Takeoff and landing area lighting design

Abstract

A system includes a takeoff and landing area. The system also includes a plurality of beacons non-uniformly spaced throughout the takeoff and landing area. A first beacon of the plurality of beacons has first spatial coordinates. A second beacon of the plurality of beacons has second spatial coordinates.

Description

TAKEOFF AND LANDING AREA LIGHTING DESIGN CROSS-REFERENCE TO RELATED APPLICATION

[0001] The present application claims priority to U.S. Provisional Patent Application No. 63 / 608,817, filed December 11, 2023, the entire contents of which are hereby incorporated by reference as if fully set forth in this description. BACKGROUND

[0002] An aircraft may land at a designated takeoff and landing area, such as a vertiport. The aircraft may be autonomous or automated such that it is only partially controlled by a human operator. Vertiports may be located in a variety of designated locations and environments to facilitate a variety of activities, including for example, to transport passengers and / or objects, perhaps in an urban environment that includes a variety of buildings, businesses, homes, and other man-made structures.

[0003] The aircraft may operate at different time segments of the day and in various environmental conditions. In some scenarios, the aircraft may have to land on a vertiport during instrument meteorological conditions (IMCs). For example, the aircraft may have to land during weather conditions that require pilots to fly primarily by reference to instruments, as opposed to flying by outside visual references. During IMCs, it may be challenging to guide and / or localize the aircraft relative to the vertiport. As a result, safely landing the aircraft on the vertiport during IMCs can be particularly challenging.

[0004] It is with respect to these and other considerations that the disclosure made herein is presented.SUMMARY

[0005] The present disclosure describes implementations that relate to a lighting system for a takeoff and landing area, and a method of using the lighting system to position an aircraft.

[0006] In a first example embodiment, the present disclosure describes a system. The system includes a takeoff and landing area. The system also includes a plurality of beacons non-uniformly spaced throughout the takeoff and landing area. A first beacon of the plurality of beacons has first spatial coordinates. A second beacon of the plurality of beacons has second spatial coordinates.

[0007] In a second example embodiment, the present disclosure describes a method. The method includes detecting, by one or more sensors of an aircraft, a plurality of beacons non-uniformly spaced throughout a takeoff and landing area. A first beacon of the plurality of beacons has first spatial coordinates, and a second beacon of the plurality of beacons has second spatial coordinates. The method also includes in response to detecting the plurality of beacons, identifying, by a processor of the aircraft, the takeoff and landing area. The method also includes in response to identifying the takeoff and landing area, estimating, by the processor, a pose of the aircraft with respect to the takeoff and landing area. The method also includes, based on the pose, maneuvering the aircraft to land on the takeoff and landing area.

[0008] In a third example embodiment, the present disclosure describes an aircraft. The aircraft includes one or more actuators, one or more sensors, and a processor. The one or more sensors are configured to detect a plurality of beacons non-uniformly spaced throughout a takeoff and landing area. A first beacon of the plurality of beacons has first spatial coordinates, and a second beacon of the plurality of beacons has second spatial coordinates. The processor is configured to in response to the one or more sensors detecting the plurality of beacons, identify the takeoff andlanding area. The processor is also configured to in response to identifying the takeoff and landing area, estimate a pose of the aircraft with respect to the takeoff and landing area. The processor is also configured to generate, based on the pose, maneuvering commands to land on the takeoff and landing area. The processor is also configured to control, based on the maneuvering commands, the one or more actuators to land the aircraft.

[0009] In a fourth example embodiment, the present disclosure describes a non-transitory computer-readable medium. The non-transitory computer-readable medium comprises instructions that, when executed by one or processors of an aircraft cause the one or more processors to perform operations. The operations include detecting a plurality of beacons non- uniformly spaced throughout a takeoff and landing area. A first beacon of the plurality of beacons has first spatial coordinates, and a second beacon of the plurality of beacons has second spatial coordinates. The operations also include in response to detecting the plurality of beacons, identifying the takeoff and landing area. The operations also include in response to identifying the takeoff and landing area, estimating, by the processor, a pose of the aircraft with respect to the takeoff and landing area. The operations also include, based on the pose, maneuvering the aircraft to land on the takeoff and landing area.

[0010] The foregoing summary is illustrative only and is not intended to be in any way limiting. In addition to the illustrative aspects, implementations, and features described above, further aspects, implementations, and features will become apparent by reference to the drawings and the following detailed description.BRIEF DESCRIPTION OF THE FIGURES

[0011] Figure 1A illustrates a perspective view of a takeoff and landing area lighting system and an aircraft, according to exemplary embodiments of the present invention.

[0012] Figure 1B illustrates beacon parameters of the beacons in the takeoff and landing area lighting system of Figure 1A, according to exemplary embodiments of the present invention.

[0013] Figure 2 illustrates the aircraft of Figure 1A, according to exemplary embodiments of the present invention.

[0014] Figure 3 illustrates a camera frame of a plurality of beacons captured from an aerial perspective, according to exemplary embodiments of the present invention.

[0015] Figure 4 illustrates another camera frame of a plurality of beacons captured from an aerial perspective, according to exemplary embodiments of the present invention.

[0016] Figure 5 is an illustration of a computing device, in accordance with exemplary embodiments of the present invention.

[0017] Figure 6 illustrates a method, in accordance with exemplary embodiments of the present invention.DETAILED DESCRIPTION

[0018] Disclosed herein is a takeoff and landing area lighting system for an aircraft (e.g., an autonomous aircraft) operating during IMCs. In some embodiments, the takeoff and landing area may include a vertiport. The takeoff and landing area lighting system described herein improves guidance and localization of aircraft relative to a vertiport. In particular, the takeoff and landing area lighting system, as described herein, may be placed in a touch-down and lift-off (TLOF) and final approach and takeoff (FATO) area and may be easily identified in different weather conditions.

[0019] In some embodiments, lights (e.g., beacons) in the takeoff and landing area lighting system may be non-uniformly separated such that the lights provide a recognizable sign (e.g., a unique design). In particular, by providing a recognizable sign with embedded fault detection, the lights in the takeoff and landing area lighting system may have a pattern that increases the accuracy and robustness of an aircraft guidance and localization system.

[0020] The aircraft described herein may be any type of aircraft, such as a quadcopter, a helicopter, or a winged aircraft, for example. In some embodiments, the aircraft may be a vertical takeoff and landing (VTOL) vehicle. Further, in some embodiments, the aircraft may use electric power to hover, takeoff, and / or land vertically.

[0021] The aircraft may include a computing device. In some embodiments, the computing device may include one or more processors, a non-transitory computer readable medium, and a communication interface. The aircraft may have automated functions or may operate autonomously at different times and in various environmental conditions. To perform automated functions, or to operate autonomously, the aircraft may include sensors to gather information regarding surrounding environments. In some scenarios, the aircraft may be tasked with landingon a small footprint vertiport with high precision. The vertiport may be located in an urban or rural environment, and the aircraft can be tasked with landing on the vertiport in different conditions (e.g., night, day, rain, snow, and fog).

[0022] To ensure that the aircraft may safely land on the vertiport, the aircraft may detect the vertiport from a relatively far distance. For example, the detection of the vertiport (e.g., by the aircraft) may be performed at least 2500 feet away from the vertiport (e.g., in the horizontal direction) as the aircraft starts its decent procedure. The decent and landing flight path of the aircraft may include a glideslope between 3° and 8°, lateral deviations of ±5°, and aircraft attitudes having a yaw of ±30°, a pitch of ±20°, and a roll of ±30°. Using the vertiport lighting system described herein, guidance and navigation of the aircraft may be improved significantly in all weather conditions.

[0023] In some embodiments, the aircraft may include infrared (IR) cameras. Further, in some embodiments, IR cameras of the aircraft may be used in various domains for low visibility. Moreover, in some embodiments, the aircraft may have two wings and two IR cameras, a first IR camera may be disposed on one wing, and a second IR camera may be disposed on another wing.

[0024] Using the takeoff and landing area lighting system described herein and one or more calibrated IR cameras on the aircraft, the techniques described herein may enable localization of the aircraft relative to a reference frame, usually to the center of the TLOF area of the vertiport. The aircraft may follow a specified trajectory during the approach and landing phase of the flight allowing for an accurate and long-range pose localization.

[0025] In some embodiments, the aircraft may include visible spectrum cameras. Localization using visible spectrum cameras may be performed by detecting a known-size object at the vertiportlevel. For example, localization may be performed by pose estimation using fiducial markers. The fiducial markers may have a unique shape and design, and the aircraft pose may be estimated using detection and tracking algorithms.

