The ACTS Project was originated at NASA Glenn Research Center in the early 1980's to sponsor the development and application of technology that was intended to be used by the private sector. The program was formulated with the underlying philosophy of maintaining US leadership in satellite communications while focusing technology development for efficient use of the frequency spectrum. This report chronicles the execution and results of the program from the perspective of its technology managers, from inception through hardware and system development to on-orbit experiments and demonstrations of the technology. The first eight sections of the report discuss programmatic background, the specific satellite and ground terminal technology and the results generated by the program including industry relevance. A federally funded program of this type attracted strong advocates and adversaries and the resulting impact on the project schedule is also discussed. The last two sections are a list of useful acronyms and extensive references.

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ACTS: Technology Description and Results

This paper provides discussion of key system design considerations and enabling technologies for ground mobile WGS Satcom for disadvantaged terminals. The modem/waveform performance is critical and technologies demonstrated at other frequency bands could be re-used in the Ka/X bands. The suitability of existing fixed terminal standards applicable to these bands and adaptation of waveforms specifically developed for mobile satcom-on-the-move are considered.

Ground Mobile WGS Satcom for Disadvantaged Terminals

The ACTS propagation campaign is focusing on two broad areas: 1) Rain/signal attenuation data collection at seven sites in North America, 2) Theoretical and empirical consideratons for a global model to predict first & second order temporal and spatial statistics on attenuation, scintillation, conherence bandwidth, and depolarization due to weather (precipitation and atmospheric including interaction of weather with the antenna) for satellite systems at Ka-band.

Nasser Golshan

Papers

Interim Findings of ACTS Ka-Band Propagation Campaign