摘要:

ABSTRACTThis paper describes the evolution of Collins GPS receiver architecture as it has matured from Phase I. The growth in functional capabilities required of the receiver over the course of the GPS program has necessitated the development of various processes and techniques to ensure that User Equipment (UE) could be produced at low cost while meeting the imposed performance requirements. The results of Life Cycle Cost (LCC) trade studies became the driving force in determining receiver architecture as the receiver design progressed from Phase I. Phase I, Concept Validation was structured to prove three major tasks. These were: (1) GPS validity as a navigational system, (2) verification of the engineering concept chosen for implementation, and (3) demonstration of military utility. These tasks necessitated the development of various types of User Equipment (eg, GDM, High and Medium Dynamic sets, Manpacks) tailored to provide certain test data without, necessarily, optimizing for costs or producibility. Phase 2, Full Scale Development, demonstrated the integration of GPS Receivers into a select group of eight Host Vehicles (HVs) representing a wide range of HV types across low, medium and high dynamic applications. The emphasis in this phase was to utilize available technology to produce receivers (in a factory environment) that provided the required performance and survived the Host Vehicle environment. LCC results played the key role in determining the Phase IIB architecture—the production baseline for Phase III. Phase III is concentrating on optimizing the integration concepts to take full advantage of the increased functional capabilities of the GPS receiver. Improvements in Hardware (HW), as well as an inventive interface processing approach in Software (SW) have allowed the receiver to offer the basic navigational data in a wide range of functional “flavors” while minimizing the HW and SW changes from Phase IIB. Finally, a glimpse of improvements planned for future receivers will be

ISSN:0028-1522    

DOI:10.1002/j.2161-4296.1986.tb00920.x

出版商:Blackwell Publishing Ltd    

年代:1986

数据来源: WILEY

摘要:

ABSTRACTLORAN and GPS are both well known navigation systems, and both have advantages and disadvantages. By combining both, the navigator can get the advantages of both and minimize the disadvantages of each.When GPS becomes fully operational, it will replace virtually all other navigation systems. Until that time (late 1988), there will be substantial lapses of coverage. It is during this time that LORAN provides the backup. This combination is the first system that can provide the transoceanic vessel with real time, accurate navigation information at both ports and periodic accurate navigation information enroute.This paper will review the two systems and then show how the whole is greater than the sum of the parts. In particular, data will be presented to show how the combined product can yield better navigation information than either system by itself.

ISSN:0028-1522    

DOI:10.1002/j.2161-4296.1986.tb00921.x

出版商:Blackwell Publishing Ltd    

年代:1986

数据来源: WILEY

摘要:

ABSTRACTThe Radio Technical Commission for Maritime Service (RTCM) established Special Committee 104 on Differential NAVSTAR/GPS Service in November 1983 to address the methods to be used to provide differential GPS service and to develop standards for the data format. The Special Committee has finished the first phase of its deliberations, which involves data message and format standards, and recommendations for communications bands and a proposed design for pseudolite operation. This paper describes the recommendations of the RTCM SC‐104. The standard message provides range and range‐rate corrections, along with the satellite and station health, and issue of data (which provides satellite message timing). Auxiliary messages are defined, to be interposed occasionally, which provide ground station location, constellation health, tropospheric model parameters, and further range corrections to adjust for satellite message changes. A special message type is defined to support surveying applications. This message provides high‐precision Doppler counts using carrier phase measurements, which make possible centimeter resolution for stationary platforms. Navigation and communication bands are identified for the provision of public and private radionavigation and radiolocation. The use of the marine radiobeacon band, in particular, appears attractive for marine navigation in harbor/harbor approach and restricted wate

ISSN:0028-1522    

DOI:10.1002/j.2161-4296.1986.tb00922.x

出版商:Blackwell Publishing Ltd    

年代:1986

数据来源: WILEY

摘要:

ABSTRACTAnyone involved in the design of GPS user equipment should be concerned with the potential impact of pseudolite signals. It is quite possible that pseudolite transmitters will be located near the majority of all airports and heliports, both rural and urban, in the United States and around the world. Therefore, even if a receiver is not intended for aircraft navigation or will not use the pseudolite signals, it may be affected by these signals.Differential GPS can improve the reliability, integrity, and accuracy of GPS navigation, but it cannot overcome the inherent geometric limitations of an 18 satellite constellation, especially when one of the satellites is out of service. Pseudolites transmit the differential correction message at the GPS L1 frequency, thus also providing an additional pseudorange measurement which overcomes poor satellite geometry. The key problem was to develop a GPS‐like pseudolite signal structure which does not interfere with reception of GPS satellite signals even when a receiver is very close to a pseudolite transmitter. A simple and effective signal has been defined, but receiver manufacturers must assure that their designs are immune to pseudolite interference. This paper defines the proposed signal and describes the appropriate receiver design consideration

ISSN:0028-1522    

DOI:10.1002/j.2161-4296.1986.tb00923.x

出版商:Blackwell Publishing Ltd    

年代:1986

数据来源: WILEY

摘要:

ABSTRACTIn the Time Service Department of the U.S. Naval Observatory, there are several operational programs that utilize time from the Global Positioning System (GPS) satellites in one form or another.1The monitoring of GPS time, derived from the ensemble of satellites, to ensure that it stays within one microsecond of the U.S. Naval Observatory Master Clock and to determine the quality of its performance between uploads.2The monitoring of the individual spacecraft clocks to determine their performance, both over the short term and the long term.3The monitoring of Coordinated Universal Time (UTC) as derived from GPS time in order to ensure that the accuracy of GPS as a time distribution system is good to 100 nanoseconds.4The performance of common‐view time transfers between the Naval Observatory and other worldwide laboratories, to monitor timescales and to investigate signal propogation through the ionosphere.This paper describes these four projects and discusses their importance to the Global Positioning System and to the world timing communit

ISSN:0028-1522    

DOI:10.1002/j.2161-4296.1986.tb00924.x

出版商:Blackwell Publishing Ltd    

年代:1986

数据来源: WILEY

摘要:

Book reviewed in this article:CELESTIAL FOR THE CRUISING NAVIGATORMerle B. Turner, Cornell Maritime Press

ISSN:0028-1522    

DOI:10.1002/j.2161-4296.1986.tb00925.x

出版商:Blackwell Publishing Ltd    

年代:1986

数据来源: WILEY

ISSN:0028-1522    

DOI:10.1002/j.2161-4296.1986.tb00926.x

出版商:Blackwell Publishing Ltd    

年代:1986

数据来源: WILEY

ISSN:0028-1522    

DOI:10.1002/j.2161-4296.1986.tb00927.x

出版商:Blackwell Publishing Ltd    

年代:1986

数据来源: WILEY

ISSN:0028-1522    

DOI:10.1002/j.2161-4296.1986.tb00928.x

出版商:Blackwell Publishing Ltd    

年代:1986

数据来源: WILEY