Method and system for transporting inventory items

1. A system for navigation, comprising:

a plurality of fiducial marks arranged in a two-dimensional grid in a workspace;

a mobile drive unit, comprising:

a position sensor operable to sense information associated with a first fiducial mark in the two-dimensional grid;

a processing unit operable to process the information to produce information that identifies a location associated with the first fiducial mark within the two-dimensional grid; and

a wireless transmission module operable to wirelessly transmit the information identifying the location associated with the first fiducial mark to a remote control module, wherein the remote control module utilizes the information identifying the location associated with the first fiducial mark to facilitate navigation within the workspace.

2. The system of claim 1 , wherein the remote control module is further operable to:

wirelessly receive the identifying information;

determine that the mobile drive unit is located at the first fiducial mark based at least in part upon the information identifying the first fiducial mark; and

calculate a path to a second fiducial mark in the two-dimensional grid based at least in part upon the information identifying the first fiducial mark.

3. The system of claim 2 , wherein the first and second fiducial marks comprise unique identifiers that are affixed to a floor of the workspace.

4. The system of claim 1 , wherein the transmitting of the information identifying the location associated with the first fiducial mark indicates to the remote control module that the mobile drive unit is proximate to the first fiducial mark.

5. The system of claim 1 , wherein the mobile drive unit further comprises a docking mechanism operable to:

raise a docking head of the mobile drive unit towards a surface of an inventory holder; and

engage a docking head with the surface of the inventory holder.

6. The system of claim 1 , wherein the position sensor comprises a camera operable to optically detect the first fiducial mark in response to sensing that a fiducial mark is in a view of the camera.

7. The system of claim 1 , wherein the remote control module is further operable to:

determine locations of one or more other mobile drive units in the workspace based on receiving information associated with fiducial marks from the other mobile drive units; and

calculate a path from one fiducial mark to another fiducial mark that avoids collisions with the one or more other mobile drive units based at least in part upon the information.

8. A mobile drive unit operable to:

detect a first fiducial mark within a two-dimensional grid of fiducial marks in a workspace, wherein the second fiducial mark identifies a fixed location of the mobile drive unit within the two-dimensional grid of fiducial marks in the workspace;

determine the location of the mobile drive unit within the two-dimensional grid of fiducial marks in the workspace based on the identified particular location; and

navigate from the first fiducial mark to a second fiducial mark by providing the location of the mobile drive unit to a remote control module.

9. The mobile drive unit of claim 8 , wherein the mobile drive unit is further operable to:

transmit information associated with the first fiducial mark to the remote control module; and

receive, from the remote control module, a path from the first fiducial mark to the second fiducial mark in the two-dimensional grid of fiducial marks.

10. The mobile drive unit of claim 9 , wherein the path is calculated to avoid collisions with objects in the workspace.

11. The mobile drive unit of claim 8 , wherein detect the first fiducial mark comprises sensing the first fiducial mark using a position sensor.

12. The mobile drive unit of claim 8 , wherein:

the second fiducial mark in the two-dimensional grid of fiducial marks is associated with an inventory holder; and

the mobile drive unit is further operable to:

determine that the inventory holder is located at the second fiducial mark; and

dock with the inventory holder at the second fiducial mark.

13. The mobile drive unit of claim 8 , wherein the particular location comprises a position of the mobile drive unit in relation to one or more fixed objects in the workspace.

14. A method for transporting inventory items, comprising:

sensing, by a mobile drive unit, information associated with a first fiducial mark within a two-dimensional grid of fiducial marks;

processing, by the mobile drive unit, the information to produce an identifier associated with a location of the first fiducial mark within the two-dimensional grid of fiducial marks;

transmitting, by the mobile drive unit, the information identifying the identifier associated with the location of the first fiducial mark to a remote control module; and

receiving, by the mobile drive unit, navigation information from the remote control module instructing the mobile drive unit to move to a second fiducial mark, the navigation information calculated by the remote control module based at least in part upon the information identifying the identifier associated with the location of the first fiducial mark.

15. The method of claim 14 , wherein the information identifying the identifier associated with the location of the first fiducial mark is used by the remote control module to calculate a location of the mobile drive unit based on a known fixed position of the first fiducial mark in a workspace.

16. The method of claim 14 , further comprising moving the mobile drive unit to the second fiducial mark based at least upon the navigation information.

17. The method of claim 14 , wherein the first and second fiducial marks are affixed to a floor of a workspace.

18. The method of claim 14 , further comprising:

docking the mobile drive unit with an inventory holder at the second fiducial mark; and

moving the mobile drive unit away from the second fiducial mark.

19. The method of claim 18 , further comprising undocking the mobile drive unit from the inventory holder at a third fiducial mark.