  The problem of distributed control and estimation for multi-agent systems
with limited sensing capabilities is a practical challenge motivated by
incomplete and imperfect sensing. This article addresses an important case
where each agent in a network can only sense the relative bearings to their
nearest neighbors. The study of this topic is motivated mainly by the rapid
development of bearing-only sensors such as optical cameras or sensor arrays.
This article provides a tutorial review on this topic focusing on the problems
of formation control and network localization. A key component of this review
is a presentation of the recently developed bearing rigidity theory, which
defines a necessary architectural feature of multi-agent systems aiming to
solve these two problems. This article presents a high-level summary of
recently developed algorithms solving these problems, various simulation
examples, and discussions pointing to the relevant literature and important
remaining challenges in this area.
