CROSS-REFERENCE TO RELATED APPLICATION

[0001] This application claims the benefit of and priority to U.S. Provisional Application No. 63/335,407, filed on April 27, 2022, and titled “ULTRA-WIDEBAND ANGLE OF ARRIVAL DETERMINATION,” the content of which is herein incorporated by reference in its entirety for all purposes.

BACKGROUND

[0002] Determining a direction from a first device to a second device can be useful for many reasons, including finding the second device or confirming that the correct device has been selected for pairing. However, determining an accurate direction to another device in a relatively small environment can be difficult. Embodiments detailed herein provide effective arrangements for accurately detecting the direction to another device.

SUMMARY

[0003] Various embodiments are described related to a computerized device that determines a direction using ultra-wideband (UWB) communications. In some embodiments, a computerized device that determines a direction using ultra-wideband (UWB) communications is described, device may comprise a first UWB antenna. The device may comprise a second UWB antenna. The second UWB may be located a distance from the first UWB antenna. The device may comprise a processing system, comprising one or more processors in communication with the first UWB antenna and the second UWB antenna. The processing system may be configured to determine a first range based on a first UWB message received by the first UWB antenna. The processing system may be configured to determine a second range based on a second UWB message received by the second UWB antenna. The processing system may be configured to calculate an angle of arrival using the first range, the second range, and the stored distance indication. The processing system may be configured to output an indication of the angle of arrival.

[0004] Embodiments of such a device may include one or more of the following features: the device may further comprise an electronic display. The processing system may be configured to access a stored distance indication of the distance between the first UWB antenna and the second UWB antenna. The processing system being configured to output the angle of arrival may comprise a graphical indicator of direction being presented by the electronic display, the graphical indicator of direction being based on the angle of arrival. The first UWB message and the second i UWB message may be a same message. The processing system may be further configured to cause a third UWB message to be transmitted that may be indicative of the angle of arrival. The computerized device may be selected from the group consisting of a tablet computer, a laptop computer, a hand-held gaming device, and a smartphone. The first UWB message may comprise a first timestamp indicative of a first time of transmission. The second UWB message may comprise a second timestamp indicative of a second time of transmission. The device may further comprise a third UWB antenna. The third UWB may be located a second distance from the first UWB antenna. The processing system may be further configured to determine a third range based on a third UWB message received by the third UWB antenna. The processing system may be further configured to access a second stored distance indication of the second distance between the first UWB antenna and the third UWB antenna. The processing system may be further configured to calculate a second angle of arrival using the first range, the third range, and the second stored distance indication. The indication of the angle of arrival may be further based on the second angle. The device may further comprise a speaker. The processing system being configured to output the angle of arrival may comprise an auditory indicator of direction being output by the speaker based on the angle of arrival. The auditory indicator may be speech indicative of a direction. The processing system can be further configured to perform a pairing process between the computerized device and a remote device from which the first UWB message and the second UWB message was received, the pairing process being performed at least in part based on the calculated angle of arrival.

[0005] In some embodiments, a method for determining a direction using ultra-wideband (UWB) communications is described. The method may comprise determining, by a computerized device, a first range based on a first UWB message received by a first UWB antenna of the computerized device. The method may comprise determining, by the computerized device, a second range based on a second UWB message received by a second UWB antenna of the computerized device. The method may comprise accessing, by the computerized device, a stored distance indication of the distance between the first UWB antenna and the second UWB antenna. The method may comprise calculating, by the computerized device, an angle of arrival using the first range, the second range, and the stored distance indication. The method may comprise outputting, by the computerized device, an indication of the angle of arrival.

