Fully-coupled positioning process and system thereof

• US 6,278,945 B1
• Filed: 11/20/1998
• Issued: 08/21/2001
• Est. Priority Date: 11/24/1997
• Status: Expired due to Term

• Current Assignee: American GNC Corporation
• Original Assignee: American GNC Corporation
• Inventors: Lin, Ching-Fang
• Primary Examiner(s): Issing, Gregory C.
• Application Number:
  US09/197,958
• Time in Patent Office: 1,005 Days
• Field of Search: 701/216, 342/357.14
• US Class Current: 701/216
• CPC Class Codes: G01C 21/165 combined with non-inertial navigation instruments
• CPC Class Codes: G01S 19/26 involving a sensor measurement for aiding acquisition or tracking
• CPC Class Codes: G01S 19/44 Carrier phase ambiguity resolution; Floating ambiguity; LAMBDA [Least-squares AMBiguity Decorrelation Adjustment] method
• CPC Class Codes: G01S 19/49 whereby the further system is an inertial position system, e.g. loosely-coupled

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 fully-coupled positioning process for a vehicle, comprising the steps of:

(a) receiving initial global positioning system (GPS) radio frequency signals within an epoch by using one single global positioning system (GPS) receiving set carried by said vehicle;

(b) deriving initial GPS pseudoranges, delta ranges, and carrier phase measurements from said initial GPS radio frequency signals received by said GPS receiving set;

(c) providing initial angular rate measurements and initial acceleration measurements within said epoch for said vehicle from an inertial measurement unit (IMU) carried by said vehicle, and initial position, velocity and attitude measurements within said epoch for said vehicle to compute an initial inertial navigation solution;

(d) resolving a carrier phase ambiguity to obtain carrier phase ambiguity numbers within said epoch, based on said GPS peudoranges, said delta ranges, said carrier phase measurements, and said initial inertial navigation solution within said epoch;

(e) detecting cycle slip occurring within said epoch to obtain a plurality of slip cycles based on said GPS peudoranges, said delta ranges, said carrier phase measurements, and said initial inertial navigation solution within said epoch, wherein said initial carrier phase ambiguity numbers within said epoch are corrected by using said slip cycles when said cycle slip is detected; and

(f) combining said GPS pseudoranges, said delta ranges, said carrier phase measurements, said carrier phase ambiguity numbers, and said initial inertial navigation solution within said epoch to provide a fully-coupled positioning solution for said epoch.

2. The fully-coupled positioning process, as recited in claim 1, after obtaining said fully-coupled positioning solution for said epoch, further comprising the steps of:

(g) receiving global positioning system (GPS) radio frequency signals within a current epoch by using said GPS receiving set;

(h) deriving GPS pseudoranges, delta ranges, and carrier phase measurements for said current epoch from said GPS radio frequency signals received within said current epoch by said GPS receiving set;

(i) resolving carrier phase ambiguity to obtain a plurality of carrier phase ambiguity numbers within said current epoch, based on said GPS pseudoranges, said delta ranges, said carrier phase measurements within said current epoch, and said fully-coupled positioning solution previously obtained in last said epoch;

(j) detecting cycle slip occurring within said current epoch to obtain a plurality of slip cycles for said current epoch based on said GPS pseudoranges, said delta ranges, said carrier phase measurements within said current epoch, and said fully-coupled positioning solution previously obtained in last said epoch, wherein said carrier phase ambiguity numbers within said current epoch are corrected by using said slip cycles when said cycle slip is detected within said current epoch;

(k) computing an inertial navigation solution by receiving said angular rate measurements and said acceleration measurements within said current epoch from said inertial measurement unit (IMU), wherein said inertial navigation solution includes a position vector, a velocity vector, and an attitude vector; and

(l) combining said GPS pseudoranges, said delta ranges, said carrier phase measurements, said carrier phase ambiguity numbers, and said inertial navigation solution within said current epoch to obtain a current fully-coupled positioning solution for said current epoch for a plurality of optimal estimates of a plurality of inertial navigation solution errors.

3. The fully-coupled positioning process, as recited in claim 2, after the step (l), further comprising the steps of:

(m) continuously obtaining a next current fully-coupled positioning solution for each next current epoch by repeating the step (g) to step (l).

