Abstract:
This disclosure provides systems, methods, and apparatus for intercepting a moving target by a plurality of interceptors that individually have insufficient capability to achieve intercept. An electronic processor can receive information corresponding to a state of the moving target at a first time. The electronic processor can determine a plurality of hypotheses for the future maneuvers of the moving target. The hypotheses can be based in part on the state of the moving target at the first time and the location of any defended assets. The electronic processor can assign a respective target maneuver hypothesis or set of hypotheses to each of a plurality of interceptors. The electronic processor can assign firing times and/or initial guidance commands to each interceptor. The electronic processor can update the set of feasible hypotheses based on additional receipt of information on the motion of the target and communicate this information to interceptors in flight via a communication subsystem. The electronic processor, or a secondary electronic processor located on each interceptor, can control each interceptor to maneuver such that the moving target is intercepted, based on the respective target maneuver hypotheses.

Description:
RELATED APPLICATION 
       [0001]    This application claims priority to and the benefit of U.S. Provisional Patent Application No. 62/060,388, titled “MULTI-HYPOTHESIS FIRE CONTROL AND GUIDANCE”, filed on Oct. 6, 2014, the contents of which are hereby incorporated by reference in their entirety for all purposes. 
     
    
     BACKGROUND 
       [0002]    Defending assets from missiles, guided munitions, or other moving targets presents many challenges. To intercept such a moving target with a high probability of success, the interceptor generally needs to be more maneuverable than the moving target. However, many moving targets are highly maneuverable. Therefore, maintaining an interceptor maneuverability advantage over moving targets can be difficult, impossible, or, at a minimum, cost prohibitive. 
       SUMMARY 
       [0003]    The systems, methods and devices of the disclosure each have several innovative aspects, no single one of which is solely responsible for the desirable attributes disclosed herein. 
         [0004]    One innovative aspect of the subject matter described in this disclosure can be implemented in a method for intercepting a moving target. The method includes receiving, by an electronic processor, information corresponding to a state of the moving target at a first time. The method includes determining, by the electronic processor, a plurality of target maneuver hypotheses. The target maneuver hypotheses can be based in part on the state of the moving target at the first time. The method includes assigning, by the electronic processor, a respective target maneuver hypothesis to each of a plurality of interceptors. The method includes controlling, by the electronic processor, each interceptor to maneuver so as to intercept the moving target, based on the respective target maneuver hypotheses. 
         [0005]    In some implementations, the information corresponding to the state of the moving target at the first time includes at least one of position information, velocity information, acceleration information, and orientation information. In some implementations, determining the plurality of target maneuver hypotheses can include determining the plurality of target maneuver hypotheses based on ballistic motion of the moving target. In some implementations, determining the plurality of target maneuver hypotheses can include determining the plurality of target maneuver hypotheses based on a maximum maneuverability of the moving target. 
         [0006]    In some implementations, the number of available interceptors is less than the number of target maneuver hypotheses. The method can therefore include evaluating, by the electronic processor, each of the plurality of target maneuver hypotheses to determine a probability for each target maneuver hypothesis and assigning, by the electronic processor, the target maneuver hypotheses to the interceptors based on the determined probabilities. 
         [0007]    In some implementations, the method can include receiving, by the electronic processor, information corresponding to a state of the moving target at a second time occurring after the first time. The method can include updating, by the electronic processor, at least one target maneuver hypothesis to generate an updated target maneuver hypothesis, based in part on the state of the moving target at the second time. The method can include controlling, by the electronic processor, the at least one respective interceptor to maneuver so as to intercept the moving target based on the updated target maneuver hypothesis. 
         [0008]    In some implementations, the method can include determining, by the electronic processor, a type of the moving target. In some implementations, controlling each interceptor to maneuver so as to intercept the moving target can include wirelessly transmitting flight instructions to each interceptor. In some implementations, the step of assigning a respective target maneuver hypothesis to each of the plurality of interceptors is performed prior to deployment of the interceptors. The method also can include deploying each of the plurality of interceptors. In some implementations, deploying the interceptors includes launching a missile. In some implementations, deploying the interceptors includes firing guided munitions. 
