Location Identification and Intent Determination Based on UWB Temporal Signatures

Abstract

Method and program code for determining location and / or intent of a user (or device) holding, carrying, wearing, or carrying a UWB enabled device. An exemplary computer-readable medium for determining a user's location and / or intent comprises program code that, when executed by one or more processors, causes the one or more processors to perform the steps of: determining a current time signature for a first device moving within an environment, comparing the current time signature to at least a portion of a stored reference time signature corresponding to a secured asset within the environment, and making an access control decision corresponding to the secured asset based on whether the current time signature is determined to correspond to at least a portion of the stored reference time signature.

Description

[Technical Field]

[0001] The embodiments described herein relate generally to locating a user and detecting or determining the user's intent (e.g., to access a secure asset) based on ultra-wideband (UWB) communications with a device held or carried by a person, and in particular based on UWB temporal signatures. [Background technology]

[0002] UWB location sensing technology has recently begun to be incorporated into various models of mobile devices, such as smartphone devices, mobile tablet devices, and other mobile systems. UWB technology is generally capable of providing more accurate location estimates compared to alternative technologies, such as Bluetooth (e.g., BLE) or WiFi. UWB's greater accuracy enables many different use cases. As an example, when UWB location sensing is integrated into an access control reader of an access control system (ACS), such as a physical access control system (PACS), and into a user's mobile device, such as the user's smartphone, the UWB location estimate of the user's mobile device can generally be used to make an appropriate decision regarding whether the user is authorized to access a secured asset secured by the access control reader based on the user's location and / or determined intent to access the secured asset. For example, if an access control reader controls access to a door or other entryway, UWB position estimation can generally be used to make appropriate decisions regarding whether to lock (or keep locked) or unlock the door / entryway based on the user's location and / or determined intent to pass through the door / entryway. In such an example, a particularly important aspect of position estimation is determining whether the user is outside or on the unsecure side of the door / entryway, or inside or on the secure side of the door / entryway. That distinction is important because the behavior of the PACS can be significantly different based on whether the user is on the secure side of the door / entryway, as opposed to the unsecure side of the door / entryway, even if the user is the same distance from the door / entryway in both cases.For example, if an authorized user approaches a controlled door / entry from the outside / unsecured side of the door / entry, the PACS should unlock the door / entry if the user's credential(s) are authenticated. Conversely, if the same authorized user is inside / secured and near the door / entry, the PACS may not automatically unlock the door / entry because the user may be approaching the door / entry for reasons other than the user's own access, such as simply passing by the door / entry on their way to another destination, or approaching the door / entry to verify the identity of an unknown person on the outside / unsecured side of the door / entry.

[0003] UWB location detection in UWB systems is typically performed in two distinct steps. One step involves determining an estimate of the radial distance (D) between a UWB transmitter (or transceiver) and a UWB receiver (or transceiver). This distance estimate is typically determined as a time-of-flight measurement operating on ultrashort UWB pulses. The resulting estimate is typically fairly accurate and robust to the radio frequency (RF) environment in which the UWB system resides. The second step involves determining an estimate of the UWB transmitter's angle of arrival (AoA), which describes the angular direction of the UWB transmitter relative to the UWB receiver. A common approach to determining UWB AoA measurements is to incorporate two or more antennas within the UWB receiver, separated by a distance and azimuth. In this way, received UWB signals are detected by each of the antennas, and the AoA is estimated using the phase relationship between the detected UWB signals. One such antenna pair can be used to estimate radial distance and AoA in a two-dimensional (2D) plane, with a 180° ambiguity around the line of symmetry of the antenna pair. If necessary or desired, multiple pairs of antennas and / or antenna arrays can be used to locate (e.g., estimate radial distance and AoA) a UWB transmitter in three-dimensional (3D) space.

[0004] While the aforementioned methods work well in ideal "line-of-sight" (LoS) environments, they are highly susceptible to RF reflections and other multipath effects in non-line-of-sight (NLoS) environments. In NLoS environments, which are very common, AoA estimates are often very noisy, distorted, and / or inaccurate, which in turn impairs the ability to determine the precise location of the UWB transmitter. In some cases, multiple AoA measurements may be obtained and aggregated (e.g., averaged) in some way, thereby reducing AoA errors. In one common arrangement, UWB antennas are positioned so that measurements from both sides of a security asset (e.g., a door / entrance) provide AoA estimates with nominally opposite signs (e.g., if the UWB antenna is positioned outside the security asset, the inside corresponds to angles 0 to −90 degrees, and the outside corresponds to angles 0 to +90 degrees). In such cases, the signs of the AoA measurements are summed over a set of measurements and an inside / outside decision is derived from the sign of the sum. However, in general, the results of such methods are still significantly prone to error.

