System and method for nulling or suppressing interfering signals in dynamic conditions

A system and method for nulling or suppressing interfering signals directed toward moving platforms based, at least in part, on dynamic motion data of the moveable platform is provided. The system may be an interference nulling system carried by a moveable platform and may include an antenna array including two or more antenna elements that generates at least one initial steerable null radiation pattern, dynamic motion data logic that determines dynamic motion data of the moveable platform; and update logic that updates the at least one initial steerable null radiation pattern based, at least in part, on the dynamic motion data. The at least one updated steerable null radiation pattern is directed toward a direction from which interfering signals are being transmitted from an interfering signal source.

BACKGROUND

Technical Field

The present disclosure relates generally to nulling or suppressing interfering signals. More particularly, the present disclosure relates to nulling or suppressing interfering signals directed toward moveable platforms. Specifically, the present disclosure relates to nulling or suppressing interfering signals directed toward moveable platforms based, at least in part, on dynamic motion data of the platform.

Background Information

Generally, the Global Positioning System (GPS) is a global navigation satellite system that provides geolocation, time, and range information to a GPS receiver anywhere on or near the Earth where there is an unobstructed line of sight to four or more GPS satellites. Modern tactical systems, such as tactical systems carried by vehicles, typically rely on GPS data for navigation and other purposes. However, a typical concern associated with GPS technology is GPS interference. Typical sources of GPS interference include, but are not limited to, radio frequency (RF) signals in frequency bands proximate to the GPS signals, intentional or unintentional jamming, naturally occurring meteorological conditions, and multipath effects.

One particular type of interference that may affect modern tactical systems is jamming, which may be defined as transmitting signals for the purpose of obstructing reception of GPS signals. As many operations associated with modern tactical systems are dependent upon GPS data, such as, for example, navigation capabilities, jamming may cause deleterious effects.

One conventional method of nulling or suppressing interference is beam forming which is defined as a signal processing technique used in sensor arrays for directional signal transmission or reception. Beamforming is accomplished by combining antenna elements in an antenna array in such a way that signals at particular angles experience constructive interference while others experience destructive interference. For example, a dynamic platform, such as, but not limited to, a guided shell, missile, aircraft, or ship, may utilize two or more antenna elements in an antenna array to null out one or more interfering signal sources, such as one or more GPS jammers. This is accomplished by phase shifting and weighting the antenna outputs and summing the results, so that one or more nulls are placed in the direction of the one or more interfering signal sources. However, since the position and orientation of the dynamic platform changes, the direction of the null, relative to the dynamic platform, changes. This requires changes or updates in the phase shifts and weight values. One conventional method that accounts for the changes in the direction of the null is to readjust the antenna weight coefficients in response to the received level of interfering signals transmitted from the GPS jammer. Since the adjustments are based on a response to the received level of interfering signals transmitted from the GPS jammer, the conventional method may be subject to delays and may have difficulty nulling out the interfering signals due to the rapidly changing dynamics of the platform.

SUMMARY

Issues continue to exist with nulling or suppressing interfering signals directed toward moving platforms. The present disclosure addresses these and other issues by providing a system and method for nulling or suppressing interfering signals directed toward moving platforms based, at least in part, on dynamic motion data of the platform.

In one aspect, an exemplary embodiment of the present disclosure may provide an interference nulling system for a moveable platform, comprising an antenna array including two or more antenna elements that generates at least one initial steerable null radiation pattern; wherein the at least one initial steerable null radiation pattern is directed toward a direction from which interfering signals are being transmitted from at least one interfering signal source; at least one sensor that senses dynamic motion data of the moveable platform; wherein the dynamic motion data includes at least one or more rotational movements of the moveable platform; dynamic motion data logic that processes the dynamic motion data of the moveable platform; and update logic that updates the at least one initial steerable null radiation pattern based, at least in part, on the dynamic motion data; wherein the at least one updated steerable null radiation pattern is directed toward the direction from which the interfering signals are being transmitted from the at least one interfering signal source. The at least one initial steerable null radiation pattern is based, at least in part, on an initial set of weight coefficients of the two or more antenna elements; and wherein the at least one updated steerable null radiation pattern is based, at least in part, on an updated set of weight coefficients of the two or more antenna elements. The dynamic motion data represents at least one of: (i) one or more rotational motions of the moveable platform; and/or (ii) one or more translational motions of the moveable platform.

The interference nulling system may further include logic, processes, instructions, or algorithms, that determine a first set of weight coefficients of the two or more antenna elements; wherein the at least one initial steerable null radiation pattern is based, at least in part, on the first set of weight coefficients.

