ESA quadrant mechanical reconfiguration

A system and method for ESA quadrant mechanical reconfiguration functions to shift some of the complexity from algorithmic manipulation of received radar data to mechanical transformation of a simple panel structure to achieve desired performance in a desired ESA boresight. The system receives a rotation trigger based on an external event such as altitude and mission and causes two or more simple ESA panels to rotate from a first azimuthal position to a second common azimuthal position without stopping at an intermediate azimuth. Once positioned, each individual rotational ESA panel is combined to function as a single aggregate ESA enabling desired performance in field of view, resolution, and range along a common boresight.

BACKGROUND

Beamforming may be complex on angled, multi panel electronically scanned array (ESA) surfaces requiring signal delays as well as return signal integration across varying sets of quadrants. These multi panel ESA configurations may be considerably expensive compared to the supporting hardware and mechanical fixtures. In an angled multi panel design, an apparent aperture size may reduce as the directed beam moves away from boresight which results in lower gain, lower range and increased interference.

Traditional multi-axis rotation system may require heavy and power consuming alignment hardware. These complex mechanical scanning systems may continuously drive the ESA in azimuth or elevation and require algorithmically complex and power consuming computers to process the received radar signals.

Therefore, a need remains for a system and related method which may overcome these limitations and provide a novel solution to simply mechanically rotating a portion or an entirety of two or more ESA panels and electrically combining the rotated ESA panels to form a single aggregate ESA.

SUMMARY

In one embodiment of the inventive concepts disclosed herein, a system for mechanically positioning an electronically scanned array (ESA) panel may comprise two or more rotational ESA panels onboard an aircraft, the two rotational ESA panels configured for a rotation, the rotation about a vertical axis. For rotation, each of the two rotational ESA panels may be individually operational in a first azimuthal position having a first boresight and collectively operational in a second azimuthal position having a common boresight, the second azimuthal position of each of the two rotational ESA panels being equal, the first azimuthal position distant from the second azimuthal position by the rotation.

To manipulate the rotational ESA panels, an actuator may be coupled with each of the two rotational ESA panels, the actuator configured to mechanically cause the rotation. The system may also include a radar display available to one of a pilot and an autopilot of the aircraft.

For overall control, the system may include a controller operatively coupled with each of the two rotational ESA panels and the actuator and a tangible, non-transitory memory configured to communicate with the controller, the tangible, non-transitory memory having instructions stored therein that, in response to execution by the controller, cause the controller to carry out each function of the system.

The controller may receive a rotation trigger for commanding the actuator to rotate the two rotational ESA panels and command the actuator to rotate the two rotational ESA panels from the first azimuthal position to the second azimuthal position without stopping in an intermediate azimuthal position. The controller may further electronically couple the two rotational ESA panels while in the second azimuthal position to coherently operate as a single aggregate ESA having the common boresight and receive a radar signal from the single aggregate ESA having the common boresight.

For crew awareness, the system may display the radar signal on the radar display. Once the rotation trigger may no longer be active, the controller may receive a de-rotation trigger to rotate the two rotational ESA panels from the second azimuthal position to the first azimuthal position and command the actuator to de-rotate the two rotational ESA panels from the second azimuthal position to the first azimuthal position.

An additional embodiment of the inventive concepts disclosed herein is directed to a method for mechanically positioning an electronically scanned array (ESA) panel. The method may comprise receiving a rotation trigger for commanding an actuator to rotate two rotational ESA panels onboard an aircraft and commanding an actuator to mechanically rotate the two rotational ESA panels about a vertical axis from a first azimuthal position to a second azimuthal position.

The method may include electronically coupling the two rotational ESA panels while in the second azimuthal position to coherently operate as a single aggregate ESA having a common boresight and receiving a radar signal from the single aggregate ESA having the common boresight. The method may further include displaying the radar signal on a radar display onboard the aircraft.

