  Since the first atom interferometry experiments in 1991, measurements of
rotation through the Sagnac effect in open-area atom interferometers has been
studied. These studies have demonstrated very high sensitivity which can
compete with state-of-the-art optical Sagnac interferometers. Since the early
2000s, these developments have been motivated by possible applications in
inertial guidance and geophysics. Most matter-wave interferometers that have
been investigated since then are based on two-photon Raman transitions for the
manipulation of atomic wave packets. Results from the two most studied
configurations, a space-domain interferometer with atomic beams and a
time-domain interferometer with cold atoms, are presented and compared.
Finally, the latest generation of cold atom interferometers and their
preliminary results are presented.
