Relative navigation and machine vision for automated aerial refueling system and method

A system and method for Automated Aerial Refueling (AAR) may combine unrelated capabilities to provide a high integrity solution to boom manipulation and insertion to couple with a receiver receptacle. Precise positioning systems on each aircraft coupled via data link provide a high integrity relative positioning solution generating a requisite integrity for positioning yet insufficient for boom insertion. High definition cameras onboard the tanker provide multi-wavelength remote vision digital images used to identify the boom fitting as well as the receptacle. Combined with boom position information from the tanker, the system determines pixel position inputs from stereo digital images to precisely identify the boom and receptacle and manipulate the boom to insert the boom fitting into the receptacle. Constant camera generated feedback and updated relative positioning alerts the system and disconnects the boom should the receiver aircraft stray outside the proper position.

BACKGROUND

Traditional aerial refueling methods may require a boom operator onboard the tanker aircraft to physically manipulate controls of a boom to “fly” the boom into a receptacle onboard a receiving aircraft. In some tankers, the boom operator may lie in a face down position and physically view the receiving aircraft through a window. In others, the boomer may sit at a station onboard the tanker and view a video of the receiving aircraft provided by one or more cameras located on the tail of the tanker.

In either case, the boomer must manually place the boom into the receiver's receptacle using a joystick or other interface to manipulate the tip of the boom in a three-dimensional arena to couple with the receptacle.

Humans may become fatigued. Visibility may often be reduced. Human perceptions may be inaccurate. Boomers may have inadequate experience for night or reduced visibility operations. Should the boomer erroneously strike the skin or body of a receiving aircraft, substantial damage may occur compromising mission success and aircraft integrity. Modern aircraft with stealth coating may be particularly susceptible to mission degrading damage from even the slightest boom strike.

Automated Aerial Refueling (AAR) may address a number of issues with current aerial refueling capabilities and provide a number of solutions to those issues. AAR has the potential to provide for life cycle cost savings to an operator by reducing both personnel and equipment required for a refueling evolution. AAR may also increase available fuel and cargo capacity.

Current positioning systems may provide a rudimentary level of positioning accuracy. However, these positioning systems may not support highly sophisticated and precise boom placement within a receiver receptacle. Some hybrid methods of relative navigation may provide a greater level of relative positioning but still lack a level of precision required for boom insertion into the receptacle.

Machine vision systems may provide accuracy, but are unable to provide integrity to ensure positive relative positioning between aircraft. Global Positioning Systems (GPS) based relative navigation may provide integrity at GPS carrier wavelength position accuracies (˜20 cm). However, neither system alone is sufficient to enable AAR, which requires high integrity due to proximity between aircraft, and high accuracy due to precise placement of the boom into the receptacle.

Therefore, a need remains for a system and related method which may overcome these limitations and provide a novel solution to AAR using high integrity relative positioning methods in cooperation with highly accurate machine vision systems.

SUMMARY

In one aspect, embodiments of the inventive concepts disclosed herein are directed to a system for automated boom placement in aerial refueling. The system may comprise a tanker positioning system operatively coupled with a tanker flight control computer (FCC) onboard a tanker aircraft and a camera suite onboard the tanker aircraft. To manipulate a refueling boom, the system may include a boom manipulating system onboard the tanker aircraft configured to three dimensionally manipulate a refueling boom onboard the tanker aircraft, the refueling boom having a boom male fitting.

The system may include a tanker controller onboard the tanker aircraft operatively coupled with the tanker positioning system, the tanker FCC, the camera suite, and the boom manipulating system and a data link operatively coupling the tanker controller with a receiver controller onboard a receiver aircraft, the receiver controller operatively coupled with a receiver positioning system and a receiver FCC, the receiver aircraft having a receiver female fitting.

