How Autonomous Robots Use Global and Local Path Planners to Navigate Safely

Autonomous robot navigation relies on two complementary systems: a global planner that maps out a full route using algorithms like A* or Dijkstra, and a local planner that reacts in real time to nearby obstacles, people, and dynamic changes. The global planner works from a broader map to determine an overall path from start to goal, while the local planner continuously adjusts velocity and trajectory based on sensor data. Both planners use costmaps to represent the environment, assigning higher costs to hazardous or undesirable areas. When no safe local trajectory exists, a robust system must also include explicit recovery behaviors to avoid deadlocks or collisions. Together, these two layers operate at different spatial and temporal scales to enable reliable, adaptive autonomous navigation.