摘要:

ABSTRACTInflight pressure pattern navigation was initiated in 1943 when readings of an aircraft's pressure and radar altimeters were first used to determine its so‐called “Bellamy Drift” and/or pressure lines of position. This led to preflight planning of single‐heading flights and optimum flight planning based on the patterns of the contours of constant‐pressure upper‐air charts. The manually constructed “4‐D” charts for such manual flight planning have since been replaced by numerical weather predictions that are used in computerized flight planning. Such flight planning is complicated by a lack of coordination among the ways vertical positions are related in aeronautical and meteorological practice that might well be alleviated by tailoring prognostic pressure pattern data for

ISSN:0028-1522    

DOI:10.1002/j.2161-4296.1996.tb01913.x

出版商:Blackwell Publishing Ltd    

年代:1996

数据来源: WILEY

摘要:

ABSTRACTThis paper primarily presents the early work on Doppler systems done by General Precision Laboratory under Air Force sponsorship. I have included some mention of others who worked in the same time frame. The time frame covered is the 1940s through declassification in 1957. I have mentioned names throughout, but I must apologize for omissions, since I am relying primarily on my memory. I do not dwell on the purely technical, which has been well documented since declassification, by Dr. Berger and others; one recent paper was by Walt Fried [1]. Throughout this paper, I discuss each subject as though it were the only activity going on. Actually, of course, many things were going on simultaneously, and interaction among the various activities was continually taking place.

ISSN:0028-1522    

DOI:10.1002/j.2161-4296.1996.tb01914.x

出版商:Blackwell Publishing Ltd    

年代:1996

数据来源: WILEY

摘要:

ABSTRACTIn June 1994, the U.S. Air Force implemented a yaw bias in the attitude control subsystem of most GPS satellites. By January 1995, all Block II and IIA satellites were biased. The yaw bias was implemented to fix a problem with the attitude control subsystem that prevented the yaw attitude of the satellite from being properly modeled during eclipse seasons.This paper describes the problem that was identified with the GPS attitude subsystem, and explains its effects on the modeling of the satellite yaw attitude and, in turn, on the modeling of the carrier phase and pseudorange observables. It provides details of a new model for the GPS yaw attitude that is suitable for biased satellites during eclipse seasons. Early results using GPS with the biased attitude control subsystem are also presented.

ISSN:0028-1522    

DOI:10.1002/j.2161-4296.1996.tb01915.x

出版商:Blackwell Publishing Ltd    

年代:1996

数据来源: WILEY

摘要:

ABSTRACTIn the application of GPS to airborne gravity measurements, the centimeter‐level phase errors of an aircraft‐mounted antenna can influence the results. Furthermore, the aircraft structure can give rise to multipath errors that are even more significant. This paper describes a project to characterize the errors of an aircraft‐mounted antenna by carrying out short‐baseline measurements over several days to build an error map as a function of satellite direction relative to the aircraft body frame. The calibration model is developed based on a set of carrier phase residuals. The effectiveness of the model is demonstrated by using an independent set of test data. This antenna calibration should improve the estimation of vertical acceleration of a

ISSN:0028-1522    

DOI:10.1002/j.2161-4296.1996.tb01916.x

出版商:Blackwell Publishing Ltd    

年代:1996

数据来源: WILEY

摘要:

ABSTRACTA display that effectively utilizes 3‐D differential GPS (DGPS) positioning was tested in piloted simulation and on a general aviation aircraft. This glass‐cockpit instrument provides a natural, “out the window” view of the world, making the horizon, runway, and desired flight path visible to the pilot in instrument flight conditions. The flight path is depicted as a series of symbols through which the pilot flies the airplane. Altitude, heading, and airspeed are presented, along with lateral and vertical glidepath deviations. The budget, power, and form‐factor constraints of light aircraft were addressed.Simulator tests and flight trials on a Piper Dakota aircraft were used to evaluate flight technical error on straight‐in approaches flown with the tunnel display and with a typical Instrument Landing System (ILS) needle display. Additionally, the tunnel display provided lateral and vertical guidance on curved missed‐approach procedures, for which ILS cannot provide positive co

ISSN:0028-1522    

DOI:10.1002/j.2161-4296.1996.tb01917.x

出版商:Blackwell Publishing Ltd    

年代:1996

数据来源: WILEY

摘要:

ABSTRACTPrior to the adoption of the Wide‐Area Augmentation System (WAAS) as the primary radionavigation system for the future, a number of different augmentation techniques for providing enhanced integrity and availability of GPS for use in the National Airspace System were analyzed. This paper examines the availability of Loran‐C augmented GPS with receiver autonomous integrity monitoring (RAIM) for use in nonprecision approach. Availability of the augmented system is calculated at approximately 2300 airports over the continental United States. It is demonstrated that GPS availability is significantly enhanced with Loran‐C and barometric altimeter augmentation. The percentage of time augmented GPS is unavailable for nonprecision approach is reduced by at least two orders of magnitude relative to nonaugmented GPS. Loran‐C is by itself an approved supplemental nonprecision approach landing system that can function as a stand‐alone backup if GPS is degraded or unavailable. It is demonstrated that the augmented system represents an improved, redundant, and generally more robust supplemental navigation system; however, the Loran‐C augmented system cannot satisfy the requirements for a primary naviga

ISSN:0028-1522    

DOI:10.1002/j.2161-4296.1996.tb01918.x

出版商:Blackwell Publishing Ltd    

年代:1996

数据来源: WILEY

摘要:

ABSTRACTIn conventional differential GPS (DGPS), a GPS receiver's navigation solution is improved by removing errors that are common with those of a reference receiver of known location. DGPS is useful in relative targeting, where the goal is to guide a vehicle accurately to a target. Two types of differential corrections are considered: one is implemented in the measurement domain and the other in the navigation solution domain. Analysis shows that if pseudorange measurement biases dominate the problem, it is better to send pseudorange corrections, whereas if reference receiver survey errors dominate the problem, it is better to send corrections to the navigation solution. In either case, the difference between the resulting corrections is shown to be relatively small.

ISSN:0028-1522    

DOI:10.1002/j.2161-4296.1996.tb01919.x

出版商:Blackwell Publishing Ltd    

年代:1996

数据来源: WILEY