Kd. Mcdonald, TECHNOLOGY, IMPLEMENTATION AND POLICY ISSUES FOR THE MODERNIZATION OFGPS AND ITS ROLE IN A GNSS, Journal of Navigation, 51(3), 1998, pp. 281-293
During the past several years, a number of important investigations, p
olicy initiatives and national commitments relating to the future of G
PS, GLONASS and their augmentations have occurred. Substantive and on-
going studies of the character and configuration of a Global Navigatio
n Satellite System (GNSS) have also been evaluated worldwide, especial
ly by the International Civil Aviation Organization (ICAO). These effo
rts have been principally directed toward the definition of near- and
far-term GNSS implementations that meet the needs and concerns of the
international community. This paper briefly reviews some of the invest
igations and addresses, in particular, the concerns and requirements t
hat may affect the future capabilities and the dual (civil/military) c
haracter of GPS. The main issues relating to the modernisation of GPS
and its subsequent transition to a component of a GNSS With a viable i
nternational character are presented. These include a discussion of ne
w signal structure options, certain changes in operating frequencies,
increased signal power levels, other system alternatives and their pot
ential impact on system performance. International issues are briefly
addressed, including future performance capabilities, assurance of ser
vice, economic participation and benefit, reasonable cost, standards a
nd international participation.