Abstract:
A method, apparatus and system are provided to permit an aerial asset to determine its current location and to, in turn, locate and track a target even as efforts are made by others to jam or otherwise hinder offboard communications that may prevent reliance upon GPS or other positioning systems. A method includes receiving, at a navigation control vehicle, information regarding the relative position of a target with respect to each of the at least two sonobuoys. The method also determines a relative position of the target with respect to the navigation control vehicle at least partially based on the information regarding the relative position of the target with respect to each of the at least two sonobuoys. The method provides information regarding the relative position of the target to an aerial asset to facilitate location of the target by the aerial asset.

Description:
TECHNOLOGICAL FIELD 
     Embodiments of the present disclosure relate generally to the determination of the position of a target and, more particularly, to the determination of the relative position of the target with respect to one or more aerial vehicles. 
     BACKGROUND 
     Various types of aerial assets, including unmanned aerial vehicles (UAVs), missiles and the like, are employed to locate, track and intercept targets. For example, missiles of one form or another had been used in combat for centuries prior to the development of guided missile technology in the World War II era. Since then numerous technologies were developed in order to guide aerial assets to their targets or to otherwise locate a target. The use of some form of radiation (e.g., laser or radio waves) has been a common element in many of these guidance systems. However, as advancements in aerial guidance have improved, target sophistication continues to improve as well. The cost and complexity of each aerial asset, although being typically only a fraction of the cost and complexity of most targets, makes it ever more imperative that each aerial asset that is deployed should be as effective as possible. Accordingly, it becomes increasingly desirable to continue to develop enhancements in target location and guidance systems to further the likelihood of success when such aerial assets are employed. 
     Aerial assets, such as missiles, with increasingly more sophisticated target location and guidance systems have been developed over the years. However, many of these target location and guidance systems require the aerial asset to be able to determine its current location in order to permit the location of the target to be determined. Aerial assets include a variety of systems for determining their current location, but most of these systems require offboard communication. For example, an aerial asset may include a global positioning system (GPS) that requires communication with a plurality of GPS satellites. In some instances, offboard communication by the aerial asset may be prevented, such as in instances in which communication by the aerial asset is jammed. In these instances, the aerial asset may be unable to determine its current location and, as a result, may be unable to determine the location of the target since the location of the target is generally determined relative to the location of the aerial asset. 
     Inertial navigation systems have been utilized in order to determine the location of an aerial asset without any requirement for offboard communication. While an inertial navigation system may not be susceptible to being jammed, the location determined by an inertial navigation system may drift over time. As such, the location of an aerial asset as determined by an inertial navigation system may not be as accurate as desired, particularly in instances in which the inertial navigation system is utilized for a period of time such that the error attributable to drift accumulates. Since an inertial navigation system may not determine the location of an aerial asset with sufficient precision, reliance upon an inertial navigation system, at least for extended periods of time, may also unable to locate and track a target in as precise a manner as is desired. 
     BRIEF SUMMARY 
     Some embodiments of the present disclosure provide for the location of a target in a manner that is both accurate and less susceptible to being jammed. As such, a method, apparatus and system of some embodiments of the present disclosure may permit an aerial asset to determine its current location and to, in turn, locate and track a target even as efforts are made by others to jam or otherwise hinder offboard communications that may prevent reliance upon GPS or other positioning systems. Additionally, the method, apparatus and system of some embodiments of the present disclosure may permit an aerial asset to determine its current location in a reliable manner that is not subject to drift or at least less subject to drift than an inertial navigation system. 
     In one example embodiment, a method is provided that includes receiving, at a navigation control vehicle, information regarding the relative position of a target with respect to each of at least two sonobuoys. The method also determines a relative position of the target with respect to the navigation control vehicle at least partially based on the information regarding the relative position of the target with respect to each of the at least two sonobuoys. Further, the method provides information regarding the relative position of the target with respect to the navigation control vehicle to an aerial asset, such as a UAV or a missile, to facilitate location of the target by the aerial asset. In this regard, the information regarding the relative position of the target with respect to the navigation control vehicle to the aerial asset may be provided without provision of an absolute position of the target. 
