Navigation system using both GPS and laser reference

• US 20070052950A1
• Filed: 10/17/2006
• Published: 03/08/2007
• Est. Priority Date: 07/13/2004
• Status: Active Grant

• Current Assignee: Trimble Navigation Limited (Trimble Inc.)
• Original Assignee: Trimble Navigation Limited (Trimble Inc.)
• Inventors: Taylor, Arthur, Talbot, Nicholas
• Granted Patent: US 8,705,022 B2
• Time in Patent Office: Days
• US Class Current: 356/139.10
• CPC Class Codes: E02F 3/842 using electromagnetic, optical or photoelectric beams, e.g. laser beams
• CPC Class Codes: E02F 9/2045 Guiding machines along a predetermined path for graders E02F3/841; machines for construction of roads E01C19/004
• CPC Class Codes: G01C 15/004 Reference lines, planes or sectors
• CPC Class Codes: G01S 17/86 Combinations of lidar systems with systems other than lidar, radar or sonar, e.g. with direction finders
• CPC Class Codes: G01S 19/45 by combining measurements of signals from the satellite radio beacon positioning system with a supplementary measurement

Abstract

A machine control system uses a laser system and global navigation satellite system to determine the position of the machine. The laser system has a laser detector positioned in a known and fixed relationship with the nominal phase center of a global navigation satellite antenna. The laser detector receives laser light transmitted from a laser transmitter. The outputs of the laser system and the global navigation satellite system are used together to determine the position of the transmitter prior to being used to determine the position of the machine.

Claims

1. A system for determining position, comprising

a laser transmitter that projects at least one laser beam that rotates about a generally vertical axis,

a GNSS receiver for determining position, the GNSS receiver having a GNSS antenna,

an optical sensor for receiving the laser beam, said optical sensor being in fixed position with respect to the phase center of said GNSS antenna, and

a device receiving signals from the GNSS receiver and signals from the optical sensor to determine and store the position of the transmitter from said signals, said device thereafter utilizing signals received from the optical sensor and from the GNSS receiver to determine the position of said GNSS receiver.

2. The system of claim 1 in which said laser transmitter projects one or more shaped beams of laser light to which the optical sensor is responsive.

3. The system of claim 1 in which said device combines the outputs from said sensor and said receiver using least squares averaging.

4. The system of claim 1 in which said device includes a Kalman filter for determining the most likely position, based on the detection signals from the optical sensor and the GNSS receiver.

5. The system of claim 1 in which the position of the transmitter is determined from receipt of said laser beam including rotation angle of the beam when received by said sensor and the distance between the transmitter and the GNSS receiver.

6. The system of claim 1 in which said device utilizes signals received from the optical sensor and from the GNSS receiver to determine the vertical position of said GNSS receiver.

7. A system for determining the position of a machine and controlling the machine, comprising

a laser transmitter, positioned at a reference position, that projects two or more fan-shaped laser beams and rotates the laser beams about a generally vertical axis, the two or more fan-shaped laser beams diverging in non-parallel, non-horizontal planes, with the line of intersection of these non-parallel, non-horizontal planes being non-vertical,

a GNSS receiver on the machine for determining the position of the machine, the GNSS receiver having a GNSS antenna mounted on the machine,

an optical sensor mounted on a machine for receiving the fan-shaped laser beams, said optical sensor being coaxial with, and at, or displaced a small distance from, the phase center of said GNSS antenna, and

a device on the machine, receiving signals from the GNSS receiver and signals from the optical sensor to determine the position of the transmitter, said device thereafter utilizing signals received from the optical sensor and the GNSS receiver to determine the position of the machine from said signals, and for providing a control signal.

8. The system of claim 7 in which said GNSS antenna and said optical sensor are located on the same mast in close proximity.

9. The system of claim 7 in which said device includes a Kalman filter for determining the most likely position of said machine, based on the detection signals from the optical sensor and the GNSS receiver.

10. A system for determining the position of a machine, comprising

a laser transmitter that projects at least one laser beam and rotates the at least one laser beam about a generally vertical axis,

a GNSS receiver on the machine for determining the position of the machine, the GNSS receiver having a GNSS antenna mounted on the machine,

an optical sensor mounted on the machine for receiving the at least one laser beam, said optical sensor being located in known positional relationship to the phase center of said GNSS antenna, and

a device on the machine, receiving signals from the GNSS receiver and signals from the optical sensor to determine the position of the machine, said device including a Kalman filter, for determining the most likely position of the machine from said signals.

11. The system of claim 10 in which the position of said laser transmitter is determined from the rotation angle of the beam when received by said sensor and the distance between said transmitter and said GNSS receiver.

12. The system of claim 10 in which said GNSS antenna and said optical sensor are located on the same mast in close proximity.

13. The system of claim 10 in which a least squares approximation is utilized to determine the most likely position, based on the signals from the optical sensor and the GNSS receiver.

14. The system of claim 10 in which said GNSS antenna and said optical sensor are mounted on said machine in close, fixed proximity to each other, and in which said GNSS antenna and said optical sensor are mounted for movement with an implement of said machine.

15. The system of claim 14 in which said device on the machine effects control of the position of said implement based on an estimated position provided by said Kalman filter, and based on a desired position.

16. A system for determining the position of a machine and controlling the machine, comprising

a laser transmitter, positioned at a reference position, that projects one or more laser beams,

a GNSS receiver on the machine for determining the position of the machine, the GNSS receiver having a GNSS antenna mounted on the machine,

an optical sensor mounted on the machine for receiving the one or more laser beams, said optical sensor being coaxial with, and displaced a small distance from, the phase center of said GNSS antenna,

an inertial sensor on machine for providing an output indicating movement and position of the machine, and

a device on the machine, receiving a signal from the GNSS receiver, a signal from the optical sensor, and an output from the inertial sensor, to determine the most likely position of the machine from said signals and output and for providing a control signal to control operation of said machine.

17. The system of claim 16 in which said laser transmitter projects a pair of fan shaped beams of laser light, and in which the optical sensor is responsive to both of said beams for determining the position.

18. The system of claim 16 in which said GNSS antenna and said optical sensor are located on the same mast in close proximity.

19. The system of claim 16 in which a least squares approximation is utilized to determine the most likely position, based on the detection signals from the optical sensor and the GNSS receiver.

20. The system of claim 16 in which said device includes a Kalman filter for determining the most likely position of said machine, based on the detection signals from the optical sensor and from the GNSS receiver.

21. The system of claim 16 in which the position of said laser transmitter is determined from the rotation angle of the beam when received by said optical sensor and the distance between said transmitter and said GNSS receiver.

22. In a machine control system utilizing a fixed position laser transmitter, a GNSS satellite system, a laser beam receiver mounted on the machine, and a GNSS receiver mounted on the machine, for position determination and guidance control of said machine, a method for transitioning between operating only under control of said GNSS receiver to operating under control of both said GNSS receiver and said laser beam receiver, comprising the steps of:

providing a reference coordinate system that is common to both said laser transmitter and said laser receiver, and to said GNSS satellite system and said GNSS receiver; and

providing a processor system on said machine configured to receive position information from said laser receiver, and to receive position information from said GNSS receiver, and

applying information from said laser receiver and information from said GNSS receiver to a Kalman filter to produce an estimate of machine position, and

controlling operation of the machine based on actual machine position and on desired machine position.

23. The method of claim 22 further comprising the step of applying information from an inertial sensor on said machine to said processor system.