Over the last decade, the number of applications that utilize global satellite navigation
systems (GNSS) has steadily increased. Perhaps the most visible manifestation
of this change is the development and wide use of consumer technologies that are
based on GNSS. For example, these days it is not unusual for automobiles or
mobile phones to be equipped with a Global Positioning System (GPS) navigation
system. Additionally, scores of applications have emerged that even the original
system designers could not have imagined. One such example is environmental
remote sensing. In view of this trend, it is reasonable to expect that more satellite
navigation based applications, in parallel with new satellite navigation systems,
will be arriving in the future