INTERCEPTOR MISSILE AND METHOD FOR STEERING THE INTERCEPTOR MISSILE

Abstract

A method for steering a steerable interceptor missile driven by an engine for intercepting a moving target during a midcourse phase of an interception, includes steering the missile with real steering commands produced at respective steering times based on free control parameters formed as a current parameter vector. The free control parameters are constantly and repeatedly optimized during the midcourse phase by an optimization method for optimizing the control parameters. The optimization method is carried out in parallel with the actual steering. Newly detected information about the movement of the target and/or information about the flight of the missile is used in the optimization method as soon as the information is available. Optimized control parameters are accepted into the current parameter vector after being provided by the optimization method. An interceptor missile contains the current parameter vector and a control and evaluation unit for carrying out the method.

Claims

1. A method for steering a steerable interceptor missile powered by an engine for intercepting a moving target during a midcourse phase of an interception, the method comprising steps of: steering the interceptor missile by using real steering commands generated at respective steering times based on free control parameters available as a current parameter vector; at least one of constantly or repetitively optimizing the free control parameters in a course of the midcourse phase by using an optimization procedure for optimizing the control parameters; carrying out the optimization procedure in parallel with an actual steering; including at least one of newly detected information about a movement of the target or information about a flight of the interceptor missile in the optimization procedure as soon the information is available; and taking optimized control parameters into the current parameter vector once the optimized control parameters are available from the optimization procedure.

2. The method according to claim 1, which further comprises performing the optimization procedure during the midcourse phase as follows: a) selecting a predeterminable parameter vector as a current candidate of a model predicted control optimization procedure to determine improved control parameters; b) in the model predicted control optimization procedure, determining a set of possible candidates for an improved parameter vector with associated quality values as follows: c1) performing a modified zero effort miss procedure based on the current candidate as follows: d1) making iterative predictions at each step time as follows: d2) a possible interceptor trajectory of the interceptor missile, taking into account virtual steering commands of the interceptor missile based on the current candidate, d3) a possible target trajectory of the target based on hypothetical maneuvers of the target, d4) repeating steps d2) to d3) iteratively until achieving a modified zero effort miss approach of the interceptor trajectory and the target trajectory, c2) based on results of the modified zero effort miss procedure, determining a current quality value based on a quality criterion and assigning the current quality value to the current candidate; c3) successively placing the current candidate in the set as a first or further candidate together with the current quality value as an assigned quality value; c4) upon not yet reaching an end criterion of the optimization: e1) using a model predicted control search procedure to vary the current candidate to a varied candidate, e2) henceforth adopting the varied candidate as the current candidate and continuing the procedure with step c1), c5) upon achieving the end criterion, proceeding with the method as follows: f) returning to step; and during the midcourse phase at predetermined correction times, selecting one of the candidates according to a correction criterion and replacing the current parameter vector with a selected candidate in order to transfer optimized control parameters into the current parameter vector as a result.

3. The method according to claim 2, which further comprises selecting the achievement of the end criterion in step c5) as the correction time, and selecting the candidate from the set to which a best quality value is assigned as the correction criterion.

4. The method according to claim 2, which further comprises selecting step c3) as the correction time, and additionally in step c3) also adopting as the correction criterion the current candidate just stored as a candidate as the current parameter vector when its assigned quality value is a best of all quality values available in the set so far.

5. The method according to claim 2, which further comprises in step e1) carrying out the variation to a varied candidate at least partially based on the candidates so far and the quality values of the candidates.

6. The method according to claim 2, which further comprises including in the quality criterion, at least as a sub criterion, a minimum deviation from the target, a maximum final speed when hitting the target, a minimum remaining flight time to the target, and a desired angle of impact on the target.

7. The method according to claim 2, which further comprises in step a) additionally determining a currently predicted remaining flight time of the interceptor missile until an end of a mission of the interceptor missile.

8. The method according to claim 7, which further comprises using as the current parameter vector a parameter vector for which at least one of the free control parameters is a value oriented to the remaining flight time or a sequence of sub values oriented to the remaining flight time.

9. The method according to claim 8, which further comprises for a variant of the sequence of sub values: in step d2) taking the predicted remaining flight time into account by dividing the predicted remaining flight time into a predetermined number of time periods in the modified zero effort miss procedure, and for each time period taking a respective different one of the sub values into account.

