Navigation system and method for tracking the position of an object

• US 6,643,587 B2
• Filed: 02/26/2002
• Issued: 11/04/2003
• Est. Priority Date: 09/16/1999
• Status: Expired due to Term

• Current Assignee: Samsung Electronics Co. Ltd.
• Original Assignee: SIRF Technology Incorporated (Qualcomm, Inc.)
• Inventors: Rounds, Stephen F., Chansarkar, Mangesh M., Brodie, Keith J.
• Primary Examiner(s): Nguyen, Tan Q.
• Assistant Examiner(s): Tran, Dalena
• Application Number:
  US10/085,667
• Publication Number:
  US 20020128775A1
• Time in Patent Office: 616 Days
• Field of Search: 701/216, 701/217, 701/220, 701/205, 701/224, 701/213, 701/214, 701/215, 342/357.14, 342/457, 342/357.02, 702/92, 702/94, 731/78.R, 340/988
• US Class Current: 701/216
• CPC Class Codes: G01C 21/165 combined with non-inertial navigation instruments
• CPC Class Codes: G01C 21/28 with correlation of data from several navigational instruments
• CPC Class Codes: G01S 19/26 involving a sensor measurement for aiding acquisition or tracking
• CPC Class Codes: G01S 19/47 the supplementary measurement being an inertial measurement, e.g. tightly coupled inertial
• CPC Class Codes: G01S 19/49 whereby the further system is an inertial position system, e.g. loosely-coupled
• CPC Class Codes: G01S 19/52 Determining velocity

Abstract

A navigation system for tracking the position of an object includes a GPS receiver responsive to GPS signals for periodically providing navigation state measurement updates to a navigation processor. The system also includes a dead-reckoning sensor responsive to movement of the object for providing movement measurements to the navigation processor. The navigation processor determines object navigation states using the navigation state measurement updates and propagates the object navigation states between measurement updates using the movement measurements.

Claims

1. A navigation processor for use in conjunction with a GPS receiver and a dead-reckoning sensor to provide navigation information related to the movement of an object, the GPS receiver adapted to provide GPS measurements for the object and the dead-reckoning sensor adapted to provide movement measurements for the object, said processor comprising:

a navigation update unit receiving as input an updated dead-reckoning measurement and the GPS measurements, and providing as output navigation measurements and a modified dead-reckoning position measurement, wherein the navigation measurements include measurement changes in speed bias;

a sensor update unit receiving as input the navigation measurements including the speed bias and the movement measurements and providing as output position changes; and

a navigation propagation unit receiving as input the position changes and the modified dead-reckoning measurement and providing as output the updated dead-reckoning measurement.

2. The processor of claim 1 wherein the navigation update unit comprises a primary filter adapted to receive as input the updated dead-reckoning measurement and the GPS measurements and provide as output an estimated velocity value.

3. The processor of claim 2 wherein the navigation update unit comprises a speed filter for estimating the change in speed bias from a measurement derived from the estimated velocity value.

4. The processor of claim 2 wherein the navigation update unit comprises a process noise model that provides a process noise matrix to the primary filter.

5. The processor of claim 2 wherein the navigation update unit comprises a heading filter for estimating changes in heading, gyro bias, and gyro scale factor from a heading measurement derived from the estimated velocity value.

6. The processor of claim 1 wherein the navigation update unit comprises a position set unit for eliminating the updated dead-reckoning measurement when the measurement is bad.

7. The processor of claim 1 wherein the navigation measurements further include measurement changes in at least one of heading, gyro bias and gyro scale factor, the movement measurements include a gyro measurement and the sensor update unit comprises a first processor for processing the changes in heading, gyro bias, and gyro scale factor along with the gyro measurement to produce a current heading value.

8. The processor of claim 1 wherein the navigation measurements further include measurement changes in speed value, the movement measurements include a speed measurement and the sensor update unit comprises a second processor for processing the changes in speed bias and speed scale factor along with the speed measurement to produce changes in direction measurements.

9. The processor of claim 1 wherein the movement measurements include a time measurement and the sensor update unit comprises a time processing unit to process the time measurement to produce a change in time value.

10. A method of providing navigation information related to the movement of an object using GPS measurements and movement measurements, said method comprising:

processing an updated dead-reckoning measurement and the GPS measurements to provide navigation measurements and a modified dead-reckoning position measurement, wherein the navigation measurements include measurement changes in speed bias;

processing the navigation measurements including the speed bias and the movement measurements to provide as output position change measurements; and

processing the position change measurements and the modified dead-reckoning measurement to provide as output the updated dead-reckoning measurement.

11. The method of claim 10 wherein processing an updated dead-reckoning measurement and the GPS measurements to provide navigation measurements comprises:

estimating a velocity value for the object;

deriving a measurement from the estimated velocity value; and

estimating the change in speed bias from the measurement.

12. The method of claim 10 wherein processing an updated dead-reckoning measurement and the GPS measurements to provide navigation measurements comprises:

estimating a velocity value for the object;

deriving a heading measurement from the estimated velocity; and

estimating changes in heading, gyro bias, and gyro scale factor using the heading measurement.

13. The method of claim 10 wherein the movement measurements include a gyro measurement, the navigation measurements further include measurement changes in at least one of heading, gyro bias, gyro scale factor and processing the navigation measurements and the movement measurements comprises processing changes in heading, gyro bias, and gyro scale factor along with a gyro measurement to produce a current heading value.

14. The method of claim 10 wherein the movement measurements include a speed measurement, the navigation measurements further include measurement changes in speed scale factor and processing the navigation measurements and the movement measurements comprises processing the changes in speed bias and speed scale factor along with the speed measurement to produce changes in direction measurements.

15. The method of claim 10 wherein the movement measurements include a time measurement and processing the navigation measurements and the movement measurements comprises processing the time measurement to produce a change in time value.

16. A navigation update unit for use in tracking the movement of an object, said unit comprising:

a primary filter adapted to receive as input an updated dead-reckoning measurement and GPS measurements, both related to the object, and provide as output an estimated velocity value for the object;

a heading filter adapted to receiver as input a heading measurement derived from the estimated velocity value and provide as output estimated changes in heading, gyro bias, and gyro scale factor; and

a speed filter for estimating the change in speed bias and speed scale factor from a measurement derived from an estimated velocity value.

17. The navigation update unit of claim 16 further comprising an object odometer for providing a zero turn-rate measurement to the heading filter.

18. A method of providing navigation information related to the movement of an object using GPS measurements from a GPS receiver and movement measurements from a dead-reckoning sensor, said method comprising:

calibrating the dead-reckoning sensor with an estimate of at least a speed bias;

calculating navigation measurements and a modified dead-reckoning position measurement from an updated dead-reckoning measurement and the GPS measurements;

sampling movement measurements;

processing position change measurements from the navigation measurements and the movement measurements; and

propagating the updated dead-reckoning measurement using the position change measurements and the modified dead-reckoning measurement.