     The method of one embodiment may determine a relative position of each of the at least two sonobuoys with respect to the navigation control vehicle. In this embodiment, the determination of the relative position of the target with respect to the navigation control vehicle may include determining the relative position of the target with respect to the navigation control vehicle at least partially based upon the relative position of each of the at least two sonobuoys with respect to the navigation control vehicle. The method of one embodiment may also place a swarm of sonobuoys in a spaced apart relationship relative to one another and relative to the target. In one embodiment in which the information regarding the relative position of the target with respect to each of the at least two sonobuoys is based upon a direction of the target relative the respective sonobuoy, the method may also determine the relative position of the target with respect to the at least two sonobuoys based upon triangulation. 
     In another embodiment, an apparatus is provided that includes a receiver configured to receive information regarding the relative position of a target with respect to each of the at least two sonobuoys. The apparatus may also include a processor configured to determine a relative position of the target with respect to the navigation control vehicle at least partially based on the information regarding the relative position of the target with respect to each of the at least two sonobuoys. The apparatus may further include a transmitter configured to provide information regarding the relative position of the target with respect to the navigation control vehicle to an aerial asset, such as a UAV or a missile, to facilitate location of the target by the aerial asset. In this regard, the transmitter may be configured to provide the information regarding the relative position of the target with respect to the navigation control vehicle to the aerial asset without provision of an absolute position of the target. 
     The processor of one embodiment may be further configured to determine a relative position of each of the at least two sonobuoys with respect to the navigation control vehicle. In this embodiment, the processor may be configured to determine the relative position of the target with respect to the navigation control vehicle by determining the relative position of the target with respect to the navigation control vehicle at least partially based upon the relative position of each of the at least two sonobuoys with respect to the navigation control vehicle. In one embodiment in which the information regarding the relative position of the target with respect to each of the at least two sonobuoys is based upon a direction of the target relative the respective sonobuoy, the processor may be further configured to determine the relative position of the target with respect to the at least two sonobuoys based upon triangulation. 
     In a further embodiment, a system is provided that includes at least two sonobouys configured to detect a target and to determine a relative position of the target with respect to each of the at least two sonobuoys. For example, the system of one embodiment may include a swarm of sonobuoys in a spaced apart relationship relative to one another and relative to the target. The system may also include a navigation control vehicle configured to receive information regarding the relative position of a target with respect to each of the at least two sonobuoys, to determine a relative position of the target with respect to the navigation control vehicle at least partially based on the information regarding the relative position of the target with respect to each of the at least two sonobuoys, and to provide information regarding the relative position of the target with respect to the navigation control vehicle. The system may also include an aerial asset, such as a UAV or a missile, configured to receive the information regarding the relative position of the target with respect to the navigation control vehicle and to determine a relative position of the target with respect to the aerial asset at least partially based on the information regarding the relative position of the target with respect to the navigation control vehicle. 
     The navigation control vehicle may be further configured to provide the information regarding the relative position of the target with respect to the navigation control vehicle without provision of an absolute position of the target. In this embodiment, the aerial asset may be further configured to determine the relative position of the target with respect to the aerial asset without receipt of the absolute position of the target. 
     The navigation control vehicle of one embodiment may be further configured to determine a relative position of each of the at least two sonobuoys with respect to the navigation control vehicle and to determine the relative position of the target with respect to the navigation control vehicle by determining the relative position of the target with respect to the navigation control vehicle at least partially based upon the relative position of each of the at least two sonobuoys with respect to the navigation control vehicle. The aerial asset of one embodiment may be further configured to determine a relative position of the navigation control vehicle with respect to the aerial asset and to determine the relative position of the target with respect to the aerial asset by determining the relative position of the target with respect to the aerial asset at least partially based upon the relative position of the navigation control vehicle with respect to the aerial asset. 
     The aerial vehicle may include a master aerial vehicle that is further configured to generate a composite multi-dimensional representation of the target based on radar data received from other aerial vehicles that have collected projections over an area in which the target is located and further based on radar data collected by the master aerial vehicle. The master aerial vehicle of this embodiment is also configured to identify the target based on the composite multi-dimensional representation and to generate aimpoint data regarding the target based on an identity of the target. The master aerial vehicle is further configured to identify the target based on the composite multi-dimensional representation. The master aerial vehicle may be further configured to generate aimpoint data regarding the target based on an identity of the target. The aimpoint data may define a most vulnerable point on the target. 
