Determination of guided-munition roll orientation

Patent metadata

Field	Value
Publication number	US-11175115-B2
Application number	US-201716467357-A
Country	US
Kind code	B2
Filing date	Jan 5, 2017
Priority date	Jan 5, 2017
Publication date	Nov 16, 2021
Grant date	Nov 16, 2021

Abstract

Techniques are provided for determination of a guided-munition orientation during flight based on lateral acceleration, velocity, and turn rate of the guided-munition. A methodology implementing the techniques, according to an embodiment, includes obtaining a lateral acceleration vector measurement and a velocity of the guided-munition, and calculating a ratio of the two, to generate an estimated lateral turn vector of the guided-munition. The method also includes integrating the estimated lateral turn vector, over a period of time associated with flight of the guided-munition, to generate a first type of predicted attitude change. The method further includes obtaining and integrating a lateral turn rate vector measurement of the guided-munition, over the period of time associated with flight of the guided-munition, to generate a second type of predicted attitude change. The method further includes calculating a gravity direction vector based on a difference between the first and second types of predicted attitude change.

First claim

What is claimed is:

1. A method for determination of a guided munition roll orientation, the method comprising:
calculating, by a processor-based system, a ratio of a lateral acceleration vector measurement of the guided munition to a velocity of the guided munition, to generate an estimated lateral turn rate vector of the guided munition;
integrating, by the processor-based system, the estimated lateral turn rate vector, over a period of time that is anytime between launch and impact, to generate a first type of predicted attitude change;
obtaining, by the processor-based system, a lateral turn rate vector measurement of the guided munition;
integrating, by the processor-based system, the measured lateral turn rate vector, over the period of time associated with flight of the guided munition, to generate a second type of predicted attitude change;
calculating, by the processor-based system, a gravity direction vector based on a difference between the first type of predicted attitude change and the second type of predicted attitude change; and
providing the gravity direction vector to a guidance and control system of the guided munition for execution of guided munition maneuvers.

2. The method of claim 1 , further comprising calculating a ground-pointing orientation angle based on the gravity direction vector.

3. The method of claim 1 , wherein the lateral acceleration vector measurement is calculated as a vector sum of data provided by a first lateral acceleration sensor and data provided by a second lateral acceleration sensor, the second lateral acceleration sensor orthogonal to the first lateral acceleration sensor; and the lateral turn rate vector measurement is calculated as a vector sum of data provided by a first lateral turn rate sensor and data provided by a second lateral turn rate sensor, the second lateral turn rate sensor orthogonal to the first lateral turn rate sensor.

4. The method of claim 3 , wherein the first lateral turn rate sensor and the second lateral turn rate sensor comprise at least one of a gyroscope and a micro-electrical-mechanical system.

5. The method of claim 1 , wherein the guided munition maneuvers comprise at least one of turning the guided munition towards ground after launch and controlling a terminal flight path angle of the guided munition.

6. The method of claim 1 , wherein the method is carried out on-board the guided munition.

7. A system for determination of a guided munition orientation, the system comprising:
an accelerometer configured to measure a lateral acceleration vector of the guided munition, wherein the accelerometer comprises a first acceleration sensor and a second acceleration sensor, the second acceleration sensor being orthogonal to the first acceleration sensor;
a vector addition circuit configured to calculate the lateral acceleration vector as a sum of data provided by the first acceleration sensor and data provided by the second acceleration sensor;
a vector division circuit configured to calculate a ratio of the lateral acceleration vector measurement to a velocity of the guided munition, to generate an estimated lateral turn rate vector of the guided munition;
a temporal integration circuit configured to integrate the estimated lateral turn rate vector, over a period of time that is anytime between launch and impact, to generate a first type of predicted attitude change;
a lateral turn rate sensor configured to measure a lateral turn rate vector of the guided munition; wherein the lateral turn rate sensor comprises a first turn rate sensor and a second turn rate sensor, the second turn rate sensor orthogonal to the first turn rate sensor; and wherein the vector addition circuit is configured to calculate the lateral turn rate vector as a sum of data provided by the first turn rate sensor and data provided by the second turn rate sensor;
the temporal integration circuit is further configured to integrate the measured lateral turn rate vector, over the period of time associated with flight of the guided munition, to generate a second type of predicted attitude change; and
a vector subtraction circuit configured to calculate a gravity direction vector based on a difference between the first type of predicted attitude change and the second type of predicted attitude change.

8. The system of claim 7 , wherein the first turn rate sensor and the second turn rate sensor comprise at least one of a gyroscope and a micro-electrical-mechanical system.

9. The system of claim 7 , wherein the system is further configured to provide the gravity direction vector to a guidance and control circuit of the guided munition to enable execution of guided munition maneuvers.

10. The system of claim 9 , wherein the guided munition maneuvers comprise at least one of turning the guided munition towards ground after launch and controlling a terminal flight path angle of the guided munition.

11. The system of claim 7 , wherein the system is on-board the guided munition.

12. At least one non-transitory computer readable storage medium having instructions encoded thereon that, when executed by one or more processors, result in the following operations for determination of a guided munition orientation, the operations comprising:
calculating a ratio of a lateral acceleration vector measurement of the guided munition to a velocity of the guided munition, to generate an estimated lateral turn rate vector of the guided munition;
integrating the estimated lateral turn rate vector, over a period of time associated with flight of the guided munition, to generate a first type of predicted attitude change;
obtaining a lateral turn rate vector measurement of the guided munition;
integrating the measured lateral turn rate vector, over the period of time that is anytime between launch and impact, to generate a second type of predicted attitude change; and
calculating a gravity direction vector based on a difference between the first type of predicted attitude change and the second type of predicted attitude change.

13. The computer readable storage medium of claim 12 , the operations further comprising calculating a ground-pointing orientation angle based on the gravity direction vector.

14. The computer readable storage medium of claim 12 , wherein the lateral acceleration vector measurement is calculated as a vector sum of data provided by a first lateral acceleration sensor and data provided by a second lateral acceleration sensor, the second lateral acceleration sensor orthogonal to the first lateral acceleration sensor; and the lateral turn rate vector measurement is calculated as a vector sum of data provided by a first lateral turn rate sensor and data provided by a second lateral turn rate sensor, the second lateral turn rate sensor orthogonal to the first lateral turn rate sensor.

15. The computer readable storage medium of claim 14 , wherein the first lateral turn rate sensor and the second lateral turn rate sensor comprise at least one of a gyroscope and a micro-electrical-mechanical system.

16. The computer readable storage medium of claim 12 , the operations further comprising providing the gravity direction vector to guidance and control circuitry of the guided munition for execution of guided munition maneuvers, wherein the guided munition maneuvers comprise at least one of turning the guided munition towards ground after launch and controlling a terminal flight path angle of the guided munition.

17. The computer readable storage medium of claim 12 , wherein the computer readable storage medium is on-board the guided munition.

Assignees

• Bae Sys Inf & Elect Sys Integ

Inventors

• Schorr David J
• Batchelder Jason H
• Gibson Jeremy B
• Steenson Jr James H
• Vasile Joseph D

Classifications

• G01C21/185

  for gravity · CPC title

• G05D2109/28

  Missiles · CPC title

• G05D2105/35

  for combat · CPC title

• G05D1/49

  Control of attitude, i.e. control of roll, pitch or yaw · CPC title

• F42B15/01 Primary

  Arrangements thereon for guidance or control ({steering arrangements F42B10/60}; aircraft flight control B64C; guidance systems other than those installed aboard F41G7/00, F41G9/00; locating by use of radio or other waves G01S; flight control in general G05D1/00; computer aspects G06]) · CPC title