[0006] Embodiments of such a method may include one or more of the following features: outputting the angle of arrival may comprise a graphical indicator of direction being presented by an electronic display of the computerized device. The first UWB message and the second UWB message may be a same UWB message. The computerized device may be selected from the group consisting of a tablet computer, a laptop computer, a hand-held gaming device, and a smartphone. The first UWB message may comprise a first timestamp indicative of a first time of transmission. The second UWB message may comprise a second timestamp indicative of a second time of transmission. The method may further comprise determining, by the computerized device, a third range based on a third UWB message received by a third UWB antenna. The method may further comprise accessing, by the computerized device, a second stored distance indication of the second distance between the first UWB antenna and the third UWB antenna. The method may further comprise calculating, by the computerized device, a second angle of arrival using the first range, the third range, and the second stored distance indication. The indication of the angle of arrival may be further based on the second angle. Outputting the angle of arrival may comprise an auditory indication of direction being output by a speaker of the computerized device.

[0007] In some embodiments, a non-transitory processor-readable medium is described. The medium may comprise processor-readable instructions configured to cause one or more processors to determine a first range based on a first UWB message received by a first UWB antenna. The medium may determine a second range based on a second UWB message received by a second UWB antenna. The medium may access a stored distance indication of the distance between the first UWB antenna and the second UWB antenna. The medium may calculate an angle of arrival using the first range, the second range, and the stored distance indication. The medium may output an indication of the angle of arrival.

BRIEF DESCRIPTION OF THE DRAWINGS

[0008] A further understanding of the nature and advantages of various embodiments may be realized by reference to the following figures. In the appended figures, similar components or features may have the same reference label. Further, various components of the same type may be distinguished by following the reference label by a dash and a second label that distinguishes among the similar components. If only the first reference label is used in the specification, the description is applicable to any one of the similar components having the same first reference label irrespective of the second reference label.

[0009] FIG. 1 illustrates an embodiment of two devices located near each other for which an angle of arrival (AoA) can be calculated using ultra-wideband (UWB) signals.

[0010] FIG. 2 illustrates an embodiment of a block diagram of a computerized device which can calculate AoA based on multiple UWB range measurements.

[0011] FIG. 3 illustrates an embodiment of how range measurements can be used to calculate AoA. [0012] FIG. 4 illustrates an embodiment of a graph that indicates the relationship between range and AoA.

[0013] FIG. 5 illustrates an embodiment of a method for determining a direction using UWB communications.

DETAILED DESCRIPTION

[0014] A nearby device can be located by using one or more UWB communications to determine a range and to determine an angle of arrival (AoA) from which the UWB communication arrived. Determination of AoA for UWB communication conventionally relies on an AoA-to-phase difference lookup table. In such an arrangement, differences in phase across the frequencies used for the UWB communication can be used to look up a corresponding phase difference value in a stored lookup table. The lookup table maps the phase difference to a particular AoA.

[0015] Use of a measured phase difference across a UWB communication to determine AoA can have drawbacks. First, phase integrity degradation occurs, such as because while an azimuthal angle may change, the elevation angle may change. Further, polarization of the transmitting device can be arbitrary as user moves the transmitting device at any angle and in any direction, thus adversely affecting AoA determination.

[0016] When AoA is measured, it can be beneficial to have half wavelength separation; however, for multiband operation this can mean deviation from the half wavelength distance. If the antennas are physically too close together, mutual electromagnetic coupling can increase, which degrades performance. If the antennas are too far apart, phase wrap (aliasing) can occur. Phase wrap can occur when phase difference is used to determine AoA based on an UWB communication. Phase wrap can result in the same determined phase difference across the UWB communication being indicative of multiple AoAs, leading to ambiguity as to the real AoA. Additionally, shielding may be necessary to help protect the phase integrity, which can increase the complexity and cost of the device. Also , many devices may use a material that interferes with signal (and, thus, phase) integrity, such as a metal case. However, such a case may be preferable for other reasons, such as durability and user feel. P

[0017] In contrast to using phase difference values and an associated lookup table, embodiments detailed herein are focused on using multiple UWB range measurements in order to determine a one, two, or three dimensional direction for the AoA. Such arrangements as detailed herein can have significant benefits, such as not requiring strict placement of the antennas at half wavelength spacing. By allowing for larger spacing, coupling between the antennas can be significantly decreased.