     The features, functions and advantages that have been discussed can be achieved independently in various embodiments of the present disclosure or may be combined in yet other embodiments, further details of which can be seen with reference to the following description and drawings. 
    
    
     
       BRIEF DESCRIPTION OF THE SEVERAL VIEWS OF THE DRAWINGS 
       Having thus described the disclosure in general terms, reference will now be made to the accompanying drawings, which are not necessarily drawn to scale, and wherein: 
         FIG. 1  illustrates a system for determining the relative position of a target according to an example embodiment; 
         FIG. 2  illustrates a block diagram of hardware that may be employed on a navigation control vehicle according to an example embodiment; 
         FIG. 3  illustrates a process flow for operation of a navigation control vehicle according to an example embodiment; and 
         FIG. 4  illustrates a block diagram of hardware that may be employed on a master vehicle or any aerial asset that can function as the master vehicle according to an example embodiment. 
     
    
    
     DETAILED DESCRIPTION 
     The present disclosure now will be described more fully hereinafter with reference to the accompanying drawings, in which some, but not all embodiments are shown. Indeed, this disclosure may be embodied in many different forms and should not be construed as limited to the embodiments set forth herein; rather, these embodiments are provided so that this disclosure will satisfy applicable legal requirements. Like numbers refer to like elements throughout. 
     The method and apparatus of example embodiments may be utilized in a variety of systems in order to determine the relative position of a target, even in instances in the absolute position of the target cannot be determined, such as in instances in which the GPS or other positioning system is jammed. By way of example,  FIG. 1  illustrates a system for determining the relative location of a target. The system of  FIG. 1  illustrates a plurality of aerial assets (e.g., unmanned aerial vehicles (UAVs)  100 ,  102  and  104  and missile  120 ) and a navigation control vehicle  106  that may be in communication with the aerial assets. As shown in  FIG. 1  and as described below, the navigation control vehicle  106  may be a manned aircraft, but the navigation control vehicle of other embodiments may be a ship or other ground-based platform. Additionally, the navigation control vehicle  106  may have been the platform from which the aerial assets were launched. In other embodiments, however, at least some of the aerial assets may be launched from another platform independent of the navigation control vehicle  106 . 
     In an example embodiment, the aerial assets may be any combination of different types of missiles  120 , unmanned aerial vehicles (UAVs)  100 ,  102 ,  104  or aircraft that may be capable of interacting with the target  108 , such as by obtaining radar data pertaining to the target, intercepting the target or the like. It should also be appreciated that although four aerial assets are shown in  FIG. 1 , any number of aerial assets could be employed in some embodiments (e.g., including fewer or more aerial assets). 
     In addition to the navigation control vehicle  106  and the aerial assets, the system of an example embodiment may also include two or more sonobuoys  130 . Indeed, the system of one embodiment may include a swarm of sonobuoys, that is, three or more sonobuoys. The sonobuoys  130  are generally disposed in the vicinity of the target  108 . The sonobuoys  130  may be disposed in various configurations, such as a generally linear configuration, e.g., a picket fence-type configuration, or as a closed shape, such as a circle. In either instance, the sonobuoys  130  may be positioned proximate the target  108  and, in an embodiment in which the sonobuoys are positioned in a closed shape, such as a circle, the sonobuoys may be positioned around the target, such as shown in  FIG. 1 . As also shown in  FIG. 1 , the sonobuoys  130  may be spaced apart, not only from the target  108 , but also from one another. The sonobuoys  130  may be deployed in various manners. In one embodiment, however, the sonobuoys  130  are deployed from an aircraft, such as the navigation control vehicle  106 . 
     Once deployed, the sonobuoys  130  are configured to receive incoming signals and to detect the presence of the target  108 . For example, the sonobuoys  130  may include a communications unit including a receiver configured to receive signature signals from the target, such as signals indicative of engine noise, rudder noise, protrusion noise or the like. In response to the receipt of the signals from the target  108 , the sonobuoys  130  may be configured to determine the relative location of the target with respect to the sonobuoys. In this regard, each sonobuoy  130  may include a processor that is configured to determine the direction or angle of the target  108  with respect to the sonobuoy. The relative location of the target  108  with respect to the sonobuoy  130  may therefore be defined in terms of the direction or angle to the target. 
