  This work reviews the topic of rotation sensing with compact cold atom
interferometers. A representative set of compact free-falling cold atom
gyroscopes is considered because, in different respects, they establish a
rotation-measurement reference for cold guided-atom technologies. This review
first discusses enabling technologies relevant to a set of key functional
building blocks of an atom chip-based compact inertial sensor with cold guided
atoms. These functionalities concern the accurate and reproducible positioning
of atoms to initiate a measurement cycle, the coherent momentum transfer to the
atom wave packets, the suppression of propagation-induced decoherence due to
potential roughness, on-chip detection, and vacuum dynamics because of its
impact on sensor stability, which is due to the measurement dead time. Based on
the existing enabling technologies, the design of an atom chip gyroscope with
guided atoms is formalized using a design case that treats design elements such
as guiding, fabrication, scale factor, rotation-rate sensitivity, spectral
response, important noise sources, and sensor stability.
