IL314161B2 - Systems and methods for transfer alignment - Google Patents

Description

P11112-IL SYSTEMS AND METHODS FOR TRANSFER ALIGNMENT BACKGROUND id="p-1"

[0001] Head-mounted displays (HMDs) can be employed for providing a user virtual, augmented, and/or mixed reality visual content. For example, HMDs can be configured to overlay an environment viewed through and/or displayed by the HMD with graphical objects for assisting a user in controlling a vehicle in the environment, and/or for monitoring parameters relating to the vehicle’s operation, among other applications. id="p-2"

[0002] Realizing applications involving virtual, augmented, and/or mixed reality requires correct alignment of the displayed information with a reference frame to the HMD, such as the reference frame of the earth. id="p-3"

[0003] The description above is presented as a general overview of related art in this field and should not be construed as an admission that any of the information it contains constitutes prior art against the present patent application.

P11112-IL BRIEF DESCRIPTION OF THE DRAWINGS id="p-4"

[0004] Some embodiments of the disclosed subject matter are described, by way of example only, with reference to the accompanying drawings. With specific reference now to the drawings in detail, it is stressed that the particulars shown are by way of example and for purposes of illustrative discussion of the preferred embodiments of the present disclosed subject matter only and are presented in the cause of providing what is believed to be the most useful and readily understood description of the principles and conceptual aspects of the disclosed subject matter. In this regard, no attempt is made to show structural details of the disclosed subject matter in more detail than is necessary for a fundamental understanding of the disclosed subject matter, the description taken with the drawings making apparent to those skilled in the art how the several forms of the disclosed subject matter may be embodied in practice.

In the drawings: id="p-5"

[0005] Figure 1 schematically shows misalignment between rotation axes of an IMU and the rotation axes of a reference platform. id="p-6"

[0006] Figure 2 is a schematic illustration of the principal axes of rotation of a platform. id="p-7"

[0007] Figure 3 is a schematic illustration of a control station comprising a station-mounted IMU, and the axes of rotation of a pilot’s head or of a display device worn by a pilot that is located in the control station. id="p-8"

[0008] Figure 4A schematically shows a first scenario where a first reticle symbol represents a true LOS of a user, and a second reticle symbol represents a computed LOS, both overlaid over scene, where the first "true LOS" reticle and the second "computed LOS" reticle are misaligned. id="p-9"

[0009] Figure 4B schematically shows a second scenario where the first "true LOS" reticle symbol conforms with the position of the second "computed LOS" reticle, according to some embodiments. id="p-10"

[0010] Figure 5 is a schematic illustration of a control station without a station-mounted IMU, according to some embodiments. id="p-11"

[0011] Figure 6 is a schematic illustration of a control station comprising a station-mounted non-inertial tracker component and which is free of a station-mounted IMU, according to some embodiments. id="p-12"

[0012] Figure 7 is a schematic block diagram illustration of a tracking system that is free of a station-mounted IMU and free of a station-mounted non-inertial tracker component, according to some embodiments.

P11112-IL id="p-13"

[0013] Figure 8is a flowchart of a method for tracking orientation of an object relative to a reference frame, according to some embodiments.

DETAILED DESCRIPTION id="p-14"

[0014] Tracking the orientation of a user’s head and/or the orientation of a Head-Mounted Display (HMD) worn by a user relative to a reference frame may allow realizing, for example, augmented, virtual and/or mixed reality display applications. Embodiments disclosed herein pertain to transfer harmonization or alignment to account and/or correct for orientational misalignment between an HMD-tracking sensor and the reference frame. Performing transfer alignment ensures that tracked sensor outputs conform with the reference frame. The reference frame may pertain, for example, to a platform and/or the World Reference Frame. Embodiments may pertain systems and methods configured to obviate the need of employing a control station-mounted Inertial Measurement Unit (station-mounted IMU) for tracking the HMD relative to the control station or platform. In other words, embodiments of tracking systems and methods discussed herein may be free of a station-mounted IMU. The expression "tracking orientation", as well as variations thereof, may pertain to tracking an object’s azimuth, pitch, and/or roll relative to a reference frame. Processes and/or steps disclosed herein may be performed in real-time or substantially in real-time. id="p-15"

[0015] In some embodiments, the position of the HMD or users’ head relative to a reference frame may be tracked as well. In some scenarios, a canopy’s curvature may distort how objects that are located external to the canopy are seen or perceived through the HMD’s visor. It may therefore be beneficial to determine a distance between the HMD and the cockpit canopy, e.g., to correspondingly adapt how to display symbology in association with such external objects. id="p-16"

[0016] A position may be referred to with respect to a reference coordinate system, e.g., in cartesian coordinate values X,Y,Z. In some embodiments, a user’s gaze direction may also be tracked. A user’s gaze direction may be tracked, for example, through camera-based and/or reflection-based eye-movement tracking. However, merely to simplify the discussion that follows, and without be construed as limiting, embodiments and examples set forth herein may refer to tracking the orientation of an HMD, which is worn by a user, relative to a reference frame. id="p-17"

[0017] The term "tracking" may pertain to determining instant orientations of an HMD relative to a reference frame. An inertial measurement unit (IMU) and/or non-inertial sensor arrangements may be employed for implementing HMD tracking, e.g., as described herein. An IMU may comprise one or more inertial sensors such as accelerometers and/or gyroscope. A non-inertial sensor arrangement may for P11112-IL example include optical tracker units. The tracking may be performed in real-time or substantially in real-time. id="p-18"

[0018] In some example implementations, the user may be located within a control station of an (e.g., vehicular) platform, which may be located in an environment or scene. The control station comprises I/O modules allowing the user to control (e.g., pilot) the platform. id="p-19"

[0019] Although embodiments disclosed herein pertain to HMD orientation tracking, this should by no means be construed in a limiting manner. Accordingly, systems and methods described herein may also be applicable in conjunction with the tracking of the orientation and/or acceleration, for example, of sensory equipment, Input/Output (I/O) devices, and/or any other object, relative to a reference frame. Such objects can include cameras, IMUs, sources of electromagnetic radiation (e.g., lasers, infrared emitters); X-ray sources; magnetic field sources; magnetic field sensors; ultrasound emitters; antennas; transmitters; receivers; detectors; sensors; speakers; microphones; and/or the like. For instance, an IMU may be rigidly associated with a camera (e.g., a camera may comprise an IMU), in a manner such that the IMU’s local coordinate system can be considered to be aligned with the camera’s local coordinate system axes. id="p-20"

[0020] An HMD or HMD system may include a graphical object display area. The HMD may be configured such that a position of the HMD’s display area relative to the reference frame changes according to a change in position of the user’s head wearing the HMD. id="p-21"

[0021] Tracking data that is output by the one or more sensors may be descriptive of information such as, for example, angular velocity, linear acceleration, of the HMD orientation relative to the reference frame. Mathematical integration of angular velocity information results may be employed for determining an angular position of the HMD relative to one or more points of reference of an (optional same) reference frame. Integration of acceleration may be employed for determining linear velocity information, and further integration of the linear velocity information may result in HMD position information relative to a second reference point, which may be identical to the first reference point. id="p-22"