         [0009]    Another innovative aspect of the subject matter described in this disclosure can be implemented in a system for intercepting a moving target. The system includes a plurality of interceptors. The system includes a sensor configured to determine information corresponding to a state of the moving target at a first time. The system includes an electronic processor communicatively coupled to the sensor and to the plurality of interceptors. The electronic processor is configured to determine a plurality of target maneuver hypotheses based in part on the state of the moving target at the first time. The electronic processor is configured to assign a respective target maneuver hypothesis to each of the plurality of interceptors. The electronic processor is configured to control each interceptor to maneuver so as to intercept the moving target, based on the respective target maneuver hypotheses. 
         [0010]    In some implementations, the information corresponding to the state of the moving target at the first time includes at least one of position information, velocity information, acceleration information, and orientation information. In some implementations, the electronic processor is further configured to determine the plurality of target maneuver hypotheses based on ballistic motion of the moving target. In some implementations, the electronic processor is further configured to determine the plurality of target maneuver hypotheses based on a maximum maneuverability of the moving target. 
         [0011]    In some implementations, the number of available interceptors is less than the number of target maneuver hypotheses. The electronic processor can be further configured to evaluate each of the plurality of target maneuver hypotheses to determine a probability for each target maneuver hypothesis and assign the target maneuver hypotheses to the interceptors based on the determined probabilities. 
         [0012]    In some implementations, the electronic processor is further configured to receive information corresponding to a state of the moving target at a second time occurring after the first time. The electronic processor also can be configured to update at least one target maneuver hypothesis to generate an updated target maneuver hypothesis, based in part on the state of the moving target at the second time. The electronic processor also can be configured to control the at least one respective interceptor to maneuver so as to intercept the moving target based on the updated target maneuver hypothesis. 
         [0013]    In some implementations, the electronic processor is further configured to determine a type of the moving target. In some implementations, the electronic processor is further configured to control each interceptor to maneuver so as to intercept the moving target by wirelessly transmitting flight instructions to each interceptor. In some implementations, the electronic processor is configured to perform the step of assigning a respective target maneuver hypothesis to each of the plurality of interceptors prior to deployment of the interceptors and then to deploy each of the plurality of interceptors. 
     
    
     
       BRIEF DESCRIPTION OF THE DRAWINGS 
         [0014]      FIG. 1  shows a graph of an example relationship between interceptor maneuverability and cost. 
           [0015]      FIG. 2  shows two interceptors used collaboratively to intercept a moving target. 
           [0016]      FIG. 3  shows a block diagram of a system for deploying multiple interceptors to intercept a moving target, according to an illustrative implementation. 
           [0017]      FIG. 4  shows a flow chart of a process for intercepting a moving target, according to an illustrative implementation. 
       
    
    
       [0018]    Like reference numbers and designations in the various drawings indicate like elements. 
       DETAILED DESCRIPTION 
       [0019]      FIG. 1  shows a graph  100  of an example relationship between interceptor maneuverability and cost. Modern weapons systems make use of highly maneuverable targets, such as missiles, guided munitions, or maneuverable reentry vehicles, to attack vulnerable assets. Defending assets against such moving targets can be technically challenging and expensive. For example, in order to increase the probability of successfully intercepting a target, an interceptor typically must be more maneuverable than the target. The interceptor can then respond more easily to movement of the target, which facilitates intercepting the target before the target reaches its intended destination (e.g., a defended asset such as a building, a ship, an aircraft, or a person). However, as shown in the graph  100 , increasing the maneuverability of an interceptor can cause the cost of the interceptor to increase exponentially. Other characteristics, such as the size and weight of the interceptor, may also scale exponentially with interceptor maneuverability. 
         [0020]    In some instances, interceptor maneuverability and cost may not have an exponential relationship. For example, cost may instead scale linearly with maneuverability. However, as a general rule, increased maneuverability cannot be achieved without increased cost, and as a result the graph of the relationship between maneuverability and cost is an increasing function for the vast majority of weapons systems. In some cases, the engineering challenges and increased costs associated with producing highly maneuverable interceptors may be prohibitive for reliably intercepting targets. Furthermore, once such an interceptor has been produced and deployed on the battlefield, further increasing its maneuverability (e.g., in response to increased enemy target capability) can also be prohibitively expensive. 
