Digital sight for hand-carried projectile-firing device and method of controlling the same

• US 10,222,214 B2
• Filed: 11/13/2014
• Issued: 03/05/2019
• Est. Priority Date: 11/05/2014
• Status: Active Grant

• Current Assignee: Agency For Defense Development (Government of The Republic of China)
• Original Assignee: Agency For Defense Development (Government of The Republic of China)
• Inventors: Lee, Tae-Gyoo, Jang, Suk-Won, Lee, Jin-Seung, Choi, Jae-Gun, Moon, Hong-Key
• Primary Examiner(s): Lee, Benjamin P
• Application Number:
  US15/506,219
• Publication Number:
  US 20180216938A1
• Time in Patent Office: 1,573 Days
• CPC Class Codes: F41F 1/06 Mortars base plates therefor F41A23/54
• CPC Class Codes: F41G 1/46 for particular applications
• CPC Class Codes: F41G 1/50 for trench mortars or for other mortars
• CPC Class Codes: F41G 11/00 Details of sighting or aiming apparatus; Accessories tools for adjustment of sights F41G1/545
• CPC Class Codes: F41G 11/004 Mountings with clamping means on the device embracing at least a part of the firearm, e.g. the receiver or a dustcover F41G11/003 takes precedence
• CPC Class Codes: F41G 3/02 using an independent line of sight
• CPC Class Codes: F41G 3/16 Sighting devices adapted for indirect laying of fire
• CPC Class Codes: F41G 7/36 using inertial references
• CPC Class Codes: G01C 17/00 Compasses; Devices for ascertaining true or magnetic north for navigation or surveying purposes using gyroscopic effect G01C19/00
• CPC Class Codes: G01C 19/38 with north-seeking action by other than magnetic means, e.g. gyrocompasses using earth's rotation
• CPC Class Codes: G01C 21/1654 with electromagnetic compass
• CPC Class Codes: G01P 15/14 by making use of gyroscopes gyroscopes per se G01C19/00

Abstract

The present invention relates to a digital sight for a hand-carried projectile-firing device and a method of controlling the digital sight. A digital sight for a hand-carried projectile-firing device according to an embodiment of the present invention is a digital sight for a hand-carried projectile-firing device, the digital sight including an inertial sensor package and a manual rotation device, wherein the inertial sensor package includes a gyroscope and an accelerometer module. In accordance with the present invention, equipment for measuring the firing direction of a hand-carried projectile-firing device such as a mortar is replaced with a digital sight for a hand-carried projectile-firing device, which reduces an estimation error while using a single medium-low level gyroscope, thus enabling the projectile-firing device to precisely and promptly fire a projectile and improving the operability thereof.

Claims

1. A method of controlling a digital sight for a hand-carried projectile-firing device, comprising:

an aligning step (S100) of, by using a vertical accelerometer and a horizontal accelerometer, performing horizontal alignment and then aligning a gyroscope measurement axis with a firing direction;

a step (S200) of, after the aligning step (S100), acquiring a first approximate azimuth angle from auxiliary information;

a step (S300) of, after the step (S200) of acquiring the first approximate azimuth angle, calculating a second approximate azimuth angle; and

a step (S400) of, after the step (S300) of calculating the second approximate azimuth angle, calculating a first precise azimuth angle,

wherein the step (S300) of calculating the second approximate azimuth angle comprises;

a determining step (S310) of determining availability of the first approximate azimuth angle acquired at the step (S200) of acquiring the first approximate azimuth angle;

a first rotation step (S320) of, if it is determined at the determining step (S310) that the first approximate azimuth angle is available, rotating the gyroscope measurement axis so that the gyroscope measurement axis is coincident with a due east direction with respect to the first approximate azimuth angle;

a first average acquisition step (S330) of, after the first rotation step (S320), acquiring a first average (Ω

₁) of gyroscope measurement values of the digital sight for the hand-carried projectile-firing device for a preset first time period (T₁);

a second rotation step (S340) of, after the first average acquisition step (S330), rotating the gyroscope measurement axis at an angle of 180°

;

a second average acquisition step (S350) of, after the second rotation step (S340), acquiring a second average (Ω

₂) of gyroscope measurement values of the digital sight for the hand-carried projectile-firing device for the preset first time period (T₁);

an approximate bias calculation step (S360) of calculating an approximate bias from the first average (Ω

₁) and the second average (Ω

₂);

a step (S370) of, after the approximate bias calculation step (S360), determining whether latitude information at a current position is retained; and

a step (S380) of, if it is determined at the step (S370) that the latitude information at the current position is retained, calculating the second approximate azimuth angle from the first average (Ω

₁) and the second average (Ω

₂).