It is to be understood that both the foregoing general description and the following detailed description are exemplary and explanatory only and are not necessarily restrictive of the inventive concepts as claimed. The accompanying drawings, which are incorporated in and constitute a part of the specification, illustrate embodiments of the inventive concepts and together with the general description, serve to explain the principles of the inventive concepts disclosed herein.

DETAILED DESCRIPTION OF EXEMPLARY EMBODIMENTS

As used herein the term “approximately” in claim language as well as specification language may refer to a range of values plus or minus twenty percent (+/−20%) of the claimed value. For example, “approximately 100” may refer to, and therefore claim, the range of 80 to 120.

Overview

Broadly, embodiments of the inventive concepts disclosed herein are directed to a system and method for ESA quadrant mechanical reconfiguration. The system functions to shift some of the complexity from algorithmic manipulation of received radar data to mechanical transformation of a simple panel structure to achieve desired performance in a desired ESA boresight. The system receives a rotation trigger based on an external event such as altitude and mission and causes two or more simple ESA panels to rotate from a first azimuthal position to a second common azimuthal position without stopping at an intermediate azimuth. Once positioned, each individual rotational ESA panel is combined to function as a single aggregate ESA enabling desired performance in field of view, resolution and range at a common boresight.

Referring toFIG.1, a diagram of a system100for mechanically positioning an electronically scanned array panel in accordance with an embodiment of the inventive concepts disclosed herein is shown. Generally, a system for mechanically positioning an electronically scanned array panel may include angularly, mechanically manipulating rotational ESA panels from a first azimuthal position to a second, common azimuthal position. Once rotated, the system may function to electronically couple the two rotational ESA panels while in the second azimuthal position to coherently operate as a single aggregate ESA having a common boresight.

System Description

In one embodiment of the inventive concepts disclosed herein, the system for mechanically positioning an electronically scanned array panel100may include at least two rotational ESA panels which may include a left rotational ESA122and a right rotational ESA124. In some configurations, the two rotational ESA panels may be in a chevron configuration as shown inFIG.1. Additional configurations of the rotational ESA panels may fall directly within the scope of the inventive concepts disclosed herein.

The rotational ESA122124may be installed onboard an aircraft and configured for a rotation which may be about a vertical axis as well as a horizontal axis. In some embodiments, the rotational ESA panels may rotate about the vertical axis which is also aligned perpendicularly with a longitudinal axis of the aircraft.

As used herein, the vertical (Z) axis may be associated with a lift vector of the aircraft about which the aircraft may yaw. A Longitudinal (X) axis may be the axis about which the aircraft may roll (e.g., centerline). The horizontal (Y) axis may be the axis about which the aircraft may pitch.

In some embodiments, the left rotational ESA122may rotate about a vertical rotation axis126in a vertical rotation direction128. While in the first azimuthal position (here, shown at 45 degrees left of the longitudinal axis), the left rotational ESA122may maintain a left ESA scan volume132as well as a left ESA boresight142. Similarly, the right rotational ESA124may maintain a right ESA scan volume134and a right ESA boresight144when positioned to the first azimuthal position. In some embodiments, each of the at least two rotational ESA panels may be individually operational in the first azimuthal position having a first boresight and collectively operational in a second azimuthal position having a common boresight, the second azimuthal position of each of the at least two rotational ESA panels being equal, the first azimuthal position distant from the second azimuthal position by the rotation. In some embodiments, the first boresight142of the left rotational ESA panel122may be distant from the first boresight144of the right rotational ESA panel134by at least 45 degrees. In another embodiment, the rotation from the first azimuthal position to the second azimuthal position may be approximately 45-60 degrees.

As used herein, an azimuthal position may include a boresight of the rotational ESA panel122in azimuth. The azimuthal position may be physically limited by aircraft internal configuration (e.g. nose radome area, aircraft structure blocking radar energy). Generally, each azimuthal position herein may be discussed surrounding a forward-looking radar system (e.g. +/−120 degrees of the nose). However, additional azimuthal positions (e.g., aft, side) and elevational positions (e.g. down, up) may fall directly within the scope of the inventive concepts disclosed herein.

