Patent Application
20210081037
Embodiments of the inventive concepts disclosed herein are directed generally to head-worn or helmet-worn display systems and more particularly to head-tracking systems compatible with said display systems.
Head tracking systems provide precise head pose data (e.g., the position and orientation of the user's head at any given moment) to ensure that helmet-mounted displays, which move with the user's head, accurately reflect what the user should be seeing at that moment, in either a real-world or simulated environment. These systems may be bulky and thus impractical for helmet-mounted use. Further, head trackers generally incorporate inertial measurement units (IMU) which provide relative positioning information (e.g., relative to some reference position or frame) but are subject to inherent drift over time. As a result, head tracking systems may have a limited useful range. Finally, a large-area head tracker that receives positioning signals from remotely located transmitters may be detectable by other receivers within that area.
A large-area boresighting system is disclosed. In embodiments, the large-area boresighting system includes directional transmitters fixed to a reference frame (e.g., attached to a vehicle or fixed within a structure). The directional transmitters transmit high-frequency directional signals within a limited range. The large-area boresighting system includes head-worn (e.g., helmet-mounted) boresighting systems worn by users within the mobile platform or structure. The head-worn systems include paired receivers on opposing sides of the embodying helmet (e.g., left-side and right-side receivers). The corresponding paired receivers each receive the transmitted directional signals and generate an associated radio frequency (RF) signal. Helmet-mounted boresight processors receive the paired RF signals and generate boresight signals based on the orientation of the helmet (and the head of the user) relative to the directional transmitters as determined by the paired RF signals (e.g., received on the left and right sides). The boresight signals may be used for, e.g., calibration of a helmet-mounted head tracker system or adjustment of a helmet-mounted display configured for display of images and symbology to the user based on the correct orientation of the user's head relative to the mobile platform or structure.
A head-worn (e.g., helmet-mounted) tracker is also disclosed. In embodiments, the head-worn tracker includes paired receivers on opposing sides of the embodying helmet (e.g., left-side and right-side receivers). The corresponding paired receivers each receive transmitted directional signals (e.g., millimeter-wave signals of limited range) and generate paired radio frequency (RF) signal based on the directional signals. The head-worn trackers include inertial measurement units (IMU; e.g., accelerometers, gyrometers, or other relative position sensors) for generating estimated head pose data (e.g., a position and orientation of the user's head) relative to a reference frame (e.g., to the earth frame or to a vehicle or mobile platform). The head-worn trackers include boresight processors for receiving the paired RF signals from the receivers on each side, generate boresighting data therefrom, and update the estimated head pose (e.g., correcting or calibrating the head tracker) based on the boresighting data.
This Summary is provided solely as an introduction to subject matter that is fully described in the Detailed Description and Drawings. The Summary should not be considered to describe essential features nor be used to determine the scope of the Claims. Moreover, it is to be understood that both the foregoing Summary and the following Detailed Description are example and explanatory only and are not necessarily restrictive of the subject matter claimed.
The detailed description is described with reference to the accompanying figures. The use of the same reference numbers in different instances in the description and the figures may indicate similar or identical items. Various embodiments or examples (“examples”) of the present disclosure are disclosed in the following detailed description and the accompanying drawings. The drawings are not necessarily to scale. In general, operations of disclosed processes may be performed in an arbitrary order, unless otherwise provided in the claims. In the drawings:
and
Before explaining one or more embodiments of the disclosure in detail, it is to be understood that the embodiments are not limited in their application to the details of construction and the arrangement of the components or steps or methodologies set forth in the following description or illustrated in the drawings. In the following detailed description of embodiments, numerous specific details may be set forth in order to provide a more thorough understanding of the disclosure. However, it will be apparent to one of ordinary skill in the art having the benefit of the instant disclosure that the embodiments disclosed herein may be practiced without some of these specific details. In other instances, well-known features may not be described in detail to avoid unnecessarily complicating the instant disclosure.
As used herein a letter following a reference numeral is intended to reference an embodiment of the feature or element that may be similar, but not necessarily identical, to a previously described element or feature bearing the same reference numeral (e.g., 1, 1 a, 1 b). Such shorthand notations are used for purposes of convenience only and should not be construed to limit the disclosure in any way unless expressly stated to the contrary.