The interference nulling system may further include first position logic that determines a current position of the moveable platform based, at least in part, on the dynamic motion data; second position logic that determines a predicted position of the moveable platform based, at least in part, on the dynamic motion data; and adaptive weight logic that determines a second set of weight coefficients of the two or more antenna elements based, at least in part, on a change between the current position of the moveable platform and the predicted position of the moveable platform; wherein the at least one updated steerable null radiation pattern is based, at least in part, on the second set of weight coefficients.

The interference nulling system may further include first orientation logic that determines a current orientation of the moveable platform based, at least in part, on the dynamic motion data; second orientation logic that determines a predicted orientation of the moveable platform based, at least in part, on the dynamic motion data; and adaptive weight logic that determines a second set of weight coefficients of the two or more antenna elements based, at least in part, on a change between the current orientation of the moveable platform and the predicted orientation of the moveable platform; wherein the at least one updated steerable null radiation pattern is based, at least in part, on the second set of weight coefficients.

The interference nulling system may further include position and velocity logic that determines a position and velocity of the interfering signal source; tracking logic that tracks movement of the at least one interfering signal source; adaptive weight logic that determines a second set of weight coefficients of the two or more antenna elements based, at least in part, on the movement of the at least one interfering signal source; wherein the at least one updated steerable null radiation pattern is based, at least in part, on the second set of weight coefficients.

In one particular embodiment, the moveable platform may be a precision guidance kit for a guided projectile; wherein the interference nulling system is carried by the precision guidance kit; and wherein the precision guidance kit comprises a canard assembly including at least one canard that is moveable. In one example, the dynamic motion data may represent one or more rotational motions of the precision guidance kit (e.g. coning and other angular motions of the precision guidance kit). In another example, the dynamic motion data may represent one or more translational motions of the precision guidance kit.

In another aspect, an embodiment of the present disclosure may provide a method comprising generating at least one initial steerable null radiation pattern of an array antenna including two or more antenna elements carried by a moveable platform; obtaining dynamic motion data of the moveable platform; wherein the dynamic motion data includes at least one or more rotational movements of the moveable platform; updating the at least one initial steerable null radiation pattern based, at least in part, on the dynamic motion data of the moveable platform; and directing the at least one updated steerable null radiation pattern toward a direction from which interfering signals are being transmitted from an interfering signal source. The at least one initial steerable null radiation pattern is based, at least in part, on an initial set of weight coefficients of the two or more antenna elements; and wherein the at least one updated steerable null radiation pattern is based, at least in part, on an updated set of weight coefficients of the two or more antenna elements. The dynamic motion data represents one of: (i) one or more rotational motions of the moveable platform; and (ii) one or more translational motions of the moveable platform.

The method may further include determining a first set of weight coefficients of the two or more antenna elements; wherein the at least one initial steerable null radiation pattern is based, at least in part, on the first set of weight coefficients.

The method may further include determining a current position of the moveable platform based, at least in part, on the dynamic motion data; determining a predicted position of the moveable platform based, at least in part, on the dynamic motion data; and determining a second set of weight coefficients of the two or more antenna elements based, at least in part, on the current position of the moveable platform and the predicted position of the moveable platform; wherein the at least one updated steerable null radiation pattern is based, at least in part, on the second set of weight coefficients.

The method may further include determining a current orientation of the moveable platform based, at least in part, on the dynamic motion data; determining a predicted orientation of the moveable platform based, at least in part, on the dynamic motion data; and determining a second set of weight coefficients of the two or more antenna elements based, at least in part, on the current position of the moveable platform and the predicted position of the moveable platform; wherein the at least one updated steerable null radiation pattern is based, at least in part, on the second set of weight coefficients.

The method may include determining and updating a position and velocity of the interfering signal source; tracking the movement of the at least one interfering signal source; and determining a second set of weight coefficients of the two or more antenna elements based, at least in part, on the movement of the at least one interfering signal source; wherein the at least one updated steerable null radiation pattern is based, at least in part, on the second set of weight coefficients.

In one particular embodiment, the moveable platform may be a precision guidance kit mounted on a guided projectile; wherein the interference nulling system is carried by the precision guidance kit; and wherein the precision guidance kit comprises a canard assembly including at least one canard that is moveable. In one example, the method may further include rotating the precision guidance kit in one or more rotational motions; wherein the dynamic motion data represents the one or more rotational motions. In another example, the method may further include translating the precision guidance kit in one or more translational motions; wherein the dynamic motion data represents the one or more translational motions.

