Patent Description:
<CIT> discloses an artificial reality system that implements adaptive degrees-of-freedom selection tracking frames of reference and rendering artificial reality content.

According to a first aspect of the invention, a system as claimed in claim <NUM> is disclosed.

In some embodiments of the system, the instructions further cause the one or more processors to receive a sensor signal from one or more sensors and use the sensor signal to determine the quality-of-service value.

In some embodiments of the system, the quality-of-service value comprises an accuracy characteristic.

In some embodiments of the system the quality-of-service value comprises a precision characteristic.

In some embodiments of the system the quality-of-service value comprises a signal strength characteristic.

In some embodiments of the system the degraded symbol is configured as a removed symbol.

In some embodiments of the system the degraded symbol is configured with a different color than the default symbol.

In some embodiments of the system the degraded symbol is configured with a different line width or different from than the default symbol.

In some embodiments of the system the degraded symbol is configured with a different line type than the default symbol.

In some embodiments of the system wherein the controller is communicatively coupled to a vision system.

In some embodiments of the system, the system further comprises an inertial sensor communicatively coupled to at least one of the head worn display or the tracking processing unit.

In some embodiments of the system, the symbol represents a confidence line of a path.

In some embodiments of the system, the path is configured as a runway.

From a further aspect of the invention, a method as claimed in claim <NUM> is provided.

In one or more embodiments of the method, the method further includes receiving a sensor signal from one or more sensors. In one or more embodiments of the method, the method further includes using the sensor signal to determine the quality-of-service value.

Disclosed is a system and method for presenting accuracy adaptive symbology to a head worn display (HWD). In general, HWDs require tracking devices that track the movement of the head of a user. This tracking allows HWD systems to correctly display symbology onto the eyepieces of the HWD. Tracking devices require constant signaling between HWD components for correct displaying of symbology. This signaling can become suboptimal due to component failure, environmental factors (e.g., jamming) and other system malfunctions. Suboptimal signaling can be catastrophic if the user is heavily dependent upon the HWD for hazardous tasks, such as landing an aircraft in low visibility conditions. Within the disclosed system, a quality characteristic of signal between the head tracker and HWD components is determined, and the symbology displayed on the eyepieces of the HWD are altered based on the quality characteristic. The modified symbology quickly communicates to the user a confidence value on the accuracy of the symbology based on the tracker signaling without distracting or misleading the user.

<FIG> is a diagram of a HWD system <NUM>, in accordance with one or more embodiments of the disclosure. The HWD system <NUM> includes a HWD <NUM>. The HWD <NUM> may be of any size or type, and includes any head mounted display (HMD), head-mounted projected displays (HMPD) and retinal scanning displays (RSD), The HWD <NUM> includes one or two eyepieces <NUM> that receive and display symbology to the user. The eyepieces <NUM> may be of any type of display technology including organic light emitting displays (OLED), light emitting diode (LED) displays, liquid crystal displays (LCD), liquid crystal on silicon (LCoS) displays, and mini cathode ray tube (mini-CRT) displays.

The eyepieces <NUM> may be configured as spectacles/goggles, or may be incorporated into a helmet <NUM>, hat or other head-worn equipment. The HWD system <NUM> further includes a camera <NUM> (e.g., a head tracking camera) coupled to the helmet <NUM>, the eyepieces <NUM>, or other aspects of the HMD system <NUM>. The HWD system <NUM> may further include fiducials <NUM> arranged within the environment of the of the HWD system <NUM> (e.g., located on an interior surface of a cockpit) The fiducials <NUM> are recognizable by the HWD system <NUM> via the camera <NUM>, and HWD system componentry, which enable the HWD system <NUM> to determine the position and orientation of the eyepieces <NUM> based on the angle and/or distances between each fiducial <NUM> and the camera. The fiducials <NUM> may be of any number (e.g., three to twenty), of any shape, and of any type. For example, the fiducials <NUM> may be configured as a set of four square bar-codes or QR codes.

The HWD system <NUM> further includes a tracker processing unit <NUM> configured to receive and process data from the camera (e.g., optical position/orientation data). In some embodiments, the tracker processing unit <NUM> is also configured to receive and process data from an inertial (acceleration and/or gyroscopic), or magnetic sensor.