4. The fully-coupled positioning process, as recited in claim 1, wherein said initial attitude measurements is provided from at least one external sensor carried by said vehicle.

5. The fully-coupled positioning process, as recited in claim 2, wherein said initial attitude measurements is provided from at least one external sensor carried by said vehicle.

6. The fully-coupled positioning process, as recited in claim 3, wherein said initial attitude measurements is provided from at least one external sensor carried by said vehicle.

7. The fully-coupled positioning process, as recited in claim 1, wherein said initial attitude measurements are provided from said GPS receiving set.

8. The fully-coupled positioning process, as recited in claim 2, wherein said initial attitude measurements are provided from said GPS receiving set.

9. The fully-coupled positioning process, as recited in claim 5, wherein said initial attitude measurements are provided from said GPS receiving set.

10. The fully-coupled positioning process, as recited in one of claims 4 to 6, wherein said inertial measurement unit is a tactical inertial measurement unit installed on a platform and said external sensor is a platform inertial measurement unit, wherein measurements or navigation parameters of said tactical inertial measurement unit and said platform inertial measurement unit are filtered by an alignment filter to provide optimal initialization information for said tactical inertial measurement unit.

11. The fully-coupled positioning process, as recited in one of claims 7 to 9, wherein said inertial measurement unit is a tactical inertial measurement unit installed on a platform, wherein measurements or navigation parameters of said tactical inertial measurement unit are filtered by an alignment filter to provide optimal initialization information for said tactical inertial measurement unit.

12. The fully-coupled positioning process, as recited in claim 10, wherein in the step (a), said GPS frequency signals are tracked by a plurality of carrier phase locked loops and a plurality of code tracking loops of said GPS receiving set, and said carrier phase locked loops and said code tracking loops of said GPS receiving set are aided by said fully-coupled positioning solution.

13. The fully-coupled positioning process, as recited in claim 11, wherein in the step (a), said GPS frequency signals are tracked by a plurality of carrier phase locked loops and a plurality of code tracking loops of said GPS receiving set, and said carrier phase locked loops and said code tracking loops of said GPS receiving set are aided by said fully-coupled positioning solution.

14. The fully-coupled positioning process, as recited in one of claims 1 to 3, wherein a plurality of errors of said inertial navigation solution are removed with said optimal estimates of said inertial navigation solution errors.

15. The fully-coupled positioning process, as recited in claim 12, wherein a plurality of errors of said inertial navigation solution are removed with said optimal estimates of said inertial navigation solution errors.

16. The fully-coupled positioning process, as recited in claim 13, wherein a plurality of errors of said inertial navigation solution are removed with said optimal estimates of said inertial navigation solution errors.

17. The fully-coupled positioning process, as recited in one of claims 1 to 3, wherein, in the step (f), said GPS pseudoranges, said delta ranges, said carrier phase measurements, and said initial inertial navigation solution are combined by an integrated Kalman filter.

18. The fully-coupled positioning process, as recited in claim 2 or 3, wherein, in the step (f), said GPS pseudoranges, said delta ranges, said carrier phase measurements, and said initial inertial navigation solution are combined by an integrated Kalman filter, and that in the step (l), said GPS pseudoranges, said delta ranges, said carrier phase measurements, and said inertial navigation solution within said subsequent epoch are also combined by said integrated Kalman filter.

19. The fully-coupled positioning process, as recited in claim 1, wherein in step (6), in the step (f), said GPS pseudoranges, said delta ranges, said carrier phase measurements, and said initial inertial navigation solution are combined by a multi-mode robust Kalman filter that selects an operation modes from the following operation modes:

a GPS/INS position and velocity integration mode, wherein said position vector and said velocity vector from said GPS receiving set are combined with said inertial navigation solution to derive an integrated navigation solution;

a GPS/IMU pseudorange and delta range integration mode, wherein said GPS pseudoranges and said delta ranges are combined with said inertial navigation solution to derive an integrated navigation solution;

a GPS/IMU pseudorange and delta range integration mode with aiding of GPS tracking loops, wherein said GPS pseudoranges and said delta ranges are combined with said inertial navigation solution to derive an integrated navigation solution, wherein said global positioning system radio frequency signals are tracked by a plurality of carrier phase locked loops and a plurality of code tracking loops of said GPS receiving set, and said carrier phase locked loops and said code tracking loops of said GPS receiving set are aided by said fully-coupled positioning solution obtained in step (g);