         [0021]    Thus, in some implementations, the costs associated with developing a sufficiently maneuverable interceptor, as shown in the graph  100 , can make it difficult or impossible to field an effective defense system using a single interceptor. However, in some implementations, it may be possible to develop a system including two or more interceptors, each of which may be less maneuverable or may have only a marginal maneuverability advantage relative to the moving target, that can intercept the moving target as reliably as a single highly maneuverable interceptor. The interceptors can be used collaboratively to intercept the moving target. Because the costs of an interceptor can scale exponentially with its maneuverability, a system having many less maneuverable interceptors can also be significantly cheaper than a system having a single highly maneuverable interceptor. Therefore, the cost to intercept a moving target using a group of individually less maneuverable interceptors can be substantially cheaper. Moreover, increasing the effectiveness of such a system can also be done more easily, for example by adding additional low-cost interceptors. Therefore, the system is less likely to become obsolete due to enhanced target maneuverability. 
         [0022]      FIG. 2  shows a diagram  200  of three interceptors  202   a ,  202   b , and  202   c  (generally referred to as interceptors  202 ) used collaboratively to intercept a moving target  205 . The interceptors  202  are used as part of a defensive system to protect an asset  210  from being damaged or destroyed by the moving target  205 . For example, in some implementations, the moving target  205  can be an enemy missile or other projectile launched with the intention of striking the asset  210 . The asset  210  can be any vulnerable resource, such as a building, a ship, a piece of equipment, or a person. The interceptors  202  can be missiles, rockets, guided munitions, or any other type of guided projectile. 
         [0023]    The diagram  200  shows the relative positions of the interceptors  202 , the target  205 , and the asset  210  at a time after the target  205  and the interceptors  202   a  and  202   b  have been deployed. The interceptor  202   c  has not yet been deployed. In the diagram, arrows formed from solid lines represent paths already traversed in the past, while arrows formed form broken lines represent potential paths that may be traversed in the future. For example, the solid line  207  represents the path traversed by the target before the time at which the interceptors  202  and target  205  are shown in  FIG. 2 . Similarly, the solid lines  209   a  and  209   b  represent the paths traversed by the interceptors  202   a  and  202   b , respectively, prior to the time at which the interceptors  202  and target  205  are shown in  FIG. 2 . The lines  207  and  209  are solid to indicate that these paths are known with certainty, because they represent past positions of the target  205  and the interceptors  209 . Several potential paths  212   a - 212   d  (generally referred to as paths  212 ) that the target  205  may follow in the future are shown in broken lines. Similarly, several potential paths  214   a - 214   d  (generally referred to as paths  214 ) of the interceptor  202   a , potential paths  216   a - 216   d  (generally referred to as paths  216 ) of the interceptor  202   b , and potential paths  218   a - 218   d  (generally referred to as paths  218 ) of the interceptor  202   c  are shown in broken lines. The broken lines indicate that that, while any of the paths  212 ,  214 ,  216 , and  218  are possible, the actual paths to be traversed by the interceptors  202  and the target  205  in the future are uncertain as of the time at which the interceptors  202  and the target  205  are shown in  FIG. 2 . It should be understood that the potential paths  212 ,  214 ,  216 , and  218  are illustrative only, and many other potential paths for each of the interceptors  202  and the target  205  may be possible. 
         [0024]    Each of the potential paths  212 ,  214 ,  216 , and  218  are generally contained within an envelope representing the manifold of future states for the respective interceptor  202  or target  205 . In some implementations, the shape of each respective envelope can be a function of the maneuverability of each of the interceptors  202  and the target  205 . For example, increasing the maneuverability of the target  205  can increase the angles at which the target  205  may turn at a given time, thereby increasing the size of its respective envelope. The same is true for the interceptors  202 . 
         [0025]    As shown, the potential paths  212  of the target  205  diverge at a wider angle than the potential paths  214  and  216  of the interceptors  202   a  and  202   b , respectively. Therefore, in this example, the target  205  is more maneuverable than the interceptors  202 . As discussed above, to reliably intercept a moving target with a single interceptor, an interceptor must maintain a maneuverability advantage over the moving target. However, in some implementations, by using two or more interceptors  202  collaboratively, the target  205  may be reliably intercepted despite the fact that each of the interceptors  202  is less maneuverable than the target  205 . 