     Each sonobuoy  130  may also be configured to provide and the navigation control vehicle  106  may be configured to receive information regarding the relative position of the target  108  with respect to the respective sonobuoy. For example, the communications unit of the sonobuoy  130  may include a transmitter configured to transmit the information regarding the relative position of the target  108  to the navigation control vehicle  106 . The navigation control vehicle  106  may, in turn, be an aerial vehicle, such as a P-3C or P-8 aircraft, that is configured to communicate with two or more sonobuoys  130 . 
     In one embodiment, for example, the navigation control vehicle  106  may include hardware  150 , such as shown in  FIG. 2 , configured to receive the information regarding the relative position of the target  108  with respect to the respective sonobuoy  130  and to perform other related functions. In this regard, the navigation control vehicle  106  may include or otherwise be in communication with a processor  152 , a memory device  154 , a sonobuoy reference system (SRS)  156  and a communications interface  158 . The memory device  154  may include, for example, one or more volatile and/or non-volatile memories. In other words, for example, the memory device  154  may be an electronic storage device (e.g., a computer readable storage medium) comprising gates configured to store data (e.g., bits) that may be retrievable by a machine (e.g., a computing device like the processor  152 ). The memory device  154  may be configured to store information, data, content, applications, instructions, or the like for enabling the hardware  150  to carry out various functions in accordance with an example embodiment. For example, the memory device  154  could be configured to store instructions for execution by the processor  152 . 
     The processor  152  may be embodied in a number of different ways. For example, the processor  152  may be embodied as one or more of various hardware processing means such as a coprocessor, a microprocessor, a controller, a digital signal processor (DSP), a processing element with or without an accompanying DSP, or various other processing circuitry including integrated circuits such as, for example, an ASIC (application specific integrated circuit), an FPGA (field programmable gate array), a microcontroller unit (MCU), a hardware accelerator, a special-purpose computer chip, or the like. 
     In an example embodiment, the processor  152  may be configured to execute instructions stored in the memory device  154  or otherwise accessible to the processor. Alternatively or additionally, the processor  152  may be configured to execute hard coded functionality. As such, whether configured by hardware or software methods, or by a combination thereof, the processor  152  may represent an entity (e.g., physically embodied in circuitry) capable of performing operations according to an embodiment of the present invention while configured accordingly. Thus, for example, when the processor  152  is embodied as an ASIC, FPGA or the like, the processor may be specifically configured hardware for conducting the operations described herein. Alternatively, as another example, when the processor  152  is embodied as an executor of software instructions, the instructions may specifically configure the processor to perform the algorithms and/or operations described herein when the instructions are executed. The processor  152  may include, among other things, a clock, an arithmetic logic unit (ALU) and logic gates configured to support operation of the processor. 
     The SRS  156  is an automatic electronic system for locating sonobuoys and may employ angle-measuring equipment, distance-measuring equipment, or both. Meanwhile, the communication interface  158  may be any means such as a device or circuitry embodied in either hardware or a combination of hardware and software that is configured to receive and/or transmit data from/to the sonobuoys  130 , the aerial assets or otherwise. In this regard, the communication interface  158  may include, for example, an antenna (or multiple antennas) and supporting hardware and/or software for enabling wireless communications, such as a receiver, a transmitter, a transceiver, etc. Additionally or alternatively, the communication interface  158  may include the circuitry for interacting with the antenna(s) to cause transmission of signals via the antenna(s) or to handle receipt of signals received via the antenna(s). 
     As described above, the sonobuoys  130  are configured to listen for signals emitted by the target  108 . Upon detection of signals emitted by the target  108 , the sonobuoys  130  and, in particular, a processor onboard a respective sonobuoy is configured to determine the relative position of the target with respect to the sonobuoy, e.g., the direction or angle to the target from the respective sonobuoy. Each sonobuoy  130 , such as a communications unit, e.g., a transmitter, may then transmit information regarding the relative position of the target  108  with respect to the sonobuoy. 
     From the perspective of the navigation control vehicle  106 , the navigation control vehicle and, in particular, the communications interface  158 , e.g., a receiver, onboard the navigation control vehicle may be configured to receive information from at least two sonobuoys  130  regarding the relative location of the target  108  with respect to the sonobuoys. See operation  170  of  FIG. 3 . The information provided by a respective sonobuoy  130  may relate to the relative location of the target  108  in various manners including, for example, the angular direction of the target with respect to the respective sonobuoy. Although the communications interface  158 , e.g., receiver, of the navigation control vehicle  106  may receive the information regarding the relative position of the target  108  from two sonobuoys  130 , the communications interface of the navigation control vehicle may receive information regarding the relative position of the target from a swarm of sonobuoys, each of which have listened for the target, have received signals from the target and have determined the relative position of the target with respect to the respective sonobuoy. 