[0022] A current or present orientation of an object (e.g., an HMD and/or of a graphical object displayed by the HMD) with respect to a fixed or reference coordinate system (CS) may be expressed by attitude or orientation angles formed by the object's principal rotation axes (also: principal axes) relative to the reference coordinate system. To determine the orientation of an object relative to a reference coordinate system, the object's principal axes are transformed into the reference coordinate system by using the Euler angles. The Euler angles are thus the angles through which the object's coordinate system must be rotated to bring its axes to coincidence with the reference coordinate system. Accordingly, the Euler angles describe P11112-IL an HMD’s roll (also: bank), pitch (also: elevation), and azimuth (also: heading) orientation with respect to the reference coordinate system. Hence, one can define the orientation of the HMD relative to a reference coordinate system by the amount of rotation of the parts of the HMD about these principal axes. id="p-23"

[0023] As mentioned above, embodiments disclosed herein pertain to transfer harmonization or alignment to account and correct for orientational misalignment, expressible by the Euler angles, of a sensor, such as an Inertial Measurement Unit (IMU) relative to a reference frame, for determining the magnitude of the required alignment. id="p-24"

[0024] Figure 1 schematically shows misalignment between rotation axes of an IMU 500and the rotation axes of a reference platform. id="p-25"

[0025] An HMD-mounted IMU (also: HMD-IMU) may be employed for tracking acceleration and angular position of the user’s gaze relative to the world reference frame external to the platform. Furthermore, inertial sensors (also: "station-IMUs") may be fixedly mounted with the control station to deduct or offset (e.g., filter out, subtract) motions attributable to platform motion. Offsetting or deducting motions which are attributable to platform motion from station-IMU (also: station-mounted IMU) outputs allows determining HMD orientations relative to the control station. id="p-26"

[0026] In some examples, a non-inertial HMD tracker (NIT) may be employed to suppress and/or correct for drift of the station-IMU and/or HMD-IMU to result in a gaze tracker with low latency and high accuracy.

A sensor arrangement comprising both inertial and non-inertial sensors for tracking an HMD relative to the platform may herein be referred to as "hybrid station-mounted gaze tracker" or simply "hybrid gaze tracker". The station-NIT must be correctly aligned with the station-IMU. Furthermore, to allow for correctly excluding or filtering out changes of HMD orientation data attributable to platform motion, the station-IMU and the HMD-IMU must be correctly aligned with each other. In some examples, motion of station-IMU coordinate system may be expressed with respect to world coordinate system WORLDxyz . It is noted that, in some implementations, a "station-NIT" may comprise HMD-mounted components and station-mounted components that are communicably coupled with each other such to enable non-inertial (e.g., optical) tracking of the HMD orientation relative to the platform. As outlined herein, embodiments may enable obviating the need of station-mounted components for non-inertial tracking of the HMD. id="p-27"

[0027] In some embodiments, the platform may additionally include an Inertial Navigation System (INS), for determining the orientation of platform relative to the World Coordinate System. The INS may include one or more platform-mounted IMUs, and/or magnetic sensors for platform navigation based on the Earth’s magnetic field. In some examples, determining the HMD’s orientation with respect to the world coordinate P11112-IL system may require that the output of an HMD tracker (e.g., inertial, non-inertial, and/or hybrid tracker) is aligned with the platform’s INS. id="p-28"

[0028] To date, it was required to take into consideration the output of the station-IMU for determining the HMD orientation relative to the platform’s control station. For that purpose, the station-IMU and the station-NIT had to be aligned with each other. In addition, the station-IMU and the HMD-IMU had to be aligned with each other. Embodiments of Systems and Methods disclosed herein reduce the arduous preparatory transfer alignment processes for readying an HMD for use in conjunction with a selected platform. Embodiments may pertain to a tracking system and method obviating the need for performing transfer alignment between a station-IMU and an HMD-IMU, and/or between a station-NIT and the HMD-IMU. Embodiments may also pertain to a tracking system and method obviating the need for performing transfer alignment between a station-IMU and an Platform INS. Embodiments allow for obviating the need of employing the station-IMU, a station-mounted NIT component, or both, while allowing tracking of the HMD based on the HMD-IMU, and based on an HMD-mounted NIT component. id="p-29"

[0029] Additional reference is made to Figure 2 and to Figure 3 . A (e.g., vehicular) platform 1000 comprises a control station 1100 (e.g., cockpit). In operation, a user 600 situated in the control station 1100of platform 1000 wears an HMD 1200 comprising a display 1210 . HMD 1200 may move freely within control station 1100 . id="p-30"

[0030] HMD 1200 may be configured to convey via display 1210 augmented information to the user 600 , for example, by overlaying a scene displayed to user 600 by display 1210 with graphical objects 1216 , to facilitate controlling operations of the vehicular platform 1000 and/or monitoring parameters relating to the platform’s operation. A user’s view through and/or of the HMD’s display 1210 is schematically illustrated by display frame 1211 . Display 1210may be fully transparent, partially transparent, or fully opaque. In some examples, at least a portion of display 1210 may be controllable to become selectively opaque or transparent. id="p-31"

[0031] The displayed information may include computer-generated graphical object 1216 , which may overlay in a partially or fully conformed manner with the real control station 1100 . id="p-32"

[0032] In cases where display 1210is transparent, partially transparent or opaque, HMD 1200may be configured to display to the user via display 1210one or more augmenting graphical objects 1216while at same time allowing user 600 to see through the HMD’s display to view the control station’s instruments, screens and/or through a window to view the control station’s external visual scene 10 .

P11112-IL id="p-33"

[0033] In cases where display 1210is fully opaque, HMD 1200may be configured to display to the user a virtual (e.g., computer-generated) representation of a control station 1100 and/or of an external visual scene 10 . id="p-34"

[0034] Graphical objects 1216displayed to the user for augmenting a scene can include, for example, synthetically generated digital images, textual information, graphical symbology, processed and/or unprocessed video that originated from electro-optical sensors, and any combination thereof, or the like. id="p-35"

[0035] Graphical objects 1216may for example be descriptive of the platform’s orientation relative to the world, the platform’s velocity, height and/or drift relative to ground, highlight an object in control station 1100 , highlight an object (e.g., a horizon, a target) in the external visual scene 10 , mask an object and/or the like. id="p-36"

[0036] Information may be displayed by graphical object 1216in conformal, partial conformal or non-conformal manner. A graphical object may be considered "conformal" if the information that it conveys preserves a scale and/or orientation with respect to World Coordinate System WORLDxyz . Non-limiting examples of conformal graphical objects 1216can include a display of an artificial or synthetic horizon, flight path vector (FPV), symbols descriptive of an acquired target; symbol pointing on an incoming missing, platform roll, pitch, yaw, relative to the world reference frame WORLDxyz , and/or the like. id="p-37"