[0026] Similarly, as described herein, the localization of the aircraft using IR cameras may be performed by placing IR beacons at the vertiport level.

[0027] Below, particular implementations are described herein with reference to the drawings. In the description, common features may be designated by common reference numbers throughout the drawings. In some drawings, multiple instances of a particular type of feature are used. Although these features are physically and / or logically distinct, the same reference number is used for each, and the different instances are distinguished by addition of a letter to the reference number. When the features as a group or a type are referred to herein (e.g., when no particular one of the features is being referenced), the reference number is used without a distinguishing letter. However, when one particular feature of multiple features of the same type is referred to herein, the reference number is used with the distinguishing letter. For example, referring to Figure 1A, beacons are illustrated and associated with reference numbers 110A, 110B, 110C, etc. When referring to a particular one of the beacons, such as the beacon 110A, the distinguishing letter “A” is used. However, when referring to any one of the beacons or to the beacons as a group, the reference number 110 may be used without a distinguishing letter.

[0028] Figure 1A illustrates a perspective view of a takeoff and landing area lighting system 100, according to exemplary embodiments of the present invention. The takeoff and landing area lighting system 100 includes a takeoff and landing area 102 and a plurality of beacons 110. In some embodiments, the takeoff and landing area 102 may include a vertiport. As illustrated in theembodiment of Figure 1A, the beacons 110 may be non-uniformly spaced around (or throughout) the takeoff and landing area 102.

[0029] The takeoff and landing area 102 may be an elevated structure such that the beacons 110 are detectable by electro-optical sensors of an aircraft, such as the aircraft 200 in Figure 2, in the visible spectrum and / or the infrared spectrum. The elevated structure may allow for variations in elevation of the beacons 110 as a flight path of the aircraft 200 may change due to challenging weather conditions. In some embodiments, the elevated structure may also provide improved visibility and less ambiguity as the aircraft 200 approaches with a glideslope between 3° and 8°. As described below, the elevated design of the beacons 110 in the visible and IR domains with various characteristics (e.g., power, emissivity spectrum, field of view (FOV), etc.) may allow for easy beacon detection. Further, a precise localization output of the beacons 110 may be used by both piloted aircraft as well as ones with highly automated functions.

[0030] As illustrated in the embodiment of Figure 1A, the plurality of beacons 110 may be non- uniformly spaced throughout the takeoff and landing area 102. The plurality of beacons 110 may include a beacon 110A, a beacon 110B, a beacon 110C, a beacon 110D, a beacon 110E, and a beacon 110F. Each beacon 110A-110F has spatial coordinates (e.g., longitude, latitude, and elevations). For example, the beacon 110A have spatial coordinates, the beacon 110B has spatial coordinates, the beacon 110C has spatial coordinates, the beacon 110D has spatial coordinates, the beacon 110E has spatial coordinates, and the beacon 110F has spatial coordinates. Although six beacons 110 are illustrated, in other embodiments, the takeoff and landing area lighting system 100 may include more or less than six beacons. In some embodiments, the takeoff and landing area lighting system 100 may include eight beacons 110 that are non-uniformly spaced throughout the takeoff and landing area 102. In some embodiments, the takeoff and landing area lightingsystem 100 may include four beacons 110 that are non-uniformly spaced throughout the takeoff and landing area 102.

[0031] In some embodiments, the elevation of each beacon 110 may correspond to a displacement (e.g., an altitude) of the respective beacon 110 relative to sea level. For example, the elevation component of the spatial coordinates for each beacon 110 may indicate the vertical displacement of each beacon 110 relative to sea level.

[0032] In some embodiments, the elevation of each beacon 110 may correspond to a vertical displacement 120 of each beacon 110 relative to the takeoff and landing area 102. For example, each beacon 110 may have a vertical displacement 120 relative to the takeoff and landing area 102 that enables the aircraft 200 to detect the beacons 110 during IMCs. For example, the beacon 110A may have a vertical displacement 120A relative to the takeoff and landing area 102, the beacon 110B may have a vertical displacement 120B relative to the takeoff and landing area 102, the beacon 110C may have a vertical displacement 120C relative to the takeoff and landing area 102, the beacon 110D may have a vertical displacement 120D relative to the takeoff and landing area 102, the beacon 110E may have a vertical displacement 120E relative to the takeoff and landing area 102, and the beacon 110F may have a vertical displacement 120F relative to the takeoff and landing area 102.

[0033] In some embodiments, the vertical displacement 120 of some beacons 110 may be different than the vertical displacement 120 of other beacons 110. For example, in the embodiment illustrated in Figure 1A, the vertical displacement 120A of the beacon 110A may be different from (e.g., greater than) the vertical displacement 120D of the beacon 110D. Additionally, in some embodiments, the vertical displacement 120 of some beacons 110 may be similar or equal to the vertical displacement 120 of other beacons 110. For example, in the embodiment illustrated inFigure 1A, the vertical displacement 120F of the beacon 110F may be equal to the vertical displacement 120E of the beacon 110E. In some embodiments where the vertical displacement 120 of each beacon 110 is the same, the beacons 110 may be coplanar.

[0034] In some embodiments, the beacons 110 may have a vertical displacement 120 of at least three meters above the takeoff and landing area 102. To reduce danger of collisions during landing, beacon risers may be removed from the takeoff and landing area 102. For example, if the diameter of the takeoff and landing area 102 is approximately fifteen meters, the beacon risers may be dispersed with a diameter of approximately thirty meters.

[0035] The vertical displacements 120 of the beacons 110 may enable one or more sensors on the aircraft 200 to detect the beacons 110 and / or capture an image frame of the beacons 110. In response to detecting the beacons 110, the aircraft 200 may identify the takeoff and landing area 102 during IMCs and estimate a pose with respect to the takeoff and landing area 102. Based on the estimated pose, the aircraft 200 may maneuver during IMCs to safely land on the takeoff and landing area 102.

[0036] In addition to elevation (e.g., the vertical displacement 120 or a “z-coordinate”), the spatial coordinates of each beacon 110 may also include a longitude (e.g., an “x-coordinate”) and a latitude (e.g., a “y-coordinate”). For example, the beacon 110A may have a latitude and a longitude, the beacon 110B may have a latitude and a longitude, the beacon 110C may have a latitude and a longitude, the beacon 110D may have a latitude and a longitude, the beacon 110E may have a latitude and a longitude, and the beacon 110F may have a latitude and a longitude.

[0037] In some embodiments, the longitude and latitude of each beacon 110 may be different. In some embodiments, one or more of the beacons 110 may have the same longitude or the samelatitude. For example, in some embodiments, the beacon 110A and the beacon 110B may have the same longitude and different latitudes. As another example, in some embodiments, the beacon 110A and the beacon 110B may have the same latitude and different longitudes.

[0038] The longitude and / or latitude of the beacons 110 may enable one or more sensors on the aircraft 200 to detect the beacons 110 and / or capture an image frame of the beacons 110. In response to detecting the beacons 110, the aircraft 200 may identify the takeoff and landing area 102 during IMCs and estimate a pose with respect to the takeoff and landing area 102. Based on the estimated pose, the aircraft 200 may maneuver during IMCs to safely land on the takeoff and landing area 102.

[0039] In some embodiments, a particular IR beacon may be identified from the other IR beacons based on shape or temperature variation. In some embodiments, the IR beacons may be spatially (e.g., horizontally and vertically) placed. The horizontal alignment may be useful for precision landing (e.g., descending) near the vertiport, while the vertical alignment may allow accurate long range pose estimation at a considerable distance from the vertiport final descent. Vertically placed IR beacons may be more visible at long ranges.

[0040] Figure 1B illustrates beacon parameters 140 of the beacons 110 in the takeoff and landing area lighting system 100, according to exemplary embodiments of the present invention. The beacon parameters 140 may enable the aircraft 200 to identify the takeoff and landing area 102 during IMCs and estimate a pose with respect to the takeoff and landing area 102. Based on the estimated pose, the aircraft 200 may maneuver during IMCs to safely land on the takeoff and landing area 102.