[0005] In addition to accurate location determination, it is also useful for a UWB system to estimate a user's intent (e.g., to access a secured asset) and respond appropriately. In the case of an access control system, a user may be near a controlled door / entrance but not actually intend to pass through. For example, the user may approach the door / entrance and stop before deciding to pass, or decide not to pass and turn around. As another example, the user may sit or otherwise remain stationary for an extended period of time within the detection range of an access control reader due to the configuration of the room and the furniture therein. In both of these examples, and in other situations, it is desirable for the access control system to determine that the user has not indicated an intent to pass through the door / entrance and therefore decide not to unlock the door / entrance. As discussed above, known methods of pointwise accumulation used to estimate AoA generally do not, by themselves, provide a good measure of user intent.

[0006] For at least these reasons, there is a need in the art for improved methods and systems for determining the location and / or intent of a user (or device) holding, carrying, wearing, or carrying a UWB-enabled device. Summary of the Invention

[0007] The following presents a simplified summary of one or more embodiments of the present disclosure in order to provide a basic understanding of such embodiments. This summary is not an extensive overview of all contemplated embodiments, and is intended to neither identify key or critical elements of all embodiments nor delineate the scope of any or all embodiments.

[0008] The present disclosure, in one or more embodiments, relates to a non-transitory computer-readable medium comprising executable program code that, when executed by one or more processors, causes the one or more processors to perform the following steps: monitoring ultra-wideband (UWB) signals between a first device and a second device, where the first device is at a fixed location and the second device is portable; determining a reference time signature associated with the first device based on the UWB signals; and storing the reference time signature on the computer-readable medium, where the reference time signature indicates an intent to access a security asset associated with the first device.

[0009] The present disclosure, in one or more embodiments, further relates to a non-transitory computer-readable medium comprising executable program code that, when executed by one or more processors, causes the one or more processors to perform the following steps: determining a current time signature for a first device moving within an environment; comparing the current time signature to at least a portion of a stored reference time signature corresponding to a secured asset within the environment; and making an access control decision corresponding to the secured asset based on whether the current time signature is determined to correspond to at least a portion of the stored reference time signature.

[0010] The present disclosure, in one or more embodiments, further relates to a method for calibrating an environment, the method including: monitoring ultra-wideband (UWB) signals between a first device and a second device, where the first device is at a fixed location and the second device is portable; determining a reference time signature associated with the first device based on the UWB signals; and storing the reference time signature in a computer-readable storage medium, where the reference time signature indicates an intent to access a security asset associated with the first device.

[0011] In one or more embodiments, the present disclosure further relates to a method for determining a location of a device within an environment, the method including determining a current time signature for a first device moving within the environment, comparing the current time signature to at least a portion of a stored reference time signature corresponding to a secure asset within the environment, and making an access control decision corresponding to the secure asset based on whether the current time signature is determined to correspond to at least a portion of the stored reference time signature.

[0012] While multiple embodiments are disclosed, still other embodiments of the present disclosure will become apparent to those skilled in the art from the following detailed description, which shows and describes illustrative embodiments of the invention. As will be understood, the various embodiments of the present disclosure are capable of modification in various obvious aspects, all without departing from the scope of the present disclosure. Accordingly, the drawings and detailed description are to be regarded as illustrative in nature and not restrictive. [Brief explanation of the drawings]

[0013] In the drawings, which are not necessarily drawn to scale, like reference numbers may describe like components in different views. Like reference numbers with different suffixes may represent different instances of like components. Some embodiments are illustrated by way of example, and not by way of limitation, in the figures of the accompanying drawings. [Figure 1] FIG. 1 is a front view of an exemplary environment in the form of an access control system (ACS) or portion thereof for determining the location and / or intent of a user holding, carrying, wearing, or carrying a UWB-enabled device, as described herein. [Figure 2] 1 is a top cross-sectional view of an exemplary environment of an ACS or some form of the ACS. [Figure 3] FIG. 2 is a schematic block diagram of various components of an exemplary reader device. [Figure 4]FIG. 1 is a schematic block diagram of various exemplary components of an exemplary machine that may be used, for example, as a control panel, host server, credential device, and / or UWB-enabled device of the present disclosure. [Figure 5] FIG. 1 is a close-up view of an exemplary environment for determining the location and / or intent of a user holding, carrying, wearing, or carrying a UWB-enabled device, as described herein. [Figure 6] 6 is a flow chart that schematically illustrates an exemplary method for calibrating an environment, such as the exemplary environment of FIGS. 1 and 5. [Figure 7] 1 is a flowchart that schematically illustrates an exemplary method for determining the location and / or intent of a user holding, carrying, wearing, or carrying a UWB-enabled device, as described herein. DETAILED DESCRIPTION OF THE INVENTION