<FIG> is a block diagram of the componentry of the HWD system <NUM>, in accordance with one or more embodiments of the disclosure. The HWD system <NUM> may include a capacity for multiple users at one time (e.g., from <NUM> to <NUM> users). For example, the HWD system <NUM> may include a HWD <NUM>, a tracking processing unit <NUM>, and a HWD control panel <NUM> for both a pilot seat <NUM> and a copilot seat <NUM> (e.g., not shown for clarity). The copilot seat <NUM> may have one or more, or all, components of the pilot seat <NUM> and vice-versa. The control panel <NUM> is configured to allow a user to modify operation aspects of the HWD <NUM> including but not limited to brightness, and the ability to turn on or off a HWD mode, where turning off the HWD would remove any symbology from the eyepieces <NUM>. It should be noted that the one or more users of the HWD system <NUM> may not be pilots or copilots, and that the HWD system <NUM> may be used for purposes other than operating a vehicle. Therefore, the above language is intended to provide an illustration of an embodiment of the HWD system <NUM>, and not a limitation.

The HWD <NUM> may further include, or be communicatively coupled to, an inertial sensor <NUM> configured to collect inertial data that is sent to the tracker processing unit <NUM>. For example, the HWD system <NUM> may be configured to operate as a hybrid optical/inertial tracking HWD system, with the inertial data generated via the inertial sensor <NUM>. The HWD <NUM> may further include a light sensor <NUM> configured to determine levels of ambient light in and around the HWD <NUM>. For example, the light sensor <NUM> may determine the amount of ambient light in a cockpit.

In embodiments, the HWD system <NUM> further includes a display computer <NUM> communicatively coupled to the tracker processing unit <NUM>. The display computer <NUM> receives position and orientation information from the tracker processing unit <NUM>, and renders images, such as symbology, based on the position and orientation information before the image is viewed on the eyepieces <NUM>. The display computer <NUM> may also modify the symbology based on a quality of signal received from the tracker processing unit <NUM>, the inertial sensor <NUM>, the camera <NUM>, the HWD <NUM>, or other componentry.

The HWD system <NUM> may include, or is communicatively coupled to, sensor and data collection componentry that provide the display computer <NUM> with information that the display computer <NUM> translates into a symbology that is imaged onto the HWD <NUM>. For example, the HWD system <NUM> may include, or is communicatively coupled to, one or more sensor input/outputs 228a-b that communicate sensor readings (e.g., sensor signals) to the HWD system <NUM>, including but not limited to airspeed readings, altitude readings, position readings (e.g., GPS position readings), and fuel level readings. In another example, the HWD system <NUM> may include, or is communicatively coupled to, a vision system <NUM> that provides an image of the surrounding environment to the display computer <NUM>. The vision system <NUM> may be configured as any type of image collecting system including but not limited to an enhanced vision system (EVS), an enhanced flight vision system (EFVS), a synthetic vision system (SVS), a combined vision system (CVS) a primary flight display (PFD)).

Components of the HWD system <NUM> as well as componentry communicatively coupled to the HWD system <NUM> rely on a digital information transfer systems (e.g., buses) for data transfer between componentry. The HWD system <NUM> may use any type of bus componentry or data transfer protocol including but not limited to an ARINC <NUM> data transfer standard/protocol and a ARINC <NUM> video interface and protocol standard. The HWD system <NUM> may use specialized data transfer links between system componentry, such as a HWD crosstalk bus <NUM> that provides communication between the HWD componentry of the pilot seat <NUM> with the HWD componentry of the Co-pilot seat <NUM>. Components of the HWD system <NUM> may utilize parallel and/or serial busses for communication with other componentry, and one or more components may include power inputs (e.g., AC power or DC power). One or more components of the HWD system <NUM> may contain a controller <NUM> configured to provide processing functionality for the HWD system <NUM>, including generating and/or modifying symbology for the HWD <NUM>. As shown in <FIG>, the display computer <NUM> includes the controller <NUM>, which comprises one or more processors <NUM>, a memory <NUM>, and a computer interface <NUM>. Other components of the HWD system <NUM>, or componentry communicatively coupled to the HWD system <NUM> may also utilize controllers to perform processing functionality for the HWD system <NUM> including but not limited to the tracker processing unit <NUM>, the HWD <NUM>, the vision system <NUM>, the sensor input/output 228a-b, the inertial sensor <NUM>, and the camera <NUM>.