In another aspect, an embodiment of the present disclosure may provide a system and method for nulling or suppressing interfering signals directed toward moving platforms based, at least in part, on dynamic motion data of the moveable platform. The system may be an interference nulling system carried by a moveable platform and may include an antenna array including two or more antenna elements that generates at least one initial steerable null radiation pattern, dynamic motion data logic that determines dynamic motion data of the moveable platform; and update logic that updates the at least one initial steerable null radiation pattern based, at least in part, on the dynamic motion data. The at least one updated steerable null radiation pattern is directed toward a direction from which interfering signals are being transmitted from an interfering signal source.

DETAILED DESCRIPTION

As depicted throughoutFIG.1throughFIG.6, an interference nulling system in accordance with certain aspects of the present disclosure is shown generally at1. The interference nulling system1includes an antenna array3having two or more antenna elements5, at least one sensor7, dynamic motion data logic9, update logic11, weight logic13, first position logic15, second position logic17, first orientation logic19, second orientation logic21, adaptive weight logic23, position and velocity logic25a, and tracking logic25b. The interference nulling system1is operably engaged with a moveable platform10. The moveable platform10may be any suitable moveable platform. Some exemplary moveable platforms include, but are not limited to, unmanned aerial vehicles (UAVs), manned aerial vehicles, land-based vehicles, sea-based vehicles, projectiles, guided projectiles, artillery shells, missiles, rockets, or any other suitable moveable platforms. Although the interference nulling system1has been described as including particular logics, it is to be understood that the interference nulling system1may include any suitable logics.

In one particular embodiment, the moveable platform10may be a precision guidance kit (PGK), which is also shown generally at10, operatively coupled with a munition body12, which may also be referred to as a projectile, to create a guided projectile14. The PGK10may be connected to the munition body12via a threaded connection; however, the PGK10may be connected to the munition body12in any suitable manner. Although the platform10is depicted as being the PGK10operatively coupled to the munition body12forming the guided projectile14, it is to be understood that the platform10may be any moveable vehicle.

FIG.1depicts that the munition body12includes a front end16and an opposite tail or rear end18defining a longitudinal direction therebetween. The munition body12includes an annular edge20(FIG.1A), which, in one particular embodiment, is a leading edge on the munition body12such that the annular edge20is a leading annular edge that is positioned at the front end16of the munition body12. The munition body12may define a cylindrical cavity22extending rearward from the annular edge20longitudinally centrally along a center of the munition body12. The munition body12is formed from material, such as metal, that is structurally sufficient to carry an explosive charge configured to detonate or explode at, or near, a target24(FIG.3). The munition body12may include tail flights (not shown) which help stabilize the munition body12during flight.

FIG.1andFIG.1Adepict that the PGK10, which may also be referred to as a despun assembly, includes, in one example, a fuze setter26, a canard assembly28having one or more canards28a,28b, a control actuation system (CAS)30, a guidance, navigation and control (GNC) section32, at least one bearing34, and a battery36. In one particular embodiment, the interference nulling system1is provided within the GNC section32of the PGK10. As such, the antenna array3having two or more antenna elements5and the at least one sensor7is carried within the GNC section of the PGK10. Although the interference nulling system1has been described as being provided within the GNC section32of the PGK10, the interference nulling system1may be provided in any suitable manner on the PGK10. In one particular embodiment, the antenna array3is a GPS antenna array27having two or more GPS antenna elements29. In one particular embodiment, the at least one sensor7is a plurality of sensors, such as, for example, a GPS receiver32a, a magnetometer32b, a microelectromechanical systems (MEMS) gyroscope32c, an MEMS accelerometer32d, at least one inertial measurement unit (IMU)32e, and at least one inertial navigation system (INS)32f. The GPS antenna array27having two or more GPS antenna elements29is operatively engaged with the GPS receiver32a. Although the at least one sensor7has been described as being particular sensors, it should be noted that in other examples the at least one sensor7may include other sensors, including, but not limited to, laser guided sensors, electro-optical sensors, imaging sensors, or any other suitable sensors. The at least one sensor7is configured to sense dynamic motion data of the PGK10. The dynamic motion data represents one or more rotational motions and/or one or more translational motions of the PGK10. The rotational motions and/or the translational motions may be depicted utilizing any suitable coordinate systems.

