Interruption free navigator

• US 20060287824A1
• Filed: 01/28/2006
• Published: 12/21/2006
• Est. Priority Date: 01/29/2005
• Status: Abandoned Application

• Current Assignee: American GNC Corporation
• Original Assignee: American GNC Corporation
• Inventors: Lin, Ching-Fang
• Application Number:
  US11/342,354
• Publication Number:
  US 20060287824A1
• Time in Patent Office: Days
• US Class Current: 701/214
• CPC Class Codes: G01C 21/1652 with ranging devices, e.g. LIDAR or RADAR
• CPC Class Codes: G01C 21/1654 with electromagnetic compass
• CPC Class Codes: G01C 21/1656 with passive imaging devices, e.g. cameras
• CPC Class Codes: G01C 21/20 Instruments for performing navigational calculations G01C21/24, G01C21/26 take precedence
• CPC Class Codes: G01C 21/206 specially adapted for indoor navigation

Abstract

An interruption free navigator includes an inertial measurement unit, a north finder, a velocity producer, a positioning assistant, a navigation processor, an altitude measurement, an object detection system, a wireless communication device, and a display device and map database. Output signals of the inertial measurement unit, the velocity producer, the positioning assistant, the altitude measurement, the object detection system, and the north finder are processed to obtain highly accurate position measurements of the person. The user'"'"'s position information can be exchanged with other users through the wireless communication device, and the location and surrounding information can be displayed on the display device by accessing a map database with the person position information.

Claims

1. An interruption free navigator, comprising:

a main IMU (Inertial Measurement Unit) based interruption-free positioning module comprising an IMU sensing motion measurements of a user and producing interruption-free positioning data of said user and a velocity producer producing relative velocity data of said user, wherein said velocity producer includes a device selected from a group consisting of radio frequency radar, sonar, laser radar, odometer, encoder, velocimeter, step counter, and pedometer; and

a positioning assistant providing interruptible positioning data for said main IMU based interruption-free positioning module to achieve an improved interruption-free positioning data of said user.

2. The interruption free navigator, as recited in claim 1, further comprising a wireless communication device exchanging said improved interruption-free positioning data with other users.

3. The interruption free navigator, as recited in claim 2, further comprising a voice device to sample a voice of said user and provide voice communication using said wireless communication device.

4. The interruption free navigator, as recited in claim 3, wherein a wireless communication ranging from said wireless communication device aids said main IMU based interruption-free positioning module for positioning.

5. The interruption free navigator, as recited in claim 1, wherein said main IMU based interruption-free positioning module further comprises a wireless communication processing system for communication device detection and message management.

6. The interruption free navigator, as recited in claim 2, wherein said main IMU based interruption-free positioning module further comprises a wireless communication processing system for communication device detection and message management.

7. The interruption free navigator, as recited in claim 1, wherein said main IMU based interruption-free positioning module further comprises a north finder producing a heading measurement of said user and a navigation processor which is connected with said IMU, said north finder, said velocity producer and said positioning assistant.

8. The interruption free navigator, as recited in claim 2, wherein said main IMU based interruption-free positioning module further comprises a north finder producing a heading measurement of said user and a navigation processor which is connected with said IMU, said north finder, said velocity producer and said positioning assistant.

9. The interruption free navigator, as recited in claim 1, wherein when said velocity producer provides relative velocity measurements of said user to a ground by sensing Doppler frequencies, Doppler effect is a shift in frequency of a wave radiated from said velocity producer when reflected by an object in motion, wherein Doppler shifts are produced by said relative motion of said user and said ground from which radio or laser or sonic waves are reflected.

10. The interruption free navigator, as recited in claim 2, wherein when said velocity producer provides relative velocity measurements of said user to a ground by sensing Doppler frequencies, Doppler effect is a shift in frequency of a wave radiated from said velocity producer when reflected by an object in motion, wherein Doppler shifts are produced by said relative motion of said user and said ground from which radio or laser or sonic waves are reflected.