The one or more processors <NUM> may include any processor or processing element known in the art. For the purposes of the present disclosure, the term "processor" or "processing element" may be broadly defined to encompass any device having one or more processing or logic elements (e.g., one or more micro-processor devices, one or more application specific integrated circuit (ASIC) devices, one or more field programmable gate arrays (FPGAs), or one or more digital signal processors (DSPs)). In this sense, the one or more processors <NUM> may include any device configured to execute algorithms and/or instructions (e.g., program instructions stored in memory <NUM>). In one embodiment, the one or more processors <NUM> may be embodied as a desktop computer, a flight computer, mainframe computer system, workstation, image computer, parallel processor, networked computer, or any other computer system configured to execute a program configured to operate or operate in conjunction with the HWD system <NUM>, as described throughout the present disclosure. Moreover, different subsystems of the system <NUM> may include a processor or logic elements suitable for carrying out at least a portion of the steps described in the present disclosure. Therefore, the above description should not be interpreted as a limitation on the embodiments of the present disclosure but merely as an illustration.

The memory <NUM> can be an example of tangible, computer-readable storage medium that provides storage functionality to store various data and/or program code associated with operation of the controller <NUM> and/or other components of the HWD system <NUM>, such as software programs and/or code segments, or other data to instruct the controller <NUM> and/or other components to perform the functionality described herein. Thus, the memory <NUM> can store data, such as a program of instructions for operating the HWD system <NUM> or other components. It should be noted that while a single memory <NUM> is described, a wide variety of types and combinations of memory <NUM> (e.g., tangible, non-transitory memory) can be employed. The memory <NUM> can be integral with the controller, can comprise stand-alone memory, or can be a combination of both. Some examples of the memory <NUM> can include removable and non-removable memory components, such as a programmable logic device, random-access memory (RAM), read-only memory (ROM), flash memory (e.g., a secure digital (SD) memory card, a mini-SD memory card, and/or a micro-SD memory card), solid-state drive (SSD) memory, magnetic memory, optical memory, universal serial bus (USB) memory devices, hard disk memory, external memory, and so forth.

The communication interface <NUM> can be operatively configured to communicate with components of the controller <NUM> and other components of the HWD system <NUM>. For example, the communication interface <NUM> can be configured to retrieve data from the controller <NUM> or other components, transmit data for storage in the memory <NUM>, retrieve data from storage in the memory <NUM>, and so forth. The communication interface <NUM> can also be communicatively coupled with controller <NUM> and/or system elements to facilitate data transfer between system components.

The display computer <NUM> and the tracking processing unit <NUM> work together to provide an accurate rendering of symbology to the display. For example, once the display computer <NUM> has generated symbology data (e.g., based on inputs from the sensor input/output 228a-b and/or vision system <NUM>), the display computer <NUM> then receives tracking data from the tracking processing unit <NUM> and modifies the symbology accordingly. For instance, the tracking processing unit <NUM> may send position and orientation data that the tracking processing unit <NUM> has itself processed from inputs from the tracker camera <NUM>, the inertial sensor <NUM>, the light sensor <NUM>, the HWD <NUM>, and/or the control panel <NUM>. The position and orientation data may include pose data, pose algorithms, command and control data, and other inputs that facilitate accurate rendering by the display computer <NUM>.

In embodiments, the HWD system <NUM> is configured to determine if a position and orientation signal (e.g., containing the position and signal data) is a quality signal (e.g., having a quality signal value). Data signaling can be disrupted at several points within the HWD system <NUM>. For example, one or more sensors (e.g., the camera <NUM>, the inertial sensor, or the light sensor), may become compromised, or otherwise not perform competently. For instance, the one or more sensors may have an internal malfunction, such as a short circuit. In another instance, the componentry of the one or more sensors (e.g., the camera <NUM>) may be affected by an environmental issue, such as smoke in a cockpit. In another example, data may be disrupted at one or more data busses that connect components of the HWD system <NUM>. One or more processors from the display computer <NUM>, the tracker processor unit <NUM>, and/or other components may determine whether one or more data signals sent to and/or received by the display computer <NUM> and/or the tracker processing unit <NUM> are high-quality data signals or low-quality data signals. The display computer <NUM> receives these inputs (e.g., as signal quality values) and generates an overall quality-of-service (QoS) value, which provides both an estimate on the accuracy and/or precision of the data, or specific data components (e.g., attitude data) received by the display computer <NUM>, and assists in determining what modifications, if any, need to be made to the symbology generated by the display computer <NUM> that communicate to the user the accuracy/precision of one or more symbols of the HWD symbology in real time.