[0037] Information provided by graphical object 1216 is "non-conformal", if the information that graphical object 1216conveys does not or only partially preserves a scale and/or orientation with respect to the World Coordinate System WORLDxyz . Examples of non-conformal graphical object 1216can include display of the aircraft's fuel level and/or status, cockpit pressure, indicated air speed (IAS), velocity relative to ground, altitude, outside temperature; outside humidity; outside pressure; cabin pressure; fuel reserves; battery power; engine thrust; instrument functionality; user vital signs; G-force on an aircraft, and/or any other type of information non-conformably describable by a scalar; speed scales; ordinal; categorical; and/or interval parameter. id="p-38"

[0038] Optionally, graphical object 1216may be descriptive of, or represent, a vehicle state vector. Such graphical object may herein be referred to as "vehicle state vector symbol". Generally, a vehicle state vector represents a state of the vehicle at a particular time instance. A vehicle state vector can for example represent values of aircraft flight parameters such as the aircraft’s flight path vector (FPV); and/or engine thrust direction and/or magnitude. Optionally, a translational position of a vehicle state vector may be adjusted in accordance with the values pertaining to the vehicle state vector. To simplify the discussion that follows, without be construed limiting, embodiments and examples pertaining to a vehicle state vector may P11112-IL be outlined with respect to an aircraft’s FPV. In some embodiments, a graphical object may be actionably engageable (e.g., gaze-based engagement, touch-based engagement) by the user. id="p-39"

[0039] Graphical object 1216 may have partial conformity, for example, if partially displayed in conformity with external visual scene and partially in conformity with the control station. id="p-40"

[0040] To augment the scene external to the control station 1100 viewable by the user 600 through the HMD 1200 with additional information, the HMD principal rotation axes Dxyz , represented by an HMD-IMU 1230 , must be mapped (also: registered) with a World Coordinate System WORLDxyz that is associated with the external visual scene 10 of the vehicular platform 1000 . In addition, to augment the control station 1100 viewable by the user 600 through the HMD 1200 with additional information (e.g., for displaying a virtual Head-Up Display), the HMD principal axes Dxyz of HMD-IMU 1230must also be mapped (also: registered) with the Platform’s Principal Axes Pxyz associated with the control station 1100 of vehicular platform 1000 . id="p-41"

[0041] To determine orientation of HMD 1200 relative to platform 1000 , IMU output that is attributable to platform motion may have to be deducted from outputs of HMD-IMU 1230 . However, platform INS outputs provided by platform-mounted IMU 1010 may not be read out directly. For that reason, it may be required to retrofit or install station-IMU 1300 . id="p-42"

[0042] To offset from HMD-IMU 1230 output that is attributable to platform motion, output of station-IMU 1300 is deducted from HMD-IMU 1230to obtain the HMD orientation relative to the platform. Based on the platform’s INS output, the orientation of the HMD relative to the world can then be determined. Accordingly, station-IMU 1300may be employed to filter out changes in HMD orientation attributable to motion of platform 1000 . id="p-43"

[0043] Furthermore, a station-mounted non-inertial tracker (NIT) 1400 and/or platform’s INS 1010may be employed to suppress and/or correct for drift of HMD-IMU 1230and/or station-IMU 1300 to result in a hybrid gaze tracker with low latency and high accuracy. Hence, to correctly filter out changes in gaze direction attributable to station-motion, HMD-IMU 4220 must be aligned with non-inertial gaze tracker 1400 , and station-IMU 1300 must be aligned with NIT 1400 . In addition, NIT 1400 must be aligned with the platform’s INS 1010 to calculate HMD’s non-inertial tracking value relative to the world reference frame WORLDxyz . id="p-44"

[0044] As mentioned above, a sensor arrangement comprising both inertial and non-inertial sensors for tracking a user’s gaze relative to station 1100 may herein be referred to as "hybrid station-mounted gaze tracker" or simply "hybrid gaze tracker" 1500 .

P11112-IL id="p-45"

[0045] The output of hybrid gaze tracker 1500 may be transfer-aligned, e.g., as known in the art, to register the gaze direction Gx with the World Coordinate System WORLDxyz . id="p-46"

[0046] Coordinate system ST - IMUxyz of station-mounted IMU 1300 , and coordinate system ST-NITxyz of station-mounted NIGT 1400 may constitute the reference coordinate systems of the HMD principal rotation axes Dxyz . The Platform Coordinate System Pxyz may constitute the reference coordinate system for the ST - IMUxyzand ST-NITxyz , which are rigidly fixed to station 1100 and, therefore to platform 1000 . id="p-47"

[0047] To simplify the discussion that follows, the two coordinate systems ST - IMUxyzand ST-NITxyz of hybrid gaze tracker 1500 may herein be collectively referred to Txyz . id="p-48"

[0048] Assuming each Platform principal rotation axis Pxyz is angularly aligned with the corresponding hybrid tracker rotation axis Txyz , then the HMD orientation relative to the corresponding Platform INS rotation axes Pxyz can be determined, enabling conformably augmenting the control station 1100 with additional information for display by the HMD 1200 . id="p-49"

[0049] Moreover, based on the HMD principal rotation axes Dxyz relative to the Platform INS rotation axes Pxyz , and further based on the orientation of the Platform INS rotation axes Pxyz relative to the world coordinate system WORLDxyz , the motion of HMD 1200 relative to the World Coordinate System WORLDxyz can be derived, enabling conformably augmenting the external visual scene 10 with additional information for display by HMD 1200 . id="p-50"

[0050] However, spatial constraints in control station 1100 , calibration errors, operational conditions such as, for example, such as vibrations, high G maneuvers, temperature changes, distortions caused by material aging, and/or the like, can cause misalignment between HMD-IMU 1230 , station-mounted IMU 1300 , and/or between HMD-IMU 1230 and a station-mounted NIT component and/or an HMD-mounted NIT component of NIT 1400 . The station-mounted and the HMD-mounted NIT components may comprise active components that are communicably coupled with each other (e.g., a camera and a detector). id="p-51"

[0051] Consequently, the display rotation axes Dxyz may become misaligned with reference to the Tracker Rotation Axes Txyz , causing misalignment of the displayed graphical objects 1216 for scene augmentation. id="p-52"

[0052] Misalignment, for example, between display rotation axes Dxyzof HMD-IMU 1230 , and station-mounted ST - IMUxyz rotation axes of station-mounted IMU 1300 , can result in incongruence between the objects seen in the user’s actual line-of-sight (LOS) or actual gaze direction Gx , and a calculated gaze direction Gx determined by hybrid gaze tracker 1500 and to which the platform's sensors adhere to.