[0014] The present disclosure generally relates to improved methods and systems for determining the location and / or intent of a user (or device) holding, carrying, wearing, or carrying a UWB-enabled device. At a very general level, embodiments of the present disclosure enable estimation of the location and / or intent of a user or device by collecting and analyzing a temporal "signature" while the user (more specifically, a UWB-enabled device held, carried, or worn by the user or carried on the device) is within UWB read range of one or more other UWB sensors (e.g., transmitters, receivers, transceivers). Such a temporal signature generally consists of a series of measurements combining two or more types of UWB signals. Determining or estimating a user's location relative to a secured asset (e.g., a door / entrance), such as whether the user is on the secured (e.g., inside) or unsecured (e.g., outside) side of the door / entrance, can be performed by comparing a current time signature for the user to one or more previously determined reference time "signatures," such as, but not limited to, one or more reference time signatures acquired in situ at some point after installation of a UWB-enabled access control reader in a particular environment. In this way, each reference time signature represents unique characteristics of the RF environment in which UWB measurements are made, thereby improving the need for AoA estimates and / or other UWB measurements to respond in an ideal manner. Although the term "user" is used throughout this disclosure to refer to a person holding, carrying, wearing, or carrying a UWB-enabled device, other embodiments of the present disclosure include methods and systems for determining the location and / or intent of a device, such as a machine, equipment, automobile, construction equipment / materials, appliance, electronic device, robot, etc., on which or associated with a UWB-enabled device is mounted or attached. Thus, use of the term "user" in this disclosure is intended to include both a human user and a device (i.e., a device "user").

[0015] 1 and 2 illustrate an exemplary environment 100 for determining the location and / or intent of a user holding, carrying, wearing, or carrying a UWB-enabled device. In the examples of FIGS. 1 and 2, the environment 100 is, or is part of, an access control system (ACS). While FIGS. 1 and 2 primarily depict a PACS, it will be appreciated that the present disclosure similarly relates to a logical access control system (LACS) or any other environment in which it is desirable to determine the location and / or intent of a user. The environment 100 may include a reader device, or simply a reader 102, associated with a secure area, access point, or other asset 104. In some examples, as in the examples shown in FIGS. 1 and 2, the secure asset 104 is a secure area secured by an access point 105, such as a door, gate, turnstile, or the like, that controls or allows authorized access to the secure area, although the secure asset 104 may alternatively be a logical asset. The reader 102 may include or be operatively connected to a control mechanism 106, such as, but not limited to, a locking mechanism in the case of a PACS or an electronic / software control mechanism in the case of a LACS, that controls whether access is granted (e.g., opened or accessible) via the access point 106, or alternatively, may control the opening and / or closing of the access point. The reader 102 may be an offline reader, e.g., a reader not connected to a control panel or host server, in which case the reader may make access control decisions and directly operate or command the control mechanism 106. The reader 102 may be a wireless reader device in that it may communicate with a credential or key device via wireless technologies such as IEEE 802.15.1, Bluetooth, Bluetooth Low Energy (BLE), Near Field Communication (NFC), ZigBee, GSM, CDMA, Wi-Fi, UWB, or other RFID or PAN technologies.Reader 102 may also include a PIN pad, touch screen, fingerprint reader, magnetic stripe reader, chip reader, or other non-wireless input means for receiving credential or other information, such as a PIN or other secret code, biometric information such as a fingerprint, or information from a magnetic stripe or chip card. Reader 102 may also include facial recognition capabilities.

[0016] In some examples, the reader 102 can be wired or wirelessly connected to the control panel 108. In such cases, the reader 102 transmits credential information to the control panel 108, and the control panel can make the access control decision or share responsibility with the reader in making the access control decision. Based on the access control decision, the control panel 108 can appropriately instruct the reader 102 to operate or command the control mechanism 106. Alternatively, the control panel 108 can be directly or wirelessly connected to the control mechanism 106, and in such cases can bypass the reader 102 and directly operate or command the control mechanism as appropriate.

