Ballistic guidance system

Patent metadata

Field	Value
Publication number	US-12050085-B2
Application number	US-202218080052-A
Country	US
Kind code	B2
Filing date	Dec 13, 2022
Priority date	Dec 13, 2022
Publication date	Jul 30, 2024
Grant date	Jul 30, 2024

Abstract

Techniques are provided for guiding a projectile. A methodology implementing the techniques according to an embodiment includes generating a roll command based on a roll angle obtained from a steering map that causes a change in range and cross range of the projectile that results in a ground motion closest to a desired ground motion. The method also includes calculating a remaining maximum maneuver distance for the projectile, over a time period extending from the current time of flight to the end of flight. The calculation is based on integration a series of maximum maneuvers, obtained from the steering map, at time intervals within the time period. The method further includes generating a lift command for the projectile based on: distance between the target location and an impact point prediction (IPP) calculated at the current time of flight; an error estimate of the IPP; and the remaining maximum maneuver distance.

First claim

What is claimed is:

1. A projectile guidance controller comprising:
a roll angle calculation circuit configured to generate a roll command to control roll canards of the projectile based on a roll angle, obtained from a steering map, that cause a change in range of the projectile and a change in cross range of the projectile that results in a ground motion of the projectile, at a current time of flight, that is closest to a desired ground motion, relative to other roll angle entries in the steering map;
a maneuver distance calculation circuit coupled to an output of the roll angle calculation circuit and configured to calculate a remaining maximum maneuver distance for the projectile, over a time period extending from the current time of flight to an ending time of flight, the calculation based on an integration of a series of maximum maneuvers, each of the maximum maneuvers obtained from the steering map, at a time interval within the time period; and
a lift calculation circuit coupled to an output of the maneuver distance calculation circuit and configured to generate a lift command to control lift canards of the projectile based on one or more of (a) a distance between a target location and an impact point prediction (IPP) of the projectile calculated at the current time of flight, (b) an estimate of error in the IPP, and (c) the remaining maximum maneuver distance.

2. The projectile guidance controller of claim 1 , wherein the roll angle calculation circuit is configured to:
calculate a range error and a cross range error based on a difference between the target location and the IPP of the projectile calculated at the current time of flight; and
determine the desired ground motion of the projectile based on the range error and the cross range error.

3. The projectile guidance controller of claim 1 , wherein the estimate of error in the IPP comprises an estimate of range error in the IPP and an estimate of cross range error in the IPP, wherein the estimate of range error in the IPP is proportional, by a first scale factor, to a calculated range to the target, and the estimate of cross range error in the IPP is proportional, by a second scale factor, to the calculated range to the target.

4. The projectile guidance controller of claim 1 , wherein the lift calculation circuit is configured to calculate the lift command as a product of a maximum lift deflection of the projectile and a scale factor, the scale factor set to the minimum of one and the square of the ratio of (1) the distance between the target location and the IPP of the projectile calculated at the current time of flight and (2) the estimate of error in the IPP.

5. The projectile guidance controller of claim 4 , wherein the scale factor is set to one if the distance between the target location and the IPP of the projectile calculated at the current time of flight is greater than the remaining maximum maneuver distance.

6. The projectile guidance controller of claim 1 , wherein the lift command is set to zero if the ground motion of the projectile associated with the roll angle obtained from the steering map differs from the desired ground motion by more than a threshold value, the threshold value in the range of 10 to 20 degrees.

7. The projectile guidance controller of claim 1 , wherein the steering map provides a maximum change in range of the projectile and a maximum change in cross range of the projectile at a given time of flight of the projectile and a given roll angle of the projectile.

8. A computer program product including one or more machine-readable mediums encoded with instructions that when executed by one or more processors cause a process to be carried out for guiding a projectile, the process comprising:
generating a roll command to control roll canards of the projectile based on a roll angle, obtained from a steering map, that cause a change in range of the projectile and a change in cross range of the projectile that results in a ground motion of the projectile, at a current time of flight, that is closest to a desired ground motion, relative to other roll angle entries in the steering map;
calculating a remaining maximum maneuver distance for the projectile, over a time period extending from the current time of flight to an ending time of flight, the calculation based on an integration of a series of maximum maneuvers, each of the maximum maneuvers obtained from the steering map, at a time interval within the time period; and
generating a lift command to control lift canards of the projectile based on one or more of (a) a distance between a target location and an impact point prediction (IPP) of the projectile calculated at the current time of flight, (b) an estimate of error in the IPP, and (c) the remaining maximum maneuver distance.

9. The computer program product of claim 8 , wherein the process further comprises:
calculating a range error and a cross range error based on a difference between the target location and the IPP of the projectile calculated at the current time of flight; and
determining the desired ground motion of the projectile based on the range error and the cross range error.

10. The computer program product of claim 8 , wherein the estimate of error in the IPP comprises an estimate of range error in the IPP and an estimate of cross range error in the IPP, wherein the estimate of range error in the IPP is proportional, by a first scale factor, to a calculated range to the target, and the estimate of cross range error in the IPP is proportional, by a second scale factor, to the calculated range to the target.

11. The computer program product of claim 8 , wherein the process further comprises calculating the lift command as a product of a maximum lift deflection of the projectile and a scale factor, the scale factor set to the minimum of one and the square of the ratio of (1) the distance between the target location and the IPP of the projectile calculated at the current time of flight and (2) the estimate of error in the IPP.

12. The computer program product of claim 11 , wherein the scale factor is set to one if the distance between the target location and the IPP of the projectile calculated at the current time of flight is greater than the remaining maximum maneuver distance.

13. The computer program product of claim 8 , wherein the lift command is set to zero if the ground motion of the projectile associated with the roll angle obtained from the steering map differs from the desired ground motion by more than a threshold value, the threshold value in the range of 10 to 20 degrees.

14. The computer program product of claim 8 , wherein the steering map provides a maximum change in range of the projectile and a maximum change in cross range of the projectile at a given time of flight of the projectile and a given roll angle of the projectile.

15. A method for guiding a projectile, the method comprising:
generating, by a processor based system, a roll command to control roll canards of the projectile based on a roll angle, obtained from a steering map, that cause a change in range of the projectile and a change in cross range of the projectile that results in a ground motion of the projectile, at a current time of flight, that is closest to a desired ground motion, relative to other roll angle entries in the steering map;
calculating, by the processor based system, a remaining maximum maneuver distance for the projectile, over a time period extending from the current time of flight to an ending time of flight, the calculation based on an integration of a series of maximum maneuvers, each of the maximum maneuvers obtain

Assignees

• Bae Sys Inf & Elect Sys Integ

Inventors

• Zemany Paul D

Classifications

• F41G7/34 Primary

  based on predetermined target position data · CPC title

• F42B10/64 Primary

  of fins · CPC title

• F41G7/346

  using global navigation satellite systems, e.g. GPS, GALILEO, GLONASS · CPC title

• F42B15/01

  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