10. The method according to claim 7, which further comprises providing at least one of the values or sub values as an ignition time dependent on the remaining flight time of a respective first or further combustion stage of the engine or engines of the interceptor missile.

11. The method according to claim 7, which further comprises providing at least one of the values or sub values as a thrust control value dependent on the remaining flight time for the engine of the interceptor missile controllable with respect to a thrust of the engine.

12. The method according to claim 7, which further comprises providing at least one of the sub values as a control value dependent on the remaining flight time for a lateral acceleration element of the interceptor missile.

13. The method according to claim 2, which further comprises selecting as the current parameter vector a parameter vector containing at least two trajectory angles for the trajectory of the interceptor missile as two free parameters.

14. The method according to claim 1, which further comprises providing the engine of the interceptor missile as a solid booster or a dual-pulse engine or a steerable engine.

15. An interceptor missile propelled by an engine, steerable by real steering commands, used to intercept a target and containing a current parameter vector of free control parameters for the interceptor missile, the interceptor missile comprising: a control and evaluation unit configured to carry out the method according to claim 1.

Description

BRIEF DESCRIPTION OF THE FIGURE

[0080] The FIGURE of the drawing is a block diagram showing the principle method according to the invention.

DETAILED DESCRIPTION OF THE INVENTION

[0081] Referring now in detail to the single FIGURE of the drawing, there is seen an illustration of a method for steering an interceptor missile 2, which is propelled by an engine 4, in this case controllable in its thrust, and steerable, by controlling tailplanes, in a manner not shown in detail. The steering is carried out by an implementation, which is not explained in detail, of real steering commands 6 in the interceptor missile 2 on the engine 4 and the tailplanes. The interceptor missile 2 is used to intercept a target 8. The method is carried out exclusively in a midcourse phase PM of the flight of the interceptor missile 2, i.e. the interception of the target 8.

[0082] The steering is based on a current parameter vector 10. The parameter vector 10 contains a series, in this case three, of free control parameters SP1-3 for the interceptor missile 2. The control parameters SP1 and SP2 are trajectory angles, the control parameter SP3 is a thrust control value for the engine 4, which includes a total of five sub values SP3a-e. A respective remaining flight time Tgo of the interceptor missile 2 until it hits the target 8 is divided into five equal time periods. In each of these time periods, the engine 4 is controlled sequentially by a corresponding thrust control value SP3a-e.

[0083] At the beginning of the procedure, the launch phase of the interceptor missile 2 has just ended and the midcourse phase PM begins. When entering the midcourse phase PM, a current parameter vector 10 is available. At respective steering times, in this case every 10 ms, a respective real steering command 6 is generated from the parameter vector 10 and the interceptor missile 2 is steered based on these steering commands 6.

[0084] The method begins with a step a) in which a predeterminable parameter vector 15 is selected as the current candidate 12 of an MPC optimization procedure or method 14. In the present case, the demand is generated in such a way that the current parameter vector 10 available from the end of the starting phase is used as a predeterminable parameter vector 15. The MPC optimization procedure or method 14 is used to determine an improved parameter vector to replace the current parameter vector 10.

[0085] Now the MPC optimization procedure 14 begins. Within this procedure (step or loop b)) a set of 16 possible candidates 18a-c is determined, three in this case in the example, each with assigned quality values 20a-c. Each of the candidates 18a-c is a possible parameter vector that could replace the parameter vector 10 if this would promise better mission success than the current actually available parameter vector 10.

[0086] Based on the current candidate 12, a modified ZEM procedure 22 is now carried out in a step c1): In a step or a loop d1) the following steps are performed iteratively at respective step times t1, 2, 3, . . . :

[0087] In a step d2) a possible intercept trajectory 24 of the interceptor missile 2 is predicted. For this purpose, virtual steering commands 7 (corresponding to the real steering commands 6) are determined based on the current candidate 12 at the respective step times t1, 2, 3, . . . , so that respective predicted locations (circles in the figure) of the interceptor missile 2 result. The trajectory 24 results from the temporal or spatial sequence of the locations. In other words, how the interceptor missile 2 would move if the current candidate 12 were to be used as a parameter vector 10 for its steering is simulated iteratively.

[0088] Furthermore, in a step d3) corresponding to the step times t1, 2, 3, . . . locations and thus iteratively a target trajectory 28, i.e. a trajectory of the target 8, are predicted, but in this case taking into account a respective hypothetical flight maneuver 26 of the target 8. For example, it is assumed that the target 8 flies a certain evasive trajectory to be adopted to elude the interceptor missile 2.