To support the tanker controller, the system may include a tangible, non-transitory memory configured to communicate with the tanker controller, the tangible, non-transitory memory having instructions stored therein that, in response to execution by the tanker controller, cause the tanker controller to carry out the function of the system. The system may function to receive a positioning solution from the tanker positioning system, receive a positioning solution from the receiver positioning system via the data link, and generate a high integrity relative positioning solution based on the received positioning solutions. To preclude midair of the aircraft, the system may generate safety boundaries around each of the tanker aircraft and the receiver aircraft based on the HIRPS, the at least two safety boundaries including a tanker protection level and a tanker alert limit, a receiver protection level and a receiver alert limit, the protection levels smaller than the alert limits.

To accurately place the boom male fitting, the system may receive a video signal from the camera suite, the camera suite configured for sensing a field of view (FOV) proximal with the refueling boom and identify, based on the video signal, the boom male fitting and the receiver female fitting. Once identified, the system may determine, based on the video signal, a three-dimensional position of the boom male fitting and a three-dimensional position of the receiver female fitting and generate a boom limit container around the boom male fitting based on the three-dimensional position of the boom male fitting. The system may monitor each of: 1) the safety boundaries and 2) the three-dimensional position of the receiver female fitting relative to the boom limit container and send an alert if either protection level reaches either alert limit and if the three-dimensional position of the receiver female fitting exceeds the boom limit container. The system may manipulate, if the three-dimensional position of the receiver female fitting is within the boom limit container, the refueling boom to couple the boom male fitting with the receiver female fitting based on the three-dimensional position of the boom male fitting relative to the three-dimensional position of the receiver female fitting.

A further embodiment of the inventive concepts disclosed herein may include a method for automated boom placement in aerial refueling. The method may comprise receiving a tanker positioning solution for a tanker aircraft and receiving a receiver positioning solution for a receiver aircraft. For a high integrity positioning determination, the method may include generating a High Integrity Relative Positioning Solution (HIRPS), based on the tanker positioning solution and the receiver positioning solution. The method may further include generating at least two safety boundaries around each of the tanker aircraft and the receiver aircraft based on the HIRPS, the safety boundaries including a protection level and an alert limit, the protection level smaller than the alert limit. For safety, the method may include continuously comparing each protection level to each alert limit and sending an alert if either protection level reaches either alert limit. For accurate boom positioning, the method may include sensing a boom position, receiving a video signal of a FOV proximal with the boom position and identifying, based on the video signal, a boom male fitting coupled with a refueling boom and a receiver female fitting onboard the receiver aircraft.

The method may include determining, based on the video signal, a three-dimensional position of the boom male fitting, a three-dimensional position of the receiver female fitting and a boom limit container around a centered position of the boom male fitting based on the three-dimensional position of the boom male fitting. To ensure accurate boom placement is possible, the method may include continuously comparing the three-dimensional position of the receiver female fitting to the boom limit container and manipulating, if the three-dimensional position of receiver female fitting is within the boom limit container, a refueling boom to couple the boom male fitting with the receiver female fitting based on the three-dimensional position of the boom male fitting relative to the three-dimensional position of the receiver female fitting

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

Overview

Broadly, embodiments of the inventive concepts disclosed herein are directed to a system and method for Automated Aerial Refueling (AAR) may combine unrelated capabilities to provide a high integrity solution to boom manipulation and insertion to couple with a receiver receptacle. Precise positioning systems on each aircraft coupled via data link provide a high integrity relative positioning solution generating a requisite integrity for positioning yet insufficient for boom insertion. High definition cameras onboard the tanker provide multi-wavelength remote vision digital images used to identify the boom fitting as well as the receptacle. Combined with boom position information from the tanker, the system determines pixel position inputs from stereo digital images to precisely identify the boom and receptacle and manipulate the boom to insert the boom fitting into the receptacle. Constant camera generated feedback and updated relative positioning alerts the system and disconnects the boom should the receiver aircraft stray outside the proper position

Referring now toFIG. 1, a diagram of a system for automated boom placement in aerial refueling in accordance with an embodiment of the inventive concepts disclosed herein is shown. Generally, a system for automated boom placement in aerial refueling100may combine two separate technologies to create a system of high accuracy and integrity enabling AAR. Machine vision may be highly accurate but inherently possess little integrity while relative navigation differential GPS may be highly accurate (e.g., approximately 20 cm) but not accurate enough for AAR. The relative navigation may provide a high integrity solution between two closely maneuvering aircraft protecting against misleading information which could lead to a midair collision. Once the relative navigation solution provides the aircraft with the guidance to arrive at and maintain a contact position, the machine vision provides the accuracy to perform the AAR.