11. The interruption free navigator, as recited in claim 7, wherein when said velocity producer provides relative velocity measurements of said user to a ground by sensing Doppler frequencies, Doppler effect is a shift in frequency of a wave radiated from said velocity producer when reflected by an object in motion, wherein Doppler shifts are produced by said relative motion of said user and said ground from which radio or laser or sonic waves are reflected.

12. The interruption free navigator, as recited in claim 8, wherein when said velocity producer provides relative velocity measurements of said user to a ground by sensing Doppler frequencies, Doppler effect is a shift in frequency of a wave radiated from said velocity producer when reflected by an object in motion, wherein Doppler shifts are produced by said relative motion of said user and said ground from which radio or laser or sonic waves are reflected.

13. The interruption free navigator, as recited in claim 1, wherein when said velocity producer measures a relative velocity with respect to a surface where said user travels, a serial of pulse signals is generated according to a speed of said user.

14. The interruption free navigator, as recited in claim 2, wherein when said velocity producer measures a relative velocity with respect to a surface where said user travels, a serial of pulse signals is generated according to a speed of said user.

15. The interruption free navigator, as recited in claim 7, wherein when said velocity producer measures a relative velocity with respect to a surface where said user travels, a serial of pulse signals is generated according to a speed of said user.

16. The interruption free navigator, as recited in claim 8, wherein when said velocity producer measures a relative velocity with respect to a surface where said user travels, a serial of pulse signals is generated according to a speed of said user.

17. The interruption free-navigator, as recited in claim 1, wherein when said velocity producer measures a relative velocity or delta distance with respect to a ground where said user travels while said user is carrying said interruption free navigator, a serial of pulse signals is generated according to a speed of said person.

18. The interruption free-navigator, as recited in claim 2, wherein when said velocity producer measures a relative velocity or delta distance with respect to a ground where said user travels while said user is carrying said interruption free navigator, a serial of pulse signals is generated according to a speed of said person.

19. The interruption free-navigator, as recited in claim 7, wherein when said velocity producer measures a relative velocity or delta distance with respect to a ground where said user travels while said user is carrying said interruption free navigator, a serial of pulse signals is generated according to a speed of said person.

20. The interruption free-navigator, as recited in claim 8, wherein when said velocity producer measures a relative velocity or delta distance with respect to a ground where said user travels while said user is carrying said interruption free navigator, a serial of pulse signals is generated according to a speed of said person.

21. The interruption free-navigator, as recited in claim 17, wherein said device of said velocity producer is a step counter or pedometer.

22. The interruption free-navigator, as recited in claim 18, wherein said device of said velocity producer is a step counter or pedometer.

23. The interruption free-navigator, as recited in claim 19, wherein said device of said velocity producer is a step counter or pedometer.

24. The interruption free-navigator, as recited in claim 20, wherein said device of said velocity producer is a step counter or pedometer.

25. The interruption free navigator, as recited in claim 19, further comprises an object detection system to capture images of a surrounding environment of said user and to derive position data of adjacent objects of said user, so as to provide a notice that an interested object has been found in neighborhood.

26. The interruption free navigator, as recited in claim 20, further comprises an object detection system to capture images of a surrounding environment of said user and to derive position data of adjacent objects of said user, so as to provide a notice that an interested object has been found in neighborhood.

27. The interruption free navigator, as recited in claim 19, further comprising a display device for visualizing said interruption-free positioning data of said user using said surrounding map information.

28. The interruption free navigator, as recited in claim 20, further comprising a display device for visualizing said interruption-free positioning data of said user using said surrounding map information.

29. The interruption free navigator, as recited in claim 19, further comprising a map database providing map data to obtain surrounding map information of location of said user by accessing said map database using said interruption-free positioning data.

30. The interruption free navigator, as recited in claim 20, further comprising a map database providing map data to obtain surrounding map information of location of said user by accessing said map database using said interruption-free positioning data.

31. The interruption free navigator, as recited in claim 20, wherein said positioning assistant includes a GPS receiver to receive interruptible GPS RF (radio frequency) signals to produce GPS positioning data to said navigation processor.