[0018] FIG. 1 illustrates an embodiment of system 100 that includes two devices located near each other for which an angle of arrival (AoA) can be calculated using ultra-wideband (UWB). System 100 can include computerized device 110-1 and computerized device 110-2. Computerized devices may be various forms of electronic devices, which can use UWB for communication and/or positioning. Computerized devices 110 can include: tablet computers; laptop computers; gaming devices; smart watches, earbuds (e.g., an earbud case, an earbud itself), headphones, UWB location tags, smartphones; smart home devices; home assistant devices; smart home hubs; and other forms of computerized devices. Computerized devices 110 can be of the same type (e.g., determining AoA from one smartphone to another smartphone) or different types (e.g., determining AoA from a smartphone to a smart watch). In general, embodiments detailed herein can be performed by any form of computerized device on which multiple UWB antennas can be installed with at least a distance of several centimeters between the UWB antennas.

[0019] In FIG. 1, computerized device 110-1 may be using one or more UWB messages transmitted by computerized device 110-2 to determine a direction toward computerized device 110-2. Generally, UWB communications occur within the range of frequencies of 3.1 GHz - 10.6 GHz; therefore, the band used for UWB communications can be over 7 GHz wide. In other embodiments, the specific frequency range over which communications are sent may vary from this defined range. Implementations of UWB may use a portion of this band, such as a frequency band spanning 500 MHz or more. Generally, UWB can be used for high-speed data transfers (e.g., 1 Gbit/s) over relatively short distances, such as 10 meters. UWB communications may be performed in accordance with IEEE 802.15.4a. While any form of payload data (e.g., files, music, contact cards, video) can be sent via UWB messages, at least some UWB messages include a precise timestamp indicative of a time of transmission. This timestamp can be used to perform a time-of-flight (ToF) analysis to determine a distance from the transmitting device to a recipient device.

[0020] Using the timestamp and performing a ToF analysis, computerized device 110-1 can determine a range (or distance) from an antenna of computerized device 110-2 to an antenna of computerized device 110-1. This distance, whether in one, two, or three dimensional space, however, is not indicative of direction. Rather, a separate AoA analysis is performed to determine a direction from computerized device 110-1 to computerized device 110-2. As illustrated, the AoA is two-dimensional; however, in other embodiments, three or one dimension may be used for the AoA instead. As illustrated, based on one or more received UWB messages from computerized device 110-2, AoA 120 may be determined. While AoA 120 is illustrated as an angle based on a horizontal (x) axis, it should be understood that AoA 120 may be translated to being an angle defined from some other axis, such as a vertical (y) axis or the z-axis.

[0021] When an AoA is determined by computerized device 110-1, the AoA may be used to present graphical indicator 111-1 of the direction to computerized device 110-2, from which the UWB message was received. Similarly, computerized device 110-1 may transmit one or more UWB messages to computerized device 110-2, which may determine an AoA to computerized device 110-1 and use the calculated AoA to present graphical indicator 111-2. Graphical indicators 111 can take many forms. For example, PCT/US2022/015278, entitled “Proximity and Direction Based Electronic Device Pairing” filed February 4, 2022, which is hereby incorporated in its entirety, details a graphical arrangement that is indicative of both direction and distance (or range). Such graphical elements can be used in place of graphical indicators 111. Further, in other embodiments, some other form of graphical indicator could be used to indicate direction and, possibly, distance. Sound and/or vibration may also be used in some embodiments to indicate distance and/or direction.

[0022] One or more of the computerized devices of FIG. 1 may use the system detailed in FIG. 2 to determine the AoA to the computerized device that transmitted one or more UWB messages. FIG. 2 illustrates an embodiment of a block diagram of a computerized device 200 which can calculate AoA based on multiple UWB range measurements. Computerized device 200 can represent, for example, computerized device 110-1 and, possibly, computerized device 110-2 of FIG. 1. Computerized device 200 can include: housing 210; UWB antennas 212 which are separated by fixed distance 213; UWB interface 214; processing system 216; display 218; and network interface 219. In other embodiments, fewer or greater numbers of components may be present. For example, inclusion of network interface 219 is not necessary for the AoA to be calculated using multiple UWB ranging measurements.

