29 MATERIALS PROCESSING Includes space-based development of products and processes for commercial applications. For biological materials see 55 Space Biology. N91-11944*# Cincinnati Univ., OH. AN INVESTIGATION INTO THE FLOW BEHAVIOR OF A (NASA-CR-185304; NAS 1.26:185304) Avail: NTIS HC/MF A03 CSCL 22A The fluid behavior in normal gravity of a single phase gas system and a two phase gas/liquid system in an enclosed circular cylinder heated suddenly and nonuniformly from above was investigated. Flow visualization was used to obtain qualitative data on both systems. The use of thermochromatic liquid crystal particles as liquid phase flow tracers was evaluated as a possible means of simultaneously gathering both flow pattern and temperature gradient data for the two phase system. The results of the flow visualization experiments performed on both systems can be used to gain a better understanding of the behavior of such systems in a reduced gravity environment and aid in the verification of a numerical model of the system. Author N91-11945*# National Aeronautics and Space Administration. Lewis Research Center, Cleveland, OH. PLASMA-ASSISTED PHYSICAL VAPOR DEPOSITION SURFACE TREATMENTS FOR TRIBOLOGICAL CONTROL 18 p Presented at the TMS Annual Meeting, New Orleans, LA, 17-21 Feb. 1991; sponsored in part by the Minerals, Metals and Materials Society (NASA-TM-103652; E-5799; NAS 1.15:103652) Avail: NTIS HC/MF A03 CSCL 13B In any mechanical or engineering system where contacting surfaces are in relative motion, adhesion, wear, and friction affect reliability and performance. With the advancement of space age transportation systems, the tribological requirements have dramatically increased. This is due to the optimized design, precision tolerance requirements, and high reliability expected for solid lubricating films in order to withstand hostile operating conditions (vacuum, high-low temperatures, high loads, and space radiation). For these problem areas the ion-assisted deposition/modification processes (plasma-based and ion beam techniques) offer the greatest potential for the synthesis of thin films and the tailoring of adherence and chemical and structural properties for optimized tribological performance. The present practices and new approaches of applying soft solid lubricant and hard wear resistant films to engineering substrates are reviewed. The ion bombardment treatments have increased film adherence, lowered friction coefficients, and enhanced wear life of the solid lubricating films such as the dichalcogenides (MoS2) and the soft metals (Au, Ag, Pb). Currently, sputtering is the preferred method of applying MoS2 films; and ion plating, the soft metallic films. Ultralow friction coefficients (less than 0.01) were achieved with sputtered MoS2. Further, new diamond-like carbon and BN lubricating films are being developed by using the ion assisted deposition techniques. Author In the model of machine repair discussed there are M + R identical machines, M operating, and R spares. All machines are independent of one another. When an operating machine fails, it is sent to a single server repair station and immediately replaced by a spare machine, if one is available. The server has two available service types to choose from. There are waiting costs, repair costs, lost production costs, and switch-over costs. The following decision problem is treated: to obtain a stationary policy which determines the service type as a function of the state of the system in order to minimize the long-run average cost when failure and repair times have second-order Coxian distribution. This control problem is represented by a semi-Markov decision process. The policy-iteration algorithm and the value-iteration algorithm are used to obtain the optimal policy. Numerical results are given for these two optimization methods. Author N91-11947# Acurex Corp., Mountain View, CA. Environmental Systems Div. USERS GUIDE FOR THE CONVERSION OF NAVY PAINT SPRAY BOOTH PARTICULATE EMISSION CONTROL SYSTEMS FROM WET TO DRY OPERATION Final Report, Jan. - Sep. 1989 Jacqueline Ayer and Darrel Tate Jun. 1990 95 p Sponsored by Naval Civil Engineering Lab., Port Hueneme, CA and EPA, Research Triangle Park, NC (AD-A224737; NCEL-CR-90.005) Avail: NTIS HC/MF A05 CSCL 11/3 Users are provided instructions and cost evaluation information for converting the water curtain particulate emission control system currently used on many Navy painting facilities to dry filter operation. Engineering and logistical issues are addressed, and example design plans are provided. Construction and operating permit requirements mandated by regulatory agencies, such as air pollution control districts and fire departments, are discussed. Cost estimates that may be used to perform comprehensive cost evaluation analyses are provided. In addition, sample calculations that illustrate how to use the cost data are included. GRA N91-11948# Pennsylvania State Univ., University Park. Dept. of Mechanical Engineering. CALCULATION OF CONTAINMENT CONCENTRATIONS WHILE COATING THE INTERIOR OF A BULK STORAGE FUEL TANK M.S. Thesis Gail Maureen Haberlin May 1990 219 p (Contract N00123-89-G-0587) (AD-A224930) Avail: NTIS HC/MF A10 CSCL 24/1 In the last decade we, as a society, have made great strides in the field of Occupational Safety and Health. The smarter we become about the hazards that surround us the more we need to learn. It is not enough to know that a substance provides a potential risk to an individual but we need to know what that risk is; specifically in a particular occupational activity, when does exposure to a chemical become hazardous and what are the effects of the exposure. Air quality may be defined as the characteristics of air that affect an individual's health and well-being in a salubrious way. More technically, air quality is a quantitative indicator of how well air satisfies the requirements for human occupancy: thermal acceptability; normal concentrations of respiratory gases (i.e., oxygen, nitrogen and carbon dioxide); and suppression of other contaminants below levels that are deleterious to health or produce unpleasant odors. GRA The development of a type of hydrophilic microfiltration membranes is described. Studies which may result in a design of microfiltration modules containing capillary membranes are presented. The membranes are prepared from a solution containing two polymers and are of flat or cylindrical geometry. Attention is focused an capillary membranes, which are tubular membranes of outer diameter 0.5 to 5 mm, prepared by means of a dry-wet spining process. Different flow conditions of the feed suspension in the modules are described. The most favorable configuration appears to be transverse flow. A model to calculate the pressure drop in the bore of the capillary membrane during filtration and backflushing is presented. ESA N91-11950# Naval Research Lab., Washington, DC. H. W. Carhart, J. T. Leonard, E. K. Budnick, R. J. Ouellette, and J. H. Shanley, Jr. 31 Jul. 1990 130 p Prepared in cooperation with Hughes Associates, Inc., Wheaton, MD (AD-A225311; NRL-MR-6673) Avail: NTIS HC/MF A07 CSCL 13/12 A series of tests was conducted to evaluate the effectiveness of Aqueous Film Forming Foam (AFFF), potassium bicarbonate powder (PKP) and Halon 1211, alone and in various combinations, in extinguishing spray fires. The sprays were generated by JP-5 jet fuel issuing from an open sounding tube, and open petcock, a leaking flange or a slit pipe, and contacting an ignition source. The results indicate that typical fuel spray fires, such as those simulated in this series, are very severe. Flame heights ranged from 6.1 m (20 ft) for the split pipe to 15.2 m (50 ft) for the sounding tube scenario. These large flame geometries were accompanied by heat release rates of 6 MW to greater than 50 MW, and hazardous thermal radiation levels in the near field environment, up to 9.1 m (30 ft) away. Successful suppression of these fires requires both a significant reduction in flame radiation and delivery of a suppression agent to shielded areas. Of the nine suppression methods tested, the 95 gpm AFFF hand line and the hand line in conjunction with PKP were particularly effective in reducing the radiant flux. GRA N91-11951# Deutsche Forschungsanstalt fuer Luft- und Raumfahrt, Brunswick (Germany, F.R.). Inst. fuer Flugfuehrung. MANUFACTURE AND MEASUREMENT OF LOW LOSS AND LOW SCATTER MIRRORS Ph.D. Thesis Tech. Univ. Brunswick 185 