32. The interruption free navigator, as recited in claim 31, wherein said positioning assistant further includes a data link for receiving said GPS positioning data from a GPS reference site to perform differential GPS positioning.

33. The interruption free navigator, as recited in claim 32, wherein said navigation processor further provides:

a new satellites/cycle slips detection module for receiving said GPS measurements from said GPS receiver and GPS reference measurement from said data link and determines whether new GPS satellites come in view or cycle slips occur; and

an on-the-fly ambiguity resolution module for receiving said GPS measurements from said GPS receiver and GPS reference measurement from said data link and is activated when either new GPS satellites come in view or cycle slips occur to fix said ambiguity integer.

34. The interruption free navigator, as recited in claim 33, wherein said on-the-fly ambiguity resolution module is activated when said new satellites/cycle slips detection module is on, and therefore, rover raw and Doppler shift measurements from said GPS receiver and reference raw measurements, Doppler shift measurements, position, and velocity from said data link to fix said integer ambiguities.

35. The interruption free navigator, as recited in claim 34, wherein said on-the-fly ambiguity resolution module, comprising the steps of:

(1) initiating an on-the-fly ambiguity resolution module as said new satellites/cycle slips detection module is on, i.e., said new satellites or cycle slips occur;

(2) fixing integer ambiguities to estimate a more accurate user navigation solution, and

(3) sending said selected integer ambiguities from said on-the-fly ambiguity resolution module to said integration Kalman filter.

36. The interruption free navigator, as recited in claim 35, wherein said step (3) further comprises said steps of:

(3.1) using intermediate ambiguity search strategy (IASS) and estimator bank to set up ambiguity set and determine said ambiguity integer; and

(3.2) validating and confirming said ambiguity integer.

37. The interruption free navigator, as recited in claim 20, wherein said navigation processor provides:

an integration Kalman filter to estimate and compensate INS errors and sensor errors;

an INS computation module, using said digital angular increments and velocity increments signals from said IMU to produce said inertial positioning measurements, including said IMU position, velocity, and attitude data;

a magnetic sensor processing module for producing said heading angle; and

a velocity processing module for producing relative position error measurements for said integration Kalman filter.

38. The interruption free navigator, as recited in claim 37, wherein said INS computation module further comprises:

a sensor compensation module for calibrating errors of said digital angular increments and velocity increments signals, which is not proportional to said user'"'"'s motion; and

an inertial navigation algorithm module for computing said IMU position, velocity, and attitude data using said compensated said digital angular increments and velocity increments signals.

39. The interruption free navigator, as recited in claim 38, wherein said inertial navigation algorithm module further comprises:

an attitude integration module for integrating said angular increments into attitude data;

a velocity integration module for transforming measured velocity increments into a suitable navigation coordinate frame by using said attitude data, wherein said transformed velocity increments are integrated into velocity data; and

a position module for integrating said navigation frame velocity data into position data.

40. The interruption free navigator, as recited in claim 39, wherein said magnetic sensor processing module for producing said heading angle further comprises:

a hard iron compensation module for receiving a digital Earth'"'"'s magnetic field vector and compensating hard iron effects in said digital earth'"'"'s magnetic field vector;

a soft iron compensation module for compensating soft iron effects in said digital earth'"'"'s magnetic field vector; and

a heading computation module for receiving said digital Earth'"'"'s magnetic field vector and pitch and roll from said inertial navigation algorithm module and computing said heading data.

41. The interruption free navigator, as recited in claim 40, wherein said velocity producer processing module further comprises:

a scale factor and misalignment error compensation module for compensating said scale factor and misalignment errors in a velocity.

a transformation module for transforming an input velocity data expressed in said body frame to said velocity expressed in said navigation frame; and

a relative position computation for receiving said IMU velocity and attitude data and said velocity to form said relative position measurements for said integration Kalman filter.