[0041] The beacon 110A may have beacon parameters 140A that enable the aircraft 200 to detect the beacon 110A during IMCs. The beacon parameters 140A may include a shape 150A of the beacon 110A, a temperature 152A of the beacon 110A, modulation parameters 154A of the beacon 110A, an electromagnetic spectrum 156A of the beacon 110A, and a radiation pattern 158A of the electromagnetic spectrum 156A. In some embodiments, the beacon parameters 140A may also include the vertical displacement 120A of the beacon 110A relative to the takeoff and landing area 102. As described below with respect to Figure 2, in some embodiments, the aircraft 200 may use the shape 150A and temperature 152A of the beacon 110A to identify (e.g., distinguish) the beacon 110A from the other beacons 110B-110F.

[0042] Similarly, the beacon 110B may have beacon parameters 140B that enable the aircraft 200 to detect the beacon 110B during IMCs. The beacon parameters 140B may include a shape 150B of the beacon 110B, a temperature 152B of the beacon 110B, modulation parameters 154B of the beacon 110B, an electromagnetic spectrum 156B of the beacon 110B, and a radiation pattern 158B of the electromagnetic spectrum 156B. In some embodiments, the beacon parameters 140B may also include the vertical displacement 120B of the beacon 110B relative to the takeoff and landing area 102. As described below with respect to Figure 2, in some embodiments, the aircraft 200 may use the shape 150B and temperature 152B of the beacon 110B to identify the beacon 110B from the other beacons 110A, 110C-110F.

[0043] The beacon 110C may have beacon parameters 140C that enable the aircraft 200 to detect the beacon 110C during IMCs. The beacon parameters 140C may include a shape 150C of the beacon 110C, a temperature 152C of the beacon 110C, modulation parameters 154C of the beacon 110C, an electromagnetic spectrum 156C of the beacon 110C, and a radiation pattern 158C of the electromagnetic spectrum 156C. In some embodiments, the beacon parameters 140C may alsoinclude the vertical displacement 120C of the beacon 110C relative to the takeoff and landing area 102.

[0044] The beacon 110D may have beacon parameters 140D that enable the aircraft 200 to detect the beacon 110D during IMCs. The beacon parameters 140D may include a shape 150D of the beacon 110D, a temperature 152D of the beacon 110D, modulation parameters 154D of the beacon 110D, an electromagnetic spectrum 156D of the beacon 110D, and a radiation pattern 158D of the electromagnetic spectrum 156D. In some embodiments, the beacon parameters 140D may also include the vertical displacement 120D of the beacon 110D relative to the takeoff and landing area 102.

[0045] The beacon 110E may have beacon parameters 140E that enable the aircraft 200 to detect the beacon 110E during IMCs. The beacon parameters 140E may include a shape 150E of the beacon 110E, a temperature 152E of the beacon 110E, modulation parameters 154E of the beacon 110E, an electromagnetic spectrum 156E of the beacon 110E, and a radiation pattern 158E of the electromagnetic spectrum 156E. In some embodiments, the beacon parameters 140E may also include the vertical displacement 120E of the beacon 110E relative to the takeoff and landing area 102.

[0046] The beacon 110F may have beacon parameters 140F that enable the aircraft 200 to detect the beacon 110F during IMCs. The beacon parameters 140F may include a shape 150F of the beacon 110F, a temperature 152F of the beacon 110F, modulation parameters 154F of the beacon 110F, an electromagnetic spectrum 156F of the beacon 110F, and a radiation pattern 158F of the electromagnetic spectrum 156F. In some embodiments, the beacon parameters 140F may also include the vertical displacement 120F of the beacon 110F relative to the takeoff and landing area 102.

[0047] In some embodiments, each beacon 110 may be characterized by (1) a spectrum of emitted electromagnetic radiance, (2), a radiation pattern (e.g., directional diagram) of the corresponding spectrum, (3) modulation parameters, and (4) shape parameters. The beacon parameters 140 may enable the aircraft 200 to detect the takeoff and landing area 102 in IMCs and estimate a pose with respect to the takeoff and landing area 102. Based on the estimated pose, the aircraft 200 may maneuver in IMCs to safely land on the takeoff and landing area 102.

[0048] Figure 2 illustrates an aircraft 200, according to exemplary embodiments of the present invention. In some embodiments, in response to detecting a plurality of beacons non-uniformly spaced throughout a takeoff and landing area, the aircraft 200 is operable to perform pose estimation. In some embodiments, the aircraft 200 may be a VTOL vehicle. Further, in some embodiments, the aircraft 200 may use electric power to hover, takeoff, and / or land vertically.

[0049] The aircraft 200 may include a processor 202, a memory 204, one or more sensors 206, and one or more actuators 208. The memory 204 may be a non-transitory computer-readable medium that stores instructions 205 executable by the processor 202 to perform techniques described herein. In some embodiments, the aircraft 200 may include additional components that are not depicted in Figure 2.

[0050] The processor 202 may include a computer vision processing unit 210, a takeoff and landing area identification unit 212, a pose estimation unit 214, and a command generation unit 216. In some embodiments, one or more components of the processor 202 may be implemented using dedicated hardware. For example, one or more components of the processor 202 may be implemented using application-specific integrated circuits (ASICs) or field programmable gate array (FPGA) devices. In some embodiments, one or more components of the processor 202 may be implemented using software. For example, the operations of one or more components of theprocessor 202 may be implemented by executing the instructions 205 stored in the memory 204. It should be understood that the components included in the processor 202 are merely for illustrative purposes and should not be construed as limiting. In some embodiments, the processor 202 may include additional components. In some embodiments, two or more components of the processor 202 may be integrated into a single component.

[0051] The one or more sensors 206 may include one or more visible light cameras 206A and / or one or more IR cameras 206B. In some embodiments, the sensors 206 may include (i) a wide- angle lens to find the takeoff and landing area 102 (e.g., the vertiport) and (ii) a narrow-angle lens to provide good signal-to-noise ratio for detecting the beacons 110 in warm environments with good navigational accuracy. When approaching the takeoff and landing area 102, the wide-angle lens may be used to capture the entire structure in the field of view.

[0052] The one or more actuators 208 may include one or more thrusters, propellers, rotors, jet engines, or control surfaces that are configured to cause the aircraft 200 to move or change direction or orientation. In some embodiments, the actuators 208 include components that facilitate movement, including one or more gearboxes that each drive one or more propellers and / or one or more propeller motors. The actuators 208 may also include multiple lift rotors that facilitate vertical takeoff and landing of the aircraft 200. Each lift rotor may be driven by a gearbox, which in turn may be driven by an electric motor. Further, the aircraft 200 may have one or more battery modules and one or more energy management systems (EMSs) that are in communication with the battery modules and that are configured as electronic regulators to monitor and control the charging and discharging of the battery modules.

[0053] During flight, the aircraft 200 may utilize the sensors 206 and the processor 202 to detect the beacons 110. For example, the visible light camera 206A or the infrared camera 206B may beused to capture one or more frames, such as the camera frame 300 of Figure 3 of the beacons 110 or the camera frame 400 of Figure 4 of the beacons 110. The beacon parameters 140 may enable the beacons 110 to be detectable by the visible light camera 206A or the IR camera 206B during IMCs.

[0054] For an accurate six degree of freedom (6-DoF) positioning, at least four unambiguously and uniquely identifiable (by color and / or modulation) beacons 110 may be in the field of view of the sensors 206. The color of the beacons 110 may be used to improve identification using a larger visibility spectrum for the sensors 206, while the modulation of the beacons 110 may reduce the effective frame rate of the sensors 206. If the beacons 110 cannot be uniquely identified (e.g., if they are all detected in only one range of EM radiation, such as long infrared without modulation), then the number of beacons 110 distinguishable in the field of view of the sensors 206 may increase to five, and the arrangement of the beacons 110 may be such that a detection problem is solved.

[0055] In some embodiments, robustness to occlusions may lead to an increase in the number of bins. Beneficially, the greater the stability is planned to be achieved, the greater the redundancy may be. Further, in some embodiments, a perspective transformation that links a planar scene with pixel coordinates, similar to a camera system, may preserve lines, and if these points and lines are uniquely identified and mapped in the camera frame 300, the beacons 110 may be identified along those lines.

[0056] The camera frame 300 and / or the camera frame 400 may be provided to the computer vision processing unit 210 for processing. For example, the computer vision processing unit 210 may detect beacon-looking objects (e.g., the beacons 110) in the camera frame 300, 400 using computer vision techniques, such as preprocessing, normalized correlation, and adaptive thresholding. In response to detecting the beacons 110, the takeoff and landing area identificationunit 212 may identify the takeoff and landing area 102 based on the location of the beacons 110 non-uniformly spaced throughout the takeoff and landing area 102. For example, the takeoff and landing area 102 may be detected based on a collective shape of the beacons 110. In some embodiments, the collective shape of the beacons 110 may be an aggregate of the shapes 150 of the beacons 110. As another example, the takeoff and landing area 102 may be detected based on a collective design of the beacons 110. In some embodiments, the collective design of the beacons may be an aggregate of the beacon parameters 140 of the beacons 110.

