Patent ID: 12228383

DETAILED DESCRIPTION OF THE INVENTION

Referring now in detail to the single FIGURE of the drawing, there is seen an illustration of a method for steering an interceptor missile2, which is propelled by an engine4, 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 commands6in the interceptor missile2on the engine4and the tailplanes. The interceptor missile2is used to intercept a target8. The method is carried out exclusively in a midcourse phase PM of the flight of the interceptor missile2, i.e. the interception of the target8.

The steering is based on a current parameter vector10. The parameter vector10contains a series, in this case three, of free control parameters SP1-3for the interceptor missile2. The control parameters SP1and SP2are trajectory angles, the control parameter SP3is a thrust control value for the engine4, which includes a total of five sub values SP3a-e. A respective remaining flight time Tgo of the interceptor missile2until it hits the target8is divided into five equal time periods. In each of these time periods, the engine4is controlled sequentially by a corresponding thrust control value SP3a-e.

At the beginning of the procedure, the launch phase of the interceptor missile2has just ended and the midcourse phase PM begins. When entering the midcourse phase PM, a current parameter vector10is available. At respective steering times, in this case every 10 ms, a respective real steering command6is generated from the parameter vector10and the interceptor missile2is steered based on these steering commands6.

The method begins with a step a) in which a predeterminable parameter vector15is selected as the current candidate12of an MPC optimization procedure or method14. In the present case, the demand is generated in such a way that the current parameter vector10available from the end of the starting phase is used as a predeterminable parameter vector15. The MPC optimization procedure or method14is used to determine an improved parameter vector to replace the current parameter vector10.

Now the MPC optimization procedure14begins. Within this procedure (step or loop b)) a set of 16 possible candidates18a-cis determined, three in this case in the example, each with assigned quality values20a-c. Each of the candidates18a-cis a possible parameter vector that could replace the parameter vector10if this would promise better mission success than the current actually available parameter vector10.

Based on the current candidate12, a modified ZEM procedure22is 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, . . . :

In a step d2) a possible intercept trajectory24of the interceptor missile2is predicted. For this purpose, virtual steering commands7(corresponding to the real steering commands6) are determined based on the current candidate12at the respective step times t1,2,3, . . . , so that respective predicted locations (circles in the FIGURE) of the interceptor missile2result. The trajectory24results from the temporal or spatial sequence of the locations. In other words, how the interceptor missile2would move if the current candidate12were to be used as a parameter vector10for its steering is simulated iteratively.

Furthermore, in a step d3) corresponding to the step times t1,2,3, . . . locations and thus iteratively a target trajectory28, i.e. a trajectory of the target8, are predicted, but in this case taking into account a respective hypothetical flight maneuver26of the target8. For example, it is assumed that the target8flies a certain evasive trajectory to be adopted to elude the interceptor missile2.

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 approach30of the interceptor trajectory24and the target trajectory28is reached. This concludes the ZEM procedure22.

The available results32of the ZEM method22in the example are the achievable ZEM approach30, an updated remaining flight duration Tgo, the impact velocity and the angle of impact of the interceptor missile2on the target8, etc.

In a step c2), a current quality value33is determined on the basis of these results32for the respective candidate12and is assigned to it. The assignment is based on a quality criterion36.

In a step c3), the current candidate12is stored together with its determined property value33in the set16as a candidate18a-cwith a quality value20a-c. In the first run, the quality value20ais assigned to the candidate18a, in later runs the quality value20bis assigned to the candidate18band stored in the set16, and so on.

In a step c4), an end criterion38for the optimization procedure14is now checked. If this is not achieved, in step e1) the current candidate12is varied to a varied candidate42using an MPC search method40. This is adopted as the current candidate12in a step e2) and the MPC optimization procedure14is started again with the now optimized or modified candidate12.

In the example, the optimization procedure14is run through three times, so that the result is three candidates18a-cwith assigned quality values20a-c. Then the end criterion38is reached, in this case the fixed number of three procedure runs.

Since the end criterion38has been reached, the procedure returns to step a) to calculate a new set16.

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

During the duration of the procedure, one of the candidates18a-cis selected at a predetermined correction time TK according to a correction criterion44and henceforth used as the current parameter vector10for the real steering of the interceptor missile2. In the example, the correction time TK is the achievement of the end criterion38. The correction criterion44is the selection of the candidate18a-cfrom the set16to which the best quality value20a-cin the current set16is assigned.

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 candidates18a-cthe parameter vector10. The best one is the one with a quality value20b-cbetter than the quality values20a-cof the candidates18a-cpreviously present in the set16.

In the present case, step a) also determines a currently predicted remaining flight time Tgo of the interceptor missile2to the target8in order to have a time base for the utilization of the control parameters SP3a-ein the step d2). An updated remaining flight time Tgo is also available as part of the results32at the end of each run of the ZEM procedure22and can be used henceforth.

The current parameter vector10is available in the interceptor missile2. The interceptor missile2also contains a control and evaluation unit50, 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.

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

REFERENCE SIGN LIST

2Interceptor missile4Engine6Steering command (real)7Steering command (virtual)8Target10Parameter vector (current)12Candidate (current)14MPC optimization method15Parameter vector (predefinable)16Set18a-cCandidate20a-cQuality value22ZEM procedure24interceptor trajectory26Flight maneuver (hypothetical)28Target trajectory30ZEM Approach32Results33Quality value (current)36Quality criterion38End criterion40MPC search method42Candidate (varies)44Correction criterion50Control and evaluation unitSP Control parameterTgo Remaining flight durationPM Midcourse Phaset1,2,3, . . . Step timeTK Correction time