P Dirk-Roger Schmitt Aug. 1990 In GERMAN; ENGLISH summary Report will also be announced as translation (ESA-TT-1239) (DLR-FB-90-19; ISSN-0171-1342; ETN-90-98042) Copyright Avail: NTIS HC/MF A09; DLR, VB-PL-DO, Postfach 90 60 58, 5000 Cologne, Fed. Republic of Germany, HC 68 Deutsche marks All necessary steps for the manufacturing of laser gyroscope mirrors are investigated, including the development of superpolished substrates and the optimization of processes to obtain low absorption layer systems. Micron bumps under 0.1 mm were observed at the substrates with a differential interference contrast process. Several dielectric layer systems were examined: TiO2/SiO2 in relation with Ag, Ta205/SiO2 and PrTiO3/SiO2. With these materials reflectivities higher than 0.995 were obtained. The lowest value for the scattering was reached with the PrTiO3/SiO2 system. The strong spectral variation of the reflection and transmission power of the layer systems was used for the development of edge filters for optical modulators on a GaAs basis. ESA N91-11952# Messerschmitt-Boelkow-Blohm G.m.b.H., Munich (Germany, F.R.). Dienstleistungsbereich. THE MECHANISM OF ELECTROCHEMICAL AND ANISOTROPIC SILICON ETCHING AND ITS APPLICATIONS Helmut Seidel 1989 19 p Presented at 3rd Togota Conference, Aichi-Ken, Japan, 22-25 Oct. 1989 (MBB-Z-0190-89-PUB; ETN-90-98146) Avail: NTIS HC/MF A03 An attempt to provide a general unifying model for all alkaline anisotropic silicon etchants is presented. The latter is a key technology in micromechanical device fabrication, and several aspects regarding this application are discussed. The three main properties of anisotropic silicon etching, dependence of the etch rate on the crystal direction, the dopant concentration and on an externally applied electric potential, are explained. Experiments and results are described. ESA (NASA-CR-186376; NAS 1.26:186376; NASA-90-002) Avail: NTIS HC/MF A03 CSCL 17B Multi-level method is a powerful technique for constructing bandwidth efficient modulation codes. It allows the construction of modulation codes systematically with arbitrary large minimum squared Euclidean distance from component codes in conjunction with proper bits-to-signal mapping. If the component codes are chosen properly, the resultant modulation code not only has good minimum squared Euclidean distance but is also rich in structural properties such as: linear structure, phase invariant property, and trellis structure. A modulation code with linear structure has invariant distance distribution. Phase invariant property is useful in resolving carrier-phase ambiguity and ensuring rapid carrier-phase resynchronization after temporary loss of synchronization. It the component codes have trellis structure, the resultant multi-level modulation code also has trellis structure. Trellis structure allows decoding of a multi-level modulation code with the soft-decision Viterbi decoding algorithm. Furthermore, the multi-level structure allows decoding of a multi-level modulation code with the multi-stage decoding. This type of decoding reduces the decoding complexity. Multi-stage decoding is not optimum even though the decoding of each component is optimum. Based on the analysis and simulation results, the difference in error performance between the optimum decoding of the overall multi-level modulation code and the suboptimum multi-stage decoding of the code is very little, a fraction of dB loss. Author to discuss studies made on radio wave propagation by investigators from domestic and international organizations. NAPEX XIV was held on May 11, 1990, at the Balcones Research Centers, University of Texas, Austin, Texas. The meeting was organized into two technical sessions: Satellite (ACTS) and the Olympus Spacecraft, while the second focused on the fixed and mobile satellite propagation studies and experiments. Following NAPEX XIV, the ACTS Miniworkshop was held at the Hotel Driskill, Austin, Texas, on May 12, 1990, to review ACTS propagation activities since the First ACTS Propagation Studies Workshop was held in Santa Monica, California, on November 28 and 29, 1989. For individual titles, see N91-11955 through N91-11972. N91-11955*# Communications Satellite Corp., Clarksburg, MD. SUMMARY