[0023] Housing 210 can house the components of computerized device 200. In some embodiments, housing 210 may be metallic. In some embodiments, rigid or semi-rigid materials, such as plastic or glass, may be used as a part of housing 210. In embodiments detailed herein, at least two UWB antennas 212 may be present. Each of UWB antennas 212 are capable of receiving a UWB message from another device. UWB antennas 212 may separately receive the same UWB message from another device. In some embodiments, a single one of UWB antennas 212 is active at a given time. Two UWB antennas 212 may be sufficient for determining a two-dimensional AoA to the device that transmitted the UWB message. In other embodiments, three UWB antennas 212 may be present to determine a three-dimensional AoA to the device that transmitted the UWB message.

[0024] The greater the number of UWB antennas present, the greater the number of degrees of freedom in determining the AoA. Further, additional UWB antennas, such as greater than four, can allow for improved processing and noise mitigation (e.g., by using a least squares solution to determine optimal fit of received data for estimation). Further, if accurate three-dimensional ranging is performed over time, velocity and acceleration can be determined.

[0025] UWB antennas 212 are separated by fixed distance 213, which can be stored by or otherwise accessible by processing system 216. The distance between UWB antennas 212 may be increased as much as practical given the dimensions of housing 210. For example, if computerized device 200 is a tablet computer, UWB antenna 212-1 may be near the top left of a front surface of computerized device 200 and UWB antenna 212-2 may be near the top right of a front surface of computerized device 200. If a third UWB antenna is present, it may be near the bottom left or right of the front surface of computerized device 200. If a third UWB antenna is present, the fixed distance from the third UWB antenna to UWB antenna 212-1, UWB antenna 212-2, or both may be stored or otherwise accessible by processing system 216.

[0026] UWB antennas 212 may come in various forms. In some embodiments, UWB antennas are surface mounted. UWB antennas 212 can use a connector such as a surface mount microcoaxial jack to be electrically connected with UWB interface 214. UWB antennas can be over various types, such as: patch, IFA (inverted-F antenna), PIFA (planar inverted-F antenna), loop, dipole, or a hybrid of these types. UWB antennas 212 can be mounted to an inner surface of computerized device 200, part of a main logic board (MLB), integrated with a speaker, or part of a slot in the housing that may or may not have a secondary function (such as a rubber foot to hold the device in place). UWB antennas 212 may also be coupled with WiFi antennas, Thread antennas, Bluetooth antennas, and/or cellular antennas. That is, multiband antennas can be used that diplex signals to the appropriate interfaces.

[0027] UWB interface 214 can separately receive and process UWB messages via UWB antenna 212-1 and UWB antenna 212-2. Therefore, while UWB interface 214 is receiving a UWB message via UWB antenna 212-1, signal received via UWB antenna 212-2 may be ignored. Therefore, two messages may be received by UWB interface 214 via UWB antennas 212 in order to determine a distance using each UWB antenna. In some embodiments, a separate UWB interface is present for each of UWB antennas 212, thus allowing a same UWB message received via each of UWB antennas 212 to be analyzed. UWB interface 214 can receive the raw RF signals via UWB antennas 212 and process such RF signals into digital data to be passed to processing system 216. In some embodiments, UWB interface 214 can be incorporated as part of processing system 216.

[0028] Processing system 216 can include one or more processors. Processing system 216 may include one or more special-purpose or general-purpose processors. Such special-purpose processors may include processors that are specifically designed to perform the functions of the components detailed herein. Such special-purpose processors may be ASICs or FPGAs which are general-purpose components that are physically and electrically configured to perform the functions detailed herein. Such general-purpose processors may execute special-purpose software that is stored using one or more non-transitory processor-readable mediums, such as random access memory (RAM), flash memory, a hard disk drive (HDD), or a solid state drive (SSD).