In one embodiment of the inventive concepts disclosed herein, the system100may be functional onboard a tanker aircraft (tanker)110equipped with a refueling boom130(boom). A receiver aircraft150(receiver) may be a recipient of an offload of fuel from the tanker110. Onboard the tanker110, a tanker positioning system112(hereinafter tanker global navigation satellite system (GNSS)) may function to determine a precise positioning solution of the tanker110.

As used herein, the GNSS may refer generically to any precise positioning system configured for receiving positioning signals from a space-based transmitter and using the received signals to provide a precise positioning solution. Contemplated herein, the system100may function using any type of global satellite system including a global positioning system (GPS) as well as others including, for example, a GLONASS, a Galileo, and a BeiDou system.

Further elements onboard the tanker110may include a tanker controller120operatively coupled with the tanker GNSS112, a tanker flight control computer (FCC)142, a camera suite124, a boom manipulating system132and a memory122.

The tanker FCC142may function as a traditional point control flight control processor receiving inputs from, for example, air data, an autopilot and flight crew and generating outputs such as commands to flight controls and management of fuel.

The camera suite124may be configured for sensing an area under a tail of the tanker proximal with the refueling boom130. Each camera within the camera suite124may be configured with a Field of View (FOV). The camera suite124may include a port tail camera114, a starboard tail camera116, and a center tail camera118. Contemplated herein, two cameras may suffice to accurately image the required elements. In embodiments, the camera suite may comprise two cameras configured for stereoscopic sensing of the FOV proximal with the refueling boom as well as one or more cameras configured for sensing a plurality of wavelengths. The system100may employ a plurality of cameras to effectively image, in a variety of atmospheric conditions, the area beneath the tail of the tanker110.

The boom manipulating system132may include a plurality of types of servos, actuators, and airfoils which may act on the boom130to three dimensionally manipulate the boom130(e.g. laterally (side-side), vertically (up-down), and horizontally (extension-retraction)). A boom tracking system134may mechanically track and supply the tanker controller120with the position of the boom130in three dimensions. In one embodiment of the inventive concepts disclosed herein, the boom tracking system134may include a series of high-resolution resolvers configured to accurately and mechanically track the refueling boom position in all axes and in extension and retraction. The tanker controller120may determine the three-dimensional position of the boom male fitting based in part on the mechanically tracked refueling boom position. In addition, the tracking system134, the boom130may include a plurality of subsystems to enable the tanker110to provide fuel to the receiver150. A conduit system within the refueling boom130may provide a path for fuel to be pumped from storage within the tanker110through the conduit system to the receiver150.

The memory122may comprise a tangible, non-transitory memory configured to communicate with the tanker controller120, the tangible, non-transitory memory having instructions stored therein that, in response to execution by the tanker controller120, cause the tanker controller120to perform the functions of the system100.

A data link140may operatively couple the tanker controller120with a receiver controller170for data sharing between the two computers. Onboard the receiver150, a receiver positioning system152(hereinafter receiver GNSS) may function to determine a precise positioning solution of the receiver aircraft150and operatively transmit the receiver position solution to the tanker controller120via the receiver controller170and the data link140. Also sited on the receiver150, a receiver receptacle154may function as a receptacle for mechanically coupling with the boom130to receive fuel inflight.