The PGK10includes a nose or front end42and an opposite tail or rear end44. When the PGK10is connected to the munition body12, a longitudinal axis X1extends centrally from the rear end18of the munition body to the front end42of the PGK10.FIG.1Adepicts one embodiment of the PGK10as generally cone-shaped and defines the nose42of the PGK10. The one or more canards28a,28bof the canard assembly28are controlled via the CAS30. The PGK10further includes a forward tip46and an annular edge48. In one embodiment, the annular edge48is a trailing annular edge48positioned rearward from the tip46. The annular edge48is oriented centrally around the longitudinal axis X1. The annular edge48on the canard PGK10is positioned forwardly from the leading edge20on the munition body12. The PGK assembly10further includes a central cylindrical extension50that extends rearward and is received within the cylindrical cavity22via a threaded connection.

Annular edge48is shaped and sized complementary to the leading edge20. In one particular embodiment, a gap52is defined between the annular edge48and the leading edge20. The gap52may be an annular gap surrounding the extension50that is void and free of any objects in the gap52so as to effectuate the free rotation of the PGK10relative to the munition body12.

PGK10may include at least one lift canard28aextending radially outward from an exterior surface54relative to the longitudinal axis X1. The at least one lift canard28ais pivotably connected to a portion of the PGK10via the CAS30such that the lift canard28apivots relative to the exterior surface54of the PGK10about a pivot axis X2. In one particular embodiment, the pivot axis X2of the lift canard28aintersects the longitudinal axis X1. In one particular embodiment, a second lift canard28ais located diametrically opposite the at least one lift canard28a, which could also be referred to as a first lift canard28a. The second lift canard28ais structurally similar to the first lift canard28asuch that it pivots about the pivot axis X2. The PGK10can control the pivoting movement of each lift canard28avia the CAS30. The first and second lift canards28acooperate to control the lift of the guided projectile14while it is in motion after being fired from a launch assembly56(FIG.3).

The PGK10may further include at least one roll canard28bextending radially outward from the exterior surface54relative to the longitudinal axis X1. In one example, the at least one roll canard28bis pivotably connected to a portion of the PGK10via the CAS30such that the roll canard28bpivots relative to the exterior surface54of the PGK10about a pivot axis X3. In one particular embodiment, the pivot axis X3of the roll canard28bintersects the longitudinal axis X1. In one particular embodiment, a second roll canard28bis located diametrically opposite the at least one roll canard28b, which could also be referred to as a first roll canard28b. The second roll canard28bis structurally similar to the first roll canard28bsuch that it pivots about the pivot axis X3. The PGK10can control the pivoting movement of each roll canard28bvia the CAS30. The first and second roll canards28bcooperate to control the roll of the guided projectile14while it is in motion after being fired from the launch assembly56(FIG.3).

With primary reference toFIG.3AandFIG.3B, the operation of the interference nulling system1carried by the guided projectile14formed by the PGK10when it is connected to the munition body12is shown. As shown inFIG.3A, the guided projectile14is fired from the launch assembly56elevated at a quadrant elevation towards the target24located at an estimated or nominal distance58from the launch assembly56. As the guided projectile14travels along a trajectory61, the guided projectile14receives GPS signals63from a plurality of GPS satellites65. As shown inFIG.3A, at least one interfering signal source67, such as a GPS jammer, transmits interfering signals69in an attempt to deny the GPS antenna array27access to the GPS signals63while the guided projectile14is at a first position FP. Although the interfering signal source67has been described as being a GPS jammer, the interfering signal source67may be any interfering signal source. For example, and not meant as a limitation, the interfering signal source67may be any radio frequency (RF) jamming device capable of jamming any RF frequency, such as, for example, an RF jamming device used to jam communications in a communications system. In another non-limiting example, the interfering signal source67may be associated with multipath interference from reflections of the signal.