[0029] Processing system 216 may be able to transmit data via UWB antenna 212-1, UWB antenna 212-2, or both via UWB interface 214. Processing system 216 may also be able to output information for presentation to display 218. For example, after processing one or more UWB messages received via UWB antennas 212, processing system 216 may determine an AoA of the one or more UWB messages and output an indication of the AoA on display 218 and/or using audio (e.g., synthesized speech). Display 218 can vary by embodiment; in some embodiments, a color LED, OLED, AMOLED, or LCD display panel is used.

[0030] Processing system 216 may further be in communication with network interface 219, which can allow for communication via one or more wired or wireless networks. Network interface 219 can use a wireless local area network (WLAN) communication protocol such as WiFi. Network interface 219 may more generally use any of the IEEE 802.11 suite of protocols. Network interface 219 may be able to communicate via a mesh network, such as using Matter or Google’s Thread mesh communication protocol. Other possible protocols that can be used by network interface 219 include short-range device-to-device communication protocols, such as Bluetooth. For a wired communication protocol, network interface 219 may communicate using Ethernet.

[0031] Processing system 216 may perform the substantive calculations for range and AoA based on the received one or more UWB messages. In some embodiments, the functionality to determine range and AoA based on one or more UWB messages can be performed by UWB interface 214. In some embodiments, UWB interface 214 is a separate one or more integrated circuits (ICs) in communication with processing system 216. Alternatively, UWB interface 214 may be incorporated as part of a system-on-a-chip (SOC) design that combines processing system 216 and UWB interface 214.

[0032] While not illustrated, other output devices may be presented as part of computerized device 200, such as an audio output device (e.g., headphone jack, wireless headphone interface, speaker) or a haptic feedback device that outputs vibrations. Such output devices can also be used to output AoA information, such as sound that appears to come from the direction of the AoA or a number of vibrations to indicate direction (e.g., one pulse of vibrations for left, two pulses for right).

[0033] FIG. 3 illustrates an embodiment of a system 300 that shows how range measurements can be used to calculate AoA based on one or more received UWB messages. In system 300, only the antennas of a computerized device, such as computerized device 200, are shown.

Computerized device 310 may transmit a UWB message, which includes a timestamp indicative of the time of transmission, using antenna 311. The UWB message may be received via UWB antenna 212-1. The processing system (or UWB interface) in communication with UWB antenna 212-1 may make a range determination based on the time-of-flight (ToF) calculated using the included timestamp. The determined range is equal to distance 320.

[0034] The same transmitted UWB message or a second UWB message transmitted at a later or earlier time by computerized device 310 (which would also include a timestamp indicative of the time of transmission) may be received by UWB antenna 212-2. If the same UWB message is received by the two (or more) antennas, the timestamp included in each received instance would be the same, but the messages would be received at slightly different times. The processing system (or UWB interface) in communication with UWB antenna 212-2 may make a second range determination based on the time-of-flight (ToF) calculated using the included timestamp. The determined range is equal to distance 330.

[0035] Distance 213 between UWB antennas 212 is fixed and is stored or otherwise accessible by the processing system. Therefore, a triangle is present with the lengths of all three sides being known. Trigonometry can then be used to determine the angles of the triangle. For example, Equation 1 represents the law of cosines. This equation can be evaluated once or twice to determine two of the angles of the triangle (and, if desired, the remaining angle can be determined by subtracting the two angles from 180°). Or, if desired, Equation 1 or similar could again be used to calculate the remaining angle. a ² = b ² + c ² — 2bc(cos zl) Eq. 1 [0036] In Equation 1, to determine angle 331 : A represents angle 331; distance 213 represents Z>; distance 330 represents c; distance 320 represents a. Since all distances are known, Equation 1 can then be solved for A to determine angle 331. In some embodiments, Equation 1 can be repeated to find angle 321, by substituting the correct distances for the variables in Equation 1.

