Precise Range And Range-Rate Equipment (PRARE) was a microwave tracking system on board the ERS-2 mission. It operated at centimetre accuracy levels for the measurement of satellite to ground range and range rate. The concept was based on an autonomous spaceborne two-way and dual frequency microwave tracking system with its own telemetry, telecommand, data storage, timing and data transmission capabilities. This allowed data analysis on a global basis within a very short time delay. Due to the microwave transmission concept, the system operated independently from weather and daylight conditions.
The initial PRARE system development started in 1982 in Germany as a response to ESA's announcement of opportunity for exploitation of Europe's new Earth-remote sensing satellite series starting with ERS-1. The project was funded by BMFT and DARA, defined/designed by Ph. Hartl (University of Stuttgart) and Ch. Reigber of DGFI (German Geodetic Research Institute), Munich and since 1992 of GFZ (GeoForschungsZentrum), Potsdam.