[0017] In some examples, the reader 102 and control panel 108, as well as the control mechanism 106, may be connected to a wired or wireless network 110 and communicate with each other via the network, as described above. Exemplary networks may include a local area network (LAN), a wide area network (WAN), a packet data network (e.g., the Internet), a mobile telephone network (e.g., a cellular network), a plain old telephone (POTS) network, a wireless data network (e.g., a network based on the IEEE 802.11 family of standards known as Wi-Fi or the IEEE 802.16 family of standards known as WiMax), a network based on the IEEE 802.15.4 family of standards, and a peer-to-peer (P2P) network. If the environment 100 is managed by a remote system, the environment may include a host server 112 that is connected to the network 110 via a wired or wireless connection and that may communicate with the reader 102 and / or the control panel 108. In such cases, the reader 102 can transmit the credential information to the host server 112 over the network 110 or to the control panel 108, which then transmits the credential information to the host server over the network. The host server 112 may be responsible for the access control decision or may share responsibility with the reader 102 and / or the control panel 108 in making the access control decision. Based on the access control decision, the host server 112 can appropriately instruct the reader 102 to operate or command the control mechanism 106, either directly or indirectly via the control panel 108. Alternatively, the host server 112 can appropriately command the control panel 108 to operate or command the control mechanism 106. In yet another example, the host server 112 can be connected to the control mechanism 106 over the network 110 and operate or command the control mechanism 106 directly, thus bypassing the reader 102 and the control panel 108.

[0018] In use, a user 114 with a credential device or key device 116 (e.g., shown as a smart card 116a or a mobile device 116b) approaches a reader 102 associated with an access point 105. The credential device 116 may communicate the user's credentials or credential data to the reader 102, for example, via appropriate RFID or PAN technology. Generally, the credential device 116 may include any device that holds evidence of the credential device's holder's entitlement to authority, status, rights, and / or privileges. The credential device 116 may be a portable device having a memory 118 that stores one or more user credentials or credential data, and a reader interface (i.e., an antenna and integrated circuit (IC) chip) 120 that enables the credential device to exchange data with a reader device, such as the reader 102, via the reader device's credential interface, such as an antenna. One example of a credential device 116 is an RFID smart card (e.g., smart card 116a) that stores data that allows the holder of the credential device to access a secured area or asset protected by reader 102, such as secured area 104. Other examples of credential devices 116 include, but are not limited to, proximity RFID-based cards, access control cards, credit cards, debit cards, passports, identification cards, key fobs, NFC-enabled devices, mobile phones (e.g., mobile device 116b), personal digital assistants (PDAs), tags, or any device configurable to emulate a virtual credential. If reader 102, control panel 108, and / or host server 112 determine that the user 114's credentials or credential data provided by credential device 116 are valid and / or authorized, reader 102, control panel 108, or host server 112 may operate control mechanism 106 to grant access to secured asset 104 by user 114 with the credential device.

[0019] 3 shows a schematic block diagram of various components of an exemplary reader 102. Generally, the reader 102 may include one or more of a memory 302, a processor 304, one or more antennas 306, a communication module 308, a network interface device 310, a user interface 312, and a power source or power supply 314. While the reader 102 is shown in FIG. 1 as a surface-mounted device, such as, for example, a wall, the reader 102 may be, but is not limited to, a freestanding device or a portable device, such as a mobile device.

[0020] Memory 302 may be used for temporary or long-term storage of program instructions or instruction sets 316 in connection with execution of application programming or instructions by processor 304, and / or credential or authorization data 318 (e.g., credential data, credential authorization data), access control data or instructions, or instructions for determining the location and / or intent of a user holding, carrying, wearing, or incorporating a UWB-enabled device, as described herein. For example, memory 302 may include executable instructions 316 used by processor 304 to operate other components of reader 102 and / or to determine the user's location and / or intent and make access decisions based on credential or authorization data 318, as described herein. Memory 302 may include computer-readable media, which may be any medium capable of containing, storing, transmitting, or transferring data, program code, or instructions for use by or in connection with reader 102. A computer-readable medium may be, for example, but not limited to, an electronic, magnetic, optical, electromagnetic, infrared, or semiconductor system, apparatus, or device. More specific examples of suitable computer-readable media include, but are not limited to, an electrical connection having one or more wires, or a tangible storage medium such as a portable computer diskette, a hard disk, a random access memory (RAM), a read-only memory (ROM), an erasable programmable read-only memory (EPROM or EEPROM), a dynamic RAM (DRAM), any solid-state storage device, generally a compact disc read-only memory (CD-ROM), or other optical or magnetic storage device. Computer-readable media should not be confused with, but includes, computer-readable storage media, which is intended to cover all physical, non-transitory, or similar embodiments of computer-readable media.

[0021] Processor 304 may correspond to one or more computer processing devices or resources. For example, processor 304 may be provided as silicon, a field programmable gate array (FPGA), an application specific integrated circuit (ASIC), any other type of integrated circuit (IC) chip, a collection of IC chips, etc. As a more specific example, processor 304 may be provided as a microprocessor, a central processing unit (CPU), or multiple microprocessors or CPUs configured to execute a set of instructions stored in internal memory 320 and / or memory 302.