a GPS/IMU pseudorange, delta range, and carrier phase integration mode, wherein said GPS pseudoranges, said delta ranges, and said carrier phase measurements are combined with said inertial navigation solution to derive an integrated navigation solution; and

a GPS/IMU pseudorange, delta range, and carrier phase integration mode with aiding of GPS tracking loops, wherein said GPS pseudoranges, said delta ranges, and said carrier phase measurements are combined with said inertial navigation solution to derive an integrated navigation solution, wherein said global positioning system radio frequency signals are tracked by a plurality of carrier phase locked loops and a plurality of code tracking loops of said GPS receiving set, and said carrier phase locked loops and said code tracking loops of said GPS receiving set are aided by said fully-coupled positioning solution.

20. The fully-coupled positioning process, as recited in claim 2 or 3, wherein in step (6), in the step (f), said GPS pseudoranges, said delta ranges, said carrier phase measurements, and said initial inertial navigation solution are combined by a multi-mode robust Kalman filter that selects an operation modes from the following operation modes:

a GPS/INS position and velocity integration mode, wherein said position vector and said velocity vector from said GPS receiving set are combined with said inertial navigation solution to derive an integrated navigation solution;

a GPS/IMU pseudorange and delta range integration mode, wherein said GPS pseudoranges and said delta ranges are combined with said inertial navigation solution to derive an integrated navigation solution;

a GPS/IMU pseudorange and delta range integration mode with aiding of GPS tracking loops, wherein said GPS pseudoranges and said delta ranges are combined with said inertial navigation solution to derive an integrated navigation solution, wherein said global positioning system radio frequency signals are tracked by a plurality of carrier phase locked loops and a plurality of code tracking loops of said GPS receiving set, and said carrier phase locked loops and said code tracking loops of said GPS receiving set are aided by said fully-coupled positioning solution obtained in step (g);

a GPS/IMU pseudorange, delta range, and carrier phase integration mode, wherein said GPS pseudoranges, said delta ranges, and said carrier phase measurements are combined with said inertial navigation solution to derive an integrated navigation solution; and

a GPS/IMU pseudorange, delta range, and carrier phase integration mode with aiding of GPS tracking loops, wherein said GPS pseudoranges, said delta ranges, and said carrier phase measurements are combined with said inertial navigation solution to derive an integrated navigation solution, wherein said global positioning system radio frequency signals are tracked by a plurality of carrier phase locked loops and a plurality of code tracking loops of said GPS receiving set, and said carrier phase locked loops and said code tracking loops of said GPS receiving set are aided by said fully-coupled positioning solution.

21. Th e fully-coupled positioning process, as recited in claim 2 or 3, wherein, in the step (l), said GPS pseudoranges, said delta ran ges, said carrier phase measurements, and said inertial navigation solution within said subsequent epoch are also combined by a multi-mode robust Kalman filter that selects an operation modes from the following operation modes:

a GPS/INS P-V (position and velocity) integration mode, wherein said position vector and said velocity vector from said GPS receiving set are combined with said inertial navigation solution to derive an integrated navigation solution;

a GPS/IMU ρ

/Δ

ν

+Δ

θ

(pseudorange and delta range) integration mode, wherein said GPS pseudoranges and said delta ranges are combined with said inertial navigation solution to derive an integrated navigation solution;

a GPS/IMU ρ

/Δ

ν

+Δ

θ

(pseudorange and delta range) integration mode with aiding of GPS tracking loops, wherein said GPS pseudoranges and said delta ranges are combined with said inertial navigation solution to derive an integrated navigation solution, wherein said global positioning system radio frequency signals are tracked by a plurality of carrier phase locked loops and a plurality of code tracking loops of said GPS receiving set, and said carrier phase locked loops and said code tracking loops of said GPS receiving set are aided by said fully-coupled positioning solution obtained in step (g);

a GPS/IMU ρ

+φ

/Δ

ν

+Δ

θ

(pseudorange, delta range, and carrier phase) integration mode, wherein said GPS pseudoranges, said delta ranges, and said carrier phase measurements are combined with said inertial navigation solution to derive an integrated navigation solution; and

a GPS/IMU ρ

+φ

/Δ

ν

+Δ

θ

(pseudorange, delta range, and carrier phase) integration mode with aiding of GPS tracking loops, wherein said GPS pseudoranges, said delta ranges, and said carrier phase measurements are combined with said inertial navigation solution to derive an integrated navigation solution, wherein said global positioning system radio frequency signals are tracked by a plurality of carrier phase locked loops and a plurality of code tracking loops of said GPS receiving set, and said carrier phase locked loops and said code tracking loops of said GPS receiving set are aided by said fully-coupled positioning solution.