     As shown in operation  172  of  FIG. 3 , the navigation control vehicle  106 , such as the processor  152  of the navigation control vehicle, may be configured to determine the relative position of the target to the at least two sonobuoys  130  that provided the information to the navigation control vehicle. Although the processor  152  of the navigation control vehicle  106  may determine the relative position of the target  108  to the sonobuoys  130  in various mariners, the processor of one embodiment is configured to determine the relative position of the target to the sonobuoys based upon triangulation from the direction of the target relative to each of the at least two sonobuoys. 
     The navigation control vehicle  106 , such as the processor  152  of the navigation control vehicle, may also be configured to determine the relative position of the sonobuoys  130 , that is, the sonobuoys that provided the information regarding the relative position of the target, with respect to the navigation control vehicle. See operation  174  of  FIG. 3 . While the navigation control vehicle  106  may determine the relative position of a respective sonobuoy  130  in various manners, the navigation control vehicle of one embodiment may include a SRS  156  as shown in  FIG. 2  that is configured to determine the relative position of a respective sonobuoy that is in communication with the navigation control vehicle. 
     In one embodiment, the navigation control vehicle  106 , such as the processor  152  of the navigation control vehicle, may include or otherwise be able to access information regarding the currents that may affect the position of the sonobuoys  130  and, as a result, may take into account drift of the sonobuoys between the time at which the information regarding the relative location of the target  108  with respect to the sonobuoys was determined and the time at which the navigation control vehicle, such as the SRS  156 , determines the relative position of the sonobuoys to the navigation control vehicle since the current may have caused the sonobuoys to move relative to the target during that time period. In this regard, the information regarding the currents in the vicinity of the sonobuoys  130  may be stored by the memory device  154  onboard the navigation control vehicle  106  or otherwise be accessible by the processor  152  of the navigation control vehicle. 
     Based upon the information provided by a respective sonobuoy  130 , such as the relative position of the target  108  with respect to the respective sonobuoy, and the relative position of the respective sonobuoy to the navigation control vehicle  106 , the navigation control vehicle, such as the processor  152  of the navigation control vehicle, may be configured to determine the relative position of the target with respect to the navigation control vehicle. See operation  176  of  FIG. 3 . Although the relative position of the target  108  with respect to the navigation control vehicle  106  may be defined in various manners, the relative position of the target with respect to the navigation control vehicle may be defined in terms of a distance to the target as well as an angular position of the target relative to a reference point. While the navigation control vehicle  106 , such as the processor  152  of the navigation control vehicle, may determine the relative position of the target  108  with respect to the navigation control vehicle based upon the information provided by two sonobuoys  130 , the navigation control vehicle of one embodiment may receive information regarding the relative position of the target from a swarm of sonobuoys and the processor  152  of the navigation control vehicle may, in turn, determine the relative position of the target with respect to the navigation control vehicle based upon the information provided by the swarm of sonobuoys. 
     As described above, the information provided by the at least two sonobuoys  130  as to the relative location of the target  108  with respect to the respective sonobuoy identifies the relative, but not the absolute location of the target. Similarly, the navigation control vehicle  106 , such as the processor  152  of the navigation control vehicle  106 , may determine the relative location of the target  108  with respect to the navigation control vehicle, but not the absolute location of the target. In this regard, the relative location is the location of the target  108  relative to another object, such as a sonobuoy  130 , the navigation control vehicle  106  or the like, and not the absolute location of the target independent of the location of any other object. Indeed, in the absence of information regarding the absolute location of the navigation control vehicle  106  or the other aerial assets, such as in an instance in which the GPS or other positioning systems are jammed, the position of the target  108  may best be defined in a relative sense. 
