Positioning and navigation method and system thereof

• US 20050234644A1
• Filed: 04/08/2005
• Published: 10/20/2005
• Est. Priority Date: 04/17/2004
• Status: Active Grant

• Current Assignee: American GNC Corporation
• Original Assignee: American GNC Corporation
• Inventors: Lin, Ching-Fang
• Granted Patent: US 7,409,290 B2
• Time in Patent Office: Days
• US Class Current: 701/214
• CPC Class Codes: G01C 21/005 with correlation of navigation data from several sources, e.g. map or contour matching G01C21/30 takes precedence
• CPC Class Codes: G01C 21/1654 with electromagnetic compass

Abstract

A improved positioning and navigation method and system thereof can substantially solve the problems encountered in global positioning system-only and inertial navigation system-only, such as loss of global positioning satellite signal, sensibility to jamming and spoofing, and inertial solution'"'"'s drift over time, in which the velocity and acceleration from an inertial navigation processor and an attitude and heading solution from an AHRS processor are used to aid the code and carrier phase tracking of the global positioning system satellite signals, so as to enhance the performance of the global positioning and inertial integration system, even in heavy jamming and high dynamic environments and when the GPS satellite signals are not available.

Claims

1. A positioning and navigation system, comprising:

an IMU (inertial measurement unit) providing inertial measurements including body angular rates and specific forces;

a GPS (Global Positioning System) processor receiving GPS satellite signals to derive position and velocity information and GPS raw measurements including pseudorange, carrier phase, and Doppler shift; and

a central navigation processor which comprises;

an INS (Inertial Navigation System) processor receiving said inertial measurements, including said body angular rates and said specific forces, for computing an inertial navigation solution which are position, velocity, acceleration, and attitude of a carrier carrying said positioning and navigation system;

a Kalman filter receiving said GPS raw measurements and said inertial navigation solution derived from said INS processor which is blended with said GPS raw measurements to derive a plurality of INS corrections and GPS corrections, wherein said INS corrections are fed back from said Kalman filter to said INS processor to correct said inertial navigation solution, wherein said Kalman filter sends out a dual antenna GPS attitude determination; and

an AHRS (Attitude and Heading Reference System) processor receiving said inertial measurements from said IMU which is blended with said dual antenna GPS attitude determination from said Kalman filter for computing an AHRS solution which are attitude and heading data of said carrier and being outputted as navigation solution.

2. The positioning and navigation system, as recited in claim 1, wherein said dual antenna GPS attitude determination is sent from said Kalman filter to said AHRS processor of said central navigation processor.

3. The positioning and navigation system, as recited in claim 2, wherein said dual antenna GPS attitude determination is sent from said Kalman filter to an integration of said AHRS processor.

4. The positioning and navigation system, as recited in claim 1, further comprising a magnetometer generating an Earth magnetic field measurement, wherein said AHRS processor receiving said Earth magnetic field measurement from said magnetometer and said inertial measurements from said IMU which is blended with said Earth magnetic field measurement for computing said AHRS solution which are attitude and heading data of said carrier and being outputted as navigation solution.

5. The positioning and navigation system, as recited in claim 3, further comprising a magnetometer generating an Earth magnetic field measurement, wherein said AHRS processor receiving said Earth magnetic field measurement from said magnetometer and said inertial measurements from said IMU which is blended with said Earth magnetic field measurement for computing said AHRS solution which are attitude and heading data of said carrier and being outputted as navigation solution.

6. The positioning and navigation system, as recited in claim 4, wherein said AHRS processor receives heading resolution from said Kalman filter when said dual antenna GPS attitude determination is available, which is used to calibrate said magnetometer and update a AHRS heading.

7. The positioning and navigation system, as recited in claim 5, wherein said AHRS processor receives heading resolution from said Kalman filter when said dual antenna GPS attitude determination is available, which is used to calibrate said magnetometer and update a AHRS heading.

8. The positioning and navigation system, as recited in claim 1, wherein said AHRS processor further comprises an input from said dual antenna GPS attitude determination of said Kalman filter output for improving said attitude measurement accuracy of said central navigation processor.

9. The positioning and navigation system, as recited in claim 5, wherein said AHRS processor further comprises an input from said dual antenna GPS attitude determination of said Kalman filter output for improving said attitude measurement accuracy of said central navigation processor.

10. The positioning and navigation system, as recited in claim 7, wherein said AHRS processor further comprises an input from said dual antenna GPS attitude determination of said Kalman filter output for improving said attitude measurement accuracy of said central navigation processor.