42. The interruption free navigator, as recited in claim 41, wherein said integration Kalman filter provides:

a motion test module for determining if said user stops automatically;

a GPS integrity monitor for determining if said GPS data is available;

a state estimation module for filtering said measurements and obtaining optimal estimates of IMU positioning errors; and

a measurement and time varying matrix formation module for formulating said measurement and time varying matrix for said state estimation module according to a motion status of said user from said motion test module and GPS data availability from said GPS integrity monitor.

43. The interruption free navigator, as recited in claim 42, wherein said state estimation module provides a horizontal filter for obtaining estimates of horizontal IMU positioning errors, and a vertical filter for obtaining said estimates of vertical IMU positioning errors.

44. The interruption free navigator, as recited in claim 43, wherein said state estimation module from time to time receives a known position obtained from said GPS receiver, a known position change obtained from said velocity processing module, a position change equal to zero obtained from said zero velocity update processing from said motion tests module, and a known heading obtained from said magnetic sensor processing module.

45. The interruption free navigator, as recited in claim 33, wherein said motion test module provides:

a velocity producer change test module for receiving said velocity producer reading to determining if said user stops or restarts;

a system velocity change test module for comparing system velocity change between a current interval and said previous interval to determine if said user stops or restarts;

a system velocity test module for comparing a system velocity magnitude with a predetermined value to determine whether said user stops or restarts; and

an attitude change test module for comparing said system attitude magnitude with a predetermined value to determine whether said user stops or restarts.

46. An interruption-free hand-held positioning method, comprising the steps of:

(a) sensing motion measurements of said user by a main IMU (Inertial Measurement Unit) to produce interruption-free positioning data of said user and producing relative velocity data of said user by a velocity producer which includes a device selected from a group consisting of radio frequency radar, sonar, laser radar, odometer, encoder, velocimeter, step counter, and pedometer;

(b) providing interruptible positioning data to assist said main IMU based interruption-free positioning module by a positioning assistant, and

(c) producing interruption-free positioning data of said user using motion measurements, and improving said interruption-free positioning data of said user when said interruptible positioning data is available.

47. The method, as recited in claim 46, after the step (c), further comprising a step (d) of exchanging said interruption-free positioning data with other users by a wireless communication device.

48. The method, as recited in claim 46, wherein said interruption-free positioning data includes digital angular increments and velocity increments signals in response to a user motion.

49. The method, as recited in claim 47, wherein said interruption-free positioning data includes digital angular increments and velocity increments signals in response to a user motion.

50. The method, as recited in claim 47, further comprising a step (e) of sampling a voice of said user and providing voice communication using said wireless communication device.

51. The method, as recited in claim 46, further comprising a wireless communication processing for communication device detection and message management.

52. The method, as recited in claim 47, further comprising a wireless communication processing for communication device detection and message management.

53. The method, as recited in claim 46, wherein the step (a) further comprises a step of providing relative velocity measurements of said user to a ground by sensing Doppler frequencies, Doppler effect being a shift in frequency of a wave radiated from said velocity producer when reflected by an object in motion, Doppler shifts being produced by said relative motion of said user and said ground from which radio or laser or sonic waves are reflected.

54. The method, as recited in claim 47, wherein the step (a) further comprises a step of providing relative velocity measurements of said user to a ground by sensing Doppler frequencies, Doppler effect being a shift in frequency of a wave radiated from said velocity producer when reflected by an object in motion, Doppler shifts being produced by said relative motion of said user and said ground from which radio or laser or sonic waves are reflected.

55. The method, as recited in claim 46, wherein the step (a) further comprises a step of measuring a relative velocity with respect to a surface where said user travels, wherein a serial of pulse signals is generated according to a speed of said user.

56. The method, as recited in claim 47, wherein the step (a) further comprises a step of measuring a relative velocity with respect to a surface where said user travels, wherein a serial of pulse signals is generated according to a speed of said user.

57. The method, as recited in claim 48, wherein the step (a) further comprises a step of measuring a relative velocity or delta distance with respect to a ground where said user travels while said user is carrying said interruption free navigator, wherein a serial of pulse signals is generated according to a speed of said person.