22. The fully-coupled positioning process, as recited in claim 20, wherein, in the step (l), said GPS pseudoranges, said delta ranges, said carrier phase measurements, and said inertial navigation solution within said subsequent epoch are also combined by a multi-mode robust Kalman filter that selects an operation modes from the following operation modes:

a GPS/INS P-V (position and velocity) integration mode, wherein said position vector and said velocity vector from said GPS receiving set are combined with said inertial navigation solution to derive an integrated navigation solution;

a GPS/IMU ρ

/Δ

ν

+Δ

θ

(pseudorange and delta range) integration mode, wherein said GPS pseudoranges and said delta ranges are combined with said inertial navigation solution to derive an integrated navigation solution;

a GPS/IMU ρ

/Δ

ν

+Δ

θ

(pseudorange and delta range) integration mode with aiding of GPS tracking loops, wherein said GPS pseudoranges and said delta ranges are combined with said inertial navigation solution to derive an integrated navigation solution, wherein said global positioning system radio frequency signals are tracked by a plurality of carrier phase locked loops and a plurality of code tracking loops of said GPS receiving set, and said carrier phase locked loops and said code tracking loops of said GPS receiving set are aided by said fully-coupled positioning solution obtained in step (g);

a GPS/IMU ρ

+φ

/Δ

ν

+Δ

θ

(pseudorange, delta range, and carrier phase) integration mode, wherein said GPS pseudoranges, said delta ranges, and said carrier phase measurements are combined with said inertial navigation solution to derive an integrated navigation solution; and

a GPS/IMU ρ

+φ

/Δ

ν

+Δ

θ

(pseudorange, delta range, and carrier phase) integration mode with aiding of GPS tracking loops, wherein said GPS pseudoranges, said delta ranges, and said carrier phase measurements are combined with said inertial navigation solution to derive an integrated navigation solution, wherein said global positioning system radio frequency signals are tracked by a plurality of carrier phase locked loops and a plurality of code tracking loops of said GPS receiving set, and said carrier phase locked loops and said code tracking loops of said GPS receiving set are aided by said fully-coupled positioning solution.

23. The fully coupled positioning process, as recited in claim 17, wherein said angular rate and said acceleration measurements from said inertial measurement unit is processed to derive said inertial navigation solution, and is passed to said integrated Kalman filter, wherein a plurality of error estimates, which are provided by said integrated Kalman filter, are fed back to said inertial navigation solution to remove errors of said position vector, said velocity vector, and inertial sensors.

24. The fully coupled positioning process, as recited in claim 18, wherein said angular rate and said acceleration measurements from said inertial measurement unit is processed to derive said inertial navigation solution, and is passed to said integrated Kalman filter, wherein a plurality of error estimates, which are provided by said integrated Kalman filter, are fed back to said inertial navigation solution to remove errors of said position vector, said velocity vector, and inertial sensors.

25. The fully coupled positioning process, as recited in claim 17, wherein said GPS radio frequency signals are received by a GPS antenna and processed in a GPS RF/IF Unit, carrier and code tracking loops, an ambiguity resolution and a 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 a GPS signal tracking process, moreover position, velocity, attitude from said inertial navigation solution being input to said ambiguity resolution to aid a GPS carrier phase integer ambiguity resolution.

26. The fully coupled positioning process, as recited in claim 18, wherein said GPS radio frequency signals are received by a GPS antenna and processed in a GPS RF/IF Unit, carrier and code tracking loops, an ambiguity resolution and a 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 a GPS signal tracking process, moreover position, velocity, attitude from said inertial navigation solution being input to said ambiguity resolution to aid a GPS carrier phase integer ambiguity resolution.