     As shown in operation  178  of  FIG. 3 , the navigation control vehicle  106  and, in one embodiment, the communications interface  158 , e.g., a transmitter, of the navigation control vehicle may be also configured to provide information regarding the relative location of the target  108  with respect to the navigation control vehicle to one or more aerial assets, such as one or more unmanned aerial vehicle (UAVs)  100 ,  102 ,  104 , one or more missiles  120  or the like. To facilitate communications between the navigation control vehicle  106  and the aerial assets, the navigation control vehicle and the aerial assets may be networked in such a manner as to utilize, for example, frequency hopping data links so as to prevent or reduce the likelihood of being jammed. The aerial asset to which the information regarding the relative location of the target  108  is directed may include a communications unit, e.g., a receiver, configured to receive the information regarding the relative location of the target with respect to the navigation control vehicle  106  that is provided by the navigation control vehicle. Additionally, the aerial asset may include a processor configured to determine the relative location of the aerial asset from the navigation control vehicle  106 , such as in terms of the distance between the aerial asset and the navigation control vehicle and the angular position of the navigation control vehicle with respect to the aerial asset, based upon, for example, the networking between the navigation control vehicle and the aerial asset. 
     The processor of the aerial asset may also be configured to determine, in turn, the relative location of the target  108  with respect to the aerial asset based upon the relative location of the target  108  with respect to the navigation control vehicle  106  and the relative location of the navigation control vehicle  106  with respect to the aerial asset. As such, the aerial asset, such as the processor of the aerial asset, may identify the relative location of the target  108  with respect to the aerial asset even though the absolute location of the target  108  and, indeed, the absolute location of the aerial asset may not be known, such as a result of the jamming of GPS and other positioning systems of the aerial asset. 
     Once the relative location of the target  108  with respect to the aerial asset is identified, the aerial asset may interact with the target in the desired manner, such as by tracking the target, capturing images of the target, intercepting the target or the like. In instances in which the target  108  is to be intercepted, such as with a missile  120  or the like, the aerial asset may increase the likelihood of success by capturing an image of the target and determining the aimpoint at which the target should ideally be intercepted. In one example embodiment in which the aerial assets include UAVs  100 ,  102  and  104  that are configured to capture an image of the target  108 , the aerial assets may each include hardware (e.g., antennas and corresponding processing equipment) for projecting beams or cones of electromagnetic radiation from corresponding radar systems onto the target and then collecting the data that returns from those beams or cones. In this example, UAV  100  projects cone  112 , UAV  102  projects cone  114 , and UAV  104  projects cone  116 . 
     In response to these cones being projected, the different aerial assets may each collect the signals that return from a corresponding one of the cones  112 ,  114  and  116  to generate respective different partial views of the target  108 . Each of the aerial assets  100 ,  102  and  104  may collect its own data that is reflective of the views it has generated over time while receiving radar data corresponding to the target  108 . The radar data may be generated responsive to active transmissions by one or more of the aerial assets  100 ,  102  and  104  (or even the navigation control vehicle  106 ). Each of these respective partial images that are generated by the aerial assets  100 ,  102  and  104  may then be fed to a single master vehicle. In this regard, any one of the aerial assets may serve as the master vehicle in order to perform the master vehicle functions described below. For purposes of illustration but not of limitation, aerial asset  100  may be initially designated as the master vehicle, although this designation may change over time. The master vehicle  100  may more easily communicate with the other aerial assets since it is typically closer in proximity to the other aerial assets than the navigation control vehicle  106  or other control node. In an example embodiment, the aerial assets  100 ,  102  and  104  may communicate with each other using communication links  118 . The master vehicle  100  may then generate a composite 3D image of the object based on the radar data received from each of the other aerial assets (which may be considered to be slave vehicles). Further details regarding the generation of a composite 3D image and the aimpoint data are provided by U.S. patent application Ser. No. 12/968,815, filed Dec. 15, 2010, entitled Method and Apparatus for Providing a Dynamic Target Impact Point Sweetener, the contents of which are incorporated herein by reference. Example embodiments of the present disclosure enable the use of radar images to examine (e.g., with the corresponding cones  112 ,  114  and  116 ) an area in which the target  108  may be located, that is, an area of uncertainty (AOU)  119  around the target  108 , in order to enable generation of a relatively complete image of the AOU  119  and the target  108  therein. The aerial assets  100 ,  102  and  104  may fly around the target  108 , which may itself also be moving. Thus, the AOU  119  may be moving. Moreover, in some cases, as indicated above, coordination of the flight paths of the aerial assets  100 ,  102  and  104  may be accomplished via the communication links  118  to provide for control over the formation and/or movement of the aerial assets to improve the quality and/or completeness of the images received therefrom. As such, a relatively accurate composite 3D image of the target  108  may be generated over time to enable identification of the target. 
