Crane boom pointing angle determination

1. A method for determining a working arm pointing angle of a crane relative to a reference direction, said method comprising:

disposing a Global Navigation Satellite System (GNSS) receiver antenna on a point along a boom assembly of said crane configured to pivot about a pivot point;

receiving a location of said pivot point;

rotating a working arm of said crane about said pivot point to point in a current direction;

determining a current location of said GNSS receiver antenna; and

determining a current working arm pointing angle relative to a reference direction for said current direction of said working arm based on said current location of said GNSS receiver antenna and said location of said pivot point.

2. The method as recited claim 1 , wherein said point along said boom assembly for said GNSS receiver antenna is selected from the group of points consisting of: on a counterweight of a working arm of said crane, a cab of said crane, a working arm of said crane, a boom of said crane, and a trolley of said crane.

3. The method as recited in claim 1 , wherein said disposing said GNSS receiver antenna comprise: disposing a plurality of GNSS receiver antennas and said determining said working arm pointing angle is based on location points of said plurality of GNSS receiver antennas.

4. The method as recited in claim 3 , wherein said plurality of GNSS receiver antennas are connected to a single GNSS receiver in a master slave relationship.

5. The method as recited in claim 3 , wherein said plurality of GNSS receiver antennas are each connected to a separate GNSS receiver.

6. The method as recited in claim 1 , wherein said reference direction is obtained by pointing said working arm of said crane to a reference point and determining a location of said GNSS receiver antenna.

7. The method as recited in claim 1 , wherein said reference direction is true north.

8. The method as recited in claim 1 , wherein said determining said current location of said GNSS receiver antenna employs a method of least squares.

9. The method as recited in claim 1 , wherein said determining said current location of said GNSS receiver antenna employs a Kalman filter.

10. The method as recited in claim 1 , wherein said point along said crane for said GNSS receiver antenna is along a principal axis of said crane.

11. The method as recited in claim 1 , wherein said point along said crane for said GNSS receiver antenna is offset from a principal axis of said crane and wherein said determining said three locations and determining said pivot point accounts for said offset.

12. The method as recited in claim 11 , wherein said offset is determined by pointing said working arm of said crane in a reference direction, then point said GNSS receiver antenna in a same directed as said reference direction and setting a difference between pointing angles as an offset.

13. The method as recited in claim 1 , wherein said GNSS receiver antenna is connected to a GNSS receiver coupled with said crane.

14. The method as recited in claim 1 , wherein said GNSS receiver antenna is remotely connected to a GNSS receiver that is not coupled with said crane.

15. The method as recited in claim 1 , wherein said determining said current location of said GNSS receiver antenna is determined in a two dimensional frame of reference.

16. The method as recited in claim 1 , wherein said determining said current location of said GNSS receiver antenna is determined in a three dimensional frame of reference.

17. The method as recited in claim 1 , wherein said location of said pivot point is determined based on:

rotating a working arm of said crane about said pivot point to at least three different positions; and

determining three locations in a geo-referenced coordinate system of said at least three different positions.

18. A computer-usable storage medium having instructions embodied therein that when executed cause a computer system to perform a method for determining a working arm pointing angle of a crane relative to a reference direction, said method comprising:

receiving data from a Global Navigation Satellite System (GNSS) receiver antenna positioned on a point along a boom assembly of said crane configured to pivot about a pivot point;

receiving a location of said pivot point;

determining a current location of said GNSS receiver antenna based on said data from said GNSS receiver antenna; and

determining a current working arm pointing angle relative to a reference direction for a current position of said working arm based on said current location of said GNSS receiver antenna and said location of said pivot point.

19. The computer-usable storage medium as recited in claim 18 , wherein said location of said pivot point is determined based on:

rotating a working arm of said crane about said pivot point to at least three different positions; and

determining three locations in a geo-referenced coordinate system of said at least three different positions.

20. A crane apparatus comprising:

a crane comprising:

a boom assembly; and

a working arm;

a Global Navigation Satellite System (GNSS) receiver antenna disposed on a point along said boom assembly of said crane configured to pivot about a pivot point; and

a processor for:

receiving data from said GNSS receiver antenna;

receiving a location of said pivot point;

determining a current location of said GNSS receiver antenna based on said data from said GNSS receiver antenna; and

determining a current working arm pointing angle relative to a reference direction for a current position of said working arm based on said current location of said GNSS receiver antenna and said location of said pivot point.

21. The crane apparatus as recited in claim 20 , wherein said location of said pivot point is determined by said processor based on:

receiving data from said GNSS receiver antenna for at least three different positions of said GNSS receiver antenna; and

determining three locations in a geo-referenced coordinate system of said at least three different positions.