The GPS antenna array27including the two or more GPS antenna elements29generates at least one steerable null radiation pattern71. In one example, the at least one steerable null radiation pattern71is generated by using the two or more GPS antennas29to shape a response pattern by determining a first set of weight coefficients of the two or more antenna elements29. In one example, the weight coefficients are complex numbers or complex weights defined by an amplitude A and phase Phi which may be written as A*exp(i*phi) where “i” is sqrt(−1). In other words, the response pattern is shaped by selection of the weight coefficients of the two or more antenna elements29. In one example, the weight logic13, which may include at least one non-transitory computer readable storage medium having instructions encoded thereon that, when executed by at least one processor, implements operations to determine the first set of weight coefficients of the two or more antenna elements29. The at least one steerable null radiation pattern71is based, at least in part, on the first set of weight coefficients determined by the weight logic13. Typically, the output from each of the two or more antenna elements29is down converted to a baseband signal, which includes complex time samples. The complex time samples are multiplied by the first set of weight coefficients to form the signal processed by the GPS receiver32a. Although a particular manner of generating the at least one steerable null radiation pattern71has been described, the at least one steerable null radiation pattern71may be generated in any suitable manner. The at least one steerable null radiation pattern71is directed towards the interfering signals69which nulls out the interfering signals69. The GPS antenna array27including the two or more GPS antenna elements29generates at least one steerable main lobe radiation pattern73which is directed towards the GPS signals63, which are the signals of interest, so only the GPS signals63are received by the GPS receiver32a. However, since the PGK10rotates and translates, the direction and/or angle of the at least one steerable null radiation pattern71changes based upon the changes in the rotation and translation of the PGK10. Since the PGK10is a seven degree of freedom (DOF) system, the PGK10can rotate relative to the munition body12and the motion of the munition body12can be accounted for. An exemplary change in the direction and/or angle of the at least one steerable null radiation pattern71is shown inFIG.3Bwhere the guided projectile is at a second position SP that is different than the first position FP. In the event there are two or more interfering signal sources67, withFIG.5showing one exemplary scenario, the teachings of the present disclosure can be applied to null or suppress the interfering signals69being transmitted from the two or more interfering signal sources67. Another exemplary change in the direction and/or angle of the at least one steerable null radiation pattern71is shown inFIG.4AandFIG.4B. As shown inFIG.4A, the guided projectile14is at a particular orientation and position and the at least one steerable null71is directed toward the interfering signals69at a first angle α1, and as shown inFIG.4B, the guided projectile14is at a different orientation and a different position and the at least one steerable null71is directed toward the interfering signals69at a second angle α2. One conventional method that accounts for the changes in the direction of the at least one steerable null radiation pattern71readjusts the first set of weight coefficients in response to the received level of interfering signals69coming from the interfering signal source67. Since the readjustments are based on a response to the received interfering signals69coming from the interfering signal source67, the conventional method may be subject to delays and may have difficulty nulling out the interfering signals69due to the rapidly changing dynamics of the PGK10. Further, if the interfering signal source67ceases transmission of the interfering signals69, the interfering signal source67cannot typically be tracked. When the interfering signal source67activates transmission of the interfering signals69, the at least one steerable null71typically will not be pointing in the direction of the interfering signals69due to the change in the geometry related to the dynamics of the PGK10which typically causes a time delay before the at least one steerable null radiation pattern71is pointed toward the interfering signals69. Therefore, there is a need for, and the present disclosure provides, an updated mechanism that accounts for rotations and/or translations of the PGK10, such as, for example, changes in roll, pitch or yaw and/or translations as the PGK10travels along the trajectory61as more fully described below.

The dynamic motion data logic9may include at least one non-transitory computer readable storage medium having instructions encoded thereon that, when executed by at least one processor, implements operations to determine dynamic motion data of the PGK10. The dynamic motion data may represent one or more rotational and/or translational motions of the PGK10. For example, and not meant as a limitation, the dynamic motion data logic9may determine, inter alia, the position, orientation, and velocity of the PGK10based, at least in part, on the measurements from the at least one sensor7. In one non-limiting example, position data of the PGK10may be provided by the GPS antenna elements29and the GPS receiver32aand the orientation and velocity data of the PGK10may be provided by one or more of the magnetometer32b, the MEMS gyroscope32c, the MEMS accelerometer32d, the at least one IMU32e, and the at least one INS32f. Although a particular manner of determining the position, orientation, and velocity of the PGK10has been described, the position, orientation, and velocity of the PGK10may be determined in any suitable manner.

In one particular embodiment, the update mechanism may be update logic11which may include at least one non-transitory computer readable storage medium having instructions encoded thereon that, when executed by at least one processor, implements operations to update the at least one steerable null radiation pattern71based, at least in part, on the dynamic motion data as more fully described below. The at least one updated steerable null radiation pattern71is directed toward a direction from which the interfering signals69are being transmitted from the interfering signal source67.

The first position logic15, which may include at least one non-transitory computer readable storage medium having instructions encoded thereon that, when executed by at least one processor, implements operations to determine a current position of the PGK10based, at least in part, on the dynamic motion data. The second position logic17, which may include at least one non-transitory computer readable storage medium having instructions encoded thereon that, when executed by at least one processor, implements operations to determine a predicted position of the PGK10based, at least in part, on the dynamic motion data. The predicted position of the PGK10may be determined by utilizing a projectile dynamics model, such as a seven DOF model; however, any suitable projectile dynamics model may be utilized. For example, and not meant as a limitation, the projectile dynamics model may be a three DOF model including, at least in part, a Jacobian reference, a three DOF model including, at least in part, a drag profile, a three DOF model including, at least in part, a steering Jacobian reference accounting for, at least in part, steering applied to the guided projectile14, a five DOF model, a six DOF model, and a seven DOF model. The various DOF models, such as the augmented three DOF model, the five DOF model, the six DOF model, and the seven DOF model may vary in accuracy and complexity and the type of DOF model utilized with the teachings of the present disclosure may depend on particular applications and configurations. The adaptive weight logic23, which may include at least one non-transitory computer readable storage medium having instructions encoded thereon that, when executed by at least one processor, implements operations to determine a second set of weight coefficients of the two or more antenna elements29based, at least in part, on the current position of the PGK10and the predicted position of the PGK10. In this example, the at least one updated steerable null radiation pattern71is based, at least in part, on the second set of weight coefficients.

