ISSN:0028-1522    

DOI:10.1002/j.2161-4296.1978.tb01308.x

出版商:Blackwell Publishing Ltd    

年代:1978

数据来源: WILEY

摘要:

ABSTRACTOn july20, 1976, Viking Lander I became the first unmanned spacecraft to land and operate successfully on the planet Mars. This was followed by a second successful landing on September 3, 1976. This paper gives a detailed description of the autonomous onboard navigation process to perform the guidance, control, and entry navigation functions. Also, the functions performed on the ground to generate and validate the guidance commands sent to the spacecraft prior to descent are described. In‐flight measures of navigation system performance are compared against a–priori error estimates to show that the descents were completely nominal in all respects. The final landing errors were 25 km and 10 km for Missions 1 and 2, respectiv

ISSN:0028-1522    

DOI:10.1002/j.2161-4296.1978.tb01309.x

出版商:Blackwell Publishing Ltd    

年代:1978

数据来源: WILEY

摘要:

ABSTRACTIn a high densityterminal area, speed control and radar vectoring are typically used to optimize the sequence and assure the spacing of landing aircraft for maximum runway utilization. Fuel conservative descent and landing approaches tend to offer reduced control capability to the extent that they depend upon relatively inflexible paths and rigid speed profiles. Under high traffic demands the loss in terminal controllability could adversely impact both airport capacity and fuel consumption through increased delays.This paper describes an approach for the ATC system in the terminal area to accommodate fuel conserving landing approaches. Analytical results are presented that illustrate the impact of fuel economic design on terminal controllability and airport capacity. Peak hour trade–offs between conserving fuel and maximizing runway utilization are also included in the paper. An analytical fuel consumption model is used to estimate the fuel benefits of lifting the 250 knots speed restriction below 10,000 ft. MSL, for both arrivals and departure

ISSN:0028-1522    

DOI:10.1002/j.2161-4296.1978.tb01310.x

出版商:Blackwell Publishing Ltd    

年代:1978

数据来源: WILEY

ISSN:0028-1522    

DOI:10.1002/j.2161-4296.1978.tb01311.x

出版商:Blackwell Publishing Ltd    

年代:1978

数据来源: WILEY

摘要:

ABSTRACTRecent groundings oferrant supertankers have resulted in disasters unacceptable to an ecology conscious nation. Of particular concern is that these have occurred despite the fact that the past twenty years have seen an order of magnitude improvement in marine navigation technology due primarily to the operational need of our missile firing submarines. This paper presents a brief insight into the evolution of submarine navigation during the past two decades with a glimpse into the near future. Perhaps knowledge of the methods and technology developed for our modern submarines can be of value in solving the critical problem of safe navigation for other vessels such as supertankers. This paper may serve as a step toward that end.

ISSN:0028-1522    

DOI:10.1002/j.2161-4296.1978.tb01312.x

出版商:Blackwell Publishing Ltd    

年代:1978

数据来源: WILEY

摘要:

ABSTRACTThe Omega Navigation Systemwas approved for full implementation in 1968 based on successful experimental VLF studies and actual low power station operations conducted in the early 1960's. Presently OMEGA has reached a point of progress where full system potentialities should be realized by 1982. The first permanent, high powered station started signal transmissions at La Moure, North Dakota in 1972; seven permanent and one low power temporary station are now useable for navigational purposes. This paper covers management planning of implementation of the full system with a limited technical discussion of station operations, navigational science efforts leading to system validation/calibration, and engineering support functions to enhance reliability and maintainability. Some of the highlights to be discussed are: Implementation of OMEGA—Australia; Transfer of synchronization responsibilities to the Japanese Maritime Safety Agency (JMSA); Worldwide monitor program and system calibration/validation; Navigational science investigations; User documentation, manuals and correction tables; Signal format optimization; Field strength measurements; Station off–air time schedule for maintenance; U.S. Navy to U.S. Coast Guard system transit

ISSN:0028-1522    

DOI:10.1002/j.2161-4296.1978.tb01313.x

出版商:Blackwell Publishing Ltd    

年代:1978

数据来源: WILEY

摘要:

ABSTRACTBeing master in one‘s own houseis an ideal that can barely stand up to the alluring advantages of international cooperation in technology. How does a nation respond to prospects of a superb navigation grid, “as free as the air”, capable of supplanting almost all it has built up in navigation systems over the decades? The hand on the switch is another man's hand, and no matter how friendly the hand, therein lies the rub.Canada's ground–based air navigation systems have closely parallelled developments in the United States, a very natural and satisfactory situation. On the seas, the situation has been similar with the notable exception of the East Coast. Now we are jointly expanding Loran‐C in the west, and are considering doing so in the east. But vast areas of Canada's skies and waters remain unserved by any Canadian‐based long range aids; and U.S. VLF aids are not fully proven in much of our environment.The paper explores some implications of adoption of global aids, and, having regard to the systems in place, explores options for the future. While hard decisions are still in the making, some personal appraisals of the shape of navigation in Canada for the rest of the century are put forth.This paper represents views and opinions of the author and does not necessarily reflect departmental or governmental poli

ISSN:0028-1522    

DOI:10.1002/j.2161-4296.1978.tb01314.x

出版商:Blackwell Publishing Ltd    

年代:1978

数据来源: WILEY

ISSN:0028-1522    

DOI:10.1002/j.2161-4296.1978.tb01315.x

出版商:Blackwell Publishing Ltd    

年代:1978

数据来源: WILEY

摘要:

ABSTRACTthere has been recent concernwithin the government about the “proliferation of radio navigation systems.” Today, the prime domestic civil air navigation system (VOR/DME) is essentially only usable by aviation due to line–of–sight restrictions. With the availability of wider coverage systems, and low cost microprocessor based user equipment, it may be possible to consolidate air, marine, and land navigation services into one system to be operated by the government. However, each of these services has its own peculiar requirements.The purpose of this paper is to evaluate the feasibility of introducing other navigation systems into the VOR/DME system environment. In particular, two of the most promising systems, LORAN–C and NAVSTAR–GPS, are considered. The issues that are addressed concern the distribution of costs between the users and government, distribution of costs among the various classes of users, user amortization of VOR/DME equipment, signal–in–space redundancy requirements, relationships to landing and communications airborne equipment, and satisfaction of operational requirements. Future implementation scenarios are outlined and subjected to economic analysis. One of the main conclusions drawn from the economic analysis is that a reasonable transition plan to either LORAN–C or NAVSTAR–GPS, if they are successful, would be to accommodate the more high performance users with these systems, and retain only the VOR part of the VOR/DME system for service to lowe

ISSN:0028-1522    

DOI:10.1002/j.2161-4296.1978.tb01316.x

出版商:Blackwell Publishing Ltd    

年代:1978

数据来源: WILEY

摘要:

ABSTRACTThis paper will bean overview of the critical orbital flight missions for which navigation performance is well defined relative to the various mission phases and key events (e.g. ascent, orbital coast, deorbit, entry, drag acquisition, post blackout, Terminal Area Energy Management and Autoland). Special emphasis will be given to those missions, events and performance parameters that are drivers of navigation accuracy. The navigation sensors will be described and their usefulness in keeping navigation accuracy within specified limits will be discussed by mission phases.

ISSN:0028-1522    

DOI:10.1002/j.2161-4296.1978.tb01317.x

出版商:Blackwell Publishing Ltd    

年代:1978

数据来源: WILEY