J.A. Davis

Publications (2)0 Total impact

• Conference Proceeding: Europe's role in the next millennium towards the development of the next generation of global navigation satellite systems (GNSS)

  C.C. Hodge, J.A. Davis
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  ABSTRACT: This paper studies the state-of-the-art in time and frequency technologies: future clocks, time-transfer and time-dissemination techniques, and their application towards the next-generation of global navigation satellite systems. The requirement for an upgrade to GPS is discussed, and the potential opportunities for European industry are discussed with an identification of key future market areas. We briefly describe the exciting developments towards a seamless, international, wholly-civil GNSS, and show the importance of frequency-band allocation issues in defining the GNSS system architecture. It is concluded that 10 millimetre real-time position determination and 30 picosecond time-transfer capability is technologically achievable, but that the political and institutional issues must first be resolved
  Satellite Systems for European Markets - Looking to the Next Millennium (Digest No. 1997/024), IEE Colloquium on; 02/1997
• Conference Proceeding: Timing options and frequency control concepts for meeting user requirements with the second-generation global navigation satellite system (GNSS2)

  C.C. Hodge, J.A. Davis
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  ABSTRACT: This paper has described the first phase of an on-going study of work investigating the feasibility of a wholly-civil European second-generation Global Navigation Satellite System. The issues of time and frequency underpin the whole system, and this has been highlighted through the options available for frequency-band allocation, clock development, and time-transfer techniques for global navigation and global time- and frequency-dissemination. The NPL propose that further studies on issues such as local real-time ionospheric and tropospheric delay evaluation, two-way time-transfer to geostationary satellites for real-time satellite ephemeris determination, and multipath effects and methods to ameliorate them through multi-frequency receivers and directional antennae, would be beneficial towards developing the next-generation of global navigation satellite systems
  European Frequency and Time Forum, 1996. EFTF 96., Tenth (IEE Conf. Publ. 418); 04/1996