Further, unless expressly stated to the contrary, “or” refers to an inclusive or and not to an exclusive or. For example, a condition A or B is satisfied by any one of the following: A is true (or present) and B is false (or not present), A is false (or not present) and B is true (or present), and both A and B are true (or present).
In addition, use of “a” or “an” may be employed to describe elements and components of embodiments disclosed herein. This is done merely for convenience and “a” and “an” are intended to include “one” or “at least one,” and the singular also includes the plural unless it is obvious that it is meant otherwise.
Finally, as used herein any reference to “one embodiment” or “some embodiments” means that a particular element, feature, structure, or characteristic described in connection with the embodiment is included in at least one embodiment disclosed herein. The appearances of the phrase “in some embodiments” in various places in the specification are not necessarily all referring to the same embodiment, and embodiments may include one or more of the features expressly described or inherently present herein, or any combination or sub-combination of two or more such features, along with any other features which may not necessarily be expressly described or inherently present in the instant disclosure.
Broadly speaking, embodiments of the inventive concepts disclosed herein are directed to a large-area boresighting system capable of supporting multiple users within a real-world or simulated environment such as a ship or other mobile platform or a multilevel/multi-room structure. The head tracker systems are accurate yet neither excessively heavy or cumbersome. Further, the boresighting system allows high mobility throughout the environment for helmet-wearing users, but is undetectable beyond the mobile platform or environment.
Referring to
In embodiments, the large-area boresighting system 100 may be compatible with the HMD systems 108, 110 throughout the ship 102 (e.g., providing a position/orientation (pose) reference for head tracker systems incorporated within each individual HMD system) but undetectable beyond the ship 102. For example, the aft and forward directional transmitters 104, 106 (e.g., the aft directional transmitter 104 may be mounted aft of the ship 102 but oriented in a generally forward direction) may each generate and transmit a directional signal, e.g., a substantially 60 GHz millimeter-wave (milliwave; more generally Extremely High Frequency (EHF) signals between 30-300 GHz) signal, via directional antenna elements. Each HMD system 108, 110 may include paired receiver antennas (112a-b, 114a-b) on opposing sides (e.g., left-side antennas 112a, 114a; right-side antennas 112b, 114b) of the helmet to which the HMD system components are mounted.
Regardless of their positions on the ship 102 (e.g., while moving throughout the ship), the users/wearers of the HMD systems 108, 110 may continually receive (e.g., via the paired receiver antennas 112a-b, 114a-b) the transmitted directional signals so long as the users are within range (116, 118) or the respective forward and aft directional transmitters 104, 106. For example, the HMD system 108 may, while within the range 116 of the aft directional transmitter 104, receive the directional signals transmitted thereby via the left-side and right-side antennas 112a-b, each antenna producing its own radio frequency (RF) signal based on the received directional signal. The HMD system 108 may sum the RF signals received by the left-side and right-side antennas 112a-b (e.g., based on a common directional signal from the aft directional transmitter 104) to determine an alignment or orientation of the HMD system relative to the aft directional transmitter. Similarly, if the HMD system 108 is within the range 118 of the forward directional transmitter 106, the left-side and right-side antennas 112a-b may also receive directional signals transmitted thereby, generating an additional pair of RF signals via the left-side and right-side antennas and determining the current alignment of the HMD system 108 relative to the forward directional transmitter 106.
In embodiments, the aft and forward directional transmitters 104, 106 may each be aligned to the ship 102 (e.g., based on the reference frame or relative position of the ship), allowing each HMD system 108, 110 to determine its position or orientation (e.g., pose) relative to the ship. Multiple directional transmitters may be positioned throughout the ship 102 such that the HMD systems 108, 110 may track their relative orientations at any location within the ship via at least one directional transmitter. However, the placement of the aft and forward directional transmitters 104, 106 (and any other directional transmitters deployed throughout the ship) may be such that the range 116, 118 of any directional transmitter does not extend significantly beyond the ship 102. Accordingly, the large-area boresighting system 100 may be used in conjunction with HMD systems 108, 110 throughout the ship 102 but undetectable outside the ship. In some embodiments, the large-area boresighting system 100 may be operable as a short-range tracker system within the range of the directional transmitters 104, 106.
