Rail transit fare collection: Policy and technology assessment

The impact of fare policies and fare structure on the selection of equipment was investigated, fare collection systems are described, hardware and technology related problems are documented, and the requirements of a fare collection simulation model are outlined. Major findings include: (1) a wide variation in the fare collection systems and equipment, caused primarily by historical precedence; (2) the reliability of AFC equipment used at BART and WMATA discouraged other properties from considering use of similar equipment; (3) existing equipment may not meet the fare collection needs of properties in the near future; (4) the cost of fare collection operation and maintenance is high; and (5) the relatively small market in fare collection equipment discourages new product development by suppliers. Recommendations for fare collection R&D programs include development of new hardware to meet rail transit needs, study of impacts of alternate fare policies increased communication among policymakers, and consensus on fare policy issues

Exploring the next generation Deep Space Network

As the current 70-meter antennas are quite old (28-35 years) it is necessary to consider replacing these antennas in the near term as well as providing a capability beyond 70-meters in the future. A study was conducted that investigated the remaining service life of the existing antennas and considered alternatives for eventual replacement of the 70 m-subnet capability. This paper examines several of the concepts considered and explores some of the options for the next generation Deep Space Network

Structural design options for the new 34 meter beam waveguide antenna

In addition to the successful network of 34 m High Efficiency antennas recently built by JPL, the Deep Space Network (DSN) is embarking on the construction of a 34 m high performance, research and development antenna with beam waveguide optics at the Venus site. The construction of this antenna presents many engineering challenges in the area of structural, mechanical, RF, and pointing system design. A set of functional and structural design requirements is outlined to guide analysts in the final configuration selection. Five design concepts are presented covering both the conventional center-fed beam optics as well as the nonconventional, by-pass beam configuration. The merits of each concept are discussed with an emphasis on obtaining a homologous design. The preliminary results of structural optimization efforts, currently in progress, are promising, indicating the feasibility of meeting, as a minimum, all X-band (8.4 GHz) requirements, with a goal towards meeting Ka-band (32 GHz) quality performance, at the present budget constraints

Exploring the next generation Deep Space Network

As the current 70-meter antennas are quite old (28-35 years) it is necessary to consider replacing these antennas in the near term as well as providing a capability beyond 70-meters in the future. A study was conducted that investigated the remaining service life of the existing antennas and considered alternatives for eventual replacement of the 70 m-subnet capability. This paper examines several of the concepts considered and explores some of the options for the next generation Deep Space Network