P11112-IL Consequently, platform-based target acquisition and gaze-based engagement of the same target may be impaired, as described in the example that follows. id="p-53"

[0053] Figure 4A schematically shows a first scenario where a first reticle symbol 1216A represents a true LOS of a user, and a second reticle symbol 1216B represents a computed LOS, both overlaid over scene 10 . As shown, first "true LOS" reticle 1216A and second "computed LOS" reticle 1216Bare misaligned. id="p-54"

[0054] Figure 4Bschematically shows a second scenario where the first "true LOS" reticle symbol 1216A conforms with the position of the second "computed LOS" reticle 1216B . The scenario shown in Figure 4Bthus allows reliable scene augmentation, target acquisition, target tracking, etc. id="p-55"

[0055] Additional reference is now made to Figure 5, Figure 6and to Figure 7 . In some embodiments, a conformal gaze tracking system 4000 may be implemented by components of control station 4100 , e.g., as outlined herein, for performing virtual transfer alignment between an HMD-IMU fixedly accommodated by an HMD worn by a user, , and a station-mounted non-inertial active gaze tracker (station-NIT). id="p-56"

[0056] An HMD 4200 worn by user 600 may comprise a display 4210 , and an HMD-IMU 4220 fixedly accommodated by HMD 4200 . System 4000may further include a station-mounted IMU 4300and a non-inertial HMD tracker (also: NIT) 4400 . Analogous to the description above, a sensor arrangement comprising both inertial and non-inertial sensors for tracking a user’s gaze relative to station 4100 may herein be referred to as "hybrid station-mounted gaze tracker" or simply "hybrid gaze tracker" 4500 . id="p-57"

[0057] System 4000 is configured to obviate the need of employing a station-mounted IMU 4300 configured to output station-mounted IMU rates 4020 . id="p-58"

[0058] A first IMU output of HMD-IMU 4230 is attributable to both motion of platform 1000 and to motion of HMD 4200 . A second output of station-NIT 4400 is (only) attributable to motion of HMD relative to station 4100 . In some embodiments, the second output of station-NIT 4400 is subtracted from the first output of HMD-IMU 4230 , resulting in a third IMU output pertaining (only) to platform motion relative to WORLDxyz . The third IMU output may herein also be referred to as "virtual station-IMU output". The resulting third IMU output may be transfer aligned with the platform’s INS, e.g., as known in the art, for determining the HMD’s LOS with respect to WORLDxyz . Sensor drift of the third (virtual) IMU output may be corrected by the non-inertial tracker(s). id="p-59"

[0059] Platform INS may output information (e.g., angular rates relative to Earth coordinates) at lower (also: first) frequencies compared to the output frequency of a (virtual) station-mounted IMU. In some embodiments, outputs of a (virtual) station-mounted IMU may be utilized for determining INS platform position estimates relative to the Earth at increased (also: second) frequencies. In some examples, the P11112-IL output of INS platform may be synched with the output of the virtual station-mounted IMU for determining, based on the outputs of virtual station-mounted IMU, estimates of INS platform rates at the increased frequency. For example, based on the (virtual) station-mounted IMU output, estimates of INS platform rates may be derived (e.g., through interpolation) at a comparatively increased INS output frequency, which corresponds (e.g., equals) the output frequency of the (virtual) station-mounted IMU output. Deriving or determining, based on a (virtual) station-mounted IMU output, increased INS platform rates may herein also be referred to as upsampling the first INS platform output frequency to the second INS platform output frequency. id="p-60"

[0060] As further shown schematically in Figure 7 , display device 4210 may include a visor 4212 and an optical unit (not shown). Display device 4210 may include a processor (not shown) configured to generate and render graphical objects for displaying by display device 4210 . The optical unit may be configured to augment images (e.g., video stream) and/or a real scene (e.g., instrument panel 4102 ) viewable by user 600 through visor 4212 . id="p-61"

[0061] Merely to simplify the discussion that follows, without be construed limiting, example scenarios described herein may pertain to scenarios of augmenting a real scene 10 with graphical object 4218 to provide user 600 with augmented scene information. However, embodiments may also be applicable for augmenting a virtual scene displayed to user 600 . Such virtual scene may be composed of synthetically generated digital images (e.g., video) representing a real scene. id="p-62"

[0062] Non-inertial tracker 4400may be based on various gaze tracking technologies for determining the orientation of HMD 4200 relative to station 4100 , for example, optical, electromagnetic, and/or sonic-based technologies. For example, non-inertial tracker 4400 may include a station-mounted NIT unit 4410comprising, for example, a detector; and an HMD-mounted NIT unit 4420 comprising, for example, an emitter. detector 4410 may be configured to detect optical signals Topt emitted by HMD-mounted optical emitter 4420 to output electronic signals encoding information about the motion of HMD 4200 . Alternative, or additional NIT tracker configurations may be conceived. Accordingly, in some examples, NIT 4400 may be considered to employ both station-mounted and HMD-mounted non-inertial active tracker components (also: units, apparatuses, or devices) that are communicably coupled with each other. id="p-63"

[0063] Conformal gaze tracking system 4000 may further include a memory 4002 , a processor 4004 , a communication module 4006and a power module 4008 for powering the various components of conformal gaze tracking system 4000.

P11112-IL id="p-64"

[0064] Memory 4002 may include and/or receive data and instructions which, when processed by processor 4004 , results in a Virtual Transfer Alignment Application 4010for aligning the output of HMD-IMU 4220 with the platform’s INS, without requiring the employment of a station-IMU. id="p-65"

[0065] Equation 1 below describes subtracting motion rates (e.g., angular rates) of motion of Station-NIT from motion rates of HMD-IMU 4220 , to determine motion rates of HMD-IMU 1230 relative to the world: HMD-mounted IMU(rates) WORLDxyzminus station-mounted NIT(rates) STATIONxyz = HMD WORLDxyz motion rates relative to WORLDxyz (1) id="p-66"

[0066] It is noted that prior to performing the above subtraction (equation 1 ), various testing and/or calibration techniques may be employed, e.g., in a lab setup and/or during flight, to perform alignment between HMD-IMU 4220 and HMD-NIT tracker unit 4420 . id="p-67"

[0067] In some embodiments, a station-mounted NIT may comprise a station-mounted NIT component. Station-mounted NIT component may be a passive component. Station-mounted NIT component may be an object comprised in the cockpit that can be used as a reference by an HMD-mounted NIT (e.g., a camera) for tracking the HMD orientation relative to the station-mounted NIT component and, based thereon, the orientation of the HMD relative to the cockpit. In some examples, a plurality of station-mounted NIT components may be utilized for the tracking HMD orientation in the cockpit. id="p-68"

[0068] In some examples, an HMD-mounted component may be passive component (e.g., a reference marker on the HMD used as a reference by a station-mounted camera for tracking the HMD position). [0069] Depending on the gaze direction, different station-mounted reference points may be utilized for tracking orientation of an HMD, optionally, with an HMD-mounted non-inertial (e.g., active) tracker component, such as camera. For example, when gazing towards a first field-of-view (FOV) of the platform, a first reference point of the station may be used as a first platform-based HMD tracking reference. When gazing towards a second field-of-view (FOV) that is different from the first FOV, a second reference point of the platform may be used as a second platform-based HMD tracking reference. The second reference point may be located in the control station (e.g., cockpit) at a second location which is different from the first location of the first reference point. This way, as is schematically shown in Figure 6 , by employing an HMD-mounted active NIT (e.g., a camera), and a passive station-mounted NIT component (e.g., a reference marker), a tracking system may in some embodiments not only be free of a station-mounted IMU, but also P11112-IL be free of a station-mounted (active) NIT component, such as a camera. Such systems may also include an HMD-mounted IMU. [0070] In some embodiments, any object comprised in the station (e.g., as display, a control element) may be utilized as a reference point or marker for determining the HMD orientation relative to the platform, e.g., provided that the object is within a current field-of-view of the HMD-mounted active NIT component. [0071] In some examples, no steps may be required for installing the object in the cockpit, as the object may be an integral (e.g., pre-installed) part thereof. Any real-world object in the control station may serve as a reference point including for example, a display, a screen, and/or a control element (switches, dials, knobs, push buttons, levers, indicators, wheels, and/or handles). [0072] In some embodiments, an HMD-mounted NIT may comprise one or more cameras simultaneously covering multiple FOVs around the HMD for simultaneously acquiring images of the HMD’s surroundings, for tracking the HMD position relative to the platform. [0073] As mentioned above, the motion of HMD-IMU coordinate system may always expressed with respect to world coordinate system WORLDxyz . [0074] As schematically illustrated in Figure 7 , in some embodiments, HMD-IMU 4220 outputs HMD-IMU rates, expressed in WORLDxyz(block 4012 ), non-inertial gaze tracker 4400outputs NIGTxyz rates expressed in tracker coordinate system xyz (block 4014 ). id="p-75"