Each of the tanker110and the receiver150may employ air data sensors including a tanker Air Data Computer (ADC)162and a receiver ADC164to supply each FCC142144with air data (e.g., altitude, airspeed, temperature, etc.) to assist the tanker controller120in generating the precise relative positioning solution.

Referring now toFIG. 2, a diagram of a side view of AAR in accordance with an embodiment of the inventive concepts disclosed herein is shown. The side view200may indicate relative positions of the tanker110and receiver150while performing AAR. In AAR operation, the receiver150may be flown into a contact position either through pilot action or commanded by the tanker controller120via automated flight controls guided by the tanker controller120and communicated to the receiver controller170via the data link140. Similarly, once within the contact position the tanker controller120may send a flight control solution via the datalink140to the receiver controller170to remain within the contact position.

In one embodiment of the inventive concepts disclosed herein, the tanker controller120may receive a positioning solution from the tanker GNSS112directly and from the receiver GNSS152via the data link140. Based on the positioning solutions, the tanker controller120may then generate a high integrity relative position solution (HIRPS). The tanker controller120may determine the HIRPS using a plurality of methods to produce an accurate relative positioning solution. The relative positioning methods may bound a position error with a very high degree of certainty and assign a probability or confidence level sufficient for safe and functional positioning (formation).

One method may include a real time kinematic (RTK) analysis of a differential carrier phase GNSS measurements. Use of the differencing carrier phase measurements between the tanker GNSS112and the receiver GNSS152using RTK may remove common errors and increase accuracy of the HIRPS. In one embodiment of the inventive concepts disclosed herein, the receiver GNSS152may provide carrier phase measurements to the tanker controller120for accurate analysis. Another embodiment may include a receiver GNSS152without an ability to send the carrier phase measurements via the data link140. In this case, the relative navigation solution may be less accurate, but still sufficiently accurate for a pilot monitored AAR.

In another method for highly accurate positioning solution, the tanker controller120may employ a high accuracy relative navigation method such as a Geometry Extra-Redundant Almost Fixed Solutions (GERAFS) technique to provide decimeter level accuracies with high integrity for airborne station keeping. GERAFS may be best described within U.S. Pat. No. 7,768,451 B2 to Wu, et al. which is incorporated by reference herein in its entirety.

Generally, Wu, et. al. teach receiving two or more sets of reference GPS measurements and using a geometric extra-redundant (GER) system of equations to solve for a single baseline vector to compute a float solution and use of a wide lane float solution to guarantee better than 99%, for example, system availability. Wu, et. al. continue where a plurality of almost fixed solutions are lumped together with a correctly fixed solution, forming what is termed an enlarged pull-in region (EPIR) to determine the almost fixed solution (AFS).

An additional method of generating the HIRPS may be found in U.S. Pat. No. 10,274,606 to Phan, et. al which is incorporated by reference herein in its entirety. Phan teaches determining precision navigation solutions via decorrelation of a GPS carrier-phase ambiguities derived from multiple-source GPS information via Least-squares AMBiguity Decorrelation Adjustment (LAMBDA) algorithms, and fixes a subset of the decorrelated integer ambiguities within the LAMBDA domain. To maintain high accuracy, a partial almost fix solution is generated using the subset of the decorrelated ambiguities to be fixed in the LAMBDA domain. The subset of decorrelated ambiguities is used to compute protection levels and the probability of almost fix (PAF), or that the navigation solution corresponding to the decorrelated ambiguities is within the region of correctly—fixed or low—error almost fixed ambiguities. The partial list of fixed ambiguities is used to generate the optimal navigation solution (floating point, partial almost-fix, or fully fixed) while maintaining protection levels within alert limits and PAF above the desired threshold.

Safety Boundaries

The tanker controller120may generate multiple and individual safety boundaries, GNSS-based and video-based, to ensure safe and effective AAR. A first set of GNSS-based safety boundaries may function to prevent a midair collision between the tanker110and the receiver150. These GNSS-based safety boundaries may include a tanker protection level280and a tanker alert limit282based on the HIRPS. The protection level280may be generally defined as a calculated position based on the HIRPS inclusive of associated errors to create an uncertainty region. The uncertainty region may equate to the protection level280. The alert limit282may be generally defined as an outer limit of uncertainty that if the protection level may reach the alert limit, the HIRPS may be invalid and further AAR should be discontinued.

