摘要:

ABSTRACTThe Instrument Landing System (ILS) may set a record for major electronic system longevity. Stemming from early experiments dating back to 1919, it was developed into its present basic signal format in the mid‐1980s. It was well on its way to national standardization by the time of U.S. entry into World War II. At that time, it was strictly a national system, almost unknown outside of the United States.In January 1944, the Aircraft Radio Laboratory at Wright Field sponsored a mission to have the SCS‐51 military ILS tested by the RAF and the 8th Air Force. The code name for the mission was SOXO AIR SIG S‐7. A small team and production ground and airborne equipment were sent to England for joint British‐American trials. Tests were conducted at an RAF Flight Research airfield in central England. The tests gave a large number of key aviation officials their first look at ILS. As the program progressed, the ready availability of ground stations allowed both military and civil operators to become familiar with the system, so that when postwar international conferences were held to select a landing system, ILS had a distinct advantage and was selected as the international s

ISSN:0028-1522    

DOI:10.1002/j.2161-4296.1993.tb02298.x

出版商:Blackwell Publishing Ltd    

年代:1993

数据来源: WILEY

摘要:

ABSTRACTThis paper traces the history of the development and applications of Doppler radar navigation systems from their inception in the mid‐1940s to the present. The early design concepts, problems, tribulations, and obstacles are discussed. With only noncoherent pulse radar transmitters available at that time, a unique technique of self‐coherence had to be invented and implemented in order to allow Doppler signal extraction. Similarly, the severe leakage problems of continuous wave (CW) radars had to be overcome. In spite of these problems, both pulse Doppler and CW Doppler radar navigation systems were successfully developed and produced. The next problem needing a solution was the measurement of negative velocity as required in helicopter operation. This lead to the development of coherent pulse and frequency modulated (FM)‐CW Doppler radars and new frequency trackers, with wide application for navigation and hovering indication over land and water.The development and production of Doppler systems for the commercial airlines followed, and these systems were used for civil over‐ocean navigation for many years. A Doppler radar was used for velocity measurement on the Surveyor and the Appollo Lunar Excursion Module for the achievement of soft landing on the moon. Most modern military helicopters and strategic aircraft, as well as many drones, are currently implemented with Doppler navigation radars, and this is. likely to continue. In addition, the Doppler navigation radar concepts have been applied to the so‐called precision velocity update (PVU) mode of conventional military airborne search and tracki

ISSN:0028-1522    

DOI:10.1002/j.2161-4296.1993.tb02299.x

出版商:Blackwell Publishing Ltd    

年代:1993

数据来源: WILEY

摘要:

ABSTRACTThe LF band used for Loran‐C navigation is susceptible to the effects of atmospheric noise. The two main components of LF atmospheric noise are background Gaussian noise and impulsive lightning noise. As the FAA continues in its efforts to incorporate Loran‐C into the National Airspace System for use as a supplementary navigation aid, it is necessary to develop a better understanding of the effect of atmospheric noise on the accuracy, availability, and integrity of Loran‐C. A simulation facility has been developed which provides a controlled, repeatable, and realistic noise environment for the calibration and testing of Loran receivers. This paper describes three of the noise models used in the simulator, and how they are created, calibrated, and used in the evaluation of Loran rece

ISSN:0028-1522    

DOI:10.1002/j.2161-4296.1993.tb02300.x

出版商:Blackwell Publishing Ltd    

年代:1993

数据来源: WILEY

摘要:

ABSTRACTCivil aviation authorities have a requirement for the application of devices that are capable of determining the geometric height of aircraft above flight level 290 with a high degree of precision. These devices, called height monitoring units (HMUs), should pave the way for the safe and expeditious introduction of a reduced vertical separation of 1000 ft above flight level 290 (29,000 ft).This paper outlines the design philosophy, as well as the prototype development, of such an HMU, called the Dual‐synchronized Autonomous Monitoring System (DAMS). This device operates fully independently of any airborne equipment, such as secondary surveillance radar transponders. The configuration consists basically of two standard marine radars with both axes of revolution situated in a horizontal plane. With this configuration, it is possible to determine the trajectory of an aircraft and, in particular, the geometric height above ground level within typical radar slant range coverage of some 18 k

ISSN:0028-1522    

DOI:10.1002/j.2161-4296.1993.tb02301.x

出版商:Blackwell Publishing Ltd    

年代:1993

数据来源: WILEY

摘要:

ABSTRACTFlight tests were conducted to evaluate the capability of local area C/A‐code differential GPS (DGPS) to provide accuracy suitable for precision approach operations under Category I conditions.An aircraft was equipped with DGPS receiving equipment and additional computing capability that derived GPS‐based instrument approach paths, converted DGPS position information to lateral/vertical deviations from the approach path, and drove the appropriate aircraft flight instruments. A mobile ground station using identical DGPS receiving equipment and a VHF data transmitter was employed to send differential corrections to the airborne system. Other than the differential corrections, no other augmentation of the airborne data was employed.Analysis of data collected from 82 hand‐flown approaches using ground truth provided by theodolite or laser tracker shows that the system achieved vertical accuracies meeting Category I requirements with a substantial margin when narrow‐correlator spacing GPS receivers were used. Lateral accuracies met Category III requi

ISSN:0028-1522    

DOI:10.1002/j.2161-4296.1993.tb02302.x

出版商:Blackwell Publishing Ltd    

年代:1993

数据来源: WILEY

摘要:

ABSTRACTIn late 1991, the FAA formed a group called the Satellite Operational Implementation Team to accelerate the introduction of satellite navigation and communications into the National Airspace System (NAS). Since then, the team has been addressing major technical and operational issues that need to be resolved before GPS is used in instrument flight rules (IFR) operations in the NAS. One of the most critical criteria for the operational approval of near‐term use of GPS in the NAS is availability of receiver autonomous integrity monitoring (RAIM) detection and identification functions. To improve RAIM availability, SOFT members suggested that relatively simple GPS augmentations in the form of barometric altimeter aiding and clock coasting be considered. This paper analyzes GPS RAIM availability with these augmentations and presents the technical analyses used by the team to support its recommendation

ISSN:0028-1522    

DOI:10.1002/j.2161-4296.1993.tb02303.x

出版商:Blackwell Publishing Ltd    

年代:1993

数据来源: WILEY

摘要:

ABSTRACTThe initialization of real‐time centimeter‐accuracy GPS (i.e., based on carrier phases) can be performed while in motion. Although included results are postprocessed, the algorithms are currently being implemented for real‐time navigation, and the results will be essentially the same. The goal of the initialization procedure is to determine the double‐difference carrier phase integer ambiguities.This paper reports the benefit to the initialization procedure of additional knowledge or constraints. As an example, it shows the speedup (meaning fewer epochs, not computational speed) of the initialization procedure and increased reliability using a priori knowledge of the average ellipsoidal height of the antenna phase center on a marine platform. As another example, it shows the benefit of prior knowledge of one or two double‐difference integer biases, either alone or coupled with a priori knowledge of the ellipsoidal height of the antenna pha

ISSN:0028-1522    

DOI:10.1002/j.2161-4296.1993.tb02304.x

出版商:Blackwell Publishing Ltd    

年代:1993

数据来源: WILEY