         [0026]    For example, in some implementations, each interceptor  202  may be configured to intercept the target  205  under the assumption that the target  205  will choose a particular subset of its potential paths  212 . The subsets of potential target paths  212  assigned to each interceptor  202  may be substantially non-overlapping, so that the interceptors can together be configured to reliably intercept the target  205  regardless of the potential path  212  actually traversed by the target  205 . For example, hypotheses relating to the potential paths  212  most likely to be traversed by the target  205  can be computed. In some implementations, the hypotheses may be generated based on information relating to the state of the target  205 , such as its size, weight, current position, and maneuverability, as well as the shape and position of the path  207  already traversed by the target  205 . Sensors (e.g., radar systems) may be used to collect such information. In some implementations, the hypotheses may be evaluated, and the most likely hypotheses may be assigned to the interceptors  202  to improve the probability of successfully intercepting the target  205 . 
         [0027]    In some implementations, a system for defending the asset  210  may include additional interceptors  202 . Three interceptors  202  are shown in  FIG. 2  for illustrative purposes, but any number of interceptors  202  may be used. Each of the interceptors  202  may be assigned a different subset of hypotheses for potential maneuver strategies or paths  212  of the target  205 . For example, in implementations in which the interceptors  202  do not maintain a significant maneuverability advantage over the target  205 , it may be advantageous to increase the number of interceptors  205  used to intercept the target  205 . Each interceptor may be capable of defending the asset  210  from only a relatively small subset of potential paths  212  to be traversed by the target  205 , and therefore increasing the number of interceptors may be necessary to cover a sufficiently broad range of the potential paths  212 . On the other hand, if the interceptors  202  are more maneuverable, fewer interceptors  202  may be required to reliably intercept the target  205  because each interceptor  202  can cover a larger subset of the potential paths  212  that the target  205  might take towards the asset  210 . 
         [0028]    In some implementations, the hypotheses of the most likely potential paths  212  to be traversed by the target  205  can be generated before any of the interceptors  202  are launched. For example, a fire control system may collect data relating to target  205 , such as its position, velocity, and acceleration, as it moves toward the asset  210 . Based on this data, the fire control system can determine a set of hypotheses for the movement of the target  205  in the future. In some implementations, a subset of hypotheses is assigned to each interceptor  202 , and the interceptors  202  are launched according to their respective subsets of hypotheses. In some implementations, the fire control system can determine that some of the interceptors  202  should not be launched. As shown in  FIG. 2 , interceptors  202   a  and  202   b  may be launched, while interceptor  202   c  is not. In some implementations, the interceptors  202  may be launched at different times. For example, interceptors  202   a  and  202   b  can be launched while interceptor  202   c  remains on the ground. Subsequently, if the fire control system determines that another interceptor is required to achieve a desired probability of intercepting the target  205 , a subset of hypotheses can be assigned to the interceptor  202   c , and the interceptor  202   c  can be launched towards the target  205 . 
         [0029]    In some implementations, the hypotheses of the most likely potential paths  212  to be traversed by the target  205  may be updated while the interceptors  202  are in flight. For example, sensors may be used to track the target  205  and interceptors  202  to provide additional information that can be used to more accurately predict the potential path  212  to be traversed by the target. In some implementations, instructions relating to the updated hypotheses may be transmitted to each of the targets  202  during flight, so that the targets  202  may alter their flight paths to increase the probability of successfully intercepting the target  205 . 
         [0030]      FIG. 3  shows a block diagram of a system  300  for deploying multiple interceptors to intercept a moving target, according to an illustrative implementation. The system includes a fire control system  301  in communication with the interceptor  202  via a prelaunch data link  345  and an in-flight data link  348 . Both the fire control system  301  and the interceptor  202  are also configured to receive information about the target  205 , for example through the use of sensors configured to detect the motion or the target  205 . 
         [0031]    The fire control system  301  includes a fire control targeting sensor  305 , a target state estimator  310  including a plurality of filters  312  and a blending/selection module  314 , a plurality of predictive target models  315 , a battle-space manager  322 , a weapon tasking logic module  324 , a launch system  330 , a fire control tracking sensor  335 , and an interceptor state estimator  340 . The interceptor  202  includes an interceptor sensor  350 , a target state estimator  351  including a plurality of filters  352  and a blending/selection module  354 , a predictive target model  355 , and a control system  360 . The modules making up the system  300  may be implemented in hardware, software, or a combination thereof. For example, the modules may include sensors, memory devices, and processors configured to perform the tasks discussed below. 