In one embodiment of the inventive concepts disclosed herein, the system for mechanically positioning an electronically scanned array panel100may include an actuator120coupled with each of the at least two rotational ESA panels, the actuator configured to mechanically cause the rotation. The actuator120may be a single actuator120functional to rotate both of the at least two rotational ESA panels as well as multiple actuators120configured to individually rotate an individual ESA panel or multiple rotational ESA panels.

In one embodiment, the system for mechanically positioning an electronically scanned array panel100may further include a radar display114available to a pilot and/or an autopilot of the aircraft. The radar display114used herein may be defined as an information device configured for presenting radar information in a format recognizable by the intended recipient. Here, a pilot may be the intended recipient wherein a visual display may be appropriate. In some embodiments, the display may be an interface configured for information exchange in a format recognizable by a mission computer or autopilot processor for autonomous operation. In some embodiments, the system for mechanically positioning an electronically scanned array panel100may include a positioning system116configured for supplying a position as well as an altitude of the aircraft.

Also, as used herein, the term aircraft may apply to any aerial vehicle to which an ESA panel may be operationally coupled. Exemplary aerial vehicles may include a manned aircraft, an unmanned aircraft system (UAS), as well as a rotorcraft and multi (e.g., quad) rotor copter.

In one embodiment of the inventive concepts disclosed herein, the system for mechanically positioning an electronically scanned array panel100may include a controller110operatively coupled with each of the at least two rotational ESA panels and the actuator. The controller110may function to control the radar operation of each ESA panel as well as the rotation of each ESA panel.

In embodiments, the system for mechanically positioning an electronically scanned array panel100may further include a tangible, non-transitory memory112configured to communicate with the controller110, the tangible, non-transitory memory112may have instructions stored therein that, in response to execution by the controller, cause the controller to carry out each function of the systems herein.

Referring now toFIGS.2A-C, diagrams of a top view full panel center rotation in accordance with an embodiment of the inventive concepts disclosed herein are shown. A full panel center rotation diagram200may indicate a rotation of each of the left rotational ESA panel122and the right rotational ESA panel124about a vertical rotation axis126aligned with the longitudinal axis of the aircraft.

System Function

In one embodiment of the inventive concepts disclosed herein, the controller110may receive a rotation trigger for commanding the actuator120to rotate the at least two rotational ESA panels122124and command the actuator120to rotate the at least two rotational ESA panels122124from the first azimuthal position to the second azimuthal position without stopping in an intermediate azimuthal position. In one embodiment, the first azimuthal position and the second azimuthal position are separated by approximately 45 degrees

In embodiments, the rotation trigger may be related to a plurality of factors causing a change in the boresight of the left122and right124rotational ESA panels. In some embodiments, the rotation trigger may be any of an altitude trigger, a mission trigger, a threat trigger including a radar warning receiver (RWR) indication, a ground proximity warning, a traffic trigger, a manual trigger via pilot interaction with the radar display, and an environmental trigger such as weather, windshear, turbulence, etc. For example, an altitude trigger may be associated with a specific altitude (e.g., below 3000 ft AGL) of the aircraft received by the positioning system116. At low altitude, one employment operation may include a forward-looking radar where each rotational ESA panel122124may be positioned to the second azimuthal position. The altitude related trigger may offer the ability to automatically position the rotational ESA panels to the desired common boresight152.

In one embodiment, the mission trigger may include a specific desired common boresight152for accomplishing a specific mission. For example, one mission may be a ground mapping radar mission where a forward common boresight152may be desirable. A terrain following mission may also provide a mission trigger to cause the controller110to command a specific common boresight152. Additionally, the controller110may receive a windshear or traffic alert and cause the controller110to take action. In one embodiment, the controller may automatically rotate and de-rotate the rotational ESA panels122124based on the altitude.

In one embodiment, the common boresight may be aligned with the longitudinal axis of the aircraft to enable a forward-looking radar system for a plurality of mission related purposes (e.g., ground proximity, traffic awareness, weather awareness).

