Method and device for calculating velocity

Patent metadata

Field	Value
Publication number	US-10101355-B2
Application number	US-201414781895-A
Country	US
Kind code	B2
Filing date	Mar 11, 2014
Priority date	Apr 12, 2013
Publication date	Oct 16, 2018
Grant date	Oct 16, 2018

Abstract

A velocity calculating device is provided, which can accurately calculate a moving velocity of a movable body without depending on signals obtained externally. A navigation device includes an acceleration acquiring module, an angular velocity acquiring module, a time difference detecting module, and a velocity calculating module. The acceleration acquiring module acquires the vertical acceleration of one of the axle of the front wheels and the axle of the rear wheels. The angular velocity acquiring module acquires a pitch angular velocity of the automobile. The time difference detecting module detects a time difference between the acceleration in the vertical directions and the pitch angular velocity. The velocity calculating module calculates a moving velocity of the automobile based on a rate of a wheelbase with respect to the time difference.

First claim

The invention claimed is:

1. A velocity calculating device to be mounted on a movable body having at least a front wheel and a rear wheel and for moving on a traveling surface, comprising:
processing circuitry;
an acceleration sensor operatively coupled to the processing circuitry and configured to sense an acceleration of an axle of one of the front and rear wheels in vertical directions of the movable body; and
an angular velocity sensor operatively coupled to the processing circuitry and configured to sense a pitch angular velocity of the movable body, wherein
the processing circuitry is configured:
to acquire the acceleration of the axle of one of the front and rear wheels in the vertical directions of the movable body;
to acquire the pitch angular velocity of the movable body;
to detect a time difference between the acceleration in the vertical directions and the pitch angular velocity; and
to calculate a moving velocity of the movable body based on a ratio of a wheelbase with respect to the time difference, the wheelbase being a distance between the axle of the front wheel and the axle of the rear wheel,

wherein the processing circuitry includes a high-pass filter and a low-pass filter configured to remove components of the acceleration in the vertical directions and the pitch angular velocity with frequencies outside a range from 1 Hz to 2 Hz; and
wherein the acceleration sensor and the angular velocity sensor are incorporated within the velocity calculating device.

2. The velocity calculating device of claim 1 , comprising:
a case configured to accommodate the acceleration sensor, the angular velocity sensor, and the processing circuitry,
wherein the processing circuitry is further configured to:
acquire the acceleration in the vertical directions based on an output of the acceleration sensor, and
acquire the pitch angular velocity based on an output of the angular velocity sensor.

3. The velocity calculating device of claim 2 , wherein the processing circuitry is further configured:
to acquire GNSS signals received from GNSS satellites;
to perform positioning of a current position of the movable body based on the GNSS signals in a case where the GNSS signals are successfully and appropriately received; and
to calculate the current position based on the moving velocity, in a case where the GNSS signals are not successfully and appropriately received.

4. The velocity calculating device of claim 3 ,
wherein the processing circuitry is further configured:
to calculate the wheelbase based on the moving velocity and the time difference, and
to calculate the moving velocity of the movable body based on the ratio of the wheelbase with respect to the time difference.

5. The velocity calculating device of claim 4 , wherein the processing circuitry is further configured:
to acquire an acceleration of the movable body in longitudinal directions thereof, and
calculate the moving velocity of the movable body based on the ratio of the wheelbase with respect to the time difference, and the acceleration in the longitudinal directions.

6. The velocity calculating device of claim 5 , wherein the processing circuitry is configured to obtain the time difference based on a difference between a timing at which the acceleration in the vertical directions reaches an extremum and a timing at which the pitch angular velocity reaches an extremum.

7. The velocity calculating device of claim 4 , wherein the processing circuitry is configured to obtain the time difference based on a difference between a timing at which the acceleration in the vertical directions reaches an extremum and a timing at which the pitch angular velocity reaches an extremum.

8. The velocity calculating device of claim 3 , wherein the processing circuitry is further configured:
to acquire an acceleration of the movable body in longitudinal directions thereof, and
to calculate the moving velocity of the movable body based on the ratio of the wheelbase with respect to the time difference, and the acceleration in the longitudinal directions.

9. The velocity calculating device of claim 2 , wherein the processing circuitry is further configured:
to acquire an acceleration of the movable body in longitudinal directions thereof, and
to calculate the moving velocity of the movable body based on the ratio of the wheelbase with respect to the time difference, and the acceleration in the longitudinal directions.

10. The velocity calculating device of claim 2 , wherein the processing circuitry is further configured to obtain the time difference based on a difference between a timing at which the acceleration in the vertical directions reaches an extremum and a timing at which the pitch angular velocity reaches an extremum.

11. The velocity calculating device of claim 1 , wherein the processing circuitry is further configured:
to acquire GNSS signals received from GNSS satellites;
to perform positioning of a current position of the movable body based on the GNSS signals in a case where the GNSS signals are successfully and appropriately received; and
to calculate the current position based on the moving velocity, in a case where the GNSS signals are not successfully and appropriately received.

12. The velocity calculating device of claim 11 ,
wherein the processing circuitry is further configured:
to calculate the wheelbase based on the moving velocity and the time difference, and
to calculate the moving velocity of the movable body based on the ratio of the wheelbase with respect to the time difference.

13. The velocity calculating device of claim 12 , wherein the processing circuitry is further configured:
to acquire an acceleration of the movable body in longitudinal directions thereof, and
to calculate the moving velocity of the movable body based on the ratio of the wheelbase with respect to the time difference, and the acceleration in the longitudinal directions.

14. The velocity calculating device of claim 12 , wherein the processing circuitry is further configured to obtain the time difference based on a difference between a timing at which the acceleration in the vertical directions reaches an extremum and a timing at which the pitch angular velocity reaches an extremum.

15. The velocity calculating device of claim 11 , wherein the processing circuitry is further configured:
to acquire an acceleration of the movable body in longitudinal directions thereof, and
to calculate the moving velocity of the movable body based on the ratio of the wheelbase with respect to the time difference, and the acceleration in the longitudinal directions.

16. The velocity calculating device of claim 11 , wherein the processing circuitry is further configured to obtain the time difference based on a difference between a timing at which the acceleration in the vertical directions reaches an extremum and a timing at which the pitch angular velocity reaches an extremum.

17. The velocity calculating device of claim 1 , wherein the processing circuitry is further configured:
to acquire an acceleration of the movable body in longitudinal directions thereof, and
to calculate the moving velocity of the movable body based on the ratio of the wheelbase with respect to the time difference, and the acceleration in the longitudinal directions.

18. The velocity calculating device of claim 17 , wherein the processing circuitry is further configured to obtain the time difference based on a difference between a timing at which the acceleration in the vertical directions reaches an ex

Assignees

• Furuno Electric Co

Inventors

• Takayama Youji
• Toda Hiroyuki

Classifications

• G01C21/00

  Navigation; Navigational instruments not provided for in groups G01C1/00 - G01C19/00 (measuring distance traversed on the ground by a vehicle G01C22/00; control of position, course, altitude or attitude of vehicles G05D1/00; traffic control systems for road vehicles involving transmission of navigation instructions to the vehicle G08G1/0968) · CPC title

• G01P3/00 Primary

  Measuring linear or angular speed; Measuring differences of linear or angular speeds (G01P5/00 - G01P11/00 take precedence; {direction and speed indication G01P13/045}; counting mechanisms G06M) · CPC title

• G01P3/803

  in devices of the type to be classified in G01P3/66 · CPC title

• G01P3/66 Primary

  using electric or magnetic means (G01P3/80 takes precedence; measuring short time intervals G04F8/00, G04F10/00) · CPC title