         [0032]    The fire control system  301  includes a fire control targeting sensor  305  that can receive information about the target  205 . In some implementations, the fire control targeting sensor  305  can be a radar system. The fire control targeting sensor  305  can receive or determine information such as the velocity, position, and size of the target  205 . The fire control targeting sensor  305  can also communicate target information to the target state estimator  310 . In some implementations, the fire control targeting sensor  305  can track the target  205  over a period of time, and can continuously collect target data by tracking the target  205  during the period of time. 
         [0033]    The target state estimator  310  can use the target information received from the fire control targeting sensor  305  to determine state information of the target at a particular time. In some implementations, the target state estimator  310  can determine several possibilities for the current state of the target  205 , each of which can be based on a filtering technique applied by one of the plurality of filters  312 . For example, the filters  312  may use raw data received from the fire control targeting sensor  305 , such as radar or sonar data, to determine a velocity, acceleration, and/or maximum maneuverability of the target  205 . In some implementations, the targeting state estimator  310  also can determine the type of target  205  tracked by the targeting sensor  305 . For example, the targeting state estimator  310  may determine that the target  205  is a missile, a guided munition, or a maneuverable reentry body based on information relating to the target&#39;s size or velocity received from the targeting sensor  305  and processed by the filters  312 . Information from the filters  312  is delivered to the blending/selection module  314 . The blending/selection module  314  can use the output of the filters  312  to determine the current state of the target  205 . In some implementations, the blending/selection module  314  can make this determination by selecting the output of one of the filters  312  and discarding the outputs of the others. In other implementations, the blending/selection module  314  can determine the current state of the target  205  based on a composite of the outputs of two or more of the filters  312 . The targeting state estimator  310  can communicate this information to the predictive target models  315 . 
         [0034]    Each of the predictive target models  315  can use the information received from the targeting state estimator  310  to generate hypotheses relating to the paths that may be traversed by the target  205  in the future. For example, the predictive target models  315  may compute hypotheses relating to the potential paths  212  shown in  FIG. 2 . In some implementations, the predictive target models  315  may generate hypotheses based on a maximum maneuverability of the target  205 . In some implementations, the predictive target models  315  may generate hypotheses based on common flight patterns of targets similar to the target  205 . For example, the predictive target models  315  may generate a hypotheses indicating that the target  205  is likely to weave at particular frequencies and amplitudes that are within the range of capability of the target  205 . Many other hypothesis scenarios may be possible based on the state of the target  205  and the relative position of the asset that the target  205  is attempting to strike. An arbitrary number of predictive target models  315  can be included in the fire control system  301   
         [0035]    The battle-space manager  322  can evaluate the hypotheses generated by the predictive target models  315 . For example, the battle-space manager  322  may determine that the target  205  is more likely to follow the trajectories associated with some hypotheses than with others. In some implementations, the battle-space manager  322  may assign greater weight to the hypotheses that make use of the maximum maneuverability of the target  205 , as it may be likely that the target  205  will attempt to use its maneuverability to avoid interception. The battle-space manager  322  may also group the hypotheses into hypothesis families. For example, a hypothesis family could include a subset of trajectory hypotheses that are spatially close to one another. 
         [0036]    In some implementations, the battle-space manager  322  can use the hypothesis information to determine how to deploy any available interceptors  202  to intercept the target  205 . For example, the battle-space manager  322  may determine a number of interceptors  202  to be deployed in a mission to intercept the target  205 , based on the hypotheses. In some implementations, the hypotheses may indicate that the target  205  has a very high probability of following one of a limited number of potential paths. Therefore, the battle-space manager  322  may determine that relatively few interceptors  202  are needed to reliably intercept the target  205 . In other implementations, the battle-space manager  322  may determine that many interceptors  202  are required to provide a sufficiently high probability of successfully intercepting the target  205 . The battle-space manager  322  can transmit this information to the weapon tasking logic module  324 , which can assign a hypothesis or subset of hypotheses to each of the interceptors  202  to be deployed via the prelaunch data link  345  or the in-flight data link  348 . The weapon tasking logic module can also transmit to the launch system  330  an instructions indicating the time at which each of the respective interceptors  202  should be launched. 