[0022] The antenna 306 may correspond to one or more antennas and may be configured to provide, for example, wireless communication between the reader 102 and a credential or key device or other device. The one or more antennas 306 may be configured to operate using one or more wireless communication protocols and operating frequencies, including, but not limited to, IEEE 802.15.1, Bluetooth, Bluetooth Low Energy (BLE), Near Field Communication (NFC), ZigBee, GSM, CDMA, Wi-Fi, RF, UWB, and the like. By way of example, the one or more antennas 306 may be one or more RF antennas and thus may transmit / receive RF signals over free space to be received / transmitted by a credential or key device having an RF transceiver. In examples of the present disclosure generally relating to improved methods and systems for determining the location and / or intent of a user (or device) holding, carrying, wearing, or carrying a UWB-enabled device, antenna 306 may include at least one or more UWB sensors, such as one or more UWB transmitters, UWB receivers, or UWB transceivers, one or more UWB antenna pairs, and / or a UWB antenna array.

[0023] The communications module 308 can be configured to communicate with one or more different systems or devices, either remote or local to the reader 102, such as one or more controls 106 or control panels 108, according to any suitable communications protocol.

[0024] The network interface device 310 includes hardware for enabling communication with other devices, such as the control panel 108 or the host server 112, over a communications network, such as the network 110, utilizing any one of several transport protocols (e.g., frame relay, internet protocol (IP), transmission control protocol (TCP), user datagram protocol (UDP), hypertext transfer protocol (HTTP), etc.). Exemplary communications networks include a local area network (LAN), a wide area network (WAN), a packet data network (e.g., the Internet), a mobile telephone network (e.g., a cellular network), a plain old telephone (POTS) network, a wireless data network (e.g., a network based on the IEEE 802.11 family of standards known as Wi-Fi or the IEEE 802.16 family of standards known as WiMax), a network based on the IEEE 802.15.4 family of standards, and a peer-to-peer (P2P) network. In some examples, the network interface device 310 may include an Ethernet port or other physical jack, a Wi-Fi card, a network interface card (NIC), a cellular interface (e.g., antennas, filters, and associated circuitry), etc. In some examples, the network interface device 310 may include one or more antennas for wireless communication using, for example, at least one of single-input multiple-output (SIMO) techniques, multiple-input multiple-output (MIMO) techniques, or multiple-input single-output (MISO) techniques.

[0025] User interface 312 may include one or more input devices and / or display devices. Examples of suitable user input devices that may be included in user interface 312 include, but are not limited to, one or more buttons, a keyboard, a mouse, a touch-sensitive surface, a stylus, a camera, a microphone, a PIN pad, a touch screen, a fingerprint reader, a magnetic stripe reader, a chip reader, etc. Examples of suitable user output devices that may be included in user interface 312 include, but are not limited to, one or more LEDs, an LCD panel, a display screen, a touch screen, one or more lights, a speaker, etc. It should also be understood that user interface 312 may include combined user input and user output devices, such as a touch-sensitive display, etc.

[0026] The power supply 314 may be any suitable internal power source, such as a battery, a capacitive power source, or a similar type of charge storage device, and / or may include one or more power conversion circuits suitable for converting external power into power suitable for the components of the reader 102 (e.g., converting externally supplied AC power to DC power). The power supply 314 may also include some implementations of surge protection circuitry for protecting the components of the reader 102 from power surges.

[0027] The reader 102 may also include one or more interlinks or buses 322 operable to transmit communications between the various hardware components of the reader. The system bus 322 may be any of several types of commercially available bus structures or bus architectures.

[0028] Although various exemplary components of the reader 102 are described and illustrated, not all components are required in each reader described herein, and the readers described herein are not limited to including only the exemplary components described and illustrated herein. For example, any of the readers 102 described herein may include different sets and / or combinations of the exemplary components described and illustrated herein.