[0057] To detect and track the design of the beacons 110, the takeoff and landing area identification unit 212 may be configured to perform pattern detection. For example, the region of interest (RoI) that potentially includes the beacons 110 may be detected. Single beacon detection and registration may also be performed. For example, within the RoIs, beacon-looking objects may be detected using computer vision techniques (e.g., using the computer vision processing unit 210) that include preprocessing, normalized correlation, and adaptive thresholding. The beacon-looking objects may be registered within a camera plane as ^^^. Once the beacons 110 are identified, the 2D image pattern may be associated to the beacons 110 in the 3D world (with the location ^^^).

[0058] After the takeoff and landing area 102 is identified, the pose estimation unit 214 may execute a pose estimation algorithm 220 to estimate the pose 222 of the aircraft 200 with respect to the takeoff and landing area 102. During execution of the pose estimation algorithm, localization may be performed using a 3D-2D perspective-n-projection (PnP) analysis. The 3D point coordinate refers to the real-world 3D coordinate values of the beacons 110 relative to a known reference frame (such as the center of the TLOF), while the 2D point refers to the image coordinates of the beacons 110 in the camera. The association of the 3D and 2D points from thedesign of the beacons 110 may be used for pose estimation. The beacons 110 may provide the flexibility of forming planes in different orientations for long-distance viewing compared to the visible camera ambiguous, almost linear projection.

[0059] In some scenarios, using a set of world points ^^ ଷ^ ^^ ^^ , ^^ ^^ ^1, … ,^^^ captured with acalibrated sensor 206 and projected to the frame: ^^^may be defined in distance terms (e.g., the distance between the projective center and the world 3D points) of in transformation terms (e.g., the 2D rigid body transformation between the object-centered coordinate system, world coordinate system, ^^ଷ). Assuming a calibrated sensor 206, i.e., given the intrinsic matrix:The projection equation for such a sensor 206 is:

[0060] In the above projection equation, Π is a perspective projection, and ^^்ೈshows the projection from the world (W) coordinate system to the sensor (C) coordinate system. ^^ ^^ ^^^^ is a rotation matrix, t stands for translation, and 0 =

[0000] . Thus, the projection equation (with no measurement noise) for the ithpoint is:where ^^^is the sca

[0061] ^^^^^ ^^ଷstands for the world^^^^^^^ projected to the point in camera coordinates ^^் ൌ ^^^^^^^^, 1 ^^ ^^ଷ is a unit vector with ith ^ ^T^ ^ ^ ^ element equal to 1, i.e., 1^ ൌ 0, 0, 1 .Computation of a sensor pose means computation of the rotation matrix (R) and translation vector (t) such that: re,ோெHe^ା௧^^య^ோெ^ା௧^is the projection of the world point ^^^onto the sensor plane. ^^^refers to the real- worldvalues of the beacons 110, while the 2D points ^^^refers to the image coordinates of the beacon 110 in the sensor 206. In some embodiments, the beacons 110 may provide flexibility of forming planes in different orientations for long-distance viewing compared to the projection of the sensor 206.

[0062] According to techniques described herein, the intensity of irradiation may be determined by the distance from the sensor 206 to the beacons 110, the sensitivity of the sensor 206, the range of visibility in the selected frequency range in the range of weather conditions, and the distinguishability of objects against the background of the environment. The long-wave infrared (LWIR) range may be selected based on atmospheric transparency windows to enhance all- weather optical navigation. In some implementations, the total number of beacons 110 in thedesign may be more than enough to perform localization to account for false negatives due to occlusion. The spatial configuration of the beacons 110 may ensure that the beacons 110 are optically distinguishable from different angles and views.

[0063] In some embodiments, a particular beacon 110 may be identified from the other beacons 110 based on variations in the shape 150 or the temperature 152. Additionally, a particular beacon 110 may be identified based on its detection frequency over a short window (e.g., period of time), which may enable association for the 3D and 2D points. Moreover, the design shape and frequency may enable filtering out misleading other detection that may be available in the scene.

[0064] The vertical alignment (e.g., the vertical displacement 120) of the beacons 110 may allow accurate long-range pose estimation at a considerable distance from the takeoff and landing area 102 before the final descent. Vertically placed beacons 110 may be more visible at long ranges. The horizontal alignment of the beacons 110 may be useful for precision landing (e.g., descending) near the takeoff and landing area 102.

[0065] At distances far away from the takeoff and landing area 102, when it is difficult to estimate the pose 222, the correct glideslope of the aircraft 200 for approach may still be uniquely identified from the temperature variations of the beacons 110 directed at two different angles above and below the glideslope.

[0066] Based on the pose 222, the command generation unit 216 may be configured to generate one or more maneuvering commands 230 for landing the aircraft 200 on the takeoff and landing area 102. For example, the processor 202 may use the maneuvering commands 230 to control the actuators 208 to safely land the aircraft 200 during IMCs. For example, based on the maneuvering commands 230, the aircraft 200 may begin a landing phase started at approximately 2500 feethorizontal distance and 250 feet vertical distance from the takeoff and landing area 102, and the aircraft 200 may end the landing phase at approximately zero feet horizontal distance and 50 feet vertical distance from the takeoff and landing area 102.

[0067] In some scenarios, there may be a need of non-uniformity within the upper hemisphere directional pattern of beacons 110, the main lobe in the direction(s) of landing. Sources of electromagnetic radiation with high directivity may be characterized by a narrow directivity diagram in the polar angle and in the azimuth. If visibility of a sufficient number of beacons 110 in a wide azimuth (e.g., up to 360 degrees) is needed, then, either each beacon 110 might have to be surrounded by narrowly directed emitters, or each landing direction might be provided with its own beacons 110.

[0068] Figure 3 illustrates a camera frame 300 of the plurality of beacons 110 captured from an aerial perspective, according to exemplary embodiments of the present invention. In some embodiments, the camera frame 300 may be captured by the aircraft 200 of Figure 2 to enable the aircraft 200 to estimate a pose of the aircraft 200 with respect to the takeoff and landing area 102. Because of IMCs, the camera frame 300 may not be able to visibly capture the takeoff and landing area 102.

[0069] The design (e.g., the layout) of the beacons 110 in the camera frame 300 may be unique and relatively easy to decipher. In some embodiments, the design of the beacons 110 may be (1) unique (e.g., no ambiguity and no symmetry), (2) robust to occlusion and changes in the flight path of the aircraft 200, and (3) relatively easy to detect and decipher in low illumination and challenging weather conditions.

[0070] Figure 4 illustrates another camera frame 400 of the plurality of beacons 110 captured from an aerial perspective, according to exemplary embodiments of the present invention. In Figure 4, additional beacons 110G, 110H may be captured. In some embodiments, the camera frame 400 may be captured by the aircraft 200 of Figure 2 to enable the aircraft 200 to estimate a pose of the aircraft 200 with respect to the takeoff and landing area 102. Because of IMCs, the camera frame 400 may not be able to visibly capture the takeoff and landing area 102. In some embodiments, the plurality of beacons 110 in the camera frame 300 or the camera frame 400 may be a beacon pattern.

[0071] Figure 5 is a simplified block diagram showing some of the components of an example computing device 500 in accordance with exemplary embodiments of the present invention. In some embodiments, an aircraft (e.g., the aircraft 200 described with reference to Figure 2) may include the computing device 500. As illustrated in Figure 5, the computing device 500 may include a network interface 502, a user interface 504, a processor 506, and data storage 508. The network interface 502, the user interface 504, the processor 506, and / or the data storage 508 may be communicatively linked together by a bus 510 (e.g., an electrical interconnect defined on one or more printed circuit boards).

[0072] The network interface 502 may be used by the computing device 500 to communicate with other computing devices over one or more networks. For example, the network interface 502 may be used to communicate with ground station as the aircraft 200 begins a descent on the takeoff and landing area 102.

[0073] The user interface 504 may function to allow computing device 500 to receive input from and / or provide output to a user. As such, the user interface 504 may include inputs, such as a keypad, a keyboard, a touch-screen, a computer mouse, a microphone, a microphone jack, etc.,and / or outputs, such as a cathode-ray tube (CRT) display, a liquid-crystal display (LCD), a light- emitting diode (LED) display, a speaker, a speaker jack, headphones, a headphone jack, etc.

