Positioning process and system thereof

• US 6,311,129 B1
• Filed: 04/06/1999
• Issued: 10/30/2001
• Est. Priority Date: 04/06/1998
• Status: Expired due to Term

• Current Assignee: American GNC Corporation
• Original Assignee: American GNC Corporation
• Inventors: Lin, Ching-Fang
• Primary Examiner(s): Cuchlinski, Jr., William A.
• Assistant Examiner(s): DONNELLY, ARTHUR D
• Application Number:
  US09/287,574
• Time in Patent Office: 938 Days
• Field of Search: 701/214, 701/207, 701/213, 701/200, 342/357, 342/442, 375/207, 380/34
• US Class Current: 701/214
• CPC Class Codes: G09B 9/08 for teaching control of aircraft, e.g. Link trainer
• CPC Class Codes: Y10S 345/952 Simulation

Abstract

A positioning method and a system are disclosed for measuring a position of a vehicle on land, air, and space, using measurements from a global positioning system receiver and an inertial measurement unit. In the present invention, an integrated Kalman filter processes the all-available measurements of the global positioning system: pseudorange, delta range, carrier phase, and the solution of an inertial navigation system. The integrated Kalman filter is a multi-mode, robust kalman filter, in which optimal integrated mode is selected based on the measurement availability and filter stability. The high accurate solution of the inertial navigation system, which is corrected by the Kalman filter, is used to aid on-the-fly resolution of the carrier phase integer ambiguity of global positioning system in order to incorporate the carrier phase measurements into the Kalman filter, and to aid the carrier phase and code tracking loops of the receiver of the global positioning system to improve the receiver jamming and high dynamic resistance.

Claims

1. A positioning system for a vehicle, comprising:

a global positioning system (GPS) radio frequency (RF) unit for receiving global positioning system (GPS) radio frequency (RF) signals, amplifying said GPS RF signals and down converting said GPS RF signals into intermediate frequency (IF) signals;

a GPS digital signal processing unit for sampling said IF signal and deriving GPS pseudorange, delta range, and carrier phase measurements;

an IMU data sampling unit for collecting angular rate and acceleration measurements of said vehicle from an inertial measurement unit (IMU);

a centralized navigation Kalman filter for receiving and processing said GPS pseudorange, delta range, and carrier phase measurements for said GPS and said angular rate and acceleration measurements from said IMU;

at least an interface which is a serial signal interface, including synchronous communication interface and asynchronous communication interface, for realizing said data and control communication with other avionics systems, wherein said interface is connected with said centralized navigation Kalman filter to realize communication with said avionics systems; and

a time synchronizer for providing said time signal and local reference signal to said avionics system devices.

6. The positioning system, as recited in claim 1, wherein said IMU data sampling circuit, which is connected with said centralized navigation Kalman filter and said time synchronizer, is a serial digital signal communication-based circuit for adapting said IMU with said serial digital signal interface.

2. A positioning system for a vehicle, comprising:

a global positioning system (GPS) radio frequency (RF) unit for receiving global positioning system (GPS) radio frequency (RF) signals, amplifying said GPS RF signals and down converting said GPS RF signals into intermediate frequency (IF) signals;

a GPS digital signal processing unit for sampling said IF signal and deriving GPS pseudorange, delta range, and carrier phase measurements;

an IMU data sampling unit for collecting angular rate and acceleration measurements of said vehicle from an inertial measurement unit (IMU);

a centralized navigation Kalman filter for receiving and processing said GPS pseudorange, delta range, and carrier phase measurements for said GPS and said angular rate and acceleration measurements from said IMU;

at least an interface, which is a parallel digital signal interface, for realizing said data and control communication with other avionics systems, wherein said interface is connected with said centralized navigation Kalman filter to realize communication with said avionics systems; and

a time synchronizer for providing said time signal and local reference signal to said avionics system devices.

7. The positioning system, as recited in claim 2, wherein said IMU data sampling circuit, which is connected with said centralized navigation Kalman filter and said time synchronizer, is a parallel digital signal communication-based circuit for adapting said IMU with said parallel digital signal interface.

3. A positioning system for a vehicle, comprising:

a global positioning system (GPS) radio frequency (RF) unit for receiving global positioning system (GPS) radio frequency (RF) signals, amplifying said GPS RF signals and down converting said GPS RF signals into intermediate frequency (IF) signals;

a GPS digital signal processing unit for sampling said IF signal and deriving GPS pseudorange, delta range, and carrier phase measurements;

an IMU data sampling unit for collecting angular rate and acceleration measurements of said vehicle from an inertial measurement unit (IMU);

a centralized navigation Kalman filter for receiving and processing said GPS pseudorange, delta range, and carrier phase measurements for said GPS and said angular rate and acceleration measurements from said IMU;

at least an interface, which is a network adapter, for realizing said data and control communication with other avionics systems, wherein said interface is connected with said centralized navigation Kalman filter to realize communication with said avionics systems; and

a time synchronizer for providing said time signal and local reference signal to said avionics system devices.