Similarly, the tanker controller120may generate a receiver protection level290and a receiver alert limit292also based on the HIRPS. Each protection level280290must be within each alert limit282292in order for the system100to prevent midair and begin safe AAR. Should either protection level280290touch or exceed either alert limit282292, the system100may declare an integrity event and send an alert.

A video-based boom limit container294may function to protect the refueling boom130. The boom limit container294may comprise a three-dimensional container surrounding a centered position of the boom male fitting402(FIG. 4). The boom limit container294may comprise a shaped volume (e.g., a sphere, cylinder, cuboid, etc.) having a dimension corresponding to a capability of the tanker110refueling boom130limits of movement. The boom limit container294may be oriented along a longitudinal axis of the receiver150, but also oriented along a boom axis and centered on the tip of the refueling boom as shown to ensure boom maneuvering during AAR may not exceed the boom limits of movement. The boom limit container294may be fixed relative to the tanker110to ensure the boom130remains within an operational limit.

For example, a large sized tanker110may possess boom limits of an exemplary +/−30 degrees of a conical shape around the boom130and an extension limit of an exemplary +/−8 feet. Here, the corresponding boom limit container294may be large in size compared to a boom limit container294of a smaller tanker130. The boom limit container294may comprise a three-dimensional container surrounding the receiver female fitting254.

To ensure the receptacle154of the receiver150is within the boom limit container294, the tanker controller120may compare the boom limit container294with the receiver position solution and generate and send a contact position report when the receiver150is stable within the boom limit container294. Here a tanker110flight crew as well as a receiver150flight crew may be interested in knowing when the receiver position solution matches the boom limit container294. Also, should the receptacle154on the receiver150begin to stray outside of the boom limit container294, the tanker controller120may send an alert.

In one embodiment of the inventive concepts disclosed herein, the system100may function to monitor each of: 1) the at least two safety boundaries including each protection level280290and each alert limit282292and 2) the three-dimensional position of the receiver female fitting254relative to the boom limit container294. Should any of these safety boundaries be approached, reached, or exceeded, the system100may send an alert if either protection level reaches either alert limit.

To avoid an alert, the system100may function to slave the receiver150to maintain the contact position during the AAR. The tanker controller120may function to determine a flight control solution for the receiver150, send the receiver flight control solution via the data link140to the receiver controller170to command the receiver FCC144to position the receiver female fitting254(FIG. 3) within the boom limit container294.

The receiver150may possess a plurality of physical characteristics able to be sensed by the camera suite124including a receiver canopy156, the receptacle154, a receiver left vertical tail158, and a receiver left horizontal tail160.

Each camera within the camera suite124may be limited by a camera field of view (FOV)214. In one embodiment, the port camera114may have a FOV approximately equal to the size of the boom limit container294while in another embodiment, the FOV214may be much larger offering the capability of one or more of the cameras within the camera suite124to image a large size (e.g., C-17) aircraft.

While accurate enough for station keeping, the HIRPS is not alone sufficient for terminal guidance of the refueling boom130to the receptacle154. However, once the receiver is within the receiver protection level290, the tanker controller120may employ the camera suite124enabling machine vision over a small FOV214to provide terminal guidance of the boom130to the receptacle154. Once an accurate relative position (with integrity) is established between tanker110and receiver150, the machine vision problem may be reduced to a much smaller image set to process, simplifying the algorithm, reducing false detections, and increasing the probability of correctly identifying the refueling receptacle154.

Contemplated herein, the HIRPS and subsequent safety boundaries may be solely determined by the tanker controller120. However, in one embodiment, each of the tanker controller120and the receiver controller170may share the processing responsibility for cooperatively producing and maintaining the HIRPS. In this case, the receiver controller170may then supply the receiver FCC144with a flight control solution to maintain the desired position and station keeping relative to the tanker110.