The HUD system <NUM> is configured to display symbology on the HWD <NUM> that is modified based on the predicted accuracy of the symbology (e.g., QoS value). Modifications to any symbol of symbology may be made upon any accuracy prediction. For example, the for HWD system <NUM> operating with high-accuracy and/or high QoS values (e.g., indicating a <NUM>% of accuracy or high precision), a symbol within the symbology may appear as a default symbol, or as a symbol modified to represent high accuracy. Conversely, for a HWD system <NUM> operating with low-accuracy and/or low QoS values (e.g., indicating less than <NUM>% accuracy or low precision), a symbol may appear as a degraded symbol modified to represent low accuracy or may be removed entirely. Other modifications between a default symbol, a degraded symbol, and/or a high-accuracy/precision symbol may include changes in color, and changed in line type (e.g., dotted line versus solid line).

Examples of the symbology from HWD systems <NUM> operating under high or low QoS values are shown in <FIG>, which illustrate snapshots of displayed HWD images 300a-d derived from the vision system <NUM>, each including a runway 304a-d (e.g., a path), in accordance with one or more embodiments of the disclosure. The displayed HWD images 300a-d emulate what a pilot would see when attempting to land and aircraft via the HWD <NUM> under different QoS value conditions (e.g., 304a under high QoS, 304b-d, under low QoS). These different QoS value conditions are based on the accuracy/precision of incoming data from the tracker processing unit <NUM> and indicate to the pilot the relative accuracy of the runway in an Earth-centered/Earth-fixed coordinate (ECEF) frame. For example, in displayed HWD image 300a, a high-confidence line 308a is shown that mimics the boundary of the runway 304a. This singular high-confidence line 308a may indicate that the HWD system <NUM> is working under high QoS value conditions, and that the display as shown is highly correlative (e.g., accurate and/or precise) to the actual environment. For example, the high-confidence line 308a may indicate to the pilot that the midline <NUM> of the runway <NUM> as shown is a predicted to be within <NUM>% to be within one meter of the actual midline of the actual runway.

Symbology modifications based on QoS value conditions may be applied to a single symbol within the symbology displayed on the display, a set of symbols within the symbology displayed on the display, or all symbology displayed on the display. For example, changes in a QoS value may result in all earth-referenced/conformal signals being modified. For instance, and in reference to <FIG>. all earth-referenced signals, including the outline/boundary of the runway <NUM>, may be altered according to the QoS value. Therefore, the above description should not be considered a limitation of the HWD system <NUM>, but as an illustration.

The modification of a symbol within the symbology to show high or low confidence may be presented in any number of ways. For example, the displayed HWD image 300b may show a differentially-colored low-confidence line 310b (e.g., indicated by the thickened line), indicating a low QoS condition (e.g., poor signals received from the tracker processing unit <NUM>, the camera <NUM>, or the inertial sensor <NUM>). In another example, the displayed HWD image 300c may present the low-confidence line 310c in addition to the default high-confidence line 308c. For instance, the distance between the low-confidence line 312c and the high confidence line 308c may give an indication of the confidence level that the displayed runway <NUM> is presented correctly (e.g., the greater distance indicating a decreased QoS condition). In another example, the HWD image 300d, may present the low-confidence line 312d as a dotted line.

In some embodiments, the QoS value comprises an accuracy characteristic, for which a symbol is modified based on the accuracy characteristic and displayed on the HWD <NUM>. For example, the symbol may be displayed as a degraded or missing signal. For instance, and as shown above, upon a determination that the QoS value has a low accuracy characteristic (e.g., less than <NUM>% accurate), the high-confidence line <NUM> may be removed. The symbol may also be modified based on a precision characteristic, for which a symbol is modified based on the accuracy characteristic and displayed on the HWD <NUM>. For example, and as shown above, upon a determination that the QoS value has a low precision characteristic (e.g., less than one meter of precision), the high-confidence line <NUM> may be replaced with a low-precision line <NUM> (e.g., a degraded symbol).

In some embodiments, the symbology with the HWD system <NUM> is configured to change quantitatively based on the QoS value. For example, the high-confidence line 308a may transform from a solid line to a highly broken/dotted line increase depending on the level of accuracy of the symbol as determined by the QoS value. For instance, a symbol with a predicted accuracy of <NUM>% may be configured as a solid high-confidence line 308a, whereas a symbol with a predicted accuracy of <NUM>% may be configured as a dashed high-confidence line 308a (e.g., <NUM> dashes per cm), and a symbol with a predicted accuracy of <NUM>% may be configured as a dotted high confidence line 308a (e.g., <NUM> dots per cm). The symbology may utilize any type of transformation of a symbol to represent a change in QoS.