     The master vehicle (e.g., aerial asset  100 ) may receive radar data from each of the other vehicles and combine the received radar data with the radar data collected locally at the master vehicle  100  in order to generate a composite 3D image of the target  108 . The composite 3D image may, in some cases, also include data indicative of some internal features of the target  108  in instances where the electromagnetic radiation generated by the radar systems of the aerial assets  100 ,  102  and  104  has sufficient power to permit the transmitted electromagnetic waves to penetrate (at least to some degree) the target and to reflected by or otherwise returned following interaction with the internal features of the target. The composite 3D image (with or without data indicative of internal features) may then be compared to a target library to determine an accurate model and/or identity of the target  108  as described in greater detail below. Once the target  108  has been identified (or its identity confirmed), aimpoint data may be generated and shared with the other vehicles based on the class or identity of the target. The aimpoint data may then be used by the vehicles to guide prosecution of an attack on the target  108  based on vulnerabilities of the target as determined by the identity or classification of the target. This aimpoint data may, in one embodiment, define the most vulnerable point on the target. In this regard, missile  120  may utilize this aimpoint data in the prosecution of the target  108 . 
     Accordingly, example embodiments may provide for observation of a target  108  to be performed by a plurality of aerial assets in which at least one of the aerial assets is capable of guiding the observation and also performing tomographic reconstruction of a composite 3D image of the target using data received from the aerial assets. The corresponding one of the aerial assets may also be configured to identify the target  108  based on the composite 3D image and share information determined based on the identity (e.g., the composite 3D image itself and/or aimpoint data for the identified target) with the other aerial assets. 
       FIG. 4  illustrates a block diagram of hardware that may be employed on the master vehicle  100 . It should be appreciated that, as indicated above, in some embodiments, all or at least a plurality of the aerial assets have the capability of functioning as the master vehicle  100 . Thus, each aerial asset may, in some embodiments, include the structure described in  FIG. 4 . 
     As shown in  FIG. 4 , the aerial assets, such as UAVs  100 ,  102  and  104 , may include a data processing system  200  to process data received responsive to locally received radar returns or return data received by other aerial assets and generate the composite 3D image of the target  108 . The data processing system  200  may include a communication bus  202  or other communication fabric to provide communication between the various components of the data processing system  200 . The data processing system  200  components may include a processor  204 , a memory  206 , a communication unit  208  and an input/output unit  210 . In an example embodiment, the processor  204  may be configured to execute instructions stored in a memory device (e.g., memory  206 ) or otherwise accessible to the processor  204 . By executing stored instructions or operating in accordance with hard coded instructions, the processor  204  may control the operation of the data processing system  200  by directing functionality of the data processing system  200  associated with implementing composite 3D image generation and target identification described herein. In an example embodiment, the input/output unit  210  may provide for connection to any other modules that may be used in connection with the data processing system  200 . Thus, for example, the input/output unit  210  may provide for an interface with a radar system for generating transmissions and receiving and/or processing return data. The input/output unit  210  may also provide for any other interface needed with other components to provide, receive, process, store, or otherwise manipulate data that may be generated or used within the data processing system  200 . 