[0075] In some embodiments, conformal gaze tracking system 4000 subtracts (block 4016 ) the NIT rates from the HMD-IMU rates to obtain, expressed in WORLDxyz , HMD rates 4018 relative to the World. id="p-76"

[0076] Non-inertial gaze tracker 4400 that may utilize one or more electromagnetic (e.g., optical) emitters fixedly mounted with HMD 4200to implement helmet-mounted non-inertial helmet-mounted tracker unit 4420 , and one or more electromagnetic (EM) (e.g., optical) detectors, configured to detect electromagnetic radiation (EM) output by the emitters, may be fixedly coupled with control station 4100as station-mounted non-inertial tracker unit 4410 . id="p-77"

[0077] In another example, one or more EM emitters may be fixedly coupled with control station 4100 to implement station-mounted tracker unit 4410 , and one or more EM detectors may be fixedly coupled with HMD 4200 to implement helmet-mounted tracker unit 4420 . In either implementation, based on detected EM radiation emitted by the one or more EM emitters, the one or more EM detectors output a gaze tracking signal relating to the orientation of HMD 4200 relative to control station 4100 . It is noted that, where applicable, the expression "mounted with", "coupled with" and/or the like, also encompasses the meaning of the term "included in". Accordingly, control station 4100 may include station-mounted non- P11112-IL inertial tracker unit 4410 , and HMD 4200 may include a helmet-mounted non-inertial helmet-mounted tracker unit 4420. id="p-78"

[0078] When employing for instance electromagnetic-based technologies for gaze tracking, alternating electric field generators (not shown) can be employed that are operable to produce an alternating electric field in control station 4100 of platform 1000 . Non-inertial gaze tracker 4400 may for example include conductive coils (not shown) configured to generate an alternating field in multiple different axes within control station 4100relative to the HMD 4200 . Based on the produced electrical signal, non-inertial gaze tracker 4400 can determine an estimate of the position and orientation of HMD 4200relative to station 4100 of platform 1000for providing a video output of graphical objects according to the determined instant relative HMD current position and orientation within control station 4100 and/or relative platform’s external world reference frame WORLDxyz . id="p-79"

[0079] While the embodiments disclosed herein may relate to aircrafts, this should by no means be construed limiting. Accordingly, embodiments disclosed herein may additionally or alternatively be employed in conjunction with platforms including, for example, land-based vehicles such as, for instance, a passenger car, a motorcycle, a bicycle, a transport vehicle (e.g., a bus, truck, a rail-based transport vehicle, etc.), a watercraft, a submarine, a spaceship, a multipurpose vehicle such as a hovercraft, and/or the like. Accordingly, a control station may include, for example, a cockpit, a flight deck, a bridge, a passenger cabin, and/or the like. id="p-80"

[0080] In some examples, aircrafts can include a passenger plane, a combat aircraft, a vertical takeoff-and-landing (VTOL) aircraft, a tiltrotor aircraft, a transport aircraft, a fixed-wing aircraft, a rotary-wing aircraft, and/or a combined fixed/rotary-wing aircraft). In some examples, the platform can include, for instance, a passenger ship, a frigate, an aircraft carrier, a freighter. Land-based vehicles can include, for example, a car, bus, truck, and/or armored fighting vehicle. The platforms can also include, for example, a submarine; a spacecraft, and/or any other vehicle. In some examples, the platform may pertain to a control simulator (e.g., a flight simulator, a passenger car driving simulator); and/or any other vehicle command or control room, e.g., for on-site or remote controlling of a vehicle. Additional vehicles may include unpowered aircrafts such as, for example, aerostats, parachutes, gliders, wingsuit applications, and/or the like. Additional platforms may pertain to motorcycles, bicycles, snowboards, skis, slides, and/or the like. For example, motorcycles helmets, sunglasses, ski goggles, and/or the like may be configured to augment a scene viewable by the user through the goggles with additional information including, for example, routes, obstacles, topography, body orientation relative to ground, velocity, acceleration, terrain conditions, etc.

P11112-IL id="p-81"

[0081] Although examples disclosed herein pertain to conformably tracking gaze with respect to a platform and control station thereof with respect to a world or earth coordinate system WORLDxyz , this should by no means be construed in a limiting manner. Accordingly, the platform’s frame of reference may in some embodiments pertain to a fixed coordinate system established in space, or combination of the earth coordinate system with a fixed coordinate system established in space. id="p-82"

[0082] Memory 4002 may be implemented by various types of memories, including transactional memory and/or long-term storage memory facilities and may function as file storage, document storage, program storage, or as a working memory. The latter may for example be in the form of a static random-access memory (SRAM), dynamic random-access memory (DRAM), read-only memory (ROM), cache and/or flash memory. As working memory, memory 4002 may, for example, include, e.g., temporally-based and/or non-temporally based instructions. As long-term memory, memory 4002 may for example include a volatile or non-volatile computer storage medium, a hard disk drive, a solid-state drive, a magnetic storage medium, a flash memory and/or other storage facility. A hardware memory facility may, for example store a fixed information set (e.g., software code) including, but not limited to, a file, program, application, source code, object code, data, and/or the like. id="p-83"

[0083] The term "processor", as used herein, may additionally or alternatively refer to a controller. Processor 4004 may be implemented by various types of processor devices and/or processor architectures including, for example, embedded processors, communication processors, graphics processing unit (GPU)-accelerated computing, soft-core processors, and/or general-purpose processors. id="p-84"