27. The fully-coupled positioning process, as recited in claim 20, further comprising the steps of:

(i) determining said carrier phase ambiguity numbers;

(ii) when said carrier phase ambiguity numbers are not available, selecting one of said GPS/INS position and velocity integration mode, said GPS/IMU pseudorange and delta range integration mode, and said GPS/IMU pseudorange and delta range integration mode with aiding of GPS tracking loops; and

(iii) when said carrier phase ambiguity numbers are available, switching to one of said GPS/IMU pseudorange, delta range, and carrier phase integration mode and said GPS/IMU pseudorange, delta range, and carrier phase integration mode with aiding of GPS tracking loops.

28. The fully-coupled positioning process, as recited in claim 21, further comprising the steps of:

(i) determining said carrier phase ambiguity numbers;

(ii) when said carrier phase ambiguity numbers are not available, selecting one of said GPS/INS position and velocity integration mode, said GPS/IMU pseudorange and delta range integration mode, and said GPS/IMU pseudorange and delta range integration mode with aiding of GPS tracking loops; and

(iii) when said carrier phase ambiguity numbers are available, switching to one of said GPS/IMU pseudorange, delta range, and carrier phase integration mode and said GPS/IMU pseudorange, delta range, and carrier phase integration mode with aiding of GPS tracking loops.

29. The fully-coupled positioning process, as recited in claim 27, wherein before obtaining said carrier phase ambiguity numbers said multi-mode robust Kalman filter works in said GPS/INS P-V (position and velocity) integration mode and derives an accurate integrated navigation solution which is used to reduce measurement errors in said GPS pseudorange, said delta ranges, and said carrier phase measurements so as to facilitate searching for said carrier phase ambiguity numbers;

wherein after obtaining said carrier phase ambiguity numbers said multi-mode robust Kalman filter switches to said GPS/IMU pseudorange, delta range, and carrier phase integration mode.

30. The fully-coupled positioning process, as recited in claim 28, wherein before obtaining said carrier phase ambiguity numbers said multi-mode robust Kalman filter works in said GPS/INS P-V (position and velocity) integration mode and derives an accurate integrated navigation solution which is used to reduce measurement errors in said GPS pseudorange, said delta ranges, and said carrier phase measurements so as to facilitate searching for said carrier phase ambiguity numbers;

wherein after obtaining said carrier phase ambiguity numbers said multi-mode robust Kalman filter switches to said GPS/IMU pseudorange, delta range, and carrier phase integration mode.

31. The fully-coupled positioning process, as recited in claim 27, wherein before obtaining said carrier phase ambiguity numbers said multi-mode robust Kalman filter works in said GPS/IMU pseudorange and delta range) integration mode and derives an accurate integrated navigation solution which is used to reduce measurement errors in said GPS pseudorange, said delta ranges, and said carrier phase measurements so as to facilitate searching for said carrier phase ambiguity numbers;

wherein after obtaining said carrier phase ambiguity numbers said multi-mode robust Kalman filter switches to said GPS/IMU pseudorange, delta range, and carrier phase integration mode.

32. The fully-coupled positioning process, as recited in claim 28, wherein before obtaining said carrier phase ambiguity numbers said multi-mode robust Kalman filter works in said GPS/IMU pseudorange and delta range) integration mode and derives an accurate integrated navigation solution which is used to reduce measurement errors in said GPS pseudorange, said delta ranges, and said carrier phase measurements so as to facilitate searching for said carrier phase ambiguity numbers;

wherein after obtaining said carrier phase ambiguity numbers said multi-mode robust Kalman filter switches to said GPS/IMU pseudorange, delta range, and carrier phase integration mode.

33. The fully-coupled positioning process, as recited in claim 27, wherein before obtaining said carrier phase ambiguity numbers said multi-mode robust Kalman filter works in said GPS/IMU pseudorange and delta range integration mode with aiding of GPS tracking loops and derives an accurate integrated navigation solution which is used to reduce measurement errors in said GPS pseudorange, said delta ranges, and said carrier phase measurements so as to facilitate searching for said carrier phase ambiguity numbers;

wherein after obtaining said carrier phase ambiguity numbers said multi-mode robust Kalman filter switches to said GPS/IMU pseudorange, delta range, and carrier phase integration mode.

