Algorithm 1: Modified Gap Navigation Tree

Input: sensory data (discontinuity in the environment from the depth sensor)

Output: complete T

1. T = f

2. T = {G₀}

3. Let G_i = G₀

4. Update gridmap

5. While (G_i is not cleared)

6. _jwhere j

7. If (any G_iis redundant)

8. then delete G_i

9. If (G_i is not visited)

10. then CHASE(G_i)

11. else

12. if (C_Gi is not cleared)

13. then G_i = next in order of unvisited children nodes

14. else

15. mark G_i cleared

16. make G_i a parent node.

17. end

18. report T