Satellite/Lunar Laser Ranging
- Schematic view of Lunar Laser Ranging
- © NASA Goddard Space Flight Center
Satellite/Lunar Laser Ranging is a method where a short laser pulse is generated in the ground station, and is transmitted through an optical system to the satellite or to the reflectors located on Moon’s surface. A part of the outgoing laser pulse is used to start an electronic time interval counter (user clock). The target satellite carries appropriate retro-reflectors. The reflected pulse is received at the ground station, detected, amplified, analyzed, and used to stop the electronic counter. The two-way travel time of the signal is derived from the two readings of the user clock, and is scaled into the distance.
Satellite Laser Ranging (SLR) technique provides precise geocentric positions and motions of ground stations, satellite orbits, components of Earth’s gravity field and their temporal variations, and Earth Orientation Parameters (EOP).
Lunar Laser Ranging (LLR) provides precise lunar ephemerides, information about the internal structure of the Moon, and relativistic parameters. Figure 4  depicts a schematic view of an SLR/LLR ground station. More details can be found at International Laser Ranging Service (ILRS) website (http://ilrs.gsfc.nasa.gov/ ).
Chair of Satellite Geodesy
Dept. for Geodesy and Geoinformation
Technical University of Berlin
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