Referring now toFIG. 3, a diagram of a receiver detail exemplary of an embodiment of the inventive concepts disclosed herein is shown. In addition to the canopy156, receiver150characteristics saved within the memory and conspicuous to the camera suite124may enable the machine vision to determine a locate the receiver female fitting254. Such conspicuous elements may include a right vertical tail258, a receiver right wing262, a right door250of the AR compartment, a receiver number266, a left door252, a series of guide markings256, a rear empennage260, and a left wing264.

Each of these conspicuous elements defining a plurality of aircraft types may be 1) stored within the memory122as a data set defining each element and usable by machine vision with the tanker controller120to ID the element, 2) maintain a relative arrangement including dimensions stored within the memory122, 3) maintain a physical characteristic unlike another of the elements, and 4) maintain a conspicuous nature able to be sensed by one or more of the cameras within the camera suite124. The tanker controller120may command a three-dimensional tracker algorithm to identify pixel position inputs from stereo images of the camera suite124and calculate a 3D position of the receptacle154in space.

In one embodiment of the inventive concepts disclosed herein, the camera suite124may be configured to sense a plurality of wavelengths associated with the receiver aircraft to sense a plurality of characteristics of the receiver aircraft150. In one embodiment, the camera suite124may sense a visual spectrum and identify characteristics on the surface of the receiver aircraft150. For example, the rear empennage260may be a specific color or shape and a distance between the left258and right158vertical tails may be significant to the machine vision calculations.

Some receiver150characteristics may include a size, a color, a shape, a receiver number266, and the guide marking256associated with the receiver receptacle154. Another embodiment may include an infrared camera capable of sensing an IR signature (e.g., engine heat, fuselage temperature differences, lights) of the receiver150. Some tankers110may be specifically equipped with a lighting system configured to illuminate the receiver receptacle154. Here, the camera suite124may employ a visual sensor to sense the lighted receiver receptacle154while also employing an IR sensor to sense the IR signature associated with the lighted receptacle154. The system100may further employ an IR illuminator218(FIG. 2) associated with each IR camera to successfully illuminate and sense the receiver150positioned in the boom limit container294.

Referring now toFIG. 4, a diagram of a boom detail exemplary of one embodiment of the inventive concepts disclosed herein is shown. The boom130also may maintain conspicuous characteristics apparent to the camera suite124and the machine vision capabilities within the tanker controller120. The boom detail view400may indicate those characteristics specific to each boom for each tanker110.

A boom male fitting402at the tip of the boom conduit may provide the connection point with the receiver female fitting154. A boom extension404may function as the conduit for fuel and possess a capability of extension and retraction both powered and unpowered during refueling operations.

Color may be specifically conspicuous to the camera suite124. Here, the boom extension may be painted with color primarily for boomer and receiver visual indication of maximum, desired, and minimum extensions of the boom extension404. Generally, painted as a mirror on either side of a midpoint green with yellow apple414, the boom markings may indicate a desired, minimum and maximum extension of the boom extension404during refueling.

As the boom extension404is nearly entirely retracted a min red stripe406may be visible. A set of min red chevrons408, a min yellow stripe410, a set of min yellow chevrons412may indicate an approach to maximum retraction. Similarly, a set of max yellow chevrons416, a max yellow stripe418, a set of max red chevrons420, and a max red stripe422may indicate to the boomer and receiver pilot an approach to maximum extension from a boom housing430.

Each of these boom characteristics may be stored as definitions within the memory122for use by the tanker controller120for machine vision recognition and boom130positioning for insertion in the receiver female fitting254.

For control, many booms130may possess actuators within the tanker110fuselage for control of the boom position. On some tankers, a boom horizontal stabilizer432and boom vertical stabilizer434may provide an airfoil for boom positioning control. In this case, the tanker controller120may send commands to the airfoil actuators to deflect the airfoils and maneuver the boom130.

