spacesranging
Spacesranging is a set of techniques used to determine distances and relative positions of objects in space by measuring the travel time and frequency shifts of signals exchanged between observers and targets. It includes both one-way and two-way measurements and yields range, range-rate, and trajectory information for navigation and science.
The main methods are laser ranging, radio ranging, and radar ranging. Laser ranging uses light-time measurements
Historically, ranging grew out of radar astronomy in the mid-20th century. Lunar Laser Ranging began in the
Applications include spacecraft navigation and orbit maintenance, formation flying for satellites and telescopes, ephemeris generation, and
Accuracy varies with method and distance: LLR and SLR can reach centimeter scales for near-Earth measurements;
See also: radar ranging, laser ranging, LLR, SLR, VLBI, pulsar navigation.