[0089] According to a step or a loop d4), steps d2) and d3) are repeated iteratively for as many points in time t1, 2, 3, . . . until a ZEM approach 30 of the interceptor trajectory 24 and the target trajectory 28 is reached. This concludes the ZEM procedure 22.

[0090] The available results 32 of the ZEM method 22 in the example are the achievable ZEM approach 30, an updated remaining flight duration Tgo, the impact velocity and the angle of impact of the interceptor missile 2 on the target 8, etc.

[0091] In a step c2), a current quality value 33 is determined on the basis of these results 32 for the respective candidate 12 and is assigned to it. The assignment is based on a quality criterion 36.

[0092] In a step c3), the current candidate 12 is stored together with its determined property value 33 in the set 16 as a candidate 18a-c with a quality value 20a-c. In the first run, the quality value 20a is assigned to the candidate 18a, in later runs the quality value 20b is assigned to the candidate 18b and stored in the set 16, and so on.

[0093] In a step c4), an end criterion 38 for the optimization procedure 14 is now checked. If this is not achieved, in step e1) the current candidate 12 is varied to a varied candidate 42 using an MPC search method 40. This is adopted as the current candidate 12 in a step e2) and the MPC optimization procedure 14 is started again with the now optimized or modified candidate 12.

[0094] In the example, the optimization procedure 14 is run through three times, so that the result is three candidates 18a-c with assigned quality values 20a-c. Then the end criterion 38 is reached, in this case the fixed number of three procedure runs.

[0095] Since the end criterion 38 has been reached, the procedure returns to step a) to calculate a new set 16.

[0096] The procedure ends or is terminated when the midcourse phase PM is completed.

[0097] During the duration of the procedure, one of the candidates 18a-c is selected at a predetermined correction time TK according to a correction criterion 44 and henceforth used as the current parameter vector 10 for the real steering of the interceptor missile 2. In the example, the correction time TK is the achievement of the end criterion 38. The correction criterion 44 is the selection of the candidate 18a-c from the set 16 to which the best quality value 20a-c in the current set 16 is assigned.

[0098] An alternative possibility is to select step c3) as the correction time TK and (from the second check/determination of the quality value) to make the best of the previously checked candidates 18a-c the parameter vector 10. The best one is the one with a quality value 20b-c better than the quality values 20a-c of the candidates 18a-c previously present in the set 16.

[0099] In the present case, step a) also determines a currently predicted remaining flight time Tgo of the interceptor missile 2 to the target 8 in order to have a time base for the utilization of the control parameters SP3a-e in the step d2). An updated remaining flight time Tgo is also available as part of the results 32 at the end of each run of the ZEM procedure 22 and can be used henceforth.

[0100] The current parameter vector 10 is available in the interceptor missile 2. The interceptor missile 2 also contains a control and evaluation unit 50, in this case a central computer, which is set up to carry out the method according to the invention. The “setting up” is caried out in this case by appropriately powerful hardware and programming for implementation of the method.

[0101] The following is a summary list of reference numerals and the corresponding structure used in the above description of the invention.

REFERENCE SIGN LIST

[0102] 2 Interceptor missile

[0103] 4 Engine

[0104] 6 Steering command (real)

[0105] 7 Steering command (virtual)

[0106] 8 Target

[0107] 10 Parameter vector (current)

[0108] 12 Candidate (current)

[0109] 14 MPC optimization method

[0110] 15 Parameter vector (predefinable)

[0111] 16 Set

[0112] 18a-c Candidate

[0113] 20a-c Quality value

[0114] 22 ZEM procedure

[0115] 24 interceptor trajectory

[0116] 26 Flight maneuver (hypothetical)

[0117] 28 Target trajectory

[0118] 30 ZEM Approach

[0119] 32 Results

[0120] 33 Quality value (current)

[0121] 36 Quality criterion

[0122] 38 End criterion

[0123] 40 MPC search method

[0124] 42 Candidate (varies)

[0125] 44 Correction criterion

[0126] 50 Control and evaluation unit

[0127] SP Control parameter

[0128] Tgo Remaining flight duration

[0129] PM Midcourse Phase

[0130] t1, 2, 3, . . . Step time

[0131] TK Correction time