Referring now to
In embodiments, the large-area boresighting system 100a may deploy directional transmitters 210, 212 throughout the real or simulated structure 202 to provide full coverage of the upper and lower levels 204, 206 and stairwell 208. Accordingly, users/wearers 214, 216 of the HMD systems 108, 110 may receive directional signals from the directional transmitters 210, 212 and thereby determine (e.g., via the RF signals generated by the left-side and right-side antennas (112a-b, 114a-b;
In embodiments, the directional transmitters 210, 212 may be implemented and may function similarly to the directional transmitters 104, 106 of
Referring to
In embodiments, the helmet 302 may incorporate a right-side antenna 112b and left-side antenna (112a,
In embodiments, due to the placement of the left-side and right-side antennas 112a-b on the left and right sides of the helmet 302 respectively, the boresight signal generated by the boresight processors based on the RF signals produced by the left-side and right-side antennas 112a-b may determine an alignment of the helmet (and therefore the head of the user 214) relative to a z-axis 308 (e.g., vertical axis, yaw axis) around which the head may rotate substantially left or right (308a; e.g., counterclockwise or clockwise). In embodiments, the HMD system 108 may incorporate additional paired antennas (310) disposed, e.g., on top and bottom sides of the helmet 302 respectively for determination, based on RF signals produced by the paired antennas upon receipt of directional signals from the directional transmitters 210, 212, of an alignment or orientation of the head relative to an x-axis 312 (e.g., horizontal axis, pitch axis), around which the head may rotate substantially up or down (312a).
Referring to
In embodiments, the display system 408 may include a display surface, e.g., an interior surface of a visor 408a of the helmet 302, upon which the HMD system 108 may display images to the user (214,
In some embodiments, the directional signals 412, 414 transmitted by the directional transmitter 104 may include additional position information encoded into the signal and decoded by the boresight processors 402. For example, the directional signals 412, 414 may include a platform-based inertial correction (e.g., for boresighting systems having a mobile platform-based reference frame), an absolute position solution (e.g., a GPS-derived absolute position or similar satellite-based navigational solution), a relative position solution (e.g., from a reference IMU), or a unique identifier of the directional transmitter (differentiating the directional signals 412, 414 from those transmitted by other directional transmitters (106,
In some embodiments, the directional transmitters 104 may include control processors (104a) configured for automatic control of directional signal gain levels, e.g., for increasing or decreasing the strength of the directional signals 412, 414 as needed to optimize performance in a variety of different real or simulated environments. In some embodiments, the control processors 104a may (e.g., in response to operator input) adjust the frequency of the directional signals 412, 414 via the directional transmitter 104 in order to restrict the range of the transmitted directional signals to or near the vicinity of a particular mobile platform 102 or structure (202,
Referring to
In embodiments, the directional signals 412, 414 may respectively differ slightly in phase; e.g., the substantially 60 GHz directional signals 412, 414 may be received by the left-side and right-side antennas 112a-b at respectively 90 degrees and 270 degrees of phase. When the head (and therefore the helmet 302) rotates (e.g., relative to the z-axis 308,
It is to be understood that embodiments of the methods disclosed herein may include one or more of the steps described herein. Further, such steps may be carried out in any desired order and two or more of the steps may be carried out simultaneously with one another. Two or more of the steps disclosed herein may be combined in a single step, and in some embodiments, one or more of the steps may be carried out as two or more sub-steps. Further, other steps or sub-steps may be carried in addition to, or as substitutes to one or more of the steps disclosed herein.
Although inventive concepts have been described with reference to the embodiments illustrated in the attached drawing figures, equivalents may be employed and substitutions made herein without departing from the scope of the claims. Components illustrated and described herein are merely examples of a system/device and components that may be used to implement embodiments of the inventive concepts and may be replaced with other devices and components without departing from the scope of the claims. Furthermore, any dimensions, degrees, and/or numerical ranges provided herein are to be understood as non-limiting examples unless otherwise specified in the claims.
