Attitude angle detecting apparatus

• US 6,792,380 B2
• Filed: 02/03/2003
• Issued: 09/14/2004
• Est. Priority Date: 02/12/2002
• Status: Active Grant

• Current Assignee: Furuno Electric Co, Ltd
• Original Assignee: Furuno Electric Co, Ltd
• Inventors: Toda, Hiroyuki
• Primary Examiner(s): Barlow, John
• Assistant Examiner(s): Sun, Xiuqin
• Application Number:
  US10/356,614
• Publication Number:
  US 20030154049A1
• Time in Patent Office: 589 Days
• Field of Search: 702/151, 702/146, 342/357.11, 342/357.06, 701/214, 701/215, 340/937, 362/37, 356/602, 180/168
• US Class Current: 702/151
• CPC Class Codes: G01S 19/55 Carrier phase ambiguity resolution; Floating ambiguity; LAMBDA [Least-squares AMBiguity Decorrelation Adjustment] method

Abstract

An attitude angle detecting apparatus receives radio waves transmitted from a plurality of position-fixing satellites with multiple antennas located at specific positions of a mobile unit, determines relative positions of the antennas and detects the heading and attitude of the mobile unit by determining carrier phase ambiguities quickly and accurately. When it is needed to redetermine integer ambiguities after recovery from an interruption of the radio waves from the position-fixing satellites or as a result of a change in combination of the position-fixing satellites, for example, the attitude angle detecting apparatus redetermines the integer ambiguities by using attitude angles and an attitude angle error covariance obtained from previous observation. This enables the attitude angle detecting apparatus to uninterruptedly obtain information on the heading and attitude of the mobile unit.

Claims

1. An attitude angle detecting apparatus which receives radio waves from a plurality of position-fixing satellites by means of at least two antennas mounted on a mobile unit, one of the antennas being used as a reference antenna, determines the relative position of the antenna other than the reference antenna with respect to the reference antenna, and determines the heading and attitude of the mobile unit from said relative position of the antenna, said attitude angle detecting apparatus comprising:

means for observing a single phase difference or a double phase difference and determining an integer ambiguity from the single or double phase difference;

means for calculating said relative position from the phase difference of which integer ambiguity has been determined;

means for calculating attitude angles of the mobile unit and error covariance of the attitude angles; and

integer ambiguity redetermination means for calculating at least one integer ambiguity candidate from the single phase difference for each of the position-fixing satellites or from the double phase difference for each pair of the position-fixing satellites based on the attitude angles and the error covariance of the attitude angles and redetermining the integer ambiguity from the integer ambiguity candidate.

2. The attitude angle detecting apparatus according to claim 1, wherein said means for calculating the attitude angles of the mobile unit and the error covariance of the attitude angles includes an angular velocity sensor and means for calculating the attitude angles from an output of said angular velocity sensor.

3. The attitude angle detecting apparatus according to claim 2, wherein said integer ambiguity redetermination means includes means for calculating floating ambiguities and an error covariance of the floating ambiguities.

4. The attitude angle detecting apparatus according to claim 2, wherein said integer ambiguity redetermination means includes means for determining the integer ambiguity candidate by the LAMBDA method.

5. The attitude angle detecting apparatus according to claim 1, wherein said means for calculating the attitude angles of the mobile unit and the error covariance of the attitude angles includes means for predicting the attitude angles and the error covariance of the attitude angles based on an assumed model depending on conditions of the mobile unit.

6. The attitude angle detecting apparatus according to claim 5, wherein said integer ambiguity redetermination means includes means for calculating floating ambiguities and an error covariance of the floating ambiguities.

7. The attitude angle detecting apparatus according to claim 5, wherein said integer ambiguity redetermination means includes means for determining the integer ambiguity candidate by the LAMBDA method.

8. The attitude angle detecting apparatus according to claim 1, wherein said integer ambiguity redetermination means includes means for calculating floating ambiguities and an error covariance of the floating ambiguities.

9. The attitude angle detecting apparatus according to claim 1, wherein said integer ambiguity redetermination means includes means for determining the integer ambiguity candidate by the LAMBDA method.

15. The attitude angle detecting apparatus according to claim 1 or 10, wherein said attitude angle detecting apparatus uses both said means for determining the integer ambiguity from the attitude angles and the error covariance of the attitude angles and said means for determining the integer ambiguity from the single or double phase difference, or selectively uses one of these means, in redetermining the integer ambiguity.

16. The attitude angle detecting apparatus according to claim 15 wherein said means for calculating the attitude angles of the mobile unit and the error covariance of the attitude angles includes an angular velocity sensor and means for calculating the attitude angles from an output of said angular velocity sensor.

17. The attitude angle detecting apparatus according to claim 15, wherein said means for calculating the attitude angles of the mobile unit and the error covariance of the attitude angles includes means for predicting the attitude angles and the error covariance of the attitude angles based on an assumed model depending on conditions of the mobile unit.

18. The attitude angle detecting apparatus according to claim 15, wherein said integer ambiguity redetermination means includes means for calculating floating ambiguities and an error covariance of the floating ambiguities.

19. The attitude angle detecting apparatus according to claim 15, wherein said integer ambiguity redetermination means includes means for determining the integer ambiguity candidate by the LAMBDA method.

10. An attitude angle detecting apparatus which receives radio waves from a plurality of position-fixing satellites by means of at least two antennas mounted on a mobile unit, one of the antennas being used as a reference antenna, determines the relative position of the antenna other than the reference antenna with respect to the reference antenna, and determines the heading and attitude of the mobile unit from said relative position of the antenna, said attitude angle detecting apparatus comprising:

means for observing a single phase difference or a double phase difference and determining an integer ambiguity from the single or double phase difference;

means for calculating said relative position from the phase difference of which integer ambiguity has been determined;

means for calculating attitude angles of the mobile unit and error covariance of the attitude angles and correcting the error covariance of the attitude angles; and

integer ambiguity redetermination means for calculating at least one integer ambiguity candidate from the single phase difference for each of the position-fixing satellites or from the double phase difference for each pair of the position-fixing satellites based on the attitude angles and the corrected error covariance of the attitude angles and redetermining the integer ambiguity from the integer ambiguity candidate.

11. The attitude angle detecting apparatus according to claim 10 wherein said means for calculating the attitude angles of the mobile unit and the error covariance of the attitude angles includes an angular velocity sensor and means for calculating the attitude angles from an output of said angular velocity sensor.

12. The attitude angle detecting apparatus according to claim 10, wherein said means for calculating the attitude angles of the mobile unit and the error covariance of the attitude angles includes means for predicting the attitude angles and the error covariance of the attitude angles based on an assumed model depending on conditions of the mobile unit.

13. The attitude angle detecting apparatus according to claim 10, wherein said integer ambiguity redetermination means includes means for calculating floating ambiguities and an error covariance of the floating ambiguities.

14. The attitude angle detecting apparatus according to claim 10, wherein said integer ambiguity redetermination means includes means for determining the integer ambiguity candidate by the LAMBDA method.