[0074] The processor 506 may include one or more general purposes processes (e.g., microprocessors) and / or one or more special-purpose processors (e.g., graphics processing units (GPUs) or ASICs). In some embodiments, for example, the processor 506 may include special- purpose processors capable of detecting the beacons 110, estimating the pose 222 of the aircraft 200, and generating the maneuvering commands 230 to land the aircraft on the takeoff and landing area 102.

[0075] The data storage 508 may include one or more volatile and / or non-volatile memories. For example, the data storage 508 may include a RAM, a ROM, a hard drive, a solid-state drive, etc. In some embodiments, the data storage 508 may be partially or wholly integrated with the processor 506 (e.g., a level 1 (L1) cache or a level 2 (L2) cache within a central processing unit). The data storage 508 may include removable components (e.g., a flash drive) and / or non- removable components (e.g., a ROM integrated with a motherboard).

[0076] The processor 506 may be configured to execute instructions 518 (e.g., compiled or non- compiled program logic and / or machine code) stored in the data storage 508 to carry out the methods described herein. Hence, the data storage 508 may include a non-transitory computer- readable medium, having stored thereon program instructions that, when executed by the processor 506, cause the processor 506 to carry out any of the methods, processes, or operations disclosed in this specification and / or the accompanying drawings. In some embodiments, the processor 506 may use the application data 512 while executing the instructions 518.

[0077] In some embodiments, the instructions 518 may include an operating system 522 (e.g., an operating system kernel, device driver(s), and / or other modules) and one or more applications 520 (e.g., mobile applications). As described above, the processor 506 may access the application data 512 when executing the applications 520.

[0078] The applications 520 may communicate with the operating system 522 through one or more application programming interfaces (APIs). These APIs may facilitate, for instance, the applications 520 reading and / or writing the application data 512, transmitting or receiving information via the network interface 502, receiving, and / or displaying information on the user interface 504, etc.

[0079] Figure 6 illustrates a method 600, in accordance with exemplary embodiments of the present invention. The method 600 may be performed by the aircraft 200 of Figure 2.

[0080] At a step 602, the method 600 may include detecting, by one or more sensors of an aircraft, a plurality of beacons non-uniformly spaced throughout a takeoff and landing area. A first beacon of the plurality of beacons has first spatial coordinates, and a second beacon of the plurality of beacons has second spatial coordinates. For example, referring to Figures 1A, 1B, and 2, the sensors 206 may detect the plurality of beacons 110 that are non-uniformly spaced throughout the takeoff and landing area 102. Each beacon 110 of the plurality of beacons 110 may have different spatial coordinates. The spatial coordinates of a beacon 110 include the vertical displacement 120 of the beacon 110, the longitude of the beacon 110, and the latitude of the beacon 110. In some embodiments of the method 600, a first vertical displacement (relative to the takeoff and landing area) of the first beacon is different from a second vertical displacement (relative to the takeoff and landing area) of the second beacon. For example, the vertical displacement 120A of the beacon110A may be different from (e.g., greater than) the vertical displacement 120D of the beacon 110D.

[0081] At a step 604, the method 600 may include in response to detecting the plurality of beacons, identifying, by a processor of the aircraft, the takeoff and landing area. For example, referring to Figures 1A, 1B, and 2, in response to detecting the plurality of beacons 110, the processor 202 may identify the takeoff and landing area 102.

[0082] At a step 606, the method 600 may include in response to identifying the takeoff and landing area, estimating, by the processor, a pose of the aircraft with respect to the takeoff and landing area. For example, referring to Figures 1A, 1B, and 2, in response to identifying the takeoff and landing area 102, the processor 202 may estimate the pose 222 of the aircraft 200 with respect to the takeoff and landing area 102.

[0083] At a step 608, the method 600 may include, based on the pose, maneuvering the aircraft to land on the takeoff and landing area. For example, referring to Figures 1A, 1B, and 2, the processor 202 may generate the maneuvering commands 230 based on the estimated pose 222, and the flight control circuitry 208 may execute the maneuvering commands 230 to land the aircraft 200 on the takeoff and landing area 102.

[0084] In some examples of the method 600, the takeoff and landing area 102 may be identified based on a collective shape of the plurality of beacons 110. In some examples of the method 600, the takeoff and landing area 102 may be identified based on a collective design of the plurality of beacons 110.

[0085] In some examples of the method 600, a particular beacon 110 of the plurality of beacons 110 may be detectable by the one or more sensors 206 based on beacon parameters 140 associatedwith the particular beacon 110. In some examples of the method 600, the beacon parameters 140 may include at least one of modulation parameters 154 of the particular beacon 110, an electromagnetic spectrum 156 of the particular beacon 110, a radiation pattern 158 of the electromagnetic spectrum 156, a shape 150 of the particular beacon 110, a temperature 152 of the particular beacon 110, or a vertical displacement 120 of the particular beacon 110 with respect to the takeoff and landing area 102.

[0086] In some examples of the method 600, each beacon 110 of the plurality of beacons 110 may include an infrared beacon. In some examples of the method 600, each beacon 110 of the plurality of beacons 110 may include a visual light beacon.

[0087] In some examples of the method 600, the takeoff and landing area 102 may include a vertiport.

[0088] The methods described herein may include further additional steps as described throughout the present disclosure.

[0089] Implementations of the present disclosure can thus relate to one of the example embodiments listed below.

[0090] Embodiment 1 is a system comprising: a takeoff and landing area; and a plurality of beacons non-uniformly spaced throughout the takeoff and landing area, wherein a first beacon of the plurality of beacons has first spatial coordinates, wherein a second beacon of the plurality of beacons has second spatial coordinates.

[0091] Embodiment 2 is the system according to embodiment 1, wherein the first spatial coordinates comprise at least a first longitude coordinate, a first latitude coordinate, and a firstelevation, and wherein the second spatial coordinates comprise at least a second longitude coordinate, a second latitude coordinate, and a second elevation.

[0092] Embodiment 3 is the system according to embodiment 1 or embodiment 2, wherein the plurality of beacons are detectable by an aircraft based on beacon parameters associated with the plurality of beacons, and wherein beacon parameters comprise: the first spatial coordinates of the first beacon; and the second spatial coordinates of the second beacon.

[0093] Embodiment 4 is the system according to any of embodiments 1 to 3, wherein the beacon parameters further comprise: first modulation parameters of the first beacon; and second modulation parameters of the second beacon.

[0094] Embodiment 5 is the system according to any of embodiments 1 to 4, wherein the beacon parameters further comprise: a first electromagnetic spectrum of the first beacon; and a second electromagnetic spectrum of the second beacon.

[0095] Embodiment 6 is the system according to any of embodiments 1 to 5, wherein the beacon parameters further comprise: a first radiation pattern of the first electromagnetic spectrum; and a second radiation pattern of the second electromagnetic spectrum.

[0096] Embodiment 7 is the system according to any of embodiments 1 to 6, wherein a collective shape of the plurality of beacons enables an aircraft to: identify the takeoff and landing area; and estimate a pose of the aircraft with respect to the takeoff and landing area.

[0097] Embodiment 8 is the system according to any of embodiments 1 to 7, wherein a collective design of the plurality of beacons enables an aircraft to: identify the takeoff and landing area; and estimate a pose of the aircraft with respect to the takeoff and landing area.

[0098] Embodiment 9 is the system according to any of embodiments 1 to 8, wherein each beacon of the plurality of beacons comprises an infrared beacon.

[0099] Embodiment 10 is the system according to any of embodiments 1 to 8, wherein each beacon of the plurality of beacons comprises a visual light beacon.

[0100] Embodiment 11 is the system according to any of embodiments 1 to 10, wherein the first beacon is identifiable by a first shape of the first beacon and a first temperature of the first beacon, and wherein the second beacon is identifiable by a second shape of the second beacon and a second temperature of the second beacon.

[0101] Embodiment 12 is the system according to any of embodiments 1 to 11, wherein the takeoff and landing area comprises a vertiport.

[0102] Embodiment 13 is a method comprising: detecting, by one or more sensors of an aircraft, a plurality of beacons non-uniformly spaced throughout a takeoff and landing area, wherein a first beacon of the plurality of beacons has first spatial coordinates, and wherein a second beacon of the plurality of beacons has second spatial coordinates; in response to detecting the plurality of beacons, identifying the takeoff and landing area; in response to identifying the takeoff and landing area, estimating, by the processor, a pose of the aircraft with respect to the takeoff and landing area; and based on the pose, maneuvering the aircraft to land on the takeoff and landing area.