     In an example embodiment, the processor  204  and/or the memory  206  may comprise portions of processing circuitry configured to cause the data processing system  200  to perform functionality according to the configuration either hardwired into the processor  204  or provided by the execution of instructions stored in the memory  206 . As such, the data processing system  200  may be configured to control processes associated with composite 3D image reconstruction and target identification along with the provision of aimpoint data to other vehicles as described herein. Thus, for example, the data processing system  200  may represent an apparatus that may be configured (e.g., by execution of stored instructions) to generate a composite three dimensional representation of a target based on radar data received at the apparatus from other aerial assets generating projections over an area in which the target  108  is located (e.g., the AOU  119 ) and based on radar data generated by an aerial asset in which the apparatus is located. The apparatus may be further configured to identify the target  108  based on the composite three dimensional representation, and generate aimpoint data regarding the target based on an identity of the target. This aimpoint data may define the most vulnerable point on the target  108 . In an example embodiment, the apparatus may include memory storing at least an updateable target library  232  indicating respective target parameters for a plurality of known potential targets. The processor  204  may be further configured to communicate the aimpoint data from the apparatus, acting as a master vehicle, to at least one of the other aerial assets acting as a slave vehicle. In some embodiments, identifying the target  108  may include comparing the composite three dimensional representation of the target to a plurality of known representations of targets in the target library to determine the identity of the target based on a degree of matching between the composite three dimensional representation and one of the known representations. In some cases, generating aimpoint data may include utilizing characteristics regarding vulnerable locations within the target  108  based on the identity of the target to generate coordinates for an aimpoint for attacking the target. In an example embodiment, the processor  204  may be further configured to shift the apparatus from a master vehicle status to a slave vehicle status thereby causing the apparatus to stop generating the composite three dimensional representation, identifying the target  108  and generating the aimpoint data and instead causing the apparatus to provide radar data generated by the aerial asset to one of the other aerial assets acting as a master vehicle and receive aimpoint data from the master vehicle. 
     In an example embodiment, the processor  204  of the master vehicle of  FIG. 4  may control the collection of radar data and may then use the radar data collected from various different processing units of each of the aerial assets to generate a composite 3D image of the target  108 . The composite 3D image of the target  108  may then be used to identify (or confirm the identification of) the target based on comparison of the composite 3D image to known target data. In an example embodiment, the memory  206  may store a target library including image data for various different potential targets. As such, the processor  204  may be configured to determine the class or type of target that the target  108  corresponds to and, in some cases, even perhaps the hull number of certain distinctive targets. The disclosure of commonly owned U.S. Pat. No. 7,968,831 to Meyer et al., which is incorporated herein by reference, describes an example of the use of a target image library for comparing target image data to that of stored image data to determine a specific target. 
     Example embodiments of the present disclosure may utilize the identification of a specific target  108  to determine vulnerabilities of the corresponding target. The areas on the target  108  may be determined based on known information about the corresponding identified object. This information may then be used to generate aimpoint data that may be provided from the master vehicle to other aerial assets including, for example, one or more missiles  120 . In some examples, the aimpoint data may include the relative position of a vulnerable location on the target  108 . As such, the aimpoint data may identify a “sweet spot” for hitting the specific identified target  108  based upon the relative location of the target with respect to the master vehicle. The other aerial assets that receive the aimpoint data including the relative location of the target  108  may, in turn, determine the relative location of the target with respect to itself based upon the information provided by the master vehicle and the relative location of the master vehicle with respect to the aerial asset that receives the aimpoint data as determined, for example, based upon the networking of the master vehicle and the other aerial assets. In some embodiments, the aimpoint data may be accompanied with or otherwise include the composite 3D image data as well. 
     In some example embodiments, the processor  204  may control operation of a target classifier  230  configured to identify or classify targets based on a comparison of the composite 3D image to known target data from a target library  232  (e.g., stored in the memory  206 ). The identity or classification of the target may then be used by an aimpoint generator  234  to generate aimpoint data as described above. Since each vehicle may be able to operate as the master, each vehicle may have a target library  232  on board. However, in some embodiments, only the master vehicle may actually employ the target library  232 . 
     After the master vehicle provides aimpoint data to the aerial assets, attack on the target  108  may be authorized either by virtue of the aimpoint data being provided or by separate message providing such authorization. In some cases, one or more of the aerial assets that have been provided with the aimpoint data (e.g., those vehicles that are missiles  120 ) may simply attack the target  108  based on the aimpoint data including the relative location of the target. However, in some other examples, the aerial assets may continue to generate radar data on the target  108  as they approach the target to further confirm (or even modify) the aimpoint data based on perceivable differences between the aimpoint data provided and the current position of the target  108  (e.g., due to evasive maneuvers or other factors that may change target location or orientation). 
     Many modifications and other embodiments of the disclosure set forth herein will come to mind to one skilled in the art to which these embodiments pertain having the benefit of the teachings presented in the foregoing descriptions and the associated drawings. Therefore, it is to be understood that the disclosure is not to be limited to the specific embodiments disclosed and that modifications and other embodiments are intended to be included within the scope of the appended claims. Although specific terms are employed herein, they are used in a generic and descriptive sense only and not for purposes of limitation.