Referring now toFIG. 5, a diagram of a logic flow in accordance with one embodiment of the inventive concepts disclosed herein is shown. Steps501through512may be considered steps for determining the relative positioning solution while steps514through520may comprise the machine vision and AAR steps. Steps502through510may be continuously executed to maintain a safe separation between the two aircraft while steps522through530may provide a feedback loop to maintain safety.

A step502may receive a positioning solution from the tanker positioning system while a step504may include receive a positioning solution from the receiver positioning system via the data link. A step506may generate a HIRPS based on the received positioning solutions and a step508may generate safety boundaries around each aircraft including a protection level and an alert limit based on the HIRPS. A query510may compare the protection level to the alert limit of each aircraft to determine if the protection level is within the alert limit. Should the result of query510be negative, the logic may pass to step530to send an alert.

Should the result of query510be positive, the logic may pass to a step512, where the tanker controller120may receive a video signal from the camera suite to enable machine vision methods to identify, at a step514, based on the video signal, the boom male fitting402and the receiver female fitting254. A step516may determine, based on the video signal, a three-dimensional position of the boom male fitting and a three-dimensional position of the receiver female fitting and a step518may generate the boom limit container based on the 3D position of the refueling boom.

A query520may question if the receptacle is within the boom limit container. Should the result be negative, the logic may pass to the step512to continue to receive the video signal. However, should the result of query520be positive, the logic may pass to a step522to manipulate the refueling boom to couple the boom male fitting with the receiver female fitting based on the three-dimensional position of the boom male fitting relative to the three-dimensional position of the receiver female fitting.

A query524may question if the receptacle is maintaining a position within the boom limit contain. Should the result be positive, the logic may pass to an additional query526questioning if the offload is complete. Should the result of query526be positive, the logic may pass to a step528to execute a normal breakaway. However, if the result of query524should be negative, the logic may pass to a step530to send an alert and, at a step532, the tanker controller120may initiate a command to the tanker to execute an emergency breakaway.

The system100may be specifically configured to function on a current tanker110(e.g., KC-46) with a camera suite124installed. The addition of high integrity relative navigation algorithms and machine vision to current Remote Vision Systems may enable an AAR capability for so equipped boom refueled aircraft.

Referring now toFIGS. 6A and 6B, diagrams of a method flow in accordance with one embodiment of the inventive concepts disclosed herein is shown. A method for automated boom placement in aerial refueling may comprise, at a step602, receiving a tanker positioning solution for a tanker aircraft and, at a step604, receiving a receiver positioning solution for a receiver aircraft. A step606may include generating a high integrity relative positioning solution based on the tanker positioning solution and the receiver positioning solution, and a step608may include generating at least two safety boundaries including a protection level and an alert limit around each aircraft based on the high integrity relative positioning solution while a step610may include continuously comparing each protection level to each alert limit.

A step612may include receiving a video signal of a FOV proximal with a boom position. A step614may include identifying, based on the video signal, a boom male fitting coupled with a refueling boom and a receiver female fitting onboard the receiver aircraft, and a step616may include determining, based on the video signal, a three-dimensional position of the boom male fitting and a three-dimensional position of the receiver female fitting. For boom safety, a step618may include determining a boom limit container around a centered position of the boom male fitting based on the three-dimensional position of the boom male fitting, and a step620may include continuously comparing the three-dimensional position of the receiver female fitting to the boom limit container. For AAR, a step622may include manipulating, if the three-dimensional position of receiver female fitting is within the boom limit container, a refueling boom to couple the boom male fitting with the receiver female fitting based on the three-dimensional position of the boom male fitting relative to the three-dimensional position of the receiver female fitting.

CONCLUSION

As will be appreciated from the above description, embodiments of the inventive concepts disclosed herein may provide a novel solution to AAR using high integrity relative positioning methods in cooperation with highly accurate machine vision systems.