In one embodiment, the controller110may depower each of the rotational ESA panels122124during the rotation. This depower action may function to create a two-position operation of either operation in the first azimuthal position or operation in the second azimuthal position without scanning an azimuth between the two. For example, the left rotational ESA panel122may function in the first azimuthal position with a boresight centered 45 degrees left of the aircraft nose (longitudinal axis). During rotation to the second azimuthal position the left rotational ESA panel122may be depowered during the rotation and unable to scan any azimuth during rotation. Once in the second azimuthal position, the controller110may repower the left rotational ESA panel122to scan the common boresight152aligned with the longitudinal axis.

Once the rotational ESA panels122124are in the second azimuthal position, the controller110may electronically couple the at least two rotational ESA panels while in the second azimuthal position to coherently operate as a single aggregate ESA222having the common boresight152and a combined ESA scan volume150. This may effectively create a larger synthetic planar array whose horizontal size is a plan back projection of the conformal structure. While the rotational ESA panels122124are in the second azimuthal position, the controller110may apply similar controlling logic to the single aggregate ESA222as applied to each individual rotational ESA prior to the rotation. In this manner, a simple configuration of two rotational ESA panels122124may increase function of the system for mechanically positioning an electronically scanned array panel100by shifting system complexity from a powerful computing device to a simple mechanical actuator120.

In one embodiment, the controller110may receive a radar signal from the single aggregate ESA panel222having the common boresight152and display the radar signal on the radar display. Once the rotation trigger may be no longer valid, the controller110may receive a de-rotation trigger to rotate the at least two rotational ESA panels122124from the second azimuthal position back to the first azimuthal position and command the actuator120to rotate the at least two rotational ESA panels122124from the second azimuthal position to the first azimuthal position without stopping in the intermediate azimuthal position.

Of note, the indicated scan volume150may be exemplary only wherein a typical scan volume of an ESA panel may reach 90 degrees either side of the boresight. Here for clarity of diagrams, a scan volume150may be displayed in the figures for illustrative purposes only.

In one embodiment of the inventive concepts disclosed herein, the controller110may be configured to command the actuator to perform a calibration of the at least two rotational ESA panels122124to each of the first azimuthal position and the second azimuthal position. Here, as the controller110may precisely rotate each of the rotational ESA panels122124, a calibration function embedded within the controller110may offer a system calibration for ensuring the first azimuthal position and the second azimuthal position are precisely planar.

FIG.3Partial Panel Rotation

Referring now toFIGS.3A-C, diagrams of a partial panel center rotation300exemplary of an embodiment of the inventive concepts disclosed herein are shown. In some embodiments, the system for mechanically positioning an electronically scanned array panel100may be constrained by an internal shape of an aircraft radome310. In this situation, the system for mechanically positioning an electronically scanned array panel100may not be able to rotate each full panel rotational ESA as inFIG.2. In the first azimuthal position shown inFIG.3A, each of the four ESA panels is functional and radiating with the two ESA panels on the left having the left boresight142and the two ESA panels on the right having the right boresight144. Once the controller110begins the rotation,FIG.3Bmay indicate a stationary left ESA322and a stationary right ESA324remaining in position while the rotational ESA panels122124begin to rotation to the second azimuthal position.

FIG.3Cmay indicate each of the rotational ESA panels122124complete in the rotation to the second azimuthal position and radiating as the single aggregate ESA222having the common boresight152and the scan volume150.

Referring now toFIGS.4A-F, diagrams of a partial panel lateral rotation400exemplary of one embodiment of the inventive concepts disclosed herein are shown. In one embodiment of the inventive concepts disclosed herein, the system for mechanically positioning an electronically scanned array panel100may function within a radome310of smaller size yet still enabling full rotation of the partial rotational ESA panels122124from the first to the second azimuthal position.