The first orientation logic19, which may include at least one non-transitory computer readable storage medium having instructions encoded thereon that, when executed by at least one processor, implements operations to determine a current orientation of the PGK10based, at least in part, on the dynamic motion data. The second orientation logic21, which may include at least one non-transitory computer readable storage medium having instructions encoded thereon that, when executed by at least one processor, implements operations to determine a predicted orientation of the PGK10based, at least in part, on the dynamic motion data. The predicted orientation of the PGK10may be determined by utilizing a projectile dynamics model, such as a seven degree of freedom (DOF) model; however, any suitable projectile dynamics model may be utilized. For example, and not meant as a limitation, the projectile dynamics model may be a three DOF model including, at least in part, a Jacobian reference, a three DOF model including, at least in part, a drag profile, a three DOF model including, at least in part, a steering Jacobian reference accounting for, at least in part, steering applied to the guided projectile14, a five DOF model, a six DOF model, and a seven DOF model. The various DOF models, such as the augmented three DOF model, the five DOF model, the six DOF model, and the seven DOF model may vary in accuracy and complexity and the type of DOF model utilized with the teachings of the present disclosure may depend on particular applications and configurations. The adaptive weight logic23may determine a second set of weight coefficients of the two or more antenna elements29based, at least in part, on the current orientation of the PGK10and the predicted orientation of the PGK10. In this example, the at least one updated steerable null radiation pattern71is based, at least in part, on the second set of weight coefficients.

The position and velocity logic25a, which may include at least one non-transitory computer readable storage medium having instructions encoded thereon that, when executed by at least one processor, implements operations to determine a location of the interfering signal source67. In one example, the location of the interfering signal source67is predetermined and uploaded to the interference nulling system1prior to generating the at least one steerable null radiation pattern71. In another example, determining the location of the interfering signal source67is accomplished by triangulation.

The tracking logic25b, which may include at least one non-transitory computer readable storage medium having instructions encoded thereon that, when executed by at least one processor, implements operations to track movement (e.g. a position and velocity) of the at least one interfering signal source67. In one example, the tracking logic25butilizes the position and velocity of the at least one interfering signal source67determined by the position and velocity logic25ato determine a predicted position and velocity of the at least one interfering signal source67. The adaptive weight logic23may determine a second set of weight coefficients of the two or more antenna elements29based, at least in part, on the predicted position and velocity of the at least one interfering signal source67. In this example, the at least one updated steerable null radiation pattern71is based, at least in part, on the second set of weight coefficients.

For example, and not meant as a limitation, the at least one interfering signal source67may move from one position to another position as shown inFIG.6as position A and position B. The position and velocity logic25adetermines the location of the interfering signal source at location A and the tracking logic25bdetermines a predicted position of the at least one interfering source67at position B. After the tracking logic25bdetermines the predicted position B of the at least one interfering signal source67, the at least one steerable null radiation pattern71is directed toward position B.

The above-described processes associated with the interference nulling system1may be iterated until the end of the guided projectile's14flight path or any other desired time period. For example, the interference nulling system1may continuously receive dynamic motion data over a specified period time, such as every second of the guided projectile's flight path, continuously update the at least one steerable null radiation pattern71, and continuously direct the at least one steerable null radiation pattern71toward a direction from which the interfering signals69are being transmitted from the interfering signal source67. As described above, the at least one updated steerable null radiation patterns71are generated based, at least in part, on the dynamic motion data of the PGK10. Some benefits of the interference nulling system1of the present disclosure include, inter alia, allowing the at least one steerable null radiation pattern71to be accurately directed toward interfering signals69in highly dynamic conditions, improving update latency by utilizing dynamic motion data to update the weight coefficients of the antenna elements29, allowing tracking of interfering signal sources67, and removing the need to relock nulls on an interfering signal source67after an interfering signal source67ceases and activates transmission of interfering signals69.

