Engineering topics

Knouse, G. H.

Publications and source records attributed to Knouse, G. H..

6 records

NASA NTRS1986

Mobile satellite communications technology - A summary of NASA activities

Studies in recent years indicate that future high-capacity mobile satellite systems are viable only if certain high-risk enabling technologies are developed. Accordingly, NASA has structured an advanced technology development program aimed at efficient utilization of orbit, spectrum, and power. Over the last two years, studies have concentrated on developing concepts and identifying cost drivers and other issues associated with the major technical areas of emphasis: vehicle antennas, speech compression, bandwidth-efficient digital modems, network architecture, mobile satellite channel characterization, and selected space segment technology. The program is now entering the next phase - breadboarding, development, and field experimentation.

Dutzi, E. J.↗

NASA NTRS1984

NASA's mobile satellite communications program; ground and space segment technologies

This paper describes the Mobile Satellite Communications Program of the United States National Aeronautics and Space Administration (NASA). The program's objectives are to facilitate the deployment of the first generation commercial mobile satellite by the private sector, and to technologically enable future generations by developing advanced and high risk ground and space segment technologies. These technologies are aimed at mitigating severe shortages of spectrum, orbital slot, and spacecraft EIRP which are expected to plague the high capacity mobile satellite systems of the future. After a brief introduction of the concept of mobile satellite systems and their expected evolution, this paper outlines the critical ground and space segment technologies. Next, the Mobile Satellite Experiment (MSAT-X) is described. MSAT-X is the framework through which NASA will develop advanced ground segment technologies. An approach is outlined for the development of conformal vehicle antennas, spectrum and power-efficient speech codecs, and modulation techniques for use in the non-linear faded channels and efficient multiple access schemes. Finally, the paper concludes with a description of the current and planned NASA activities aimed at developing complex large multibeam spacecraft antennas needed for future generation mobile satellite systems.

Naderi, F.↗

NASA NTRS1982

An experiment to enable commercial mobile satellite service

A Mobile Satellite Experiment (MSAT-X) is described, based on a planned cooperative U.S./Canadian program. The experiment would establish network architecture, develop system and ground-segment technology, and define the technical characteristics needed to help structure the regulatory/institutional framework needed to enable a first-generation commercial satellite service. A satellite of this type would augment terrestrial systems, both cellular and noncellular, in the thin-route/rural areas of the country where service is either unavailable or inadequate. Applications range from wide-area radio/dispatch (e.g., oil exploration and interstate trucking) to extension of the public mobile telephone service. Market estimates are provided and experiment objectives and requirements are delineated. The requirements are being developed in close coordination with the Department of Communications (DOC) of Canada and with industry and potential-user organizations. The paper closes with a development plan and milestone chart.

Lovell, R. R.↗

NASA NTRS1980

The concept of an integrated terrestrial/land mobile satellite system

Potential satellite markets in the Public Safety (disaster relief, emergency medical and law enforcement) and Common Carrier (mobile radio telephone) service areas are identified. The public mobile telephone segment is then examined to illustrate a methodology for identifying a potential satellite addressable market, including capacity requirements for roughly sizing a satellite. It is postulated that satellites could serve this lower density (mobiles/sq. km), thin-route markets at a competitive cost and thus complement terrestrial systems in the urban and more densely populated areas to provide an integrated nationwide mobile service.

Knouse, G. H.↗

NASA NTRS1979

Terrestrial/land mobile satellite considerations, NASA plans and critical issues

This paper briefly reviews the land mobile market and discusses services that might be provided by hybrid terrestrial/land mobile satellite systems (T/LMSS). In view of the expected urban/suburban patterns of planned terrestrial systems it is suggested that a satellite may prove a cost-effective complement to terrestrial systems for serving thinly populated or large geographical areas. A basic Land Mobile Satellite Service (LMSS) is described, example applications are provided, and the status and rationale for LMSS frequencies in the 806-890 MHz band is given. Next, examples are given of NASA supported land mobile satellite experiments and a preliminary T/LMSS work plan, part of an overall Narrowband Program, is presented for structuring future work. The initiation of the T/LMSS plan depends on pending management/budget decisions. The report closes with a listing of issues and potential problem areas, the solutions of which NASA believes are critical to the success of the proposed T/LMSS effort.

Knouse, G. H.↗

NASA NTRS1974

Evaluating and synthesizing broadcasting satellite systems

A system model and a computer program have been developed which are representative of broadcasting satellite systems employing several types of receiving terminals. The program provides a user-oriented tool for (1) evaluating performance/cost tradeoffs, (2) synthesizing minimum cost systems for a given set of system requirements, and (3) performing sensitivity analyses to identify critical user requirements, system parameters, and technology. The types of systems which can be evaluated are described, and the capabilities of the program are illustrated by means of several examples.

Knouse, G. H.↗