In another example, a confidence line <NUM> may be assigned a specific color based upon the predicted accuracy of the symbol (e.g., red for a predicted accuracy of <NUM>%, and green for a predicted accuracy of <NUM>%).

In some embodiments, the QoS value is based on accuracy/precision characteristics of data received by the sensor input/output 228a-b and/or vision systems <NUM>, or may be based on accuracy/precision characteristics of data received by both the sensor input/output 228a-b and/or vision systems <NUM>, as well as the tracking inputs received from the tracking processing unit <NUM> and related componentry (e.g., the inertial sensor <NUM>, the camera <NUM>, the light sensor <NUM>, and/or the HWD <NUM>. ) For example, an attitude sensor that is performing slightly out of normal operating parameters may not necessarily result in a low QoS value. However, the same attitude sensor that reports to a HWD system <NUM> with a camera <NUM> that is slightly performing out of normal operating parameters may additively result in a low QoS value condition, resulting in modified attitude symbology, such as that shown in <FIG>. Here, displayed HWD images 300e-f indicate a displayed HWD image 300e under high QoS value conditions and a displayed HWD image 300f under low QoS value conditions, the low QoS value cause by both the attitude sensor and the camera <NUM> performing slightly out of normal operating parameters. The symbology associated by the attitude sensor, the horizon pitch <NUM> and the pitch ladder <NUM> are removed from the HWD <NUM>, indicating that the attitude measurements are not to be relied on. However, because the other sensors are working properly, and do not cause low QoS value conditions even with the camera <NUM> operating out of normal operating parameters, the corresponding symbols, such as the flight path vector <NUM>, does not change.

In some embodiments, the QoS value is based on a signal strength characteristic. For example, and as shown <FIG>, the low QoS value may be due to a loss of signal strength from either the attitude sensor or the camera <NUM>.

In some embodiments, a low QoS condition may result in the appearance of one or more low QoS icons <NUM> (e.g., the "Low Q" square in <FIG>) appearing on the HWD image <NUM>. For example, the low QoS icon <NUM> may appear when the HWD orientation is not to be trusted. The low QoS icon <NUM> may be head-referenced to ensure that the symbol is always visible regardless of the head orientation or the loss of competence in the head tracker or tracker processing unit <NUM> (e.g., the low QoS icon <NUM> is internally consistent and referenced to the head). The low QoS icon <NUM> may be configured as any shape, size, or type of signal. For example, the low QoS icon <NUM> may have an appearance similar to a standby instrument symbol or an unusual altitude symbol.

<FIG> is a flowchart illustrating a method <NUM> for modifying symbology displayed on a HWD based on a quality-of-service value, in accordance with one or more embodiments of the disclosure. The method <NUM> may be used by any HWD system <NUM> including but not limited to EVS-based HWD systems <NUM> for aircraft.

In some embodiments, the method includes a step <NUM> of determining a position and orientation of the HWD <NUM>. For example, the tracking processing unit <NUM> may determine the position and orientation of the HWD <NUM>, components of the HWD (e.g., eyepieces <NUM>, and/or the head/eyes of the pilot, based on the position of HWD <NUM> and/or HWD components.

In some embodiments, the method <NUM> further includes a step <NUM> of transmitting a position and orientation signal to the controller <NUM>, wherein the position and orientation signal includes a signal quality value. For example, the tracking processing unit <NUM> may transmit a position and orientation signal to the display computer <NUM> that includes not only the calculated position and orientation of the HWD <NUM>, but also a signal quality value that indicates how precise, and/or strong the signal is.

In some embodiments, the method <NUM> further includes a step <NUM> of determining a quality-of-service value based on at least the signal quality value. For example, the display computer, having received a quality signal value from the tracker processing unit <NUM> may assign a QoS value based on the quality signal value. The QoS value may also include inputs from other components of the HWD system <NUM> and communicatively coupled componentry.