         [0037]    The interceptor  202  includes an interceptor sensor  350  that can receive information about the target  205 . In some implementations, the interceptor targeting sensor  350  can be similar to the fire control targeting system  305 . For example, the interceptor targeting sensor  350  can include a radar system or a sonar system for tracking the target  204 . The interceptor targeting sensor  350  can determine information such as the velocity, position, and size of the target  205 . Information from the control system  360  can also be transmitted to the interceptor sensor  350  through the summing junction  370 , thereby allowing the interceptor sensor  350  to determine the relative motion between the interceptor  202  and the target  205 . The interceptor sensor  350  can communicate this information to the target state estimator  351 . In some implementations, the interceptor sensor  350  can track the target  205  over a period of time, and can continuously collect target data during the period of time. 
         [0038]    The target state estimator  351  can use the target information received from the interceptor sensor  350  to determine state information of the target at a particular time. In some implementations, the target state estimator  351  can determine several possibilities for the current state of the target  205 , each of which can be based on a filtering technique applied by one of the plurality of filters  352 . For example, the filters  352  may use raw data received from the interceptor sensor  350  to determine information relating to the current state of the target  205 , in a manner similar to the filters  352  discussed above. Information from the filters  352  is delivered to the blending/selection module  354 . The blending/selection module  354  can use the output of the filters  352  to determine the current state of the target  205 , and the targeting state estimator  351  can communicate this information to the predictive target model  355 . 
         [0039]    Before the interceptor  202  has been launched, the predictive target model  355  can receive information from the weapon tasking logic module  324  through the prelaunch data link  345 . The prelaunch data link  345  can be any form of wired or wireless communications typically used in projectile communication systems. The predictive target model  355  can use the information received from the weapon tasking logic  324  and the target state estimator  351  to generate a hypothesis for the future trajectory of the target  205 , and can communicate the hypothesis to the control system  360 . 
         [0040]    The control system  360  can receive a launch command from the launch system  330 . After the interceptor  202  has been launched, the control system  360  also can receive information from the weapon tasking logic module  324  via the in-flight data link  348  and can control the interceptor  202  to execute the intercept solution provided by the predictive target model  355 . During flight, the weapon tasking logic module  324  can provide updated flight instructions to the control system  360 . In some implementations, the instructions received from the predictive target model  355  can be subordinate to instructions received from the weapon tasking logic  324 . Therefore, the fire control system  301  can re-task the interceptor  202  based on an update to the hypothesis subset assigned to the interceptor  202 . 
         [0041]    Referring again to the fire control system  301 , the fire control tracking sensor  335  can track the motion of each interceptor  202  after deployment. For example, the fire control tracking sensor  335  can be a radar system or a sonar system. Information obtained by the fire control tracking sensor  335  can be transmitted to an interceptor state estimator  340 , which can determine state information relating to each interceptor  202 . For example, the interceptor state estimator  340  may determine a velocity and position for each interceptor  202 . This information can then be provided to the battle-space manager  322 , which can update the intercept solution based on the new information. The battle-space manager  322  can relay this information to the weapon tasking logic module  324 , which can in turn provide updated commands to each interceptor  202  via the in-flight data link  348 . 
         [0042]      FIG. 4  shows a flow chart of a process  400  for intercepting a moving target, according to an illustrative implementation. The process  400  includes receiving target information at a first time (stage  405 ), determining hypotheses for trajectories of the target (stage  410 ), assigning hypotheses to respective interceptors (stage  415 ), and controlling the interceptors to maneuver to intercept the target, based on their respective hypotheses (stage  420 ). In some implementations, the process  400  also includes receiving target information at a second time (stage  425 ), updating at least one target trajectory hypothesis (stage  430 ), and controlling the respective interceptor to maneuver to intercept the target based on the updated hypothesis (stage  435 ). 
         [0043]    Referring again to  FIG. 4 , the process  400  includes receiving target information at a first time (stage  405 ). In some implementations, the target information can include bearing, range, size, velocity, acceleration, and position information. The target information may be determined, for example, by a radar system. In some implementations, sensor data (e.g., radar or optical sensor data) may be used to ascertain other information relating to the target, such as the type of target (e.g., a missile, a guided munition, a maneuverable reentry vehicle, etc.) and its maximum maneuverability. 
         [0044]    The process  400  includes determining hypotheses for trajectories of the target (stage  410 ). In some implementations, the hypotheses may be based in part on the target state information determined in stage  405 . For example, it may be hypothesized that the target will accelerate according to its maximum maneuverability as it moves toward a vulnerable asset. The hypotheses may be evaluated based on their probabilities. In some implementations, the hypotheses may be grouped into hypothesis families. For example, a hypothesis family may include all of the hypotheses that describe target trajectories within a given volume of space. 