FIG.7is a flow chart of one method or process in accordance with the present disclosure and is generally indicated at700. The method700may include generating at least one initial steerable null radiation pattern71of an array antenna3including two or more antenna elements5carried by a moveable platform10, which is shown generally at702. The method700may include obtaining dynamic motion data of the moveable platform10, which is shown generally at704. The method700may include updating the at least one initial steerable null radiation pattern71based, at least in part, on the dynamic motion data of the moveable platform10, which is shown generally at706. The method700may include directing the at least one updated steerable null radiation pattern71toward a direction from which interfering signals69are being transmitted from at least one interfering signal source67, which is shown generally at708. In one example, obtaining dynamic motion data of the moveable platform10may be accomplished by sensing the dynamic motion data with at least one sensor7carried by the moveable platform10. In one example, the dynamic motion data represents one or more rotational motions or one or more translational motions of the moveable platform10.

The method700may further include determining a first set of weight coefficients of the two or more antenna elements5, which is shown generally at710. The at least one steerable null radiation pattern71may be based, at least in part, on the first set of weight coefficients.

The method700may include determining a current position of the moveable platform10based, at least in part, on the dynamic motion data, which is shown generally at712. The method700may include determining a predicted position of the moveable platform10based, at least in part, on the dynamic motion data, which is shown generally at714. The method700may include determining a second set of weight coefficients of the two or more antenna elements5based, at least in part, on the current position of the moveable platform10and the predicted position of the moveable platform10, which is shown generally at716. The at least one updated steerable null radiation pattern71may be based, at least in part, on the second set of weight coefficients.

The method700may include determining a current orientation of the moveable platform10based, at least in part, on the dynamic motion data, which is shown generally at718. The method700may include determining a predicted orientation of the moveable platform10based, at least in part, on the dynamic motion data, which is shown generally at720. The method700may include determining a second set of weight coefficients of the two or more antenna elements based, at least in part, on the current position of the moveable platform10and the predicted position of the moveable platform10, which is shown generally at722. The at least one updated steerable null radiation pattern71may be based, at least in part, on the second set of weight coefficients. The method700may include determining a location of the interfering signal source67, which is shown generally at724.

In one example the moveable platform10may be a precision guidance kit10for a guided projectile14; wherein the interference nulling system1is carried by the precision guidance kit10; and wherein the precision guidance kit10comprises a canard assembly28including at least one canard28a,28bthat is moveable. The method700may further include rotating the precision guidance kit10in one or more rotational motions; wherein the dynamic motion data represents the one or more rotational motions, which is shown generally at726. The method700may further include translating the precision guidance kit10in one or more translational motions; wherein the dynamic motion data represents the one or more translational motions, which is shown generally at728.

FIG.8is a schematic block diagram of one method or process in accordance with the present disclosure generally indicated at800. The method800may include computing a change in the weight coefficients of the two or more antenna elements5, which may be referred to as Δw, and in one particular embodiment, is represented by the difference between the current, or first, set of weight coefficients of the two or more antenna elements5, and the updated, or second, set of weight coefficients of the two or more antenna elements5. The computation of Δw occurs at block802. The initial or first set of weight coefficients of the two or more antenna elements5are computed at block804and are fed to block806, which may also be referred to as a sample and hold block. The first set of weight coefficients are needed to steer the at least one steerable null radiation pattern71towards a direction from which interfering signals69are being transmitted from the at least one interfering signal source67. The first set of weight coefficients is stored in block806. The first set of weight coefficients, and later the current set of weights, of the two or more antenna elements5is provided to block802. In order to compute Δw, block802may be fed data from block808, which may contain data from the at least one sensor7, such as the IMU32e, from block810, which may contain data from the at least one sensor7, such as the INS32f, as well as GPS data as more fully described below. Estimated positions x(t), orientation angles φ(t), θ(t), ψ(t), angular rate of change of positions p(t), q(t), and r(t), and velocities v(t) of the PGK10are computed based on the data received from block808,810, and the GPS data, and future predictions of x(t+Δt), orientation angles φ(t+Δt), θ(t+Δt), ψ(t+Δt), angular rate of change of positions p(t+Δt), q(t+Δt), and r(t+Δt), and velocities v(t+Δt) of the PGK10, are computed based on the data received from block808,810, and the GPS data. The estimated positions, orientation angles, angular rate of change of positions, and velocities of the PGK10and the predicted positions, orientation angles, angular rate of change of positions, and velocities are fed to block802to compute the Δw. Optionally, block802may be fed data from block812, which may contain predicted positions and velocities of the at least one interfering signal source67and the data from block812may be utilized to compute Δw via a Kalman filter or any other suitable tracking process or method. Thus, Δw is computed based on the current, or first, set of weight coefficients of the two or more antenna elements5and the geometrical factors supplied from boxes808,810, and812. The current, or first, set of weight coefficients of the two or more antenna elements5are added to the Δw to compute the updated, or second, set of weight coefficients of the two or more antenna elements5, which may be referred to as w(t+Δt). The updated, or second set of weight coefficients of the two or more antenna elements5are fed to block814, which may also be referred to as a weighting and null angle estimator block, and back to block806, which is updated at every iteration of the method800. Therefore, the method800provides an updated, or second, set of weight coefficients of the two or more antenna elements5every iteration or cycle of the method800. Block816, which contains data received by the two or more antenna elements5, or the raw GPS signals received by the two or more antenna elements5, feeds data to block818, which produces data from an I and Q downconversion process, and the downconverted data is fed to block814. The weighting process associated with block814multiplies the updated, or current or second, set of weight coefficients of the two or more antenna elements5, or w(t+Δt), with the downconverted signals for each antenna element5of the two or more antenna elements5to provide a weighted signal R, which has interference suppressed or removed, which is fed to block820to be processed by the GPS receiver32a. The GPS receiver32aproduces GPS data which is fed to block822. The GPS data used to compute the estimated positions and velocities of the PGK10and the future predictions of positions and velocities of the PGK10as described above is provided by block822. Further, the GPS data includes an estimate of the position and velocity of the PGK10which is used to steer the PGK10. Block814produces a null location which is fed to block824. The null location is fed to block812and block812uses the null location to track the interfering signal source67and estimate velocities of the interfering signal source67. The steerable null radiation patterns71are utilized to remove or suppress the effect of the interfering signals69from the interfering signal source67in the weighted signal R.