[0029] FIG. 4 shows a schematic block diagram of various example components of an example machine 400 that may be used, for example, as a control panel 108, a host server 112, a credential device 116, and / or a UWB-enabled device according to the present disclosure. The example may generally include or operate by a logical component or multiple components, modules, or mechanisms within the machine 400, as described herein. A module may be hardware, software, or firmware communicatively coupled to one or more processors to perform the operations described herein. Generally, the circuitry (e.g., processing circuitry) of the example machine 400 may include a collection of circuits embodied in tangible entities of the machine 400, including hardware (e.g., simple circuits, gates, logic, etc.). Elements of the circuitry may flexibly change over time. The circuitry includes components that, when operational, can perform specified operations, either alone or in combination. In some examples, the hardware of the circuitry may be invariably designed (e.g., hardwired, etc.) to perform specific operations. In some examples, the hardware of a circuit configuration may include variable-connection physical components (e.g., execution units, transistors, simple circuits, etc.) that include machine-readable media that have been physically modified (e.g., magnetically, electrically, movable arrangements of immutable mass particles, etc.) to encode instructions for a particular operation. When connecting the physical components, the underlying electrical properties of the hardware configuration change, for example, from an insulator to a conductor (or vice versa). The instructions allow the embedded hardware (e.g., execution units or loading mechanisms) to create elements of the circuit configuration within the hardware through the variable connections to perform some of the particular operations when in operation. Thus, in some examples, the machine-readable media elements are part of the circuit configuration or are communicatively connected to other components of the circuit configuration when the device is in operation. In some examples, any one of the physical components may be used in more than one element of two or more circuit configurations.For example, during operation, an execution unit may be used in a first circuit of a first circuit configuration at one time and reused by a second circuit of the first circuit configuration, or used by a third circuit of the second circuit configuration at a different time. Additional and / or more specific examples of components related to machine 400 are provided below.

[0030] In some embodiments, machine 400 can operate as a standalone device or can be connected (e.g., networked) to other machines. In a networked configuration, machine 400 can operate as a server machine, a client machine, or both in a server-client network environment. In some examples, machine 400 can operate as a peer machine in a peer-to-peer (P2P) (or other distributed) network environment. Machine 400 can be or include a personal computer (PC), tablet PC, set-top box (STB), personal digital assistant (PDA), mobile phone, web appliance, network router, switch, or bridge, or any machine capable of executing instructions (sequential or otherwise) that specify operations to be performed by that machine. Furthermore, although only a single machine is shown, the term “machine” should also be interpreted to include any collection of machines individually or collectively executing a set (or sets) of instructions to perform any one or more of the methodologies described herein, such as cloud computing, software as a service (SaaS), other computer cluster configurations, etc.

[0031] The machine (e.g., a computer system) 400 may include a hardware processor 402 (e.g., a central processing unit (CPU), a graphics processing unit (GPU), a hardware processor core, or any combination thereof), a main memory 404, a static memory 406 (e.g., memory or storage for firmware, microcode, basic input / output system (BIOS), unified extensible firmware interface (UEFI), etc.), and / or mass storage 408 (e.g., a hard drive, tape drive, flash storage, or other block device), some or all of which may communicate with each other via an interlink (e.g., a bus) 434. The machine 400 may further include a display device 410, an input device 412, and / or a user interface (UI) navigation device 414. Examples of suitable display devices include, but are not limited to, one or more LEDs, an LCD panel, a display screen, a touch screen, one or more lights, etc. Exemplary input devices and UI navigation devices include, but are not limited to, one or more buttons, a keyboard, a touch-sensitive surface, a stylus, a camera, a microphone, etc. In some examples, one or more of the display device 410, input device 412, and / or UI navigation device 414 may be a combined unit, such as a touchscreen display. The machine 400 may further include a signal generation device 418 (e.g., a speaker), a network interface device 420, one or more antennas 430, a power source 432, one or more sensors 416, such as a global positioning system (GPS) sensor, a compass, an accelerometer, or other sensors. The machine 400 may include an output controller 428, such as a serial (e.g., universal serial bus (USB)), parallel, or other wired or wireless (e.g., infrared (IR), NFC, etc.) connection, to communicate with or control one or more peripheral devices (e.g., a printer, a card reader, etc.).

[0032] Processor 402 may correspond to one or more computer processing devices or resources. For example, processor 402 may be provided as silicon, as a field programmable gate array (FPGA), an application specific integrated circuit (ASIC), any other type of integrated circuit (IC) chip, a collection of IC chips, etc. As a more specific example, processor 402 may be provided as a microprocessor, a central processing unit (CPU), or multiple microprocessors or CPUs configured to execute a set of instructions stored in internal memory 422 and / or memories 404, 406, 408.

[0033] Any of memories 404, 406, and 408 can be used for temporary or long-term storage of program instructions or instruction sets 424 and / or other data for performing any of the functions or methods described herein, such as for determining the location and / or intent of a user holding, carrying, wearing, or mounting a UWB-enabled device as described herein, in connection with the execution of application programming or instructions by processor 402 to perform any of the functions or methods described herein. Any of memories 404, 406, 408 can comprise computer-readable media, which can be any medium that can contain, store, convey, or transfer data, program code, or instructions 424 for use by or in connection with machine 400. A computer-readable medium can be, for example, but not limited to, an electronic, magnetic, optical, electromagnetic, infrared, or semiconductor system, apparatus, or device. More specific examples of suitable computer-readable media include, but are not limited to, an electrical connection having one or more wires, or a tangible storage medium such as a portable computer diskette, a hard disk, a random access memory (RAM), a read-only memory (ROM), an erasable programmable read-only memory (EPROM or EEPROM), a dynamic RAM (DRAM), a solid-state storage device, generally a compact disc read-only memory (CD-ROM), or other optical or magnetic storage device. As noted above, computer-readable media includes, but is not to be confused with, computer-readable storage media, which is intended to encompass all physical, non-transitory, or similar embodiments of computer-readable media.