8. The positioning system, as recited in claim 3, wherein said IMU data sampling circuit, which is connected with said centralized navigation Kalman filter and said time synchronizer, is a network adapter-based circuit for adapting said IMU with said network adapter which is a network standard output.

4. A positioning system for a vehicle, comprising:

a global positioning system (GPS) radio frequency (RF) unit for receiving global positioning system (GPS) radio frequency (RF) signals, amplifying said GPS RF signals and down converting said GPS RF signals into intermediate frequency (IF) signals;

a GPS digital signal processing unit for sampling said IF signal and deriving GPS pseudorange, delta range, and carrier phase measurements;

an IMU data sampling unit for collecting angular rate and acceleration measurements of said vehicle from an inertial measurement unit (IMU);

a centralized navigation Kalman filter for receiving and processing said GPS pseudorange, delta range, and carrier phase measurements for said GPS and said angular rate and acceleration measurements from said IMU;

at least an interface, which is a bus interface, for realizing said data and control communication with other avionics systems, wherein said interface is connected with said centralized navigation Kalman filter to realize communication with said avionics systems; and

a time synchronizer for providing said time signal and local reference signal to said avionics system devices.

10. The positioning system, as recited in claim 4, wherein said IMU data sampling circuit, which is connected with said centralized navigation Kalman filter and said time synchronizer, is a bus interface-based circuit for adapting said IMU with said bus interface which is a bus standard output interface.

5. A positioning system for a vehicle, comprising:

a global positioning system (GPS) radio frequency (RF) unit for receiving global positioning system (GPS) radio frequency (RF) signals, amplifying said GPS RF signals and down converting said GPS RF signals into intermediate frequency (IF) signals;

a GPS digital signal processing unit for sampling said IF signal and deriving GPS pseudorange, delta range, and carrier phase measurements;

an IMU data sampling unit, which is a pulse/counter-based circuit for adapting said IMU with pulse output, for collecting angular rate and acceleration measurements of said vehicle from an inertial measurement unit (IMU);

a centralized navigation Kalman filter for receiving and processing said GPS pseudorange, delta range, and carrier phase measurements for said GPS and said angular rate and acceleration measurements from said IMU;

at least an interface for realizing said data and control communication with other avionics systems; and

a time synchronizer for providing said time signal and local reference signal to said avionics system devices, wherein said IMU data sampling circuit is connected with said centralized navigation Kalman filter and said time synchronizer.

9. A positioning system for a vehicle, comprising:

a global positioning system (GPS) radio frequency (RF) unit for receiving global positioning system (GPS) radio frequency (RF) signals, amplifying said GPS RF signals and down converting said OPS RF signals into intermediate frequency (IF) signals;

a GPS digital signal processing unit for sampling said IF signal and deriving GPS pseudorange, delta range, and carrier phase measurements;

an IMU data sampling unit, which is an A/D converter-based circuit for adapting said IMU with analog output, for collecting angular rate and acceleration measurements of said vehicle from an inertial measurement unit (IMU);

a centralized navigation Kalman filter for receiving and processing said GPS pseudorange, delta range, and carrier phase measurements for said GPS and said angular rate and acceleration measurements from said IMU;

at least an interface for realizing said data and control communication with other avionics systems; and

a time synchronizer for providing said time signal and local reference signal to said avionics system devices, wherein said IMU data sampling circuit is connected with said centralized navigation Kalman filter and said time synchronizer.

11. A positioning system for a vehicle, comprising:

a global positioning system (GPS) radio frequency (RF) unit for receiving global positioning system (GPS) radio frequency (RF) signals, amplifying said GPS RF signals and down converting said GPS RF signals into intermediate frequency (IF) signals;

a GPS digital signal processing unit for sampling said IF signal and deriving GPS pseudorange, delta range, and carrier phase measurements;

an IMU data sampling unit for collecting angular rate and acceleration measurements of said vehicle from an inertial measurement unit (IMU);

a centralized navigation Kalman filter for receiving and processing said GPS pseudorange, delta range, and carrier phase measurements for said GPS and said angular rate and acceleration measurements from said IMU;

at least an interface for realizing said data and control communication with other avionics systems; and

a time synchronizer for providing said time signal and local reference signal to said avionics system devices,

wherein said architecture of said connection among said GPS digital processing unit, said centralized navigation Kalman filter, said interface, said IMU data sampling circuit and said time synchronizer is a bus-based connection structure.

