摘要:

AbstractGuidance and controltechniques have been developed to permit accurate nonlinear path‐following in the terminal area using an MLS&DME data‐base. The elements of the system including trajectory generation, mean‐wind estimation, feedforward and perturbation control are described and the performance of the integrated system delineated. The investigation was made with the aid of a sophisticated digital simulation, including modelling of the sensor and environmental noise. A conventional jet transport was the subject aircraft. A conclusion of the investigation was that the integrated guidance and control system was adequate to the task of path tracking with errors within the resolution of ATC radar. A corollary is that a degraded MLS, relative to that required for the landing task, operating at low scan rates provides navigational data, of sufficient accuracy to perform the curved approach

ISSN:0028-1522    

DOI:10.1002/j.2161-4296.1973.tb01182.x

出版商:Blackwell Publishing Ltd    

年代:1973

数据来源: WILEY

摘要:

AbstractThree simpleair route capacity models arc developed. The first model is based on the assumption of a common average speed of aircraft. This model gives a quick, rough estimate of an air route capacity. The second model is based on the assumption that overtaking of one aircraft by another is not allowed. This model gives the minimum capacity of a route. The third model is based on allowance for a certain maximum number of overtakings. This model gives a relatively more realistic estimate of the air route capacity. The models are intended as preliminary design aids for planners and designers of air route networks.

ISSN:0028-1522    

DOI:10.1002/j.2161-4296.1973.tb01183.x

出版商:Blackwell Publishing Ltd    

年代:1973

数据来源: WILEY

摘要:

AbstractDuring the past several yearsthere has been increasing interest, attention and commitment directed toward exploiting the capabilities and potential of satellite‐based position determination systems. The utility of satellite systems has been extended from surface navigation and geodetic applications into air and space, and to other functional areas such as position surveillance for air traffic control, precise time and time transfer, international maritime and aeronautical position location and reporting services, and collision avoidance. This paper provides a summary of the satellite system concepts, orbital deployments and measurement techniques on which the accomplishment of the various applications is based. The systems and system concepts discussed include: Transit, the Navy Navigation Satellite System; the expanded Transit and Transit improvement program concepts; the Two‐In‐View configuration; the Defense Navigation Satellite System, including the System 621B and the Timation system concepts; the NASA Position Location and Communication Equipment (PLACE) experiment; the Maritime Satellite program of the Department of Commerce's Maritime Administration; the DOT/FAA Aeronautical Satellite Program; the Location, Identification by Transmission (LIT) and Satellite ATC and Navigation (SATAN) systems; the DOT's Advanced Air Traffic Management System concepts, and the FAA's recently developed ASTRO‐DABS

ISSN:0028-1522    

DOI:10.1002/j.2161-4296.1973.tb01184.x

出版商:Blackwell Publishing Ltd    

年代:1973

数据来源: WILEY

摘要:

AbstractThe Electrically Suspended Gyro(ESG) consists of a spinning metal sphere suspended by an electric force so that friction is virtually eliminated. This type of gyro has demonstrated performance which qualifies it for use in a system for attitude determination; a significant advantage of this system, on board a maneuvering spacecraft, would be the long‐periods of attitude performance between steller updates. The paper discusses a readout accuracy improvement in the gyro and the attitude reference system in which it may be use

ISSN:0028-1522    

DOI:10.1002/j.2161-4296.1973.tb01185.x

出版商:Blackwell Publishing Ltd    

年代:1973

数据来源: WILEY

摘要:

AbstractNASA's ATS‐5, ATS‐3 and ATS‐1satellites were used in a series of ranging, position fixing and communications experiments at L‐band and VHF. Communications included voice, digital, teletype and facsimile transmissions. Many transponders were used in the tests. They provided communications and responded automatically to ranging interrogations.When a transponder was to be located, a central ground terminal transmitted a short signal containing the individual address of the transponder through one satellite. All of the transponders received the signal, and the one that was addressed responded through two satellites. The central ground terminal determined the ranges from the two satellites to the transponder and computed its position fix. Three to ten independent position fixes could be made each second in one channel of an operational system.The DICARdigitalcommunicationsandranging technique that has developed from these experiments uses a single signalling waveform and a single modem for communications and ranging. Experiments with the signalling parameters suggested for an operational system achieved a ranging precision better than 50 feet with a modulation frequency less than 10 kHz, an RF bandwidth less than 60 kHz, and a ranging signal duration of 30 milliseconds. An automatic transponder that responds at L‐band through ATS‐5 and at VHF through ATS‐3 was located with a precision approaching 0.1 nmi., 1 sigma.Every factor that affects communications reliability and position fixing accuracy was measured and evaluated in the experimental program between 1968 and 1973. Automatic transponders were carried on ships in the Atlantic, Pacific and Gulf of Mexico and on the Mississippi River; on jet and propeller driven aircraft flying over the continental United States and North Atlantic to Shannon, Ireland and Thule, Greenland; on a buoy moored in deep water off Bermuda; and in a panel truck driven over country roads in upstate New York. Automatic transponders at Shannon, Ireland; Reykjavik, Iceland; Schenectady, New York; Kings Point, New York; Seattle, Washington; and Buenos Aires, Argentina were used to test a trilateration technique for real time satellite location and to measure propagation factors that affect communication reliability and ranging accuracy.Hundreds of hours of communications and more than a million range measurements have provided data on all factors that affect communications reliability and position fix accuracy. The experiments have confirmed that all the factors can be controlled and that high quality, reliable communications and useful position fixing accuracy can be provided to maritime and aeronautical users by practical means using satelli

ISSN:0028-1522    

DOI:10.1002/j.2161-4296.1973.tb01186.x

出版商:Blackwell Publishing Ltd    

年代:1973

数据来源: WILEY

摘要:

AbstractIn this papera new technique is developed which yields an exact solution to the position location problem in three dimensions. The method presented determines the relative location of transponders in a three‐dimensional array of transponders fixed relative to one another. The method simultaneously yields the loci of a roving interrogator relative to each of the transponders in the array. System operation is dependent upon a sequential interrogation of, or by, the array to produce simultaneous range measurements between each transponder of the array and the roving interrogator. The method yields closed‐form solutions for all transponder coordinates and all interrogator coordinates. No ambiguities arise, nor need be resolved, in the course of the solution and the results are exact in as much as the range measurements used are exact. Numerical results are presented for the sensitivities of both transponder coordinates and interrogator coordinates to variations in the range measurements. Effect of interrogator path and transponder geometry on results is discussed and the concept of critical, or singular, geometries, which produce poorly‐conditioned solutions, is intro

ISSN:0028-1522    

DOI:10.1002/j.2161-4296.1973.tb01187.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.tb01188.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.tb01189.x

出版商:Blackwell Publishing Ltd    

年代:1973

数据来源: WILEY

摘要:

History of Navigation:MAN, THE NAVIGATOR, by E. W. AndersonHistory of Flight:MR. PIPER AND HIS CUBS, by Devon FrancisMarine Navigation:PRACTICAL NAVIGATION, by W. S. KalsMarine Navigation:PRACTICAL NAVIGATION FOR THE YACHTSMAN, by Frederick L. Devereux, Jr.

ISSN:0028-1522    

DOI:10.1002/j.2161-4296.1973.tb01190.x

出版商:Blackwell Publishing Ltd    

年代:1973

数据来源: WILEY