摘要:

ABSTRACTThe USAF's plans for providing space launch capabilities through 1995 are outlined in this transcript of the speech given by Col. Martin at the National Technical Meeting of the Institute of Navigation, Santa Barbara, California, January 1988.

ISSN:0028-1522    

DOI:10.1002/j.2161-4296.1988.tb00959.x

出版商:Blackwell Publishing Ltd    

年代:1988

数据来源: WILEY

摘要:

ABSTRACTMuch of the current activity in the Omega program is in support of U.S. policy statements contained in the 1986 Federal Radionavigation Plan. The policy indicates we should plan on continuing operations until at least the year 2005. This calls for an examination of which system elements may need a capital investment for service life extension. We have begun necessary studies and can report preliminary results. Transmitting station equipments, including antennas, are being considered for redesign or replacement. Investigations also involve system monitors, system control software, and system propagation corrections. The studies will continue for the next few years and contribute to deliberations leading to biennial updates to the Federal Radionavigation Plan.

ISSN:0028-1522    

DOI:10.1002/j.2161-4296.1988.tb00960.x

出版商:Blackwell Publishing Ltd    

年代:1988

数据来源: WILEY

摘要:

ABSTRACTThis paper investigates the potential of using GPS for precision approach landing operations. The issues addressed are accuracy, integrity, and coverage reliability. The results of the investigation show that GPS performance, as specified by the GPS Joint Program Office, does not presently satisfy precision approach requirements as specified by the International Civil Aviation Organization. Although the horizontal accuracy of GPS is within the requirement specified for a precision approach to 200 ft altitude above the runway, it is shown that GPS, even when operating in a differential mode, does not achieve the required vertical accuracy. Integrity and coverage reliability are also shown to require further improvement for GPS to be considered for use as a precision approach system.

ISSN:0028-1522    

DOI:10.1002/j.2161-4296.1988.tb00961.x

出版商:Blackwell Publishing Ltd    

年代:1988

数据来源: WILEY

摘要:

ABSTRACTLoran‐C transmitters are grouped into different chains, each with a specified group repetition interval (GRI) or group repetition rate (1/GRI). Currently, Loran‐C transmitters in different chains are not tightly synchronized. Consequently, Loran receivers can compute time differences only between signals with the same GRI. In other words, they require at least two received signals from each GRI they wish to use. If the receiver can receive many stations within a GRI, this limitation is not troublesome. However, if the receiver is near the edge of coverage or if a transmitter has failed, it can be helpful to remove this limitation and allow the receiver to compute cross‐rate time differences. The time transfer capability of GPS is one way of accomplishing the required cross‐rate synchronization. In this paper, we examine (by example) the impact of cross‐rate synchronization on Loran‐C coverage. We do this by developing a Loran accuracy model and considering Loran coverage in the U.S. and Canadian West after the “mid‐continent gap” has been filled. We find that cross‐rate synchronization would be helpful in general, and especially valuable if a tra

ISSN:0028-1522    

DOI:10.1002/j.2161-4296.1988.tb00962.x

出版商:Blackwell Publishing Ltd    

年代:1988

数据来源: WILEY

摘要:

ABSTRACTThe Single Coriolis Inertial Rate and Acceleration Sensor (SCIRAS™)* measures both angular rotation and linear acceleration. By detecting Coriolis acceleration of a dithered accelerometer, it is possible to measure a direct rotation rate. Patented processing techniques have been developed which can separate Coriolis components of these signals from components due to linear acceleration with sufficient precision to achieve a few nmi/h sensor package. The sensor assembly (without electronics) weighs under 0.5 lb and fits within an 8 in3package. The system costs substantially less than comparable RLG systems and uses about half as much power. There is no wear‐out since this is an all‐flexure device. The sensor is substantially rugged, being able to survive 1000 g shocks and 30 g vibration. Wide temperature applications are possible and shelf life is indefinite, since there are no exotic fluids or gases required for operation. This represents a marked reduction in life‐cycl

ISSN:0028-1522    

DOI:10.1002/j.2161-4296.1988.tb00963.x

出版商:Blackwell Publishing Ltd    

年代:1988

数据来源: WILEY

摘要:

ABSTRACTA method for parametrically representing the surface of the earth is described. Latitude and longitude are replaced by parametric pseudolatitude and pseudolongitude. Conversions between Cartesian coordinates in three‐space and the parametric form are described. A compact and precise algorithm for Cartesian‐to‐parametric form has been developed by way of tested computer proce

ISSN:0028-1522    

DOI:10.1002/j.2161-4296.1988.tb00964.x

出版商:Blackwell Publishing Ltd    

年代:1988

数据来源: WILEY

摘要:

ABSTRACTLow‐orbit, inexpensive navigation satellite concepts applicable to civil aviation are developed as an alternative to GPS. Details are provided on orbits, signal structure, positioning software, power budget, and estimated costs and risks. Comprehensive error analysis indicates that a 2 dRMS accuracy of approximately 85 m is achievable, and that the system is fault‐tolerant. Rough estimates indicate that the satellite configuration will cost about $300 mill

ISSN:0028-1522    

DOI:10.1002/j.2161-4296.1988.tb00965.x

出版商:Blackwell Publishing Ltd    

年代:1988

数据来源: WILEY

ISSN:0028-1522    

DOI:10.1002/j.2161-4296.1988.tb00966.x

出版商:Blackwell Publishing Ltd    

年代:1988

数据来源: WILEY

ISSN:0028-1522    

DOI:10.1002/j.2161-4296.1988.tb00967.x

出版商:Blackwell Publishing Ltd    

年代:1988

数据来源: WILEY