OF THE FIRST ACTS PROPAGATION WORKSHOP David V. Rogers In JPL, California Inst. of Tech., Proceedings of the Fourteenth NASA Propagation Experimenters Meeting (NAPEX 14) and the Advanced Communications Technology Satellite (ACTS) Propagation Studies Miniworkshop 1 Jul. 1990 p 17-22 (For primary document see N91-11954 03-32) Avail: NTIS HC/MF A12 CSCL 20N The first Advanced Communications Technology Satellite (ACTS) Propagation Studies Workshop (APSW I), organized by NASA/Jet Propulsion Laboratory (JPL) to plan propagation experiments and studies with NASA's ACTS, convened in Santa Monica, California, during November 28 and 29, 1989. The objectives of APSW I were to identify general and ACTS-related propagation needs, and to prepare recommendations for a study plan incorporating scientific and systems requirements related to deployment of 8 to 10 propagation terminals in the USA in support of ACTS experimental activities. A summary of workshop activities is given. Author ACTS PROPAGATION PROGRAM Avail: NTIS HC/MF A12 CSCL 20N The Advanced Communications Technology Satellite (ACTS) Propagation Program is organized to fulfill certain needs and requirements of the ACTS community. It is hoped that issues related to propagation effects in the context of ACTS experiments can be addressed and resolved by this program. The objectives of the ACTS Propagation Program are included in but not limited to planning for propagation measurements and studies using ACTS; organizing propagation experimenters who want to use ACTS into one group; developing observation stations for ACTS propagation measurements; supervising data collection, analysis, and ensure uniformity of data recording among various experimenters; and assisting the ACTS Program Office to carry out its objectives. This program is organized and managed by the NASA Propagation Program at the Jet Propulsion Laboratory. Financial support for this program is provided by NASA. Author N91-11957*# European Space Agency. European Space Research and Technology Center, ESTEC, Noordwijk (Netherlands). OPEX PROPAGATION MEASUREMENTS AND STUDIES Avail: NTIS HC/MF A12 CSCL 20N With the launch of the telecommunications Olympus satellite a new area began for the Olympus Propagation Experiments (OPEX) group. The years of preparations are now paying off - the experiments are underway and the co-operative effort is now turning its attention to the processing and analysis of data and to the interpretation of results. The aim here is to give a short review of the accomplishments made since NAPEX 13 and the work planned for the future. When ESA's Olympus was launched in summer of 1989 it carried a payload producing three unmodulated beacons at 12.5, 19.8, and 29.7 GHz. The main purpose of these beacons is to enable scientists to carry out long term slant path propagation experiments at these frequencies. The OPEX group, which was set up under ESA auspices in 1980, had been preparing for this event very carefully. The specifications for the equipment to be used and the elaboration of standard procedures for data processing and analysis have been worked out jointly. Today the OPEX community includes approximately 30 groups of experimenters. Immediately after achieving platform stability at the orbital location at 341 degrees east, ESA performed the In-Orbit Tests. Most measurements were carried out in Belgium using terminals specially developed for this purpose. A summary of the test results is given. Author N91-11958*# Virginia Polytechnic Inst. and State Univ., Blacksburg. Satellite Communications Group. OLYMPUS PROPAGATION STUDIES IN THE US: PROPAGATION TERMINAL HARDWARE AND EXPERIMENTS Warren L. Stutzmzn In JPL, California Inst. of Tech., Proceedings of the Fourteenth NASA Propagation Experimenters Meeting (NAPEX 14) and the Advanced Communications Technology Satellite (ACTS) Propagation Studies Miniworkshop 1 Jul. 1990 p 36-42 (For primary document see N91-11954 03-32) Avail: NTIS HC/MF A12 CSCL 20N Virginia Tech is performing a comprehensive set of propagation measurements using the Olympus satellite beacons at 12.5, 20, and 30 GHz. These data will be used to characterize propagation conditions on small earth terminal (VSAT)-type networks