2. The method of claim 1, wherein the second approximate azimuth angle is used as the auxiliary information at the step (S200) of acquiring the first approximate azimuth angle.

3. The method of claim 1, wherein the step (S400) of calculating the first precise azimuth angle comprises:

a step (S410) of determining availability of the second approximate azimuth angle;

a third average acquisition step (S420) of, if it is determined that the second approximate azimuth angle is available, acquiring a third average (Ω

₃) of gyroscope measurement values of the digital sight for the hand-carried projectile-firing device for a preset second time period (T₂);

a third rotation step (S430) of, after the third average acquisition step (S420), rotating the gyroscope measurement axis at an angle of 180°

;

a fourth average acquisition step (S440) of, after the third rotation step (S430), acquiring a fourth average (Ω

₄) of gyroscope measurement values of the digital sight for the hand-carried projectile-firing device for the preset second time period (T₂);

a step (S450) of calculating a first precise bias from the third average (Ω

₃) and the fourth average (Ω

₄); and

a step (S460) of calculating the first precise azimuth angle from the third average (Ω

₃) and the fourth average (Ω

₄).

4. The method of claim 3, wherein the first precise azimuth angle is used as the auxiliary information at the step (S200) of acquiring the first approximate azimuth angle.

5. The method of claim 3, further comprising:

if it is determined that the second approximate azimuth angle is not available, a step (S470) of determining whether the second approximate azimuth angle falls within a range from 45°

to 135°

when the gyroscope measurement axis is rotated at an angle of 90°

or −

90°

; and

a fourth rotation step (S480) of rotating the gyroscope measurement axis at an angle of 90°

or −

90°

if it is determined at the step S470 that the second approximate azimuth angle falls within the range from 45°

to 135°

when the gyroscope measurement axis is rotated at the angle of 90°

or −

90°

,

wherein, after the fourth rotation step (S480), the third average acquisition step (S420) of acquiring the third average is performed.

6. The method of claim 5, further comprising:

a step (S500) of calculating a second precise azimuth angle if it is determined at the step (S470) that the second approximate azimuth angle does not fall within the range from 45°

to 135°

when the gyroscope measurement axis is rotated at the angle of 90°

or −

90°

.

7. The method of claim 6, wherein the second precise azimuth angle is used as the auxiliary information at the step (S200) of acquiring the first approximate azimuth angle.

8. The method of claim 6, wherein the step (S500) of calculating the second precise azimuth angle comprises:

a fifth average acquisition step (S510) of acquiring a fifth average (Ω

₂′

) of gyroscope measurement values of the digital sight for the hand-carried projectile-firing device for the preset second time period (T₂);

a fifth rotation step (S520) of, after the fifth average acquisition step (S510), rotating the gyroscope measurement axis at an angle of 90°

;

a sixth average acquisition step (S530) of, after the fifth rotation step (S520), acquiring a sixth average (Ω

₃′

) of gyroscope measurement values of the digital sight for the hand-carried projectile-firing device for the preset second time period (T₂);

a step (S540) of calculating a second precise bias from the fifth average(Ω

₂′

) and the sixth average (Ω

₃′

); and

a step (S550) of calculating the second precise azimuth angle from the fifth average (Ω

₂′

) and the sixth average (Ω

₃′

).

9. The method of claim 8, wherein the step (S500) of calculating the second precise azimuth angle is performed even if it is determined at the step (S370) that the latitude information at the current location is not retained.