It is to be understood that the various logics, such as the dynamic motion data logic9, the update logic11, the weight logic13, the first position logic15, the second position logic17, the first orientation logic19, the second orientation logic21, the adaptive weight logic23, the position and velocity logic25a, and the tracking logic25bmay utilize any suitable number of non-transitory computer readable storage mediums and any suitable number of processors. For example, and not meant as a limitation, the various logics can be stored on one non-transitory computer readable storage medium or multiple computer readable storage mediums and the various logics can be processed by any suitable number of processors.

Also, a computer or smartphone utilized to execute the software code or instructions via its processors may have one or more input and output devices. These devices can be used, among other things, to present a user interface. Such computers or smartphones may be interconnected by one or more networks in any suitable form, including a local area network or a wide area network, such as an enterprise network, and intelligent network (IN) or the Internet. Such networks may be based on any suitable technology and may operate according to any suitable protocol and may include wireless networks, wired networks or fiber optic networks.

“Guided projectile” or guided projectile14refers to any launched projectile such as rockets, mortars, missiles, cannon shells, shells, bullets and the like that are configured to have in-flight guidance.

“Launch Assembly” or launch assembly56, as used herein, refers to rifle or rifled barrels, machine gun barrels, shotgun barrels, howitzer barrels, cannon barrels, naval gun barrels, mortar tubes, rocket launcher tubes, grenade launcher tubes, pistol barrels, revolver barrels, chokes for any of the aforementioned barrels, and tubes for similar weapons systems, or any other launching device that imparts a spin to a munition round or other round launched therefrom.

In some embodiments, the munition body12is a rocket that employs a precision guidance kit10that is coupled to the rocket and thus becomes a guided projectile14.

Furthermore, the logic(s) presented herein for accomplishing various methods of this system may be directed towards improvements in existing computer-centric or internet-centric technology that may not have previous analog versions. The logic(s) may provide specific functionality directly related to structure that addresses and resolves some problems identified herein. The logic(s) may also provide significantly more advantages to solve these problems by providing an exemplary inventive concept as specific logic structure and concordant functionality of the method and system. Furthermore, the logic(s) may also provide specific computer implemented rules that improve on existing technological processes. The logic(s) provided herein extends beyond merely gathering data, analyzing the information, and displaying the results. Further, portions or all of the present disclosure may rely on underlying equations that are derived from the specific arrangement of the equipment or components as recited herein. Thus, portions of the present disclosure as it relates to the specific arrangement of the components are not directed to abstract ideas. Furthermore, the present disclosure and the appended claims present teachings that involve more than performance of well-understood, routine, and conventional activities previously known to the industry. In some of the method or process of the present disclosure, which may incorporate some aspects of natural phenomenon, the process or method steps are additional features that are new and useful.