Concepts are investigated for improving location precision and system capacity relative to current satellite based data collection and location systems. The TRILOC concept provides either or both improvements in location and system capacity by utilizing three measurements acquired during a single transmission from a platform for location purposes. The location algorithm is developed, and range differences are measured onboard the satellite. An error analysis then relates platform location errors to the precision with which the measurements are made. The second concept is to increase system capacity by means of directive antennas onboard the satellite for reducing interference and/or reducing platform power. The potential advantages and disadvantages of both sweeping and fixed directive antennas for random access systems are evaluated.