10. A method of controlling a digital sight for a hand-carried projectile-firing device, comprising:

an aligning step (S100) of, by using a vertical accelerometer and a horizontal accelerometer, performing horizontal alignment and then aligning a gyroscope measurement axis with a firing direction;

a step (S200) of, after the aligning step (S100), acquiring a first approximate azimuth angle from auxiliary information;

a step (S300) of, after the step (S200) of acquiring the first approximate azimuth angle, calculating a second approximate azimuth angle; and

a step (S400) of, after the step (S300) of calculating the second approximate azimuth angle, calculating a first precise azimuth angle,

wherein the step (S300) of calculating the second approximate azimuth angle comprises;

a determining step (S310) of determining availability of the first approximate azimuth angle acquired at the step (S200) of acquiring the first approximate azimuth angle;

a first average acquisition step (S330) of acquiring a first average (Ω

₁) of gyroscope measurement values of the digital sight for the hand-carried projectile-firing device for a preset first time period (T₁);

a second average acquisition step (S350) of acquiring a second average (Ω

₂) of gyroscope measurement values of the digital sight for the hand-carried projectile-firing device for the preset first time period (T₁),

wherein the step (S400) of calculating the first precise azimuth angle comprises;

a step (S410) of determining availability of the second approximate azimuth angle;

a third average acquisition step (S420) of, if it is determined that the second approximate azimuth angle is available, acquiring a third average (Ω

₃) of gyroscope measurement values of the digital sight for the hand-carried projectile-firing device for a preset second time period (T₂);

a third rotation step (S430) of, after the third average acquisition step (S420), rotating the gyroscope measurement axis at an angle of 180°

;

a fourth average acquisition step (S440) of, after the third rotation step (S430), acquiring a fourth average (Ω

₄) of gyroscope measurement values of the digital sight for the hand-carried projectile-firing device for the preset second time period (T₂);

a step (S450) of calculating a first precise bias from the third average (Ω

₃) and the fourth average (Ω

₄); and

a step (S460) of calculating the first precise azimuth angle from the third average (Ω

₃) and the fourth average (Ω

₄).

11. The method of claim 10, further comprising:

if it is determined that the second approximate azimuth angle is not available, a step (S470) of determining whether the second approximate azimuth angle falls within a range from 45°

to 135°

when the gyroscope measurement axis is rotated at an angle of 90°

or −

90°

; and

a fourth rotation step (S480) of rotating the gyroscope measurement axis at an angle of 90°

or −

90°

if it is determined at the step S470 that the second approximate azimuth angle falls within the range from 45°

to 135°

when the gyroscope measurement axis is rotated at the angle of 90°

or −

90°

,

wherein, after the fourth rotation step (S480), the third average acquisition step (S420) of acquiring the third average is performed.

12. The method of claim 10, wherein the first precise azimuth angle is used as the auxiliary information at the step (S200) of acquiring the first approximate azimuth angle.

13. The method of claim 11, further comprising:

a step (S500) of calculating a second precise azimuth angle if it is determined at the step (S470) that the second approximate azimuth angle does not fall within the range from 45°

to 135°

when the gyroscope measurement axis is rotated at the angle of 90°

or −

90°

.

14. The method of claim 13, wherein the second precise azimuth angle is used as the auxiliary information at the step (S200) of acquiring the first approximate azimuth angle.

15. The method of claim 13, wherein the step (S500) of calculating the second precise azimuth angle comprises:

a fifth average acquisition step (S510) of acquiring a fifth average (Ω

₂′

) of gyroscope measurement values of the digital sight for the hand-carried projectile-firing device for the preset second time period (T₂);

a fifth rotation step (S520) of, after the fifth average acquisition step (S510), rotating the gyroscope measurement axis at an angle of 90°

;

a sixth average acquisition step (S530) of, after the fifth rotation step (S520), acquiring a sixth average (Ω

₃′

) of gyroscope measurement values of the digital sight for the hand-carried projectile-firing device for the preset second time period (T₂);

a step (S540) of calculating a second precise bias from the fifth average (Ω

₂′

) and the sixth average (Ω

₃′

); and

a step (S550) of calculating the second precise azimuth angle from the fifth average(Ω

₂′

) and the sixth average (Ω

₃′

).

16. The method of claim 15, wherein the step (S500) of calculating the second precise azimuth angle is performed even if it is determined at the step (S370) that the latitude information at the current location is not retained.