[0103] Embodiment 14 is the method according to embodiment 13, wherein the takeoff and landing area is identified based on a collective shape of the plurality of beacons.

[0104] Embodiment 15 is the method according to embodiment 13 or embodiment 14, wherein the takeoff and landing area is identified based on a collective design of the plurality of beacons.

[0105] Embodiment 16 is the method according to any of embodiments 13 to 15, wherein a particular beacon of the plurality of beacons is detectable by the one or more sensors based on beacon parameters associated with the particular beacon.

[0106] Embodiment 17 is the method according to any of embodiments 13 to 16, wherein the beacon parameters include at least one of modulation parameters of the particular beacon, an electromagnetic spectrum of the particular beacon, a radiation pattern of the electromagnetic spectrum, a shape of the particular beacon, a temperature of the particular beacon, or a vertical displacement of the particular beacon with respect to the takeoff and landing area.

[0107] Embodiment 18 is the method according to any of embodiments 13 to 17, wherein each beacon of the plurality of beacons comprises an infrared beacon.

[0108] Embodiment 19 is the method according to any of embodiments 13 to 17, wherein each beacon of the plurality of beacons comprises a visual light beacon.

[0109] Embodiment 20 is the method according to any of embodiments 13 to 19, wherein the takeoff and landing area comprises a vertiport.

[0110] Embodiment 21 is an aircraft comprising: one or more actuators; one or more sensors configured to detect a plurality of beacons non-uniformly spaced throughout a takeoff and landing area, wherein a first beacon of the plurality of beacons has first spatial coordinates, and wherein a second beacon of the plurality of beacons has second spatial coordinates; a processor configured to: in response to the one or more sensors detecting the plurality of beacons, identify the takeoff and landing area; in response to identifying the takeoff and landing area, estimate a pose of the aircraft with respect to the takeoff and landing area; generate, based on the pose, maneuveringcommands to land on the takeoff and landing area; and control, based on the maneuvering commands, the one or more actuators to land the aircraft.

[0111] Embodiment 22 is the aircraft according to embodiment 21, wherein the takeoff and landing area is identified based on a collective shape of the plurality of beacons.

[0112] Embodiment 23 is the aircraft according to embodiment 21 or embodiment 22, wherein the takeoff and landing area is identified based on a collective design of the plurality of beacons.

[0113] Embodiment 24 is the aircraft according to any of embodiments 21 to 23, wherein a particular beacon of the plurality of beacons is detectable by the one or more sensors based on beacon parameters associated with the particular beacon.

[0114] Embodiment 25 is the aircraft according to any of embodiments 21 to 24, wherein the beacon parameters include at least one of modulation parameters of the particular beacon, an electromagnetic spectrum of the particular beacon, a radiation pattern of the electromagnetic spectrum, a shape of the particular beacon, a temperature of the particular beacon, or a vertical displacement of the particular beacon with respect to the takeoff and landing area.

[0115] Embodiment 26 is the aircraft according to any of embodiments 21 to 25, wherein each beacon of the plurality of beacons comprises an infrared beacon.

[0116] Embodiment 27 is the aircraft according to any of embodiments 21 to 25, wherein each beacon of the plurality of beacons comprises a visual light beacon.

[0117] Embodiment 28 is the aircraft according to any of embodiments 21 to 27, wherein the takeoff and landing area comprises a vertiport.

[0118] Embodiment 29 is a non-transitory computer-readable medium comprising instructions that, when executed by one or more processors of an aircraft, cause the one or more processors to perform operations comprising: detecting a plurality of beacons non-uniformly spaced throughout a takeoff and landing area, wherein a first beacon of the plurality of beacons has first spatial coordinates, wherein a second beacon of the plurality of beacons has second spatial coordinates; in response to detecting the plurality of beacons, identifying the takeoff and landing area; in response to identifying the takeoff and landing area, estimating, by the processor, a pose of the aircraft with respect to the takeoff and landing area; and based on the pose, maneuvering the aircraft to land on the takeoff and landing area.

[0119] Embodiment 30 is the non-transitory computer-readable medium according to embodiment 29, wherein the takeoff and landing area is identified based on a collective shape of the plurality of beacons.

[0120] Embodiment 31 is the non-transitory computer-readable medium according to embodiment 29 or embodiment 30, wherein the takeoff and landing area is identified based on a collective design of the plurality of beacons.

[0121] Embodiment 32 is the non-transitory computer-readable medium according to any of embodiments 29 to 31, wherein a particular beacon of the plurality of beacons is detectable by the one or more sensors based on beacon parameters associated with the particular beacon.

[0122] Embodiment 33 is the non-transitory computer-readable medium according to any of embodiments 29 to 32, wherein the beacon parameters include at least one of modulation parameters of the particular beacon, an electromagnetic spectrum of the particular beacon, a radiation pattern of the electromagnetic spectrum, a shape of the particular beacon, a temperatureof the particular beacon, or a vertical displacement of the particular beacon with respect to the takeoff and landing area.

[0123] Embodiment 34 is the non-transitory computer-readable medium according to any of embodiments 29 to 33, wherein each beacon of the plurality of beacons comprises an infrared beacon.

[0124] Embodiment 35 is the non-transitory computer-readable medium according to any of embodiments 29 to 33, wherein each beacon of the plurality of beacons comprises a visual light beacon.

[0125] Embodiment 36 is the non-transitory computer-readable medium according to any of embodiments 29 to 35, wherein the takeoff and landing area comprises a vertiport.

[0126] The following sections describe examples of (i) an estimated power for the beacons 110 to perform techniques described herein, (ii) a quantity of beacons 110 for performing techniques described herein, and (iii) beacon design for performing techniques described herein. I. Beacon Power

[0127] The takeoff and landing area 102 may correspond to a spatial / angular set of beacons 110 with a radiant flux (e.g., radiant power) and a directional radiant intensity. Techniques described herein may define the thermal properties of a background as the spatial sum of the constant ambient temperature and of zero-mean spatially distributed thermal textures. The temperature for everypoint on the plane ^^^, ^^, 0^ (e.g., the takeoff and landing area 102) except the beacons 110 may becomputed using the following equation: ^^^^^,^^, 0^ ൌ ^^^ ^ ∑^ ^^^^^^^^^^^^^^^^^^, ^^, 0^ .

[0128] Thus, each emitting surface element (e.g., beacon 110) with the area ^^^^ on the takeoff and landing area 102 may radiate, accordingly the Stefan-Boltzmann law the power: ^^^^^^^, ^^,^^^ ൌ ^^^^^^^^^^^^^,^^, 0^ସ.Here emissivity ^^ is a scalar ratio 0 ^ ^^ ^ 1 and ^^ ൌ 5.670374419...ൈ 10 െ 8 ^^ ൈ ^^ଶ ൈ ^^ିସ.

[0129] The area element may emit accordingly the Lambert’s cosine law: ^^^^^^^,^^, ^^^ cos^^^^^^^^൫^^^௫,௬,^^→^௫^,௬^,௭^^,Ω൯ ൌ ^^^Ω ^^^^ 2^^Here, the camera cone is the elliptic cone with the apex at ^^^, ^^, 0^ and the cross-section equal tothe camera lens (e.g., the lens of the sensor 206). If the lens radius is less than a threshold (e.g., three (3) millimeters), the area element may emit according to the following equation: ^^ ௗ^^௫,௬,்^ ୡ୭^ ఏ^^^^൫^^^௫,௬,^^→^௫^,௬^,௭^^൯ ^ଶగ Ω^௫,௬,^^→^^௫^,௬^,௭^^,^ట^,ఏ^,ఝ^^^.

