The state of development of radio location in spaceflight

The development of navigation and positioning technology is assessed, while those areas in which advances are most urgently needed are identified. A state of the art flow model, showing the mutual influence of different research endeavors as well as their impact on future research goals, is presented. Positioning and navigation, using satellite networks or satellite-borne systems, are considered. The application of recently developed electronic equipment, such as microprocessors and minicomputers, is mentioned. Terrestrial surface navigation capabilities are also discussed as a spin-off of spaceborne remote sensing activities.