58. The method, as recited in claim 49, wherein the step (a) further comprises a step of measuring a relative velocity or delta distance with respect to a ground where said user travels while said user is carrying said interruption free navigator, wherein a serial of pulse signals is generated according to a speed of said person.

59. The method, as recited in claim 57, wherein said device of said velocity producer is a step counter or pedometer.

60. The method, as recited in claim 58, wherein said device of said velocity producer is a step counter or pedometer.

61. The method, as recited in claim 46, further comprising a step of capturing images of a surrounding environment of the user for deriving the position data of adjacent objects, so as to provide a notice that an interested object has been found in neighborhood.

62. The method, as recited in claim 47, further comprising a step of capturing images of a surrounding environment of the user for deriving the position data of adjacent objects, so as to provide a notice that an interested object has been found in neighborhood.

63. The method, as recited in claim 47, after the step (d), further comprising the steps of:

(e) providing map data to obtain a surrounding map information of location of said user by accessing a map database using said improved interruption-free positioning data, and

(f) visualizing said interruption-free positioning data of said user using said surrounding map information by a display device.

64. The method, as recited in claim 58, wherein the step (c) comprises the steps of:

(c.1) sensing an earth'"'"'s magnetic field to measure a heading angle of said user by a magnetic sensor,

(c.2) measuring said relative velocity of said user relative to said ground by said velocity producer to produce a measured velocity, and

(c.3) blending said digital angular increments and velocity increments signals, said heading angle, said relative velocity of said user relative to said ground, and said GPS positioning data to produce optimal positioning data.

65. The method, as recited in claim 63, after the step (f), further comprising a step (g) of aiding a code and carrier phase tracking processing of said GPS signals with velocity and acceleration data to improve an anti-jamming and high-dynamics capability of said GPS receiver.

66. The method, as recited in claim 64, wherein the step (c.3) further comprises the steps of:

c.3.1 computing inertial positioning measurements using said digital angular increments and velocity increments signals;

c.3.2 computing said heading angle using said earth'"'"'s magnetic field measurements,

c.3.3 creating relative position error measurements in said velocity producer processing module using said relative velocity of said user relative to said ground for a Kalman filter, and

c.3.4 estimating errors of inertial positioning measurements by means of performing Kalman filtering computation to calibrate said inertial positioning measurements.

67. The method, as recited in claim 66, wherein the step (c.3.1) further comprises the steps of:

c.3.1.1 integrating said angular increments into attitude data, referred to as attitude integration processing;

c.3.1.2 transforming said measured velocity increments into a suitable navigation coordinate frame by use of said attitude data, wherein said transferred velocity increments are integrated into velocity data, denoted as velocity integration processing, and

c.3.1.3 integrating said velocity data into position data, denoted as position integration processing.

68. The method, as recited in claim 67, wherein the step (c.3.4) further comprises the steps of:

c.3.4.1 performing motion tests to determine whether said user stops to initiate a zero-velocity update;

c.3.4.2 determining whether GPS data available using a GPS state status indicator from said GPS receiver;

c.3.4.3 formulating measurement equations and time varying matrix for said Kalman filter; and

c.3.4.4 computing estimates of error states using said Kalman filter.

69. The method, as recited in claim 64, wherein the step (c.2) further comprises the steps of:

(c.2.

     1) transforming said measured velocity into a navigation frame;

(c.2.2) comparing said measured velocity with an IMU velocity to form a velocity difference; and

(c.2.3) integrating said velocity difference during a predetermined interval.

70. The method, as recited in claim 64, wherein the step (b) further comprises an additional step of diffentially deducing said GPS positioning data through a data link.

71. An interruption free navigator, comprising an IMU Analog Sensor Daughter Board in X Axis, an IMU Analog Sensor Daughter Board in Y Axis, a Main Analog Sensor Board, and a microcontroller based control circuit board, wherein said IMU Analog Sensor Daughter Board in X Axis and said IMU Analog Sensor Daughter Board in Y Axis are inserted on said Main Analog Sensor Board, wherein said Main Analog Sensor Board and said microcontroller based control circuit board are connected by connectors in a parallel manner.