[0034] The network interface device 420 includes hardware for enabling communication with other devices over a network 426, such as the communications network 110, utilizing any one of several transport protocols (e.g., frame relay, Internet Protocol (IP), Transmission Control Protocol (TCP), User Datagram Protocol (UDP), Hypertext Transfer Protocol (HTTP), etc.). Exemplary communications networks may include a local area network (LAN), a wide area network (WAN), a packet data network (e.g., the Internet), a mobile telephone network (e.g., a cellular network), a plain old telephone (POTS) network, a wireless data network (e.g., a network based on the IEEE 802.11 family of standards known as Wi-Fi or the IEEE 802.16 family of standards known as WiMax), a network based on the IEEE 802.15.4 family of standards, and a peer-to-peer (P2P) network. In some examples, the network interface device 420 may include an Ethernet port or other physical jack, a Wi-Fi card, a network interface card (NIC), a cellular interface (e.g., an antenna, filters, and associated circuitry), etc. In some examples, the network interface device 420 may include one or more antennas for wireless communication using, for example, at least one of single-input multiple-output (SIMO), multiple-input multiple-output (MIMO), or multiple-input single-output (MISO) techniques.

[0035] Antenna 430 may correspond to one or more antennas and may be configured to provide wireless communication between machine 400 and another device. One or more antennas 430 may be configured to operate using one or more wireless communication protocols and operating frequencies, including, but not limited to, IEEE 802.15.1, Bluetooth, Bluetooth Low Energy (BLE), Near Field Communication (NFC), ZigBee, GSM, CDMA, Wi-Fi, RF, UWB, and the like. By way of example, one or more antennas 430 may be one or more RF antennas and thus may transmit / receive RF signals over free space to be received / transmitted by another device having an RF transceiver. In examples of the present disclosure generally relating to improved methods and systems for determining the location and / or intent of a user (or device) holding, carrying, wearing, or carrying a UWB-enabled device, the antenna 430 of some machines 400, such as a credential device 116 or UWB-enabled device according to the present disclosure, may include at least one or more UWB sensors, such as one or more UWB transmitters, receivers, or transceivers, one or more UWB antenna pairs, and / or a UWB antenna array.

[0036] Power supply 432 may be any suitable internal power source, such as a battery, a capacitive power source, or similar type of charge storage device, and / or may include one or more power conversion circuits suitable for converting external power to power suitable for the components of machine 400 (e.g., converting externally supplied AC power to DC power). Power supply 432 may also include some implementations of surge protection circuitry for protecting the components of machine 400 from power surges.

[0037] As mentioned above, machine 400 may include one or more interlinks or buses 434 operable to transmit communications between various hardware components of the machine. The system bus 434 may be any of several types of commercially available bus structures or bus architectures.

[0038] Although various exemplary components of the exemplary machine 400 are described and illustrated, not all components are required in each machine or device described herein, and the machines or devices described herein are not limited to including only the exemplary components described and illustrated herein. For example, any of the various devices described herein, such as the control panel 108, host server 112, credential device 116, and / or UWB-enabled device according to the present disclosure, may include different sets and / or combinations of the exemplary components described and illustrated herein.

[0039] For ease of explanation, FIG. 5 shows an expanded view 500 of exemplary environment 100, with some elements removed for better illustration. Environment 500 includes reader 102, secured asset 104 secured by access point 105, and control mechanism 106. In some examples, secured asset 104 and access point 105 may be the same. A user 114 (or device) within or entering environment 500 may hold or carry a device, such as credential device 116 or other portable device, having one or more UWB sensors. While described herein primarily with reference to a “credential” device, it should be understood that in some examples, user 114 (or device) may hold or carry any UWB-enabled device, the same or different from the credential device, for use in methods and systems for determining the location and / or intent of a user (or device) holding, carrying, wearing, or incorporating a UWB-enabled device, as described herein. 5 also shows one or more distinct reference approaches or paths 502, 504, 506, 508, 510, 512 to the access point 105. The approaches or paths may comprise paths of any suitable distance preceded, and in some cases immediately preceded by, the access point 105. The reference approaches / paths 502, 504, 506, 508, 510, 512 are provided only as illustrative examples, and any environment, such as the environment 500, may include more, fewer, or different reference approaches / paths than those shown.

