  The Robot Operating System 2 (ROS 2) is rapidly impacting the intelligent
machines sector -- on space missions, large agriculture equipment, multi-robot
fleets, and more. Its success derives from its focused design and improved
capabilities targeting product-grade and modern robotic systems. Following ROS
2's example, the mobile robotics ecosystem has been fully redesigned based on
the transformed needs of modern robots and is experiencing active development
not seen since its inception.
  This paper comes from the desks of the key ROS Navigation maintainers to
review and analyze the state of the art of robotics navigation in ROS 2. This
includes new systems without parallel in ROS 1 or other similar mobile robotics
frameworks. We discuss current research products and historically robust
methods that provide differing behaviors and support for most every robot type.
This survey consists of overviews, comparisons, and expert insights organized
by the fundamental problems in the field. Some of these implementations have
yet to be described in literature and many have not been benchmarked relative
to others. We end by providing a glimpse into the future of the ROS 2 mobile
robotics ecosystem.