         [0045]    The process  400  includes assigning hypotheses to respective interceptors (stage  415 ). In some implementations, the only hypotheses whose probability meets a predetermined threshold are assigned to interceptors. Other hypotheses may be discarded. In some implementations, each interceptor may be assigned more than one hypothesis. For example, each interceptor may be assigned a family or families of hypotheses. In some implementations, the hypotheses are assigned to interceptors based on the capability of the interceptors to intercept targets that may move according to the hypotheses. Thus, more highly maneuverable interceptors may be assigned a greater number of hypotheses, while less maneuverable interceptors may be assigned fewer hypotheses. The hypotheses assigned to each interceptor may be non-overlapping, so that the interceptors can collaborate to cover a broad range of hypotheses for target trajectories. 
         [0046]    The process  400  includes controlling the interceptors to maneuver so as to intercept the target, based on their respective hypotheses (stage  420 ). Launch commands can be sent to the interceptors that have been chosen to be deployed for a particular mission. Guidance commands can be sent to each respective deployed interceptor to cause the interceptor to move in such a way as to intercept the target under the assumption that the target will maneuver according to the hypothesis or hypotheses assigned to the interceptor. 
         [0047]    In some implementations, the process  400  can include receiving target information at a second time (stage  425 ). For example, the system (e.g., a radar system) used to track the target at the first time (stage  405 ) may also be used to track the target at the second time. Additional information may therefore be collected at the second time that can help to determine the path of the target as it moves toward a targeted asset. In some implementations, target information can be received at additional times as well. For example, the system used to track the target can be configured to collect target information at regular or semi-regular time intervals. Updating the target information over time can allow the system to improve the hypothesis of future target trajectory. 
         [0048]    The process  400  can also include updating at least one target trajectory hypothesis based on the target information received at the second time (stage  430 ). For example, as additional target information is received (stage  425 ) at the second time, the likely trajectories of the target may be known with greater certainty, and the probabilities assigned to certain of the hypotheses may be altered. In some implementations, hypotheses not considered based on the target information received at the first time may be generated based on the target information received at the second time. 
         [0049]    The process  400  can also include controlling the respective interceptor to maneuver so as to intercept the target based on the updated hypothesis (stage  435 ). In some implementations, guidance commands may be sent to the respective interceptor whose target trajectory hypothesis information has been updated. For example, guidance commands may be sent to the interceptor wirelessly while the interceptor is in flight. The interceptor may then respond to the guidance commands by altering its flight path in response to the updated hypotheses. 
         [0050]    Various modifications to the implementations described in this disclosure may be readily apparent to those skilled in the art, and the generic principles defined herein may be applied to other implementations without departing from the spirit or scope of this disclosure. Thus, the claims are not intended to be limited to the implementations shown herein, but are to be accorded the widest scope consistent with this disclosure, the principles and the novel features disclosed herein. 
         [0051]    Certain features that are described in this specification in the context of separate implementations also can be implemented in combination in a single implementation. Conversely, various features that are described in the context of a single implementation also can be implemented in multiple implementations separately or in any suitable subcombination. Moreover, although features may be described above as acting in certain combinations and even initially claimed as such, one or more features from a claimed combination can in some cases be excised from the combination, and the claimed combination may be directed to a subcombination or variation of a subcombination. 
         [0052]    Similarly, while operations are depicted in the drawings in a particular order, this should not be understood as requiring that such operations be performed in the particular order shown or in sequential order, or that all illustrated operations be performed, to achieve desirable results. Further, the drawings may schematically depict one more example processes in the form of a flow diagram. However, other operations that are not depicted can be incorporated in the example processes that are schematically illustrated. For example, one or more additional operations can be performed before, after, simultaneously, or between any of the illustrated operations. In certain circumstances, multitasking and parallel processing may be advantageous. Moreover, the separation of various system components in the implementations described above should not be understood as requiring such separation in all implementations, and it should be understood that the described program components and systems can generally be integrated together in a single software product or packaged into multiple software products. Additionally, other implementations are within the scope of the following claims. In some cases, the actions recited in the claims can be performed in a different order and still achieve desirable results.