34. The fully-coupled positioning process, as recited in claim 28, wherein before obtaining said carrier phase ambiguity numbers said multi-mode robust Kalman filter works in said GPS/IMU pseudorange and delta range integration mode with aiding of GPS tracking loops and derives an accurate integrated navigation solution which is used to reduce measurement errors in said GPS pseudorange, said delta ranges, and said carrier phase measurements so as to facilitate searching for said carrier phase ambiguity numbers;

wherein after obtaining said carrier phase ambiguity numbers said multi-mode robust Kalman filter switches to said GPS/IMU pseudorange, delta range, and carrier phase integration mode.

35. The fully-coupled positioning process, as recited in claim 27, wherein before obtaining said carrier phase ambiguity numbers said multi-mode robust Kalman filter works in said GPS/INS position and velocity integration mode and derives an accurate integrated navigation solution which is used to reduce measurement errors in said GPS pseudorange, said delta ranges, and said carrier phase measurements so as to facilitate searching for said carrier phase ambiguity numbers;

wherein after obtaining said carrier phase ambiguity numbers said multi-mode robust Kalman filter switches to said GPS/IMU pseudorange, delta range, and carrier phase integration mode with aiding of GPS tracking loops.

36. The fully-coupled positioning process, as recited in claim 28, wherein before obtaining said carrier phase ambiguity numbers said multi-mode robust Kalman filter works in said GPS/INS position and velocity integration mode and derives an accurate integrated navigation solution which is used to reduce measurement errors in said GPS pseudorange, said delta ranges, and said carrier phase measurements so as to facilitate searching for said carrier phase ambiguity numbers;

wherein after obtaining said carrier phase ambiguity numbers said multi-mode robust Kalman filter switches to said GPS/IMU pseudorange, delta range, and carrier phase integration mode with aiding of GPS tracking loops.

37. The fully-coupled positioning process, as recited in claim 27, wherein before obtaining said carrier phase ambiguity numbers said multi-mode robust Kalman filter works in said GPS/IMU pseudorange and delta range integration mode and derives an accurate integrated navigation solution which is used to reduce measurement errors in said GPS pseudorange, said delta ranges, and said carrier phase measurements so as to facilitate searching for said carrier phase ambiguity numbers;

wherein after obtaining said carrier phase ambiguity numbers said multi-mode robust Kalman filter switches to said GPS/IMU pseudorange, delta range, and carrier phase integration mode with aiding of GPS tracking loops.

38. The fully-coupled positioning process, as recited in claim 28, wherein before obtaining said carrier phase ambiguity numbers said multi-mode robust Kalman filter works in said GPS/IMU pseudorange and delta range integration mode and derives an accurate integrated navigation solution which is used to reduce measurement errors in said GPS pseudorange, said delta ranges, and said carrier phase measurements so as to facilitate searching for said carrier phase ambiguity numbers;

wherein after obtaining said carrier phase ambiguity numbers said multi-mode robust Kalman filter switches to said GPS/IMU pseudorange, delta range, and carrier phase integration mode with aiding of GPS tracking loops.

39. The fully-coupled positioning process, as recited in claim 27, wherein before obtaining said carrier phase ambiguity numbers said multi-mode robust Kalman filter works in said GPS/IMU pseudorange and delta range integration mode with aiding of GPS tracking loops and derives an accurate integrated navigation solution which is used to reduce measurement errors in said GPS pseudorange, said delta ranges, and said carrier phase measurements so as to facilitate searching for said carrier phase ambiguity numbers;

wherein after obtaining said carrier phase ambiguity numbers said multi-mode robust Kalman filter switches to said GPS/IMU pseudorange, delta range, and carrier phase integration mode with aiding of GPS tracking loops.

40. The fully-coupled positioning process, as recited in claim 28, wherein before obtaining said carrier phase ambiguity numbers said multi-mode robust Kalman filter works in said GPS/IMU pseudorange and delta range integration mode with aiding of GPS tracking loops and derives an accurate integrated navigation solution which is used to reduce measurement errors in said GPS pseudorange, said delta ranges, and said carrier phase measurements so as to facilitate searching for said carrier phase ambiguity numbers;

wherein after obtaining said carrier phase ambiguity numbers said multi-mode robust Kalman filter switches to said GPS/IMU pseudorange, delta range, and carrier phase integration mode with aiding of GPS tracking loops.