for next generation small aperture Ka-band systems. The European Space Agency (ESA) satellite Olympus was launched July 12, 1989. The spacecraft contains a sophisticated package of propagation beacons operating at 12.5, 19.77, and 29.66 GHz (referred to as 12.5, 20, and 30 beacons). These beacons cover the east coast of the United States with sufficient power for attenuation measurements. The Virginia Satellite Communications Group is completing the hardware construction phase and will begin formal data collection in June. Author N91-11959*# Virginia Polytechnic Inst. and State Univ., Blacksburg. Satellite Communications Group. OLYMPUS PROPAGATION STUDIES IN THE US: RECEIVER DEVELOPMENT AND THE DATA ACQUISITION SYSTEM John C. McKeeman In JPL, California Inst. of Tech., Proceedings of the Fourteenth NASA Propagation Experimenters Meeting (NAPEX 14) and the Advanced Communications Technology Satellite (ACTS) Propagation Studies Miniworkshop 1 Jul. 1990 p 43-53 (For primary document see N91-11954 03-32) Avail: NTIS HC/MF A12 CSCL 20N Virginia Tech has developed two types of receivers to monitor the Olympus beacons, as well as a custom data acquisition system to store and display propagation data. Each of the receiver designs uses new hybrid analog/digital techniques. The data acquisition system uses a stand alone processor to collect and format the data for display and subsequent processing. The launch of the Olympus satellite with its coherent beacons offers new opportunities to study propagation effects at 12.5, 20, and 30 GHz. At Virginia Tech, the satellite is at 14 degrees in elevation, which allows us to measure low elevation angle effects. However, to make these measurements, a very accurate and stable measurement system is required. Virginia Tech has constructed a complex receiving system which monitors the Olympus beacons and all parameters associated with propagation research. In the current configuration, researchers have developed a receiver which frequency locks to the less fade susceptible 12.5 GHz beacon. Since all beacons on the satellite are driven from a single master oscillator, drift in the 12.5 GHz beacon implies corresponding drifts in the 20, and 30 GHz beacons. The receivers for the 20 and 30 GHz systems derive their frequency locking information from the 12.5 GHz system. This widens the dynamic range of the receivers and allows the receivers to maintain lock in severe fade conditions. In addition to monitoring the beacons, the sky noise is monitored with radiometers at each frequency. The radiometer output is used to set the clear air level for each beacon measurement. Researchers also measure the rain rate with several tipping bucket rain gauges placed along the propagation path. Author N91-11960*# Michigan Technological Univ., Houghton. Sensing and Signal Processing Lab. OLYMPUS RECEIVER EVALUATION AND PHASE NOISE Richard L. Campbell, Huailiang Wang, and Dennis Sweeney see N91-11954 03-32) Avail: NTIS HC/MF A12 CSCL 20N A set of measurements performed by the Michigan Tech Sensing and Signal Processing Group on the analog receiver built by the Virginia Polytechnic Institute (VPI) and the Jet Propulsion Laboratory (JPL) for propagation measurements using the Olympus Satellite is described. Measurements of local oscillator (LO) phase noise were performed for all of the LOS supplied by JPL. In order to obtain the most useful set of measurements, LO phase noise measurements were made using the complete VPI receiver front end. This set of measurements demonstrates the performance of the receiver from the Radio Frequency (RF) input through the high Intermediate Frequency (IF) output. Three different measurements were made: LO phase noise with DC on the voltage controlled crystal oscillator (VCXO) port; LO phase noise with the 11.381 GHz LO locked to the reference signal generator; and a reference measurement with the JPL LOS out of the system. Author N91-11961*# Jet Propulsion Lab., California Inst. of Tech., Pasadena. EXPERIMENTS FOR Ka-BAND MOBILE APPLICATIONS: THE ACTS MOBILE TERMINAL Polly Estabrook, Khaled Dessouky, and Thomas Jedrey In its Proceedings of the Fourteenth NASA Propagation Experimenters Meeting (NAPEX 14) and the Advanced Communications Technology