[0084] Communication module 4006 may be configured to enable wired and/or wireless communication between the various components and/or modules of the system and which may communicate with each other over one or more communication buses (not shown), signal lines (not shown) and/or a network infrastructure (not shown). The network infrastructure may be configured for using one or more communication formats, protocols, and/or technologies such as, for example, to internet communication, optical or RF communication, telephony-based communication technologies and/or the like. In some examples, communication module 4006 may include I/O device drivers (not shown) and network interface drivers (not shown) for enabling the transmission and/or reception of data over the network infrastructure. A device driver may, for example, interface with a keypad or to a USB port. A network interface driver may for example execute protocols for the Internet, or an Intranet, Wide Area Network (WAN), Local Area Network (LAN) employing, e.g., Wireless Local Area Network (WLAN)), Metropolitan Area Network (MAN), Personal Area Network (PAN), extranet, 2G, 3G, 3.5G, 4G, 5G, 6G mobile networks, 3GPP, LTE, LTE advanced, Bluetooth® (e.g., Bluetooth smart), ZigBee™, near-field communication (NFC) and/or any other current or P11112-IL future communication network, standard, and/or system. With respect to in-aircraft communication, the network infrastructure may, for example, operate on and/or implement various avionics Local Area Network (LAN) communication standards including, for example, Aeronautical Radio INC. (ARINC) 429, ARINC 629, MUX Bus 1553, Controller Area Network (CAN) BUS, Avionics Full-Duplex Switched Ethernet (AFDX and/or any other current or future in-aircraft communication network, standard, and/or system. id="p-85"

[0085] Power module 4008may comprise an internal power supply (e.g., a rechargeable battery) and/or an interface for allowing connection to an external power supply. id="p-86"

[0086] Control station 4100 may include one or more Input/Output (I/O devices) configured to provide and/or receive any type of data or information. I/O device may include, for example, visual presentation devices or systems such as, for example, HMD 4200 , computer screen(s), a head-up display, a head-down display, device interfaces (e.g., a Universal Serial Bus interface), and/or audio output device(s) such as, for example, speaker(s) and/or earphones. Input/output devices may be employed to access information generated by the system and/or to provide inputs including, for instance, control commands, operating parameters, queries, and/or the like. For example, the input/output devices may allow the user to perform one or more of the following: approval of system-suggested object identification and/or of their attributes; camera control; providing a command input to lock onto and track a movable platform. In some embodiments, control station 4100 may be configured to automatically or semi-automatically perform object identification and tracking of the object as a target. id="p-87"

[0087] It will be appreciated that separate hardware components such as processors and/or memories may be allocated to each component and/or module of system 4000 . However, for simplicity and without being construed in a limiting manner, the description and claims may refer to a single module and/or component. For example, although processor 4004 may be implemented by several processors, the following description will refer to processor 4004 as the component that conducts all the necessary processing functions of conformal gaze tracking system 4000 . id="p-88"

[0088] Additional reference is made to Figure 8 . An embodiment of a method for tracking, relative to a World Coordinate System and/or relative to a platform coordinate system, motion of an object that is movable within a platform, is discussed. The method may comprise performing transfer alignment between an Inertial Navigation System (INS) of the platform, and an object-mounted Inertial Measurement Unit (IMU), e.g., as known in the art. As indicated by block 8100 , the method may include, for example, determining, by an object-mounted IMU, IMU-based changing rates of the object relative to the world.

P11112-IL id="p-89"

[0089] As indicated by block 8200 , the method may include, for example, determining, by a non-inertial tracker (NIT), NIT-based changing rates of the object relative to the platform. id="p-90"

[0090] As indicated by block 8300 , the method may include, for example, id="p-91"

[0091] determining a difference between: id="p-92"

[0092] the imu-based changing rates relative to the world; and id="p-93"

[0093] the NIT-based changing rates relative to the platform to obtain object-mounted imu changing rates of the platform relative to the world. id="p-94"

[0094] Additional examples: id="p-95"

[0095] Embodiments pertain to a method for tracking, relative to a World Coordinate System and/or relative to a platform coordinate system, motion of an object that is movable within a platform by performing transfer alignment between an Inertial Navigation System (INS) of the platform, and an object-mounted Inertial Measurement Unit (IMU). id="p-96"

[0096] In embodiments, the method comprises: id="p-97"

[0097] determining, by the object-mounted IMU, IMU-based changing rates of the object relative to the World; id="p-98"

[0098] determining, by a non-inertial tracker (NIT), NIT-based changing rates of the object relative to the platform, id="p-99"

[0099] determining a difference between: the IMU-based changing rates relative to the World; and id="p-100"

[00100] the NIT-based changing rates relative to the platform, to obtain object-mounted IMU changing rates of the platform relative to the world. id="p-101"

[00101] In embodiments, the non-inertial tracker comprises a platform-mounted NIT, an object-mounted NIT, or both. id="p-102"

[00102] In embodiments, the changing rates pertain to linear acceleration and/or angular velocity and/or angular acceleration. id="p-103"

[00103] In embodiments, the object comprises a sensor, an Input/Output (I/O) Device, or both. id="p-104"

[00104] In embodiments, the I/O Device comprises a Head-Mounted Display (HMD), and wherein the sensor comprises a camera.

P11112-IL id="p-105"

[00105] In embodiments, the method comprises determining the Platform INS changing rates relative to the world; and id="p-106"

[00106] performing harmonization between object-mounted IMU changing rates of the platform and the platform INS changing rates relative to the world for tracking orientation of the HMD relative to the World. id="p-107"

[00107] In embodiments, the INS changing rates data frequency may be increased to IMU data frequency. id="p-108"

[00108] In embodiments, the object is freely movable relative to the platform. id="p-109"

[00109] In embodiments, the platform comprises a control station, and the object is freely movable in the control station. id="p-110"

[00110] In embodiments, the object comprises sensory equipment. id="p-111"

[00111] Embodiments pertain to a system for tracking, relative to a World Coordinate System and/or relative to a platform coordinate system, motion of an object that is movable within a platform by performing transfer alignment between an Inertial Navigation System (INS) of the platform, and an object-mounted Inertial Measurement Unit (IMU). id="p-112"

[00112] In embodiments, the system comprises one or more processors; and one or more memories storing software code portions executable by the one or more processors to cause the system to perform the following steps: id="p-113"

[00113] determining, by the object-mounted IMU, IMU-based changing rates of the object relative to the World; id="p-114"

[00114] determining, by a non-inertial tracker (NIT), NIT-based changing rates of the object relative to the platform, id="p-115"

[00115] determining a difference between: id="p-116"

[00116] the IMU-based changing rates relative to the World; and id="p-117"

[00117] the NIT-based changing rates relative to the platform, to obtain object-mounted IMU changing rates of the platform relative to the world. id="p-118"

[00118] In embodiments, the non-inertial tracker comprises a platform-mounted NIT, an object-mounted NIT, or both. id="p-119"

[00119] In embodiments, the changing rates pertain to linear acceleration and/or angular velocity and/or angular acceleration.

