MyRoboPath
autonomous slam16 min readUpdated 2026-03-11Intermediate

Global Path Planning: A*, Dijkstra, NavFn & Smac Planners in Nav2

Comprehensive analysis of search-based path planning algorithms in 2D costmaps: Dijkstra vs A* vs Hybrid-A* / Lattice planners for Ackermann and non-holonomic mobile robots.

Dr. Liam Sterling
Dr. Liam Sterling
Head of Autonomous Navigation

Key Engineering Takeaways

  • A* uses a heuristic distance function h(n) to guide the search frontier toward the goal, finding optimal paths 10x-50x faster than Dijkstra.
  • Standard 2D A* assumes circular holonomic robots; Hybrid-A* searches continuous 3D state space [x, y, θ] respecting minimum turning radius.
  • Smac Planner provides collision-aware Reeds-Shepp and Dubins curves for autonomous cars and warehouse tuggers.
Prerequisites
  • Graph search algorithms
  • Costmaps

Dijkstra vs A* vs Hybrid-A* Comparison

Search-based path planning evaluates the total cost $f(n) = g(n) + h(n)$, where $g(n)$ is the exact cost from start to node $n$, and $h(n)$ is the admissible heuristic estimation from node $n$ to the goal.
Tags:#Path Planning#A*#Dijkstra#Smac Planner#Hybrid A*#Nav2