Satellite (ACTS) Propagation Studies Miniworkshop 1 Jul. 1990 p 74-82 (For primary document see N91-11954 03-32) Avail: NTIS HC/MF A12 CSCL 20N To explore the potential of Ka-band to support mobile satellite services, the Jet Propulsion Laboratory (JPL) has initiated the design and development of a Ka-band land-mobile terminal to be used with the Advanced Communications Technology Satellite (ACTS). The planned experimental setup with ACTS is described. Brief functional descriptions of the mobile and fixed terminals are provided. The inputs required from the propagation community to support the design activities and the planned experiments are also discussed. N91-11962*# Pasadena. Author Jet Propulsion Lab., California Inst. of Tech., DEEP SPACE PROPAGATION EXPERIMENTS AT Ka-BAND Stanley A. Butman In its Proceedings of the Fourteenth NASA Propagation Experimenters Meeting (NAPEX 14) and the Advanced Communications Technology Satellite (ACTS) Propagation Studies Miniworkshop 1 Jul. 1990 p 85-101 (For primary document see N91-11954 03-32) Avail: NTIS HC/MF A12 CSCL 20N Propagation experiments as essential components of the general plan to develop an operational deep space telecommunications and navigation capability at Ka-band (32 to 35 GHz) by the end of the 20th century are discussed. Significant benefits of Ka-band over the current deep space standard X-band (8.4 GHz) are an improvement of 4 to 10 dB in telemetry capacity and a similar increase in radio navigation accuracy. Propagation experiments are planned on the Mars Observer Mission in 1992 in preparation for the Cassini Mission to Saturn in 1996, which will use Ka-band in the search for gravity waves as well as to enhance telemetry and navigation at Saturn in 2002. Subsequent uses of Ka-band are planned for the Solar Probe Mission and the Mars Program. Author N91-11963*# National Oceanic and Atmospheric Administration, ATTENUATION STATISTICS DERIVED FROM EMISSION E. R. Westwater, J. B. Snider, M. J. Falls, and E. Fionda (Fondazione Ugo Bordoni, Rome, Italy) In JPL, California Inst. of Tech., Proceedings of the Fourteenth NASA Propagation Experimenters Meeting (NAPEX 14) and the Advanced Communications Technology Satellite (ACTS) Propagation Studies Miniworkshop 1 Jul. 1990 p 102-109 (For primary document see N91-11954 03-32) Avail: NTIS HC/MF A12 CSCL 20N Two seasons of thermal emission measurements, running from December 1987 through February 1988 and from June through August 1988 of thermal emission measurements, taken by a multi-channel, ground-based microwave radiometer, are used to derive single-station zenith attenuation statistics at 20.6 and 31.65 GHZ. For the summer period, statistics are also derived for 52.85 GHz. In addition, data from two dual-channel radiometers, separated from Denver by baseline distances of 49 and 168 km, are used to derive two-station attenuation diversity statistics at 20.6 and 31.65 GHz. The multi-channel radiometer is operated at Denver, Colorado; the dual-channel devices are operated at Platteville and Flagler, Colorado. The diversity statistics are presented by cumulative distributions of maximum and minimum attenuation. Author Electrical Engineering SATELLITE SOUND BROADCAST PROPAGATION STUDIES AND MEASUREMENTS Wolfhard J. Vogel and Geoffrey W. Torrence In JPL, California Inst. of Tech., Proceedings of the Fourteenth NASA Propagation Experimenters Meeting (NAPEX 14) and the Advanced Communications Technology Satellite (ACTS) Propagation Studies Miniworkshop 1 Jul. 1990 p 110-123 (For primary document see N91-11954 03-32) Avail: NTIS HC/MF A12 CSCL 20N Satellite Sound Broadcasting is an attractive satellite application. Before regulatory decisions can be made in 1992, the propagation effects encountered have to be characterized. The Electrical Engineering Research Laboratory has nearly completed a system which will allow amplitude measurements to be made over 10 MHz bandwidths in the 800 to 1800 MHz frequency range. The system uses transmission from a transportable tower, and reception inside buildings or in the shadow of trees or utility poles. The goal is to derive propagation models for use by systems engineers who are about to design satellite broadcast systems. The advance of