0028-1522    

DOI:10.1002/j.2161-4296.1973.tb01157.x

出版商:Blackwell Publishing Ltd    

年代:1973

数据来源: WILEY

摘要:

Marine Disaster:IN THE WAKE OF THE TORREY CANYON(Reflections on a Disaster),by Commandant L. OudetHigh‐Speed Marine Navigation:STUDY ON THE NAVIGATION OF MARINE VEHICLES AT MORE THAN 50 KNOTS, by the French Institute of Navigation, for the French Ministry of Armament, Paris. (In French.)Infrared Navigation:STUDY ON THE APPLICATIONS OF INFRARED TO NAVIGATION, by the French Institute of Navigation, for the French Ministry of Armament. (In French

ISSN:0028-1522    

DOI:10.1002/j.2161-4296.1973.tb01158.x

出版商:Blackwell Publishing Ltd    

年代:1973

数据来源: WILEY