In some embodiments, the system includes a step <NUM> of displaying symbology on the HWD, wherein at least one symbol of the symbology is modified from a default form to a degraded form based on the QoS value. For example, and as shown in displayed HWD images 300a,d of <FIG>, a default form of a symbol, the solid high-confidence line <NUM>, may be modified to a degraded form such as the dotted low-confidence line <NUM> based on a determined QoS value.

In some embodiments, the method <NUM> further includes steps that involve sensor signals from sensors that include but are not limited to the sensor input/output 228a-b and vision systems <NUM>. For example, in some embodiments, the method <NUM> further includes a step <NUM> of receiving a sensor signal from one or more sensors. The method may further include a step <NUM> of using the sensor signal to determine the quality-of-service value. For example, and as shown in <FIG>, performance issues in the attitude sensor and the camera <NUM> may contribute to a low QoS value that leads to specific symbols of the attitude sensor, the horizon pitch <NUM> and the pitch ladder <NUM> being removed from the symbology, whereas performance issues in the attitude sensor and the camera <NUM>, when considered individually, would not lead to a change in symbology. In cases where the symbol is removed, another symbol may replace the removed symbol. For example, in the case where the horizon pitch <NUM> and the pitch ladder <NUM> symbols are removed, the symbols may be replaced by a simple heading compass.

The HWD system <NUM> and method <NUM> may be used with any type of symbology. For example, the HWD system <NUM> and method <NUM> may be used to modify aircraft-related symbology for HWD systems used on board an aircraft. For instance, the aircraft-relate symbology used may include but not be limited to command heading marker symbology, true heading indicator symbology, heading symbology, rate of climb/descent symbology, altitude symbology, barometric setting symbology, waterline symbology, course line symbology, horizon symbology, extended horizon bar symbology, elevation deviation symbology, energy symbology (e.g., an energy caret), azimuth deviation symbology, gear up/down symbology, ILS steering symbology, course line steering symbology, flight path symbology, pitch ladder symbology, AOA bracket symbology, velocity vector symbology, bank angle symbology, ghost velocity vector symbology, peak aircraft g-force symbology, aircraft g-force symbology, Mach number symbology, angle of attach symbology, airspeed symbology, landing zone symbology, great circle steering symbology, as well as symbology representing any object detected by the vision system <NUM> (e.g., a path or runway <NUM>. It should be understood that symbology may not be limited to shapes. For example, the symbology may include, or only contain, text.

In another example, the symbology modified within the method <NUM> and HWD system <NUM> may include a flight path circle, wherein the circle size is increased as an accuracy of the HWD signaling decreased to demonstrate the angular accuracy of a presentation of a flight path. The flight path circle could also be changed to a dashed or dotted line representation.

In some embodiments, the HWD system <NUM> and/or method <NUM> may be configured to remove or modify checklist action prompts if the tracking environment is degraded. For example, buttons appearing on the HWD prompting the use to check aircraft components (e.g., check status light, or check oxygen bottle) may appear in a degraded state (e.g., having a dotted outline) upon the HWD system <NUM> operating in a degraded tracking environment, which communicates to the user the degraded tracking status.

As demonstrated in <FIG>, any reference point that has symbology rendered at its location (e.g., the runway <NUM>) could utilize size, shape, and color to indicate relative accuracy in an ECEF frame. Uncertainty for such point features may also be represented by more traditional error ellipses when appropriate. For example, and as shown in <FIG>, the width of lines, such as runway lines, could be increased or otherwise modified to indicate the area where the runway is expected to be located. The runway lines could also be removed entirely if the accuracy of the head tracking solution is too low. In some cases, symbology color can be modified to reflect "binary for credit" checks against FAA regulations.

Claim 1:
A system (<NUM>), comprising:
a head worn display (<NUM>) configured to display symbology of an operating environment;
a tracking camera (<NUM>);
a tracking processing unit (<NUM>) communicatively coupled to the tracking camera configured to:
determine a position and orientation of the head worn display,
transmit a position and orientation signal to a controller (<NUM>), wherein the position and orientation signal includes a signal quality value;
a controller (<NUM>) communicatively coupled to the head worn display and the tracking camera comprising:
one or more processors (<NUM>); and
a memory (<NUM>) with instructions stored upon, that when executed by the one or more processors, cause the one or more processors to:
display the symbology on the head worn display;
determine a quality-of-service value based on at least the signal quality value;
characterised by modifying at least one symbol of the symbology based on the quality-of-service value from a default symbol to a degraded symbol if the quality-of-service value changes from a high-quality value to a low-quality value.