摘要:

SummarySince the separationsrequired for safety are a major factor in airport and airway capacity, and since new developments in ATC and avionics dilute the value of accumulated experience, there is a pressing need to formulate a universally accepted rationale for the establishment of aircraft separation standards. This paper examines the consequences of the point of view that separations must be adequate for ATC to provide effective, essentially redundant, protection against blunders or failures aboard the aircraft.The most conservative objective for separation standards is that they keep any two aircraft from reaching a position, velocity configuration from which it is possible for a collision to occur before effective ATC intervention can be accomplished. In implementing this philosophy one must consider position and velocity errors, computation and communication lags, as well as pilot and aircraft response delays. Further, however, the development requires a complete hazard detection and resolution strategy. Thus in addition to specifying separation standards, one must, in the process, also specify the primary data required for hazard assessment, the computational algorithms required for hazard determination, the complement of corrective commands, and an algorithm for the selection of the most effective command. These considerations define position and velocity thresholds which represent the last chance for effective intervention by air traffic control. Within these boundaries, air traffic control has the capability of providing assured safety. If the boundaries are penetrated, however, there are combinations of errors and delays which allow a possible unpreventable collision. If the existence of this possibility cannot be tolerated, the boundaries derived specify the minimum separation tolerable to ATC.

ISSN:0028-1522    

DOI:10.1002/j.2161-4296.1974.tb01191.x

出版商:Blackwell Publishing Ltd    

年代:1974

数据来源: WILEY

摘要:

AbstractThe National Bureau of Standards Boulder Laboratoryhas studied the use of television as a carrier for accurate time and frequency signals. The usefulness of the TvTime System applied to locating cars and other vehicles automatically is examined. Such a need exists in transit, police, taxi, utility and many commercial fleets. Past approaches to the problem are outlined. The NBS TvTime System and experimental results will be discussed. Two models of a car locating system are outlined, each having three parts: (1) a TV decoder in the car, (2) a radio link such as a mobile channel between car and central dispatch, and (3) a computer which determines the car's position. Results show that this system is capable of achieving a location accuracy of better than 60 m with 95 percent confidence. Some advantages and limitations of the system will be discussed and cost estimates for the equipment given.

ISSN:0028-1522    

DOI:10.1002/j.2161-4296.1974.tb01192.x

出版商:Blackwell Publishing Ltd    

年代:1974

数据来源: WILEY

摘要:

AbstractThe paper distinguishesbetween optimal and practical collision avoidance systems and selects a set of variables that can be used to compute collision avoidance (C/A) parameters in practical systems. Specifically, the paper studies the effects of sensor errors upon the calculation of the passing distance at CPA, the point‐of‐possible‐collision (PPC), and range over range‐rate (TAU). The possible sources of error are summarized and characterized as deterministic or random, dependent or independent, correlated or decorrelated, and fixed bias. A computer program is described that makes use of a Kalman filter to compute the effects of error upon C/A parameters. The results of computer runs are given that show that most errors have insignificant effects. The others can be reduced or removed if required. A means is provided for estimating a part of the economic return on investment in a computerized collision avoidance

ISSN:0028-1522    

DOI:10.1002/j.2161-4296.1974.tb01193.x

出版商:Blackwell Publishing Ltd    

年代:1974

数据来源: WILEY

ISSN:0028-1522    

DOI:10.1002/j.2161-4296.1974.tb01194.x

出版商:Blackwell Publishing Ltd    

年代:1974

数据来源: WILEY

摘要:

Abstracta new methodof using the Navy Navigation Satellite System (NNSS) in marine (i.e. moving‐user) applications has been developed. The technique exploits some little‐known characteristics of the received NNSS doppler signal, and has yielded more than an order of magnitude improvement in position determination accuracy when Earth referenced velocity is poorly known.Use of the technique has greatly expanded the accuracy and utility of the NNSS in marine navigation applications. Tests using at‐sea data have shown that Loran/OMEGA propagation errors can be calibrated to an accuracy of better than 300 feet (rms), irrespective of user motion. NNSS updates for an Inertial Navigation system (INS) can now be provided in both position and velocity, thus greatly increasing INS between‐pass steering performance over that derived from conventional position‐only fixes. The NNSS can now be used by itself as a complete “stand alone” navigation system, providing periodic position, speed, and course information of

ISSN:0028-1522    

DOI:10.1002/j.2161-4296.1974.tb01195.x

出版商:Blackwell Publishing Ltd    

年代:1974

数据来源: WILEY

ISSN:0028-1522    

DOI:10.1002/j.2161-4296.1974.tb01196.x

出版商:Blackwell Publishing Ltd    

年代:1974

数据来源: WILEY

摘要:

AbstractAdescriptionis given of a proposed versatile navigator's aid (NAV‐AID) made possible by recent advances in calculator technology. The NAV‐AID is a portable microdigital computer which, when used withThe Nautical Almanac, solves Celestial, Loran and Omega position fixing problems. Additionally, the NAV‐AID contains a Deduced Reckoning computer as well as the capability to perform a variety of standard piloting techniques. Subroutines enable the navigator to calculate useful course line parameters and to handle sextant altitude and Omega skywave corrections. Other course and fix‐related quantities are accessible through an Auxiliary Data Mode. An Inverse Mode allows Celestial, Loran and Omega data to be predicted, and a Calculator Mode aids in external computations. Anticipated specifications ar

ISSN:0028-1522    

DOI:10.1002/j.2161-4296.1974.tb01197.x

出版商:Blackwell Publishing Ltd    

年代:1974

数据来源: WILEY

摘要:

AbstractAsystemhas been developed, utilizing the Navy Navigation Satellites, which can provide azimuth information on a world wide basis. Two antennas, separated by 50 to 100 meters, are used in an interferometer configuration to make measurements of the received phase difference from the satellite as it passes overhead. From the data received during a single satellite pass it is possible to determine the azimuth of the baseline connecting the two antennas and their separation.This system, although useable world wide, is particularly useful in the polar regions for heading determination, where gyro compasses experience difficulties in alignment.

ISSN:0028-1522    

DOI:10.1002/j.2161-4296.1974.tb01198.x

出版商:Blackwell Publishing Ltd    

年代:1974

数据来源: WILEY

摘要:

AbstractHigh speed marine vehiclessuch as Surface Effect Ships impose several unique constraints on navigation system design. Particularly significant is the current lack of a reliable and accurate velocity sensor during high speed cruise operation.This paper describes the accuracy performance of several mixed inertial navigation systems which do not involve the use of a velocity sensor. Specifically considered are NAVSATINERTIAL, OMEGA‐INERTIAL, and NAVSAT‐OMEGA‐INERTIAL systems. The accuracy performance information which is presented presumes the use of optimal (Kalman) processing of the available position

ISSN:0028-1522    

DOI:10.1002/j.2161-4296.1974.tb01199.x

出版商:Blackwell Publishing Ltd    

年代:1974

数据来源: WILEY

ISSN:0028-1522    

DOI:10.1002/j.2161-4296.1974.tb01200.x

出版商:Blackwell Publishing Ltd    

年代:1974

数据来源: WILEY