[0130] If the sensor area ^^^^, the beacon surface area ^^^^ may be positioned on the image center. A solid angle of the right circular cone may be determined according to the following equation: Ω^^^^ ൌ 2^^൫1 െ ^^^^^^^^^௫,௬,^^→^௫^,௬^,௭^^൯,f-number, i.e., the ratio

[0131] In a scenario where the lens is not orthogonal but inclined to the direction from beacon surface area ^^^^ to the sensor 206, the elliptic cone may be determined according to the following equation: ^^ୟ୬షభೌబ షభೌబ್బା^ୟ୬್భ^ Ω^^^^^௧^^ ൌ ^^൫1 െ ^^^^^^^^^௫,௬,^^→^௫^,௬^,௭^^൯ ∗ଶఠ^^,^,బ^→^^, ^,^^,^^^by the sensor 206, the following equation may be used: Φ^^ൌ ^ ଶగ^^௫,௬^∈ி^^௧^^^^௧ ^^^^^^^, ^^, ^^^ cos ^^ Ω^^^^^௧^^ .Given the camera camera pose^^^^^ ,^^^ , ^^^^, ^^^^ ,^^^ ,^^^^^, the verticesfootprint in homogeneous coordinatescan be calculated as: ^^^ , ^^ , 1^் ൌ ^^^^^^^ ^்^ ^ ^^^ ,^^^ , ^^^ , 1 ,where ^^ is the camera intrinsic matrix, naturally assuming a centered rectangular sensor with no skew: ^^௫00 0^^^,where ^^^^ is the 4×4 camera extrinsic (translation and rotation) matrix: ^^^^^^ଷൈଷ^^ଷൈ^^,and where the coordinates of corresponding vertices on the sensor denotes as ^^^ , ^^^:^^^ ൌ േ ^^^⁄ 2^^^ ൌ േℎ^⁄ 2.

[0133] Given the sensor coordinates ^^^^ , ^^^^, the following equation may be derived:^^^ , ^^ , ^^ , 1^் ൌ ^^^^^^^^ି^^^^ , ^^ , 1^் ൌ ^^்^^ି^^^ି^^^^ , ^ ^்^ ^ ^ ^ ^ ^ ^^ , 1 .The thermalWithout loss of generality, the zero roll and yaw of the sensor 206 may be fixed and the pitch variable may remain constant. The sensor projection may turn into a trapezoid with area equal to: ^^ ^^^ ^ ^^ி^^௧^^^^௧^^ 2^^ ൌ െ^^ ^tan ^^^ ^ ^ െ tanఉ ^^ ^^^^ െ^^,where ^^, ^^, and ^^ are sides and height of the trapezoid footprint, and ^^ and ^^ are the horizontaland vertical angles of view of the camera:

[0134] The modal Lambertian pattern may be used for single-beam optical sources such as lasers and light diodes and may be expressed using the following equation:^^ ^ 1^^ா^^^, ^^^ ൌ2^^^^ா cos^^^^^,where ^^ ൌ െHere, dot-shaped emitter (e.g.,the beacon of its total energy proportional tothe solid angle of the camera lens and to the radiance in the camera direction.

[0135] One technique to increase the power and / or widen the beam lobe may include combining several emitters (e.g., beacons 110) with overlapping individual beams.

[0136] The sensors 206 may have calibration curves that map pixel intensities to temperature values. Absolute contrast means the difference between the background intensities and the addition made by the beacon. Relative contrast corresponds to the ratio between these values. The mapping of the added power given background to the camera intensity may be calculated and mapped to the temperatures to reflect the camera measurements. Moreover, all the thermal cameras including the LWIR cameras may be temperature-calibrated. II. Quantity of Beacons for the Takeoff and Landing Area

[0137] For accurate navigation in low visibility conditions, such as IMCs, long wave infrared (LWIR) emitters (e.g., the beacons 110) and the sensors 206 may be selected for physical considerations and size, weight, power, and costs (SWaP-C) considerations. For energy and safety reasons, point-shaped LWIR beacons 110 are may be selected. To increase the detection range with limited power, the radiant intensity of such beacons 110 may be optimized for the landing trajectory of the aircraft 200.

[0138] Using cameras as sensors 206 on board, it is possible to calculate the 6-DoF pose 222 of the aircraft 200 knowing the exact coordinates of the ground beacons 110. Although the beacons110 may be in the camera's field of view, the beacons 110 may be distinguishable over a wide range of distances and angles of view.

[0139] Optically, the beacons 110 may be substantially identical. Methods for projective-invariant identification of point objects may be used. In particular, Pi-tag, which uses projection invariance of the cross-section ratio on a line, may be used. To form one such line, four (4) point-shaped objects may be used. Four points are enough to solve a PnP problem if the points are not co-linear. Therefore, to get the camera pose, at least two sets of 4-point line segments in the field of view may be utilized. Thus, in the general case, eight (8) beacons 110 may be used, and if being pennywise, one common beacon 110 may be used for two lines, totaling seven (7) beacons 110.

[0140] However, in some scenarios, one or more beacons 110 may be obscured from the aircraft 200. In these scenarios, within a configuration of seven or eight beacons 110, solving the 6-DoF camera pose problem may be unachievable. In addition, by using a seven-beacon configuration, the possible azimuthal angles of the approach of the aircraft 200 may be limited.

[0141] In some embodiments, the beacon configuration may be determined based on an available space on the takeoff and landing area 102 (e.g., the vertiport) around the landing pad. Some vertiport designs are rectangular, and some of them are circular. III. Beacon Design

[0142] In some embodiments, the minimum number of non-collinear points to solve a PnP problem is four. Each component of the complete beacon set may include four points, but because the points are collinear, a setup may include at least two such components. Reliability and accuracy are important factors for a landing system, which may be achieved with additional four- point components.

[0143] For reliability and accuracy, an ^^-pointed star structure for beacon design may be used. The coordinates of the star point vertices may be such that the inverse cross-ratios ^^ of the four-point line segments be a maximum distant from each other. The bounds for ^^^^௫ ^ ^^ ^ ^^^^^ maybe predetermined. In some embodiments, the star point vertices may lay on the convex polygon forming the minimum convex hull for the structure, and the maximum Euclidian distance between any two star-point vertices may be less or equal to one. Accordingly, in some embodiments, all star-point vertices may lie within or on the boundary of a circle with radius of one, and the minimum Euclidian distance between any two points of the structure is more or equal to ^^^^^^ 1. EXAMPLE IMPLEMENTATION

[0144] As described above, the localization may be formulated as a 3D-2D PnP issue. Using a setof world points ^^^ ^^ ^^ଷ, ^^ ^^ ^1, … , ^^^ captured with a calibrated camera and projected to the camerasensor frame:^^ ^^ଶ, the PnP issues may be defined in distance terms (e.g., the distance between the projective center and the world 3D points) of in transformation terms (e.g., the 2D rigid body transformation between the object-centered coordinate system, world coordinate system, ^^ଷ).

[0145] Assuming a calibrated camera, i.e., given the intrinsic matrix:

[0146] The projection equation for such a camera is:

[0147] Here, Π is a perspective projection, and்ೈshows the projection from the world (W) coordinate system to the camera (C) coordinate system. ^^ ^^ ^^^^ is a rotation matrix, t stands for translation, and 0 =

[0000] . Thus, the projection equation (with no measurement noise) for the ithpoint is: ,where ^^^is the scale factor: .

[0148] ^^^^^ ^^ଷstands for the world points ^^்^ ൌ ^^^^^^^^^^^^^^ projected to the point in camera coordinates ^^் ൌ ^^^^^^^^, 1 ^^ ^^ଷ is a unit vector wit th ^ ^T^ ^ ^ ^ h i element equal to 1, i.e., 1^ ൌ 0, 0, 1 .

[0149] Computation of a camera pose means computation of the rotation matrix (R) and translation vector (t) such that:

[0151] Here,ோெ^ା௧^^య^ோெ^ା௧^is the projection of the world point ^^^onto the camera sensor plane. ^^^refers to the real-world coordinate values of the beacons, while the 2D points ^^^refers to the image coordinates of the beacon in the camera. The infrared beacons provide flexibility of forming planes in different orientations for long-distance viewing compared to the visible camera projection.

[0152] To detect and track the design of the beacons, techniques described herein may include pattern detection. For example, the region of interest (RoI) that potentially includes the beacons may be detected. Single beacon detection and registration may also be performed. For example, within the RoIs, beacon-looking objects can be detected using computer vision methods that include preprocessing, normalized correlation, and adaptive thresholding. The beacon-looking objects may be registered within the camera plane as ^^^. Once the beacons are identified, the 2D image pattern may be associated to the beacons in the 3D world (with the location ^^^). Pose estimation may also be performed. For example, given the projective camera transformation, along with the beacon relationship, the projection matrix ^^்ೈmay be computed. Given the rotation (R) and the translation matrix (t) within the projection matrix ^^்ೈ, the 6 DoF camera pose estimation can be computed.