11. A positioning and navigation method, comprising the steps of:

(a) receiving a plurality of global positioning system satellite signals to derive position and velocity information and a plurality of global positioning system (GPS) raw measurements, including pseudorange, carrier phase, and Doppler shift, of a carrier;

(b) sending a dual antenna GPS carrier measurement to a central navigation processor from a GPS (Global Positioning System) processor;

(c) receiving a plurality of inertial measurements including body angular rates and specific forces from an IMU (Inertial Measurement Unit);

(d) seeding said inertial measurements from said IMU to an INS (Inertial Navigation System) processor of said central navigation processor for computing an inertial navigation solution, which are position, velocity, acceleration, and attitude of said carrier;

(e) receiving an Earth magnetic field measurement from a magnetometer;

(f) sending said Earth magnetic field measurement from said magnetometer to an AHRS (Attitude and Heading Reference System) processor of said central navigation processor;

(g) injecting said dual antenna GPS carrier phase measurement from said GPS processor and a GPS correction from said Kalman filter into a carrier phase integer ambiguity resolution module to fix a plurality of GPS satellite signal carrier phase integer ambiguity numbers, which are used for said dual antenna GPS attitude determination;

(h) sending said GPS satellite signal carrier phase integer numbers from said carrier phase integer ambiguity resolution module to said Kalman filter to derive said dual antenna attitude determination;

(i) sending said dual antenna GPS attitude determination from said Kalman filter to said AHRS processor of said central navigation processor;

(j) sending said inertial measurements, including said body angular rates and the specific forces, from said IMU to said AHRS processor to blend with said Earth magnetic field measurement and said dual antenna GPS attitude determination from said Kalman filter 33 in which a Magnetic heading computation is combined with said dual antenna GPS attitude determination from said Kalman filter through an integration, for computing an AHRS solution which are attitude and heading data of said carrier;

(k) blending an inertial navigation solution derived from said INS processor and said GPS raw measurements from said GPS processor in said Kalman filter to derive a plurality of INS corrections and GPS corrections; and

(l) feeding back said INS corrections from said Kalman filter to said INS processor to correct said inertial navigation solution.

12. The method, as recited in claim 11, further comprising the steps of:

(m) injecting said dual antenna GPS carrier phase measurement from said GPS processor, said inertial navigation solution from said INS processor, and said inertial corrections and said GPS correction from said Kalman filter into a carrier phase integer ambiguity resolution module to fix a plurality of GPS satellite signal carrier phase integer ambiguity numbers, and

(n) sending said GPS satellite signal carrier phase integer numbers from said carrier phase integer ambiguity resolution module to said Kalman filter to derive a further improved navigation solution and attitude determination.

13. The method, as recited in claim 12, wherein said INS processor and said carrier phase integer ambiguity resolution module are fully integrated together.

14. The method as recited in claim 11, after step (1), further comprising the step of outputting said AHRS solution as navigation data through an I/O interface.

15. The method as recited in claim 12, after step (1), further comprising the step of outputting said AHRS solution as navigation data through an I/O interface.

16. The method as recited in claim 13, after step (1), further comprising the step of outputting said AHRS solution as navigation data through an I/O interface.

17. A positioning and navigation method, comprising the steps of:

(a) receiving a plurality of global positioning system satellite signals to derive position and velocity information and a plurality of global positioning system (GPS) raw measurements, including pseudorange, carrier phase, and Doppler shift, of a carrier;

(b) sending a dual antenna GPS carrier measurement to a central navigation processor from a GPS (Global Positioning System) processor;

(c) receiving a plurality of inertial measurements including body angular rates and specific forces from an IMU (Inertial Measurement Unit);

(d) seeding said inertial measurements from said IMU to an INS (Inertial Navigation System) processor of said central navigation processor for computing an inertial navigation solution, which are position, velocity, acceleration, and attitude of said carrier;

(e) injecting said dual antenna GPS carrier phase measurement from said GPS processor and a GPS correction from said Kalman filter into a carrier phase integer ambiguity resolution module to fix a plurality of GPS satellite signal carrier phase integer ambiguity numbers, which are used for said dual antenna GPS attitude determination;

(f) sending said GPS satellite signal carrier phase integer numbers from said carrier phase integer ambiguity resolution module to said Kalman filter to derive said dual antenna attitude determination;

(g) sending said dual antenna GPS attitude determination from said Kalman filter to said AHRS processor of said central navigation processor;

(h) sending said inertial measurements, including said body angular rates and the specific forces, from said IMU to said AHRS processor to blend with said dual antenna GPS attitude determination from said Kalman filter for computing an AHRS solution which are attitude and heading data of said carrier;

(i) blending an inertial navigation solution derived from said INS processor and said GPS raw measurements from said GPS processor in said Kalman filter to derive a plurality of INS corrections and GPS corrections; and

(j) feeding back said INS corrections from said Kalman filter to said INS processor to correct said inertial navigation solution.

18. The method, as recited in claim 17, further comprising the steps of:

(k) injecting said dual antenna GPS carrier phase measurement from said GPS processor, said inertial navigation solution from said INS processor, and said inertial corrections and said GPS correction from said Kalman filter into a carrier phase integer ambiguity resolution module to fix a plurality of GPS satellite signal carrier phase integer ambiguity numbers, and

(l) sending said GPS satellite signal carrier phase integer numbers from said carrier phase integer ambiguity resolution module to said Kalman filter to derive a further improved navigation solution and attitude determination.

19. The method, as recited in claim 18, wherein said INS processor and said carrier phase integer ambiguity resolution module are fully integrated together.

20. The method as recited in claim 19, after step (j), further comprising the step of outputting said AHRS solution as navigation data through an I/O interface.