12. A positioning system for a vehicle, comprising:

a global positioning system (GPS) radio frequency (RF) unit for receiving global positioning system (GPS) radio frequency (RF) signals, amplifying said GPS RF signals and down converting said GPS RF signals into intermediate frequency (IF) signals;

a GPS digital signal processing unit for sampling said IF signal and deriving GPS pseudorange, delta range, and carrier phase measurements;

an IMU data sampling unit for collecting angular rate and acceleration measurements of said vehicle from an inertial measurement unit (IMU);

a centralized navigation Kalman filter for receiving and processing said GPS pseudorange, delta range, and carrier phase measurements for said GPS and said angular rate and acceleration measurements from said IMU;

at least an interface for realizing said data and control communication with other avionics systems; and

a time synchronizer for providing said time signal and local reference signal to said avionics system devices,

wherein said architecture of said connection among said GPS digital processing unit, said centralized navigation Kalman filter, said interface, said IMU data sampling circuit and said time synchronizer is a communication port-based connection structure.

13. A positioning system for a vehicle, comprising:

a global positioning system (GPS) radio frequency (RF) unit for receiving global positioning system (GPS) radio frequency (RF) signals, amplifying said GPS RF signals and down converting said GPS RF signals into intermediate frequency (IF) signals;

a GPS digital signal processing unit for sampling said IF signal and deriving GPS pseudorange, delta range, and carrier phase measurements;

an IMU data sampling unit for collecting angular rate and acceleration measurements of said vehicle from an inertial measurement unit (IMU);

a centralized navigation Kalman filter for receiving and processing said GPS pseudorange, delta range, and carrier phase measurements for said GPS and said angular rate and acceleration measurements from said IMU;

at least an interface for realizing said data and control communication with other avionics systems; and

a time synchronizer for providing said time signal and local reference signal to said avionics system devices,

wherein said architecture of said connection among said GPS digital processing unit, said centralized navigation Kalman filter, said interface, said IMU data sampling circuit and said time synchronizer is a network-based connection structure.

14. A positioning process for a vehicle, comprising said steps of:

(a) accepting angular rate and acceleration measurements for said vehicle from an inertial measurement unit (IMU) to form an initial value and computing said initial value according to inertial navigation equations of said inertial measurement unit, and accepting vehicle position, velocity, and attitude measurements from at least an external sensor, and that said inertial measurement unit is a tactical munition inertial measurement unit installed on a launch platform, wherein measurements or navigation parameters of said tactical munition inertial measurement unit and said launch platform inertial measurement unit are filtered by an alignment filter to provide optimal initialization information to said tactical munition inertial measurement unit;

(b) receiving global positioning system (GPS) radio frequency (RF) signals and deriving GPS pseudorange, delta range, and carrier phase measurements from said global positioning system radio frequency signals;

(c) receiving said angular rate and acceleration information from said inertial measurement unit and solving said inertial navigation measurements of said inertial measurement unit to obtain a navigation solution which includes position, velocity, and attitude; and

(d) combining said GPS pseudorange, delta range, and carrier phase measurements, and said navigation solution to obtain a fully-coupled positioning solution.

15. The positioning process, as recited in claim 14, wherein, in step (a), said external sensor is a global positioning system receiver, wherein position and velocity of said global positioning system receiver, an inaccurate initial attitude value first as an initial value of said navigation equations of said inertial measurement unit, and an accurate alignment of said inertial measurement unit are further performed using signals of said global positioning system receiver.

16. The positioning process, as recited in claim 15, wherein in step (b), said global positioning system radio frequency signals are tracked by a carrier phase locked loop and a code tracking loop of said global positioning system receiver, and that processes in said carrier phase locked loop and said code tracking loop of said global positioning system receiver are aided by said fully-coupled positioning solution obtained from said step (d).

17. The positioning process, as recited in claim 16, wherein, in step (c), errors of said inertial navigation solution are removed with optimal estimates of said errors of said inertial navigation solution obtained from step (d).

18. The positioning process, as recited in claim 17, after step (b), further comprising an additional step of performing a carrier phase integer ambiguity resolution and cycle slip detection to incorporate said GPS carrier phase measurements to step (d).