[0153] According to techniques described herein, the intensity of irradiation in one or another direction may be determined by the distance from the camera to the beacon, the sensitivity of the camera, the range of visibility in the selected frequency range in the range of weather conditions, and the distinguishability of objects against the background of the environment. The LWIR range may be selected based on atmospheric transparency windows to enhance all-weather optical navigation. In some implementations, the total number of beacons in the design may be more thanenough to perform localization to account for false negatives due to occlusion. The spatial configuration of the beacons may ensure that the beacons are optically distinguishable from different angles and views.

[0154] The present disclosure describes various features and operations of the disclosed systems. The illustrative implementations described herein are not meant to be limiting. Certain aspects of the disclosed systems can be arranged and combined in a variety of different configurations, all of which are contemplated herein.

[0155] Further, unless context suggests otherwise, the features illustrated in each of the figures may be used separately or in combination. Thus, the figures should be generally viewed as component aspects of one or more overall implementations, with the understanding that not all illustrated features are necessary for each implementation. For example, one or more example features and / or implementations described in any of Figures 1A, 1B, 2, 3, 4, 5, and 6 may be combinable with one or more example features and / or implementations described in another figure.

[0156] Additionally, any enumeration of elements, blocks, or steps in this disclosure is for purposes of clarity. Thus, such enumeration should not be interpreted to require or imply that these elements, blocks, or steps adhere to a particular arrangement or are carried out in a particular order.

[0157] Further, devices or systems may be used or configured to perform functions presented in the figures. In some instances, components of the devices and / or systems may be configured to perform the functions such that the components are actually configured and structured (with hardware and / or software) to enable such performance. In other examples, components of thedevices and / or systems may be arranged to be adapted to, capable of, or suited for performing the functions, such as when operated in a specific manner.

[0158] By the term “substantially” or “about” it is meant that the recited characteristic, parameter, or value need not be achieved exactly, but that deviations or variations, including for example, tolerances, measurement error, measurement accuracy limitations may occur in amounts that do not preclude the effect the characteristic was intended to provide.

[0159] The arrangements described herein are for purposes of example only. As such, those skilled in the art will appreciate that other arrangements and other elements (e.g., machines, interfaces, operations, orders, and groupings of operations, etc.) can be used instead, and some elements may be omitted altogether according to the desired results. Further, many of the elements that are described are functional entities that may be implemented as discrete or distributed components or in conjunction with other components, in any suitable combination and location.

[0160] While various aspects and implementations have been disclosed herein, other aspects and implementations will be apparent to those skilled in the art. The various aspects and implementations disclosed herein are for purposes of illustration and are not intended to be limiting. Also, the terminology used herein is for the purpose of describing particular implementations only and is not intended to be limiting.

Claims

CLAIMS 1. A system comprising: a takeoff and landing area; and a plurality of beacons non-uniformly spaced throughout the takeoff and landing area, wherein a first beacon of the plurality of beacons has first spatial coordinates, and wherein a second beacon of the plurality of beacons has second spatial coordinates.

2. The system of claim 1, wherein the first spatial coordinates comprise at least a first longitude coordinate, a first latitude coordinate, and a first elevation, and wherein the second spatial coordinates comprise at least a second longitude coordinate, a second latitude coordinate, and a second elevation.

3. The system of claim 1, wherein the plurality of beacons are detectable by an aircraft based on beacon parameters associated with the plurality of beacons, and wherein beacon parameters comprise: the first spatial coordinates of the first beacon; and the second spatial coordinates of the second beacon.

4. The system of claim 3, wherein the beacon parameters further comprise: first modulation parameters of the first beacon; and second modulation parameters of the second beacon.

5. The system of claim 3, wherein the beacon parameters further comprise: a first electromagnetic spectrum of the first beacon; anda second electromagnetic spectrum of the second beacon.

6. The system of claim 5, wherein the beacon parameters further comprise: a first radiation pattern of the first electromagnetic spectrum; and a second radiation pattern of the second electromagnetic spectrum.

7. The system of claim 1, wherein a collective shape of the plurality of beacons enables an aircraft to: identify the takeoff and landing area; and estimate a pose of the aircraft with respect to the takeoff and landing area.

8. The system of claim 1, wherein a collective design of the plurality of beacons enables an aircraft to: identify the takeoff and landing area; and estimate a pose of the aircraft with respect to the takeoff and landing area.

9. The system of claim 1, wherein each beacon of the plurality of beacons comprises an infrared beacon.

10. The system of claim 1, wherein each beacon of the plurality of beacons comprises a visual light beacon.

11. The system of claim 1, wherein the first beacon is identifiable by a first shape of the first beacon and a first temperature of the first beacon, and wherein the second beacon is identifiable by a second shape of the second beacon and a second temperature of the second beacon.

12. The system of claim 1, wherein the takeoff and landing area comprises a vertiport.

13. A method comprising: detecting, by one or more sensors of an aircraft, a plurality of beacons non-uniformly spaced throughout a takeoff and landing area, wherein a first beacon of the plurality of beacons has first spatial coordinates, and wherein a second beacon of the plurality of beacons has second spatial coordinates; in response to detecting the plurality of beacons, identifying, by a processor of the aircraft, the takeoff and landing area; in response to identifying the takeoff and landing area, estimating, by the processor, a pose of the aircraft with respect to the takeoff and landing area; and based on the pose, maneuvering the aircraft to land on the takeoff and landing area.

14. The method of claim 13, wherein the takeoff and landing area is identified based on a collective shape of the plurality of beacons.

15. The method of claim 13, wherein the takeoff and landing area is identified based on a collective design of the plurality of beacons.

16. The method of claim 13, wherein a particular beacon of the plurality of beacons is detectable by the one or more sensors based on beacon parameters associated with the particular beacon.

17. The method of claim 16, wherein the beacon parameters include at least one of modulation parameters of the particular beacon, an electromagnetic spectrum of the particular beacon, a radiation pattern of the electromagnetic spectrum, a shape of the particular beacon, a temperature of the particular beacon, or a vertical displacement of the particular beacon with respect to the takeoff and landing area.

18. The method of claim 13, wherein each beacon of the plurality of beacons comprises an infrared beacon.

19. The method of claim 13, wherein each beacon of the plurality of beacons comprises a visual light beacon.

20. The method of claim 13, wherein the takeoff and landing area comprises a vertiport.

21. An aircraft comprising: one or more actuators; one or more sensors configured to detect a plurality of beacons non-uniformly spaced throughout a takeoff and landing area, wherein a first beacon of the plurality of beacons has firstspatial coordinates, and wherein a second beacon of the plurality of beacons has second spatial coordinates; a processor configured to: in response to the one or more sensors detecting the plurality of beacons, identify the takeoff and landing area; in response to identifying the takeoff and landing area, estimate a pose of the aircraft with respect to the takeoff and landing area; generate, based on the pose, maneuvering commands to land on the takeoff and landing area; and control, based on the maneuvering commands, the one or more actuators to land the aircraft.

22. The aircraft of claim 21, wherein the takeoff and landing area is identified based on a collective shape of the plurality of beacons.

23. The aircraft of claim 21, wherein the takeoff and landing area is identified based on a collective design of the plurality of beacons.

24. The aircraft of claim 21, wherein a particular beacon of the plurality of beacons is detectable by the one or more sensors based on beacon parameters associated with the particular beacon.

25. The aircraft of claim 24, wherein the beacon parameters include at least one of modulation parameters of the particular beacon, an electromagnetic spectrum of the particular beacon, a radiation pattern of the electromagnetic spectrum, a shape of the particular beacon, a temperature of the particular beacon, or a vertical displacement of the particular beacon with respect to the takeoff and landing area.

26. The aircraft of claim 21, wherein each beacon of the plurality of beacons comprises an infrared beacon.

27. The aircraft of claim 21, wherein each beacon of the plurality of beacons comprises a visual light beacon.

28. The aircraft of claim 21, wherein the takeoff and landing area comprises a vertiport.

29. A non-transitory computer-readable medium comprising instructions that, when executed by one or more processors of an aircraft, cause the one or more processors to perform operations comprising: detecting a plurality of beacons non-uniformly spaced throughout a takeoff and landing area, wherein a first beacon of the plurality of beacons has first spatial coordinates, and wherein a second beacon of the plurality of beacons has second spatial coordinates; in response to detecting the plurality of beacons, identifying the takeoff and landing area; in response to identifying the takeoff and landing area, estimating, by the processor, a pose of the aircraft with respect to the takeoff and landing area; andbased on the pose, maneuvering the aircraft to land on the takeoff and landing area.

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