P11112-IL id="p-120"

[00120] In embodiments, the object comprises a sensor, an Input/Output (I/O) Device, or both. id="p-121"

[00121] In embodiments, the I/O Device comprises a Head-Mounted Display (HMD), and wherein the sensor comprises a camera. id="p-122"

[00122] In embodiments, the system is configured to perform the following: id="p-123"

[00123] determining the Platform INS changing rates relative to the world; and id="p-124"

[00124] performing harmonization between object-mounted IMU changing rates of the platform and the platform INS changing rates relative to the world for tracking orientation of the HMD relative to the World. id="p-125"

[00125] In embodiments, the INS changing rates data frequency may be increased to IMU data frequency. id="p-126"

[00126] In embodiments, the object is freely movable relative to the platform. id="p-127"

[00127] In embodiments, the platform comprises a control station, and the object is freely movable in the control station. id="p-128"

[00128] It is important to note that the methods described herein and illustrated in the accompanying diagrams shall not be construed in a limiting manner. For example, methods described herein may include additional or even fewer processes or operations in comparison to what is described herein and/or illustrated in the diagrams. In addition, method steps are not necessarily limited to the chronological order as illustrated and described herein. id="p-129"

[00129] Any digital computer system, unit, device, module and/or engine exemplified herein can be configured or otherwise programmed to implement a method disclosed herein, and to the extent that the system, module and/or engine is configured to implement such a method, it is within the scope and spirit of the disclosure. Once the system, module and/or engine are programmed to perform particular functions pursuant to computer readable and executable instructions from program software that implements a method disclosed herein, it in effect becomes a special purpose computer particular to embodiments of the method disclosed herein. The methods and/or processes disclosed herein may be implemented as a computer program product that may be tangibly embodied in an information carrier including, for example, in a non-transitory tangible computer-readable and/or non-transitory tangible machine-readable storage device. The computer program product may be directly loadable into an internal memory of a digital computer, comprising software code portions for performing the methods and/or processes as disclosed herein. id="p-130"

[00130] The methods and/or processes disclosed herein may be implemented as a computer program that may be intangibly embodied by a computer readable signal medium. A computer readable signal medium P11112-IL may include a propagated data signal with computer readable program code embodied therein, for example, in baseband or as part of a carrier wave. Such a propagated signal may take any of a variety of forms, including, but not limited to, electro-magnetic, optical, or any suitable combination thereof. A computer readable signal medium may be any computer readable medium that is not a non-transitory computer or machine-readable storage device and that can communicate, propagate, or transport a program for use by or in connection with apparatuses, systems, platforms, methods, operations, and/or processes discussed herein. id="p-131"

[00131] The terms "non-transitory computer-readable storage device" and "non-transitory machine-readable storage device" encompasses distribution media, intermediate storage media, execution memory of a computer, and any other medium or device capable of storing for later reading by a computer program implementing embodiments of a method disclosed herein. A computer program product can be deployed to be executed on one computer or on multiple computers at one site or distributed across multiple sites and interconnected by one or more communication networks. id="p-132"

[00132] These computer readable and executable instructions may be provided to a processor of a general-purpose computer, special purpose computer, or other programmable data processing apparatus to produce a machine, such that the instructions, which execute via the processor of the computer or other programmable data processing apparatus, create means for implementing the functions/acts specified in the flowchart and/or block diagram block or blocks. These computer readable and executable program instructions may also be stored in a computer readable storage medium that can direct a computer, a programmable data processing apparatus, and/or other devices to function in a particular manner, such that the computer readable storage medium having instructions stored therein comprises an article of manufacture including instructions which implement aspects of the function/act specified in the flowchart and/or block diagram block or blocks. id="p-133"

[00133] The computer readable and executable instructions may also be loaded onto a computer, other programmable data processing apparatus, or other device to cause a series of operational steps to be performed on the computer, other programmable apparatus or other device to produce a computer implemented process, such that the instructions which execute on the computer, other programmable apparatus, or other device implement the functions/acts specified in the flowchart and/or block diagram block or blocks. id="p-134"

[00134] The term "engine" and/or "application" may comprise one or more computer modules, wherein a module may be a self-contained hardware and/or software component that interfaces with a larger system. A module may comprise a machine or machines executable instructions. A module may be P11112-IL embodied by a circuit or a controller programmed to cause the system to implement the method, process and/or operation as disclosed herein. For example, a module may be implemented as a hardware circuit comprising, e.g., custom VLSI circuits or gate arrays, an Application-specific integrated circuit (ASIC), off-the-shelf semiconductors such as logic chips, transistors, and/or other discrete components. A module may also be implemented in programmable hardware devices such as field programmable gate arrays, programmable array logic, programmable logic devices and/or the like. id="p-135"

[00135] The term "random" also encompasses the meaning of the term "substantially randomly" or "pseudo-randomly". id="p-136"

[00136] The expression "real-time" as used herein generally refers to the updating of information based on received data, at essentially the same rate as the data is received, for instance, without user-noticeable judder, latency, and/or lag. id="p-137"

[00137] In the discussion, unless otherwise stated, adjectives such as "substantially" and "about" that modify a condition or relationship characteristic of a feature or features of an embodiment of the invention, are to be understood to mean that the condition or characteristic is defined to within tolerances that are acceptable for operation of the embodiment for an application for which it is intended. Unless otherwise specified, the terms "substantially", "'about" and/or "close" with respect to a magnitude or a numerical value may imply to be within an inclusive range of -10% to +10% of the respective magnitude or value. id="p-138"

[00138] "Coupled with" can mean indirectly or directly "coupled with". id="p-139"

[00139] It is important to note that the method is not limited to diagrams and/or to the corresponding descriptions disclosed herein. For example, the method may include additional or even fewer processes or operations in comparison to what is described, e.g., in the figures. In addition, embodiments of the method are not necessarily limited to the chronological order as illustrated and described herein. id="p-140"

[00140] Discussions herein utilizing terms such as, for example, "processing", "computing", "calculating", "determining", "establishing", "analyzing", "checking", "estimating", "deriving", "selecting", "inferring" or the like, may refer to operation(s) and/or process(es) of a computer, a computing platform, a computing system, or other electronic computing device, that manipulate and/or transform data represented as physical (e.g., electronic) quantities within the computer's registers and/or memories into other data similarly represented as physical quantities within the computer's registers and/or memories or other information storage medium that may store instructions to perform operations and/or processes. The term determining may, where applicable, also refers to "heuristically determining".

P11112-IL id="p-141"

[00141] It should be noted that where an embodiment refers to a condition of "above a threshold", this should not be construed as excluding an embodiment referring to a condition of "equal or above a threshold". Analogously, where an embodiment refers to a condition "below a threshold", this should not be construed as excluding an embodiment referring to a condition "equal or below a threshold". It is clear that should a condition be interpreted as being fulfilled if the value of a given parameter is above a threshold, then the same condition is considered as not being fulfilled if the value of the given parameter is equal or below the given threshold. Conversely, should a condition be interpreted as being fulfilled if the value of a given parameter is equal or above a threshold, then the same condition is considered as not being fulfilled if the value of the given parameter is below (and only below) the given threshold. id="p-142"

[00142] It should be understood that where the claims or specification refer to "a" or "an" element and/or feature, such reference is not to be construed as there being only one of that element. Hence, reference to "an element" or "at least one element" for instance may also encompass "one or more elements". id="p-143"

[00143] Terms used in the singular shall also include the plural, except where expressly otherwise stated or where the context otherwise requires. id="p-144"

[00144] In the description and claims of the present application, each of the verbs, "comprise", "include" and "have", and conjugates thereof, are used to indicate that the data portion or data portions of the verb are not necessarily a complete listing of components, elements or parts of the subject or subjects of the verb. id="p-145"

[00145] Unless otherwise stated, the use of the expression "and/or" between the last two members of a list of options for selection indicates that a selection of one or more of the listed options is appropriate and may be made. Further, the use of the expression "and/or" may be used interchangeably with the expressions "at least one of the following", "any one of the following" or "one or more of the following", followed by a listing of the various options. id="p-146"

[00146] As used herein, the phrase "A,B,C, or any combination of the aforesaid" should be interpreted as meaning all of the following: (i) A or B or C or any combination of A, B, and C, (ii) at least one of A, B, and C; (iii) A, and/or B and/or C, and (iv) A, B and/or C. Where appropriate, the phrase A, B and/or C can be interpreted as meaning A, B or C. The phrase A, B or C should be interpreted as meaning "selected from the group consisting of A, B and C". This concept is illustrated for three elements (i.e., A,B,C), but extends to fewer and greater numbers of elements (e.g., A, B, C, D, etc.). id="p-147"

[00147] It is appreciated that certain features of the invention, which are, for clarity, described in the context of separate embodiments or examples, may also be provided in the context of a single embodiment.