Here, a left actuator422and a right actuator424may function to rotate the left122and right124rotational ESA panels about the vertical axes126(left and right) laterally displaced from the longitudinal axis of the aircraft. In this manner, internal space required for rotation may be less than a centerline vertical axis of rotation as inFIGS.2and3.

In one embodiment of the inventive concepts disclosed herein, the single aggregate ESA222may include an overlap of the individual rotational ESA panels122124once the rotation is complete. The controller110may electrically determine a partial radiation pattern of one of the panels to enable accurate ESA operation. For example, the left rotational ESA panel122may partially function with the partial radiation pattern while the right rotational ESA panel124may fully radiate.

FIGS.4D through4Fmay indicate an additional embodiment where each of the four ESA panels may rotate about a vertical axis126displaced from the longitudinal axis. Here, a left outer rotational ESA panel432and a right outer rotational ESA panel434coupled respectively with the rotational ESA panels122124may further rotate the ESA panels to the second azimuthal position.

In one embodiment, the rotational ESA panels may be directed or “aimed” to align their individual boresights at a point in space. Here, a boresight focus may intersect at a single point in the distance or the boresights may be aimed at particular points of an object in the distance.

In this embodiment, the left and right outer rotational ESA panels may combine to form the single aggregate ESA222when rotated to the second azimuthal position. Although laterally displaced from the longitudinal axis, the left432and right434outer rotational ESA panels may electrically function as the single aggregate ESA panel222with an appropriate time delay/phase shift applied between the arrays.

Referring now toFIGS.5A-C, diagrams of a partial panel center translation rotation500in accordance with one embodiment of the inventive concepts disclosed herein are shown. In one embodiment of the inventive concepts disclosed herein, the system for mechanically positioning an electronically scanned array panel100may further reduce a size necessary to perform the rotation by translating as well as rotating the rotational ESA panels122124. Here, the actuator120may be positioned on the longitudinal axis of the aircraft and translate a translating axis of rotation526along the longitudinal axis. While the translating axis of rotation moves aft in this scenario, the rotational ESA panels122124may also translate outboard along a translation rotation direction528to the second azimuthal position.

In one embodiment, the system for mechanically positioning an electronically scanned array panel100may employ a variety of mechanical subsystems to cause the rotational ESA panels122124to translate as well as rotate. For example, an actuator120including a precision jackscrew may cause the translating axis of rotation526to translate along the longitudinal axis.

Referring now toFIGS.6A-C, diagrams of an exemplary full panel lateral rotation in accordance with one embodiment of the inventive concepts disclosed herein are shown. In one embodiment, the vertical axis of rotation126may be aligned with the longitudinal axis of the aircraft (e.g.,FIG.2A), proximally offset from the longitudinal axis of the aircraft (e.g.,FIG.4A), and distally offset from the longitudinal axis (e.g.,FIG.6A).

Here, the vertical axis of rotation126may be laterally displaced at an outboard edge of the rotational ESA panels122124. The full panel lateral rotation600may maintain a significant inside overlap once the rotational ESA panels122124are rotated to the second azimuthal position. In this embodiment, the single aggregate ESA panel222may comprise a partial left radiating ESA622and a full right radiating ESA624.

Referring now toFIG.7A-C, diagrams of a right-side view700associated with one embodiment of the inventive concepts disclosed herein are shown. The right-side view700may indicate an additional embodiment wherein the system for mechanically positioning an electronically scanned array panel100may further rotate the rotational ESA panels122124in elevation about a horizontal axis of rotation726in a horizontal rotation direction728. Here,FIG.7Amay indicate the right panel124prior to the rotation about the vertical axis.FIG.7Bmay indicate the single aggregate ESA222after the rotation about the vertical axis is complete, andFIG.7Cmay detail the elevational rotation about the horizontal rotation axis726.

Once the controller110commands the single aggregate ESA222to the second azimuthal position the controller110may further rotate the single aggregate ESA222about the horizontal rotation axis726. Once complete, the single aggregate ESA222may function with a common boresight152angularly displaced from the longitudinal axis. As above, during rotation in both azimuth and elevation, the controller110may depower each rotational ESA panel122124and repower each once in the desired position.

