Positioning system using radio frequency signals

• US 10,185,034 B2
• Filed: 09/20/2013
• Issued: 01/22/2019
• Est. Priority Date: 09/20/2013
• Status: Active Grant

• Current Assignee: Caterpillar Incorporated
• Original Assignee: Caterpillar Incorporated
• Inventors: Smith, David William, Broughton, Peter John
• Primary Examiner(s): Nguyen, Chuong P
• Application Number:
  US15/021,799
• Publication Number:
  US 20160231426A1
• Time in Patent Office: 1,950 Days
• Field of Search: 342457, 701408
• CPC Class Codes: G01C 21/26 specially adapted for navigation in a road network
• CPC Class Codes: G01S 17/06 Systems determining position data of a target
• 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 17/88 Lidar systems specially adapted for specific applications
• CPC Class Codes: G01S 17/931 of land vehicles
• CPC Class Codes: G01S 5/0264 at least one of the systems being a non-radio wave positioning system
• CPC Class Codes: G01S 5/14 Determining absolute distances from a plurality of spaced points of known location
• CPC Class Codes: G01S 7/4808 Evaluating distance, position or velocity data
• CPC Class Codes: G05D 1/024 in combination with a laser lasers per se H01S
• CPC Class Codes: G05D 1/0274 using mapping information stored in a memory device navigation using map-matching G01C21/30

Abstract

A method for determining a position of a machine in a worksite is disclosed. The method may include determining, using a Lidar unit on the machine, input data. The input data may be associated with distances between the Lidar unit and respective light-reflective points in the worksite. The method may also include transmitting a radio-frequency communication between a first signal device at a known location within the worksite and a second signal device located on the machine. Further, the method may include determining position data for the machine based on at least the radio frequency communication. The method may also include determining a position of the machine based on the position data and the input data.

Claims

1. A method for determining a position of a machine in a worksite, the method comprising:

determining, using a Lidar unit located on the machine, input data associated with distances between the Lidar unit and respective light-reflective points in the worksite;

transmitting a radio-frequency communication between a first signal device at a known location within the worksite and a second signal device located on the machine;

determining position data for the machine based on at least the radio frequency communication, wherein the position data is based on a distance of the machine from the first signal device, the distance being associated with a characteristic of the radio-frequency communication; and

determining a position of the machine based on the position data and the input data.

2. The method of claim 1, wherein determining the position of the machine based on the position data and the input data comprises:

comparing the input data with first comparison data, the first comparison data including a plurality of reference data sets associated with a plurality of reference positions in the worksite, the reference positions having spacings from an initial position indicated by the position data that are less than a threshold spacing; and

determining a first position of the machine based on the first comparison data when the input data and at least one reference data set in the plurality of reference data sets satisfy a predefined condition.

3. The method of claim 2, wherein when the input data and the at least one reference data set do not satisfy the predefined condition, the method further comprises:

updating the position data based on a subsequent radio-frequency communication between the first signal device and the second signal device; and

determining the first position of the machine based on the updated position data and the input data.

4. The method of claim 2, wherein the plurality of reference data sets is a plurality of first reference data sets, the plurality of reference positions is a plurality of first reference positions, the spacings are first spacings, and the method further includes:

updating the input data;

comparing the updated input data with second comparison data, the second comparison data including a plurality of second reference data sets associated with a plurality of second reference positions in the worksite, the second reference positions having second spacings from the first position that are less than a threshold spacing; and

determining a second position of the machine based on a second reference data set in the plurality of second reference data sets corresponds to the input data.

5. The method of claim 3, wherein the characteristic is one of:

a threshold signal strength of a signal of the radio-frequency communication at said distance from the first signal device; and

a measured signal strength of a signal of the radio-frequency communication at said distance from the first signal device.

6. The method of claim 3, wherein the characteristic is a time-based characteristic of the radio-frequency communication.

7. The method of claim 6, wherein the radio-frequency signal communication is an ultra-wideband radio frequency communication.

8. The method of claim 6, wherein the radio frequency communication comprises at least one round-trip communication, the at least one round-trip communications comprising:

transmitting a first signal from an initiating device, the initiating device being one of the first signal device and the second signal devices; and

transmitting a response signal from a responding device to the initiating device, the responding device being the other of the first and second signal devices,

wherein the time-based characterization is a two-way time-of-flight associated with the radio-frequency communication, and the position data is determined based on the two-way time-of-flight.

9. The method of claim 6, wherein the radio frequency communication is a first radio frequency communication, and the method further includes:

transmitting a second radio frequency communication between the second signal device and a third signal device, the third signal device being at another known location in the worksite; and

determining the position data for the machine based on the first radio frequency communication between the first and second signal devices and the second radio frequency communication between the second and third signal devices.

10. The method of claim 8, wherein transmitting a first signal and transmitting a response signal each comprise transmitting data multiple times, wherein the data is coherently processed to determine the two-way time of flight.

11. The method of claim 8, wherein the method comprises determining the position data from a plurality of determined time-of-flights, for respective round-trip communications, using a Kalman filter.

12. The method of claim 8, wherein the method comprises determining the position data for the machine based on the radio frequency communication and on motion information derived from a motion sensor.

13. The method of claim 12, wherein the position data is determined from a plurality of determined time-of-flights using a particle filter.

14. A system for determining a position of a machine in a worksite, the system comprising:

a Lidar unit attached to the machine and configured to generate input data, the input data being associated with distances between the Lidar unit and respective light-reflective points in the worksite;

a radio frequency communication system comprising a first signal device positioned at a known location within the worksite and a second signal device attached to the machine, the communication system being configured for transmitting a radio frequency communication between the first and second signal devices; and

a control system in communication with the Lidar unit and the radio frequency communication system, the control system configured to;

determine position data for the machine based on at least the radio frequency communication, wherein the position data is based on a distance of the machine from the first signal device, the distance being associated with a characteristic of the radio-frequency communication; and

determine a position of the machine based on the position data and the input data.

15. The system of claim 14, wherein determining the position of the machine based on the position data and the input data comprises:

comparing the input data with first comparison data, the first comparison data including a plurality of reference data sets associated with a plurality of reference positions in the worksite, the reference positions having spacings from a position indicated by the position data that are less than a threshold spacing; and

determining a first position of the machine based on the first comparison data when the input data and at least one reference set in the plurality of reference data sets satisfy a predefined condition.

16. The system of claim 14, wherein the radio frequency communication comprises at least one round-trip communication, each of the at least one round-trip communications comprising:

transmitting a first signal from an initiating device, the initiating device being one of the first signal device and the second signal devices; and

transmitting a response signal from a responding device to the initiating device, the responding device being the other of the first and second signal devices,

wherein the characteristic is a two-way time-of-flight associated with the radio-frequency communication.

17. The system of claim 14, wherein the first and second signal devices are ultra-wideband radio frequency ranging devices, and the radio-frequency signal communication is an ultra-wideband radio frequency communication.

18. A method for determining a position of a machine in a worksite, the method comprising:

determining, using a Lidar unit located on the machine, associated with distances between the Lidar unit and respective light-reflective points in the worksite;

transmitting an ultra-wideband radio-frequency communication between a first signal device at a known location within the worksite and a second signal device located on the machine;

determining position data for the machine based on a distance of the machine from the first signal device, the distance being determined based at least on a two-way time-of-flight associated with the ultra-wideband radio frequency communication between the first and second signal devices; and

determining the position of the machine based on the position data and the input data.