19. The positioning process, as recited in claim 18, after step (b), further comprising an additional step of aiding said carrier phase integer ambiguity resolution and cycle slip detection with said fully-coupled positioning solution obtained from said step (d).

21. The positioning process, as recited in claim 19, wherein, in step (d), said GPS pseudorange, delta range and carrier phase measurements, and said inertial navigation solution are combined by an integrated Kalman filters.

23. The positioning process, as recited in claim 21, wherein, in step (d), said GPS pseudorange, delta range and carrier phase measurements, and said inertial navigation solution are combined by a multi-mode robust Kalman filter which comprises at least one of said following operation modes:

a GPS/INS P-V (position and velocity) integration mode;

a GPS/IMU ρ

/Δ

ν

+Δ

θ

(pseudorange and delta range) integration mode without aiding of GPS tracking loops;

a GPS/IMU ρ

/Δ

ν

+Δ

θ

(pseudorange and delta range) integration mode with aiding of GPS tracking loops;

a GPS/IMU ρ

+φ

/Δ

ν

+Δ

θ

(pseudorange, delta range, and carrier phase) integration mode without aiding of GPS tracking loops; and

a GPS/IMU ρ

+φ

/Δ

ν

+Δ

θ

(pseudorange, delta range, and carrier phase) integration mode with aiding of GPS tracking loops.

24. The positioning process, as recited in claim 21, wherein said body angular rate and acceleration information from said inertial measurement unit is processed in said inertial navigation solution, and is passed to said integrated Kalman filter, wherein error estimates, which are provided by the integrated Kalman filter, are fed back to said inertial navigation solution to remove errors of the position, velocity and inertial sensors, wherein said GPS RF signals are received by a GPS antenna and processed in said GPS RF/IF Unit, said carrier and code tracking loops, said ambiguity resolution and said message decoding being passed to said integrated Kalman filter, wherein optimal velocity and acceleration information of said integrated Kalman filter are fed back to said carrier and code tracking loops to aid GPS signal tracking process, moreover position, velocity, attitude from said inertial navigation solution being input to an ambiguity resolution to aid a GPS carrier phase integer ambiguity resolution.

20. A positioning process for a vehicle, comprising said steps of:

(a) accepting angular rate and acceleration measurements for said vehicle from an inertial measurement unit (IMU) to form an initial value and computing said initial value according to inertial navigation equations of said inertial measurement unit;

(b) receiving global positioning system (GPS) radio frequency (RF) signals and deriving GPS pseudorange, delta range, and carrier phase measurements from said global positioning system radio frequency signals;

(c) receiving said angular rate and acceleration information from said inertial measurement unit and solving said inertial navigation measurements of said inertial measurement unit to obtain a navigation solution which includes position, velocity, and attitude; and

(d) combining said GPS pseudorange, delta range, and carrier phase measurements, and said navigation solution to obtain a fully-coupled positioning solution, wherein said GPS pseudorange, delta range and carrier phase measurements, and said inertial navigation solution are combined by an integrated Kalman filters.

22. A positioning process for a vehicle, comprising said steps of:

(a) accepting angular rate and acceleration measurements for said vehicle from an inertial measurement unit (IMU) to form an initial value and computing said initial value according to inertial navigation equations of said inertial measurement unit;

(b) receiving global positioning system (GPS) radio frequency (RF) signals and deriving GPS pseudorange, delta range, and carrier phase measurements from said global positioning system radio frequency signals;

(c) receiving said angular rate and acceleration information from said inertial measurement unit and solving said inertial navigation measurements of said inertial measurement unit to obtain a navigation solution which includes position, velocity, and attitude; and

(d) combining said GPS pseudorange, delta range, and carrier phase measurements, and said navigation solution to obtain a fully-coupled positioning solution, wherein GPS pseudorange, delta range and carrier phase measurements, and said inertial navigation solution are combined by a multi-mode robust Kalman filter which comprises at least one of said following operation modes;

a GPS/INS P-V (position and velocity) integration mode;

a GPS/IMU ρ

/Δ

ν

+Δ

θ

(pseudorange and delta range) integration mode without aiding of GPS tracking loops;

a GPS/IMU ρ

/Δ

ν

+Δ

θ

(pseudorange and delta range) integration mode with aiding of GPS tracking loops;

a GPS/IMU ρ

+φ

/Δ

ν

+Δ

θ

(pseudorange, delta range, and carrier phase) integration mode without aiding of GPS tracking loops; and

a GPS/IMU ρ

+φ

/Δ

ν

+Δ

θ

(pseudorange, delta range, and carrier phase) integration mode with aiding of GPS tracking loops.