MSAT-X: A technical introduction and status report

A technical introduction and status report for the Mobile Satellite Experiment (MSAT-X) program is presented. The concepts of a Mobile Satellite System (MSS) and its unique challenges are introduced. MSAT-X's role and objectives are delineated with focus on its achievements. An outline of MSS design philosophy is followed by a presentation and analysis of the MSAT-X results, which are cast in a broader context of an MSS. The current phase of MSAT-X has focused notably on the ground segment of MSS. The accomplishments in the four critical technology areas of vehicle antennas, modem and mobile terminal design, speech coding, and networking are presented. A concise evolutionary trace is incorporated in each area to elucidate the rationale leading to the current design choices. The findings in the area of propagation channel modeling are also summarized and their impact on system design discussed. To facilitate the assessment of the MSAT-X results, technology and subsystem recommendations are also included and integrated with a quantitative first-generation MSS design

NASA's mobile satellite development program

A Mobile Satellite System (MSS) will provide data and voice communications over a vast geographical area to a large population of mobile users. A technical overview is given of the extensive research and development studies and development performed under NASA's mobile satellite program (MSAT-X) in support of the introduction of a U.S. MSS. The critical technologies necessary to enable such a system are emphasized: vehicle antennas, modulation and coding, speech coders, networking and propagation characterization. Also proposed is a first, and future generation MSS architecture based upon realized ground segment equipment and advanced space segment studies

An alternative resource sharing scheme for land mobile satellite services

A preliminary comparison between the two competing channelization concepts for the Land Mobile Satellite Services (LMSS), namely frequency division (FD) and code division (CD), is presented. Both random access and demand-assigned approaches are considered under these concepts. The CD concept is compared with the traditional FD concept based on the system consideration and a projected traffic model. It is shown that CD is not particularly attractive for the first generation Mobile Satellite Services because of the spectral occupancy of the network bandwidth. However, the CD concept is a viable alternative for future systems such as the personal access satellite system (PASS) in the Ka-band spectrum where spectral efficiency is not of prime concern. The effects of power robbing and voice activity factor are incorporated. It was shown that the traditional rule of thumb of dividing the number of raw channels by the voice activity factor to obtain the effective number of channels is only valid asymptotically as the aggregated traffic approaches infinity

Introduction to the Personal Access Satellite System Study

A recent study by the National Telecommunications and Information Administration (NTIA) has concluded that the 21st century will be the age of information in which the telecommunication infrastructure will be vital to the social and economic well being of society. To meet the challenge of the coming age, JPL has been performing studies on a personal access satellite system (PASS) for the 21st century. The PASS study can be traced back to a study in which the technical feasibility and potential applications of a high frequency, low data rate satellite system were identified using small fixed terminals. Herein, the PASS concept is described along with the strawman design. Then the key challenges are identified along with possible solutions. Finally, the plan for the future is summarized from the key results

Personal Access Satellite System (PASS) study. Fiscal year 1989 results

The Jet Propulsion Laboratory is exploring the potential and feasibility of a personal access satellite system (PASS) that will offer the user greater freedom and mobility than existing or currently planned communications systems. Studies performed in prior years resulted in a strawman design and the identification of technologies that are critical to the successful implementation of PASS. The study efforts in FY-89 were directed towards alternative design options with the objective of either improving the system performance or alleviating the constraints on the user terminal. The various design options and system issues studied this year and the results of the study are presented

A satellite-based personal communication system for the 21st century

Interest in personal communications (PCOMM) has been stimulated by recent developments in satellite and terrestrial mobile communications. A personal access satellite system (PASS) concept was developed at the Jet Propulsion Laboratory (JPL) which has many attractive user features, including service diversity and a handheld terminal. Significant technical challenges addressed in formulating the PASS space and ground segments are discussed. PASS system concept and basic design features, high risk enabling technologies, an optimized multiple access scheme, alternative antenna coverage concepts, the use of non-geostationary orbits, user terminal radiation constraints, and user terminal frequency reference are covered

Can the NHS learn about human factors from the Ministry of Defence?

The National Health Service (NHS) in England has ambitious plans to drive innovation in health information technology (HIT) to improve patient safety, quality and cost effectiveness. Acute trusts are complex socio-technical systems that are required to implement a number of large information technology projects in order to meet national targets for digital maturity. This research explored whether the Ministry of Defence (MOD) Human Factors Integration Model for the acquisition process could be applied to a HIT project. A qualitative research study was undertaken in a large English NHS acute trust using the experience of implementing an electronic observation system to explore transferability of the MOD approach to acute healthcare. Data were collected using semi-structured interviews and focus groups and analysed thematically with reference to SEIPS 2.0 (Holden et al, 2013) healthcare systems model and the MOD framework. Key findings included limited awareness of Human Factors in healthcare; information system design/specification to deliver positive outcomes around patient safety and financial savings. Human Factors negative systems issues included alert fatigue, changing mental models, inability to maximise data for patient benefit, system resilience, local and national interoperability issues

Introducing CAD/CAM into primary schools, part 1 of a case study – developing the curriculum

This paper describes the first part of a small case study in which a secondary school works with three partner primary schools to develop computer assisted design and computer assisted manufacture (CAD/CAM) expertise in primary school children in Years 2, 4 and 5. Three secondary school teachers developed units of work incorporating CAD/CAM, taught these units to small groups of primary school children who will then act as peer mentors to the rest of the pupils in their class when the entire class is taught the unit. The nature of the work produced by these small groups is discussed in terms of the design decisions made by the pupils

What Do Students Have to Say About Ecology and Evolution? Using Podcasting to Apply Integrative Biology Themes Across the Tree of Life

We describe a versatile podcasting assignment that requires students to (i) review primary and secondary literature relating to an assigned organism with the goal of identifying the main features of its ecology and evolution, (ii) prepare an enhanced podcast about their organism, and (iii) critique peer podcasts. The goal of this assignment is for each student to gain a fuller appreciation for and understanding of biological diversity. This assignment will enhance students\u27 research, technology, and communication skills while reinforcing the main themes of integrative biology