fiber-optics technology has helped to focus future development of satellite services into areas where satellites are uniquely competitive. One of these preferred satellite applications is the broadcasting of high-quality sound for stationary or mobile reception by listeners using low-cost, consumer-grade receivers. Before such services can be provided, however, the political hurdles of spectrum allocation have to be surmounted and the technical questions of standardization for world-wide compatibility have to be resolved. In order to arrive at an optimal system design, efficient in the use of our scarce spectral resources, affordable both to the broadcaster and the listener, and providing predictable performance, the propagation effects to which the service is subjected have to be characterized. Consequently, the objective of the research project is to make basic propagation measurements for direct Satellite Sound Broadcasting Service (SSBS). The data obtained should allow the development of propagation models to be used by communications engineers designing the operational systems. Such models shall describe the effects of shadowing and multipath propagation on SSBS receivers operating in a specified environment, such as inside commercial or residential buildings of various construction and also in the shadow of trees or utility poles as might be encountered by transporting or mobile listeners. Author N91-11965*# Ministry of Posts and Telecommunications, Ibaraki (Japan). SATELLITE SOUND BROADCAST RESEARCH ASPECT IN Yoshihiro Hase, Kimio Kondo, and Shingo Ohmori In JPL, Avail: NTIS HC/MF A12 CSCL 20N Researches on Satellite Sound Broadcasting Services (SSBS) have become active in the past few years. Activities of the Consultative Committee for International Radio (CCIR) and the World Administrative Radio Conference (WARC), especially about digital systems proposed in the CCIR report, are briefly reviewed. The Communications Research Laboratory (CRL) future plan of SSBS research, stressing propagation rather than communications aspects, is described. N91-11966*# Johns Hopkins Univ., Laurel, MD. Author A DESCRIPTION OF RESULTS FROM THE HANDBOOK ON SIGNAL FADE DEGRADATION FOR THE LAND MOBILE SATELLITE SERVICE In Julius Goldhirsh and Wolfhard J. Vogel (Texas Univ., Austin.) During the period 1983 to 1988 a series of experiments were undertaken by the Electrical Engineering Research Laboratory of the University of Texas and the Applied Physics Laboratory of the Johns Hopkins University in which propagation impairment effects were investigated for the Land Mobile Satellite Service (LMSS). The results of these efforts have appeared in a number of publications, technical reports, and conference proceedings. The rationale for the development of a 'handbook' was to locate the salient and useful results in one single document for use by communications engineers, designers of planned LMSS communications systems, and modelers of propagation effects. Where applicable, the authors have also drawn from the results of other related investigations. A description of sample results contained in this handbook which should be available in the latter part of 1990 is given. Author N91-11967*# Colorado Univ., Boulder. CODELESS GPS APPLICATIONS TO MULTI-PATH: CGAMP P. F. MacDoran, R. B. Miller, D. Jenkins, J. Lemmon (Institute for Telecommunication Sciences, Boulder, CO.), K. Gold, W. Schreiner, and G. Snyder In JPL, California Inst. of Tech., Proceedings of the Fourteenth NASA Propagation Experimenters Meeting (NAPEX 14) and the Advanced Communications Technology Satellite (ACTS) Propagation Studies Miniworkshop 1 Jul. 1990 p 132-139 (For primary document see N91-11954 03-32) Avail: NTIS HC/MF A12 CSCL 20N Cordless Global Positioning System (GPS) Applications to Multi-Path (CGAMP) is meeting the challenge of exploiting the L-band signals from the Global Positioning System (GPS) satellites for the measurement of the impulse response of radio transmission channels over space-Earth paths. This approach was originally suggested by E. K. Smith and has been pursued by J. Lemmon, without an affordable implementation being identifiable. In addition to the high cost of a suitable P code correlating GPS receiver, |