[0037] In some embodiments, determined angle 331 (or determined angle 321) can be used as the AoA. In some embodiments, both determined angle 331 and determined angle 321 are found, and averaged together to find an angle (e.g., with angle 321 subtracted from 180°) to determine the AoA from a point midway between UWB antennas 212 to computerized device 310.

[0038] In the embodiment of FIG. 3, a two-dimensional AoA is determined. In another embodiment, a third UWB antenna may be present, such as indicated by UWB antenna 212-3. The distance between UWB antenna 212-3 and UWB antenna 212-1 may be stored and accessible by the processing system. The process can then be repeated (or performed based on the same single UWB message) from computerized device 310 to determine an AoA in an orthogonal plane. These two AoA determinations can then be combined together to form a three-dimensional AoA.

[0039] As previously stated, all of the range measurements can be performed based on a single UWB message transmitted via the UWB antenna of computerized device 310. Alternatively, the range measurements may be performed using multiple UWB messages transmitted by computerized device 310 (e.g., two UWB messages for a two-dimensional AoA; three UWB messages for a three-dimensional AoA). Each UWB message can include a timestamp of transmission and an identifier of computerized device 310.

[0040] FIG. 4 illustrates an embodiment of graph 400 that indicates the relationship between range difference and AoA. As shown in graph 400, each range difference value corresponds to a unique AoA. Therefore, no ambiguity may be present in the AoA based on the measured range. While FIG. 1 illustrates computerized devices 110 as parallel to each other, computerized devices for which an AoA of a UWB message from one device to the other may not be parallel or even on the same plane. Graph 400 further indicates the relationship of range difference at multiple orientations. When the two computerized devices are parallel in a plane, at a 45° orientation inplane, or a 90° orientation in-plane, the relationship between range difference and AoA remains similar.

[0041] Various methods may be performed using the systems and arrangements of FIGS. 1-4. FIG. 5 illustrates an embodiment of a method 500 for determining a direction using UWB communications. Method 500 may be performed using computerized device 200 or some other form of computerized device having at least two UWB antennas that are spaced by known, fixed distances.

[0042] At block 510, a first range measurement based on a UWB message received via a first UWB antenna may be made. The first range measurement may be based on a timestamp that is included in the UWB message transmitted by another computerized device to which the AoA is to be determined. At block 520, a second range measurement based on either the same UWB message as block 510 or a second UWB message received via a second UWB antenna may be made. If a second UWB message is to be used, it may be required that the second UWB message be received within a defined time period of the first UWB message; otherwise, method 500 may need to be restarted to ensure the AoA determined is accurate. (If too much time elapses between messages, the likelihood that the positional relationship between the device may have changed can increase.) The second range measurement may be based on a timestamp that is included in the UWB message transmitted by the other computerized device to which the AoA is to be determined. If different UWB messages are used, it may be assumed for determining the AoA that neither device moved substantially between UWB messages being transmitted.

[0043] At block 530, a stored distance indication of the distance between the first and second UWB antennas may be accessed. The distance indication may be stored locally by the computerized device performing the blocks of method 500. The distance indication may also be retrieved from some other source, such as a remote server accessible via a network.

[0044] At block 540, the AoA may be computed using the first measured range, the second measured range, and the accessed stored indication of the distance between the first and second UWB antennas. As detailed in relation to Equation 1 and FIG. 3, the law of cosines (or other principles of trigonometry) may be used to calculate the angle from the computerized device performing method 500 and the antenna of the computerized device that transmitted the one or more UWB messages. In this example, the AoA calculated is two-dimensional. In another embodiment, the AoA may be three-dimensional. In a three-dimensional embodiment, a third range may be measured based on the same UWB message or another UWB message using a third UWB antenna (as detailed in relation to FIG. 3) and a second AoA may be calculated in an orthogonal plane to AoA of block 540. The two AoA may be combined to determine a three- dimensional AoA.

