Nav2 is the successor of ROS Navigation Stack, aiming to enable safe and versatile mobile robot navigation for complex tasks in various environments.
It supports tasks beyond simple point-to-point movement, such as intermediary poses and object following, and is trusted by over 50 companies as a high-quality navigation framework.
It provides perception, planning, control, localization, visualization, and much more to build highly reliable autonomous systems.
Nav2 uses behavior trees to create customized and intelligent navigation behavior via orchestrating many independent modular servers.
The diagram below will give you a good first-look at the structure of Nav2.

Nav2 Tools:

Map Management: It allows for the loading, serving, recording and storing of maps using the Map Server with slam-toolbox.
Localization: The AMCL (Adaptive Monte Carlo Localization) module helps the robot accurately determine its position on the map with EKF (Extended Kalman Filter).
Costmap Generation: The Nav2 Costmap 2D converts sensor data into costmap representations of the environment.
Path Planning: Nav2 Planner assists in planning collision-free paths from one point to another while avoiding obstacles.
Robot Control: The Nav2 Controller guides the robot along the planned path, ensuring it follows the desired trajectory.
Python3 API: Nav2 offers a Python3 API for interacting with the framework in a pythonic manner, called Simple Commander.

Detailed content for installation