In some embodiments, the system100may identify or “tune” the distance between a wall of the radome310and the ESA panel to attempt to compensate for radome imperfections and compensation. In this manner, the controller110may determine each signature of the radome310to which it is installed and compensate for various abnormalities within the radome310structure. For example, each radome310may include a frame structure, a lighting mitigation structure, and possible fasteners of variable composition (e.g., metallic, ferrous, reflective) through which radar energy may deviate from a perfect boresight. The controller110may compensate for these imperfections in processing the reflected radar energy within a specific azimuth of these imperfections.

Referring now toFIGS.8A-D, diagrams of a multi-panel rotation diagram800exemplary of one embodiment of the inventive concepts disclosed herein are shown. In one embodiment of the inventive concepts disclosed herein, the system for mechanically positioning an electronically scanned array panel100may include a six-panel rotational ESA configuration wherein the controller110may command a plurality of second azimuthal positions to enable a desired common boresight152.

FIG.8Amay indicate the six panel ESA array in a first configuration capable of a three boresight142152144operation. In an additional configuration,FIG.8Bmay indicate an additional azimuthal position of each of the six ESA panels offering the controller110an optional beam boresight where a left ESA second boresight442and a right ESA second boresight444may provide additional function.

In some embodiments, the ESA panels may be fitted within the radome310in a onetime fit of a “conformal” ESA and optimized conformal aperture size within an arbitrary radome. The subpanels may be coherently combined through time deal compensation to effectively create a conformal ESA. In other embodiments, the rotational ESA panels may be equal or unequal in size as indicated in the previous figures. In each configuration, simultaneous independent beams are possible across all the subpanels.

FIG.8Cmay indicate a folded configuration offering a chevron configuration whileFIG.8Dmay indicate each ESA panel operational and radiating in an extended chevron configuration.

In some embodiments, the plurality of rotational ESA may provide a maximum reuse with a standard ESA panel assembly that can be used and reconfigured to be compatible a host of radomes as well as additional applications (e.g., ground vehicles, watercraft, etc.) The reconfiguration may be either a onetime installation or mission dependent dynamic as described above.

In some embodiments, the mechanical rotation may be asymmetric as the application may demand. AlthoughFIGS.8A-8Dmay indicate a symmetric rotation, it is contemplated herein an asymmetric rotation (e.g., a left side rotation only) may fall well within the scope of the inventive concepts disclosed herein.

In embodiments, the mechanical rotation may be not at a 100% duty cycle, unlike existing electromechanically scanned systems, so compared with a traditional continuously scanning radar, embodiments of the inventive concepts disclosed herein may consume less DC power and maintain an increase in reliability.

In some embodiments, the separate sub-panels shown in the drawings may be made time/phase coherent to operate as a composite conformal aperture if the appropriate time delays are incorporated between the subpanels. Subpanels may function having an independently steered beam, may be a coherent conformal array, as well as toggle back and forth between these modes.

Referring now toFIG.9, a diagram of a method flow900exemplary of one embodiment of the inventive concepts disclosed herein is shown. The method flow900may include, at a step902, receiving a rotation trigger for commanding an actuator to rotate at least two rotational ESA panels onboard an aircraft, and, at a step904, commanding an actuator to mechanically rotate the at least two rotational ESA panels about a vertical axis from a first azimuthal position to a second azimuthal position.

The method may include, at a step906, electronically coupling the at least two rotational ESA panels while in the second azimuthal position to function as a single aggregate ESA having a common boresight. The method may further include, at a step908, receiving a radar signal from the single aggregate ESA having the common boresight and, at a step910, displaying the radar signal on a radar display onboard the aircraft

Conclusion

As will be appreciated from the above description, embodiments of the inventive concepts disclosed herein may provide a novel solution to simply mechanically rotating a portion or an entirety of two or more ESA panels and electrically combining the rotated ESA panels to form a single aggregate ESA.