72. The interruption free navigator, as recited in claim 71, wherein said IMU Analog Sensor Daughter Board in X Axis is connected with said Main Analog Sensor Board for producing X axis angular sensing signal and Y axis acceleration sensing signal to said microcontroller based control circuit board, wherein said IMU Analog Sensor Daughter Board in Y Axis is connected with said Main Analog Sensor Board for producing Y axis angular sensing signal and X axis acceleration sensing signal to said based control circuit board, wherein said Main Sensor Board is connected with said microcontroller based control circuit board for producing Z axis angular sensing signal and Z axis acceleration sensing signals to said microcontroller based control circuit board, wherein said microcontroller based control circuit board is connected with said IMU Analog Sensor Daughter Board in X Axis and then said IMU Analog Sensor Daughter Board in Y Axis through said Main Analog Sensor Board for processing said X axis, Y axis and Z axis angular sensing signals and said X axis, Y axis and Z axis acceleration sensing signals from said IMU Analog Sensor Daughter Board in X Axis, said IMU Analog Sensor Daughter Board in Y Axis and said microcontroller based control circuit board to produce digital angular increments and velocity increments, position, velocity, altitude and attitude solution.

73. The interruption free navigator, as recited in claim 72, wherein said Main Analog Sensor Board further comprises an IMU Z axis Gyroscope sensor generating a Z-axis rate Analog Output signal, an IMU X-axis accelerometer sensor and Y-axis accelerometer sensor generating X-axis and Y-axis accelerometer Analog Output signals, and Magnetometer sensors in X-axis, Y-axis and Z-axis generating Analog Output signals of magnetic fields in three directions under control signals of Set and Reset.

74. The interruption free navigator, as recited in claim 73, wherein said IMU Analog Sensor Daughter Board in X Axis comprises an IMU X axis Gyroscope sensor generating an X-axis rate Analog Output signal, an IMU Y-axis accelerometer sensor and Z-axis accelerometer sensor generating Y-axis and Z-axis accelerometer Analog Output signals.

75. The interruption free navigator, as recited in claim 74, wherein said IMU Analog Sensor Daughter Board in Y Axis comprises an IMU Y axis Gyroscope sensor generating a Y-axis rate Analog Output signal, an IMU X-axis accelerometer sensor and Z-axis accelerometer sensor generating X-axis and Z-axis accelerometer Analog Output signals.

76. The interruption free navigator, as recited in claim 75, wherein said microcontroller based control circuit board comprises a microcontroller chip, A/D and RS232 circuits, an interface circuit, and a power circuit, said microcontroller chip processing data that come from sensors and peripherals, said A/D circuit converting analog signals to digital signals, said RS232 circuit being used to communicate with a GPS receiver and any device connected to an IMU, said power circuit providing a power supply for said A/D converter, said RS232 circuit, said microcontroller chip and said sensor, said interface circuit providing an interface between said microcontroller chip and said peripherals.

77. The interruption free navigator, as recited in claim 71, wherein said IMU Analog Sensor Daughter Board in X Axis and said IMU Analog Sensor Daughter Board in Y Axis are assembled on top of said Main Analog Sensor Board in Z axis.

78. The interruption free navigator, as recited in claim 77, wherein said Main Analog Sensor Board in Z axis, said IMU Analog Sensor Daughter Board in Y Axis, and said IMU Analog Sensor Daughter Board in X Axis are assembled in an orthogonal way to achieve three sensing axes of an angular rate producer and an acceleration producer.

79. The interruption free navigator, as recited in claim 78, wherein said microcontroller based control circuit board is assembled under said Main Analog Sensor Board in Z axis while said Main Analog Sensor Board and said microcontroller based control circuit board are connected by said connectors to reduce a quantity of wire.