P11112-IL Conversely, various features of the invention, which are, for brevity, described in the context of a single embodiment, example and/or option, may also be provided separately or in any suitable sub-combination or as suitable in any other described embodiment, example, or option of the invention. Certain features described in the context of various embodiments, examples and/or optional implementation are not to be considered essential features of those embodiments, unless the embodiment, example and/or optional implementation is inoperative without those elements. id="p-148"

[00148] Any feature or any combination of features disclosed herein can be disclaimed. id="p-149"

[00149] It is noted that the terms "in some embodiments", "according to some embodiments", "for example", "e.g.", "for instance" and "optionally" may herein be used interchangeably. id="p-150"

[00150] The number of elements shown in the Figures should by no means be construed as limiting and is for illustrative purposes only. id="p-151"

[00151] "Real-time" as used herein generally refers to the updating of information at essentially the same rate as the data is received. More specifically, in the context of the present invention "real-time" is intended to mean that the image data is acquired, processed, and transmitted from a sensor at a high enough data rate and at a low enough time delay that when the data is displayed, data portions presented and/or displayed in the visualization move smoothly without user-noticeable judder, latency or lag. id="p-152"

[00152] It is noted that the terms "operable to" can encompass the meaning of the term "modified or configured to". In other words, a machine "operable to" perform a task can in some embodiments, embrace a mere capability (e.g., "modified") to perform the function and, in some other embodiments, a machine that is actually made (e.g., "configured") to perform the function. id="p-153"

[00153] Throughout this application, various embodiments may be presented in and/or relate to a range format. It should be understood that the description in range format is merely for convenience and brevity and should not be construed as an inflexible limitation on the scope of the embodiments. Accordingly, the description of a range should be considered to have specifically disclosed all the possible subranges as well as individual numerical values within that range. For example, description of a range such as from 1 to should be considered to have specifically disclosed subranges such as from 1 to 3, from 1 to 4, from 1 to 5, from 2 to 4, from 2 to 6, from 3 to 6 etc., as well as individual numbers within that range, for example, 1, 2, 3, 4, 5, and 6. This applies regardless of the breadth of the range. id="p-154"

[00154] The phrases "ranging/ranges between" a first indicate number and a second indicate number and "ranging/ranges from" a first indicate number "to" a second indicate number are used herein P11112-IL interchangeably and are meant to include the first and second indicated numbers and all the fractional and integral numerals there between. id="p-155"

[00155] While the invention has been described with respect to a limited number of embodiments, these should not be construed as limitations on the scope of the invention, but rather as exemplifications of some of the embodiments.

Claims (19)

P11112-IL | 314161/2 | clean claims C L AIM S What is claimed is:

1. A method for tracking, relative to a World Coordinate System and/or relative to a platform coordinate system, motion of an object that is movable within a platform by performing transfer alignment between an Inertial Navigation System (INS) of the platform, and an object-mounted Inertial Measurement Unit (IMU), the method comprising: determining, by the object-mounted IMU, IMU-based changing rates of the object relative to the World; determining, by a non-inertial tracker (NIT), NIT-based changing rates of the object relative to the platform , determining a difference between: a) the IMU-based changing rates relative to the World ; and b) the NIT-based changing rates relative to the platform ; to obtain object-mounted IMU changing rates of the platform relative to the world.

2. The method of any one or more of the preceding claims, wherein the non-inertial tracker comprises a platform -mounted NIT , an object-mounted NIT, or both.

3. The method of claim 1 or claim 2, wherein the changing rates pertain to linear acceleration and/or angular velocity and/or angular acceleration .

4. The method of any one of the preceding claims, wherein the object comprises a sensor, an Input/Output (I/O) Device, or both.

5. The method of claim 4, wherein the I/O Device comprises a Head-Mounted Display (HMD), and wherein the sensor comprises a camera.

6. The method of any one of the preceding claims, further comprising: determining the Platform INS changing rates relative to the world; and performing harmonization between object-mounted IMU changing rates of the platform and the platform INS changing rates relative to the world for tracking orientation of the HMD relative to the World.

7. The method of claim 6, wherein the INS changing rates data frequency may be increased to IMU data frequency. P11112-IL | 314161/2 | clean claims

8. The method of any one of the preceding claims, wherein the object is freely movable relative to the platform .

9. The method of any one of the preceding claims, wherein the platform comprises a control station , and the object is freely movable in the control station.

10. The method of any one of the preceding claims, wherein the object comprises sensory equipment.

11. A system for tracking, relative to a World Coordinate System and/or relative to a platform coordinate system, motion of an object that is movable within a platform by performing transfer alignment between an Inertial Navigation System (INS) of the platform, and an object-mounted Inertial Measurement Unit (IMU), the system comprising: one or more processors; and one or more memories storing software code portions executable by the one or more processors to cause the system to perform the following steps: determining, by the object-mounted IMU, IMU-based changing rates of the object relative to the World; determining, by a non-inertial tracker (NIT), NIT-based changing rates of the object relative to the platform, determining a difference between: c) the IMU-based changing rates relative to the World ; and d) the NIT-based changing rates relative to the platform ; to obtain object-mounted IMU changing rates of the platform relative to the world.

12. The system of claim 11, wherein the non-inertial tracker comprises a platform -mounted NIT , an object-mounted NIT , or both.

13. The system of claim 11 or claim 12, wherein the changing rates pertain to linear acceleration and/or angular velocity and/or angular acceleration.

14. The system of any one of the claims 11 to 13, wherein the object comprises a sensor, an Input/Output (I/O) Device, or both. P11112-IL | 314161/2 | clean claims

15. The system of claim 14, wherein the I/O Device comprises a Head-Mounted Display (HMD), and wherein the sensor comprises a camera.

16. The system of any one of the claims 11 to 15, further comprising: determining the Platform INS changing rates relative to the world; and performing harmonization between object -mounted IMU changing rates of the platform and the platform INS changing rates relative to the world for tracking orientation of the HMD relative to the World.

17. The system of claim 16, wherein the INS changing rates data frequency may be increased to IMU data frequency.

18. The system of any one of the claims 11 to 17, wherein the object is freely movable relative to the platform.

19. The system of any one of the claims 11 to 18, wherein the platform comprises a control station , and the object is freely movable in the control station.