[0045] At block 550, an indication of the AoA as determined at block 540 may be output. In some embodiments, the AoA may be presented on a display of the computerized device. In some embodiments, the AoA and/or range information may be transmitted to the device from which the one or more UWB messages were received at blocks 510 and 520 in the form of a UWB message. Additionally or alternatively, the AoA may be output in some other form, such as sound (e.g., synthesized speech indicating a direction or a tone or sound that appears to be originating from the direction of the AoA) or vibration. The AoA may also be transmitted to another device, such as via a network interface. Additionally or alternatively, an action may be performed based on the indication of the AoA. For instance, an application may require that the computerized device performing the steps of method 500 be located a particular orientation to another device. Once in the proper position, the application may perform a next action.

[0046] Presenting an AoA to a user can be highly useful in helping the user locate the device broadcasting UWB messages. For example, a UWB tag may be affixed to nearly any object. If the user needs help in locating the object, the user can use the AoA output at block 550 for presentation to determine the direction and/or distance to the object. As another example, if a user is pairing two devices, the AoA and/or distance can be presented to the user to help ensure that the user is attempting to pair with the correct device. For example, in a crowded environment (e.g., on an airplane), there may be many devices available for pairing. By using the distance and/or direction, the user can confirm that pairing is being performed between the correct devices.

[0047] Further, in some embodiments, rather than involving the user in the process, the AoA and/or direction may be used directly by the computerized device. For instance, returning to the previous example, a user may be instructed that for pairing to be completed, a remote device should be placed within a defined distance with a defined orientation (e.g., immediately to the right) relative to the computerized device. The device may use the AoA and/or distance to ensure that the remote device is in the correct location before proceeding with pairing. Again here, ensuring that the remote device is in the correct location can be useful to help ensure pairing is occurring between the desired devices.

[0048] Additionally or alternatively, other uses for determining an AoA can be present. For example, an output AoA can be used to determine if two devices have been placed in proper orientation to each other (and, possibly, at a proper distance from each other). For example, smart home devices or speakers may need to be arranged in a particular orientation to function properly. As another example, AoA may be used as part of a game, such as to direct a child on real or virtual treasure hunt. For example, upon following the AoA indication to a particular destination, the child may be provided with a real or virtual reward.

[0049] It should be noted that the methods, systems, and devices discussed above are intended merely to be examples. It must be stressed that various embodiments may omit, substitute, or add various procedures or components as appropriate. For instance, it should be appreciated that, in alternative embodiments, the methods may be performed in an order different from that described, and that various steps may be added, omitted, or combined. Also, features described with respect to certain embodiments may be combined in various other embodiments. Different aspects and elements of the embodiments may be combined in a similar manner. Also, it should be emphasized that technology evolves and, thus, many of the elements are examples and should not be interpreted to limit the scope of the invention.

[0050] Specific details are given in the description to provide a thorough understanding of the embodiments. However, it will be understood by one of ordinary skill in the art that the embodiments may be practiced without these specific details. For example, well-known processes, structures, and techniques have been shown without unnecessary detail in order to avoid obscuring the embodiments. This description provides example embodiments only, and is not intended to limit the scope, applicability, or configuration of the invention. Rather, the preceding description of the embodiments will provide those skilled in the art with an enabling description for implementing embodiments of the invention. Various changes may be made in the function and arrangement of elements without departing from the spirit and scope of the invention.

[0051] Also, it is noted that the embodiments may be described as a process which is depicted as a flow diagram or block diagram. Although each may describe the operations as a sequential process, many of the operations can be performed in parallel or concurrently. In addition, the order of the operations may be rearranged. A process may have additional steps not included in the figure.

[0052] Having described several embodiments, it will be recognized by those of skill in the art that various modifications, alternative constructions, and equivalents may be used without departing from the spirit of the invention. For example, the above elements may merely be a component of a larger system, wherein other rules may take precedence over or otherwise modify the application of the invention. Also, a number of steps may be undertaken before, during, or after the above elements are considered. Accordingly, the above description should not be taken as limiting the scope of the invention.