[0040] 6 is a flowchart that schematically illustrates an exemplary method of collecting 602 one or more reference temporal signatures associated with access points 105 and / or readers 102 in an environment, such as exemplary environment 100, 500, based on one or more reference approaches / paths 502, 504, 506, 508, 510, 512, or portion(s) thereof, for subsequent use in a method of determining a user's location and / or intent (e.g., intent to access access point 105), as described in further detail herein. Collecting one or more reference temporal signatures associated with access points 105 and / or readers 102 may be referred to as calibrating access points 105 and / or readers 102.

[0041] In one example of collecting one or more reference temporal signatures, referred to as guided collection of reference temporal signatures, in step 604, for each of one or more of the reference approaches / paths 502, 504, 506, 508, 510, 512, the device 116 is transported between a determined first point (e.g., a start point) of the reference approach / path, such as point 514 of the approach / path 502, and a determined second point (e.g., an end point) of the reference approach / path, such as point 516 of the approach / path 502. In some examples, the device 116 may alternatively or additionally be transported between the determined second point of the reference approach / path and the determined first point of the reference approach / path. In some examples, the first point may be a point along the reference approach / path that is farthest from the access point 105 and / or reader 102, and the second point may be a point along the reference approach / path that is closest to the access point and / or reader. Alternatively, the first point may be a point along the reference approach / route closest to the access point 105 and / or reader 102, and the second point may be a point along the reference approach / route farthest from the access point and / or reader.

[0042] While device 116 is being carried, such as by user 114, between the first and second points and / or the second and first points of a given reference approach / path, such as between first point 514 and second point 516 of approach / path 502, the device may monitor and / or record a temporal sequence of one or more UWB readings or signals transmitted to or from reader 102 or between the device and the reader corresponding to the reference approach / path. The UWB readings or signals may be monitored and / or recorded at any suitable intervals, such as substantially continuously, periodically, randomly, or according to any other repeating or non-repeating pattern or algorithm.

[0043] In step 606, one or more UWB measurements or UWB calculations corresponding to one or more points along a reference approach / path, such as reference approach / path 502, may be determined based on the monitored and / or recorded UWB readings or UWB signals. The one or more UWB measurements corresponding to any given interval point along the reference approach / path may include any type of measurement based on UWB readings or UWB signals, such as, but not limited to, radial distance (D), angle of arrival (AoA), signal-to-noise ratio (SNR), and / or line-of-sight (LoS) measurements. In one example, the UWB measurements corresponding to any given interval point along the reference approach / path may include only a single type of UWB measurement, such as one of radial distance (D), angle of arrival (AoA), signal-to-noise ratio (SNR), or line-of-sight (LoS) measurements, while in other examples, the UWB measurements corresponding to any given interval point along the reference approach / path may include two or more types of UWB measurements, such as two or more of radial distance (D), angle of arrival (AoA), signal-to-noise ratio (SNR), or line-of-sight (LoS) measurements. In particular examples, the UWB measurements corresponding to any given interval point along the reference approach / path include a pair of radial distance (D) and angle of arrival (AoA) or other mathematical combinations thereof. In some examples, the UWB measurements corresponding to a given interval point along the reference approach / path additionally include SNR and / or LoS measurements, or are mathematical combinations of SNR and / or LoS measurements. UWB measurements may be determined for points along the reference approach / path at any suitable intervals, such as substantially continuously, periodically, randomly, or according to any other repeating or non-repeating pattern or algorithm. UWB measurements need not be determined for or based on all UWB readings or signals monitored and / or recorded in step 604, but may be determined for or based in part on a portion of the UWB readings or signals.

[0044] In step 608, one or more UWB measurements determined along at least a portion of a reference approach / path, such as reference approach / path 502, may be stored as a reference time signature for that reference approach / path. In some examples, if the UWB measurements determined at each interval along the reference approach / path consist of two or more UWB measurements, such as a radial distance (D) and an angle of arrival (AoA), the two or more UWB measurements for each interval point may be concatenated or combined in any manner, such as using any ordering algorithm or mathematical combination. Such a concatenated or combined set of UWB measurements for at least a portion of one or more interval points along the reference approach / path may be stored as a reference time signature for the reference approach / path. In some examples, one or more UWB measurements determined along at least a portion of a reference approach / path, such as reference approach / path 502, may be further processed according to any suitable algorithm or method, the output of which may alternatively or additionally be stored as a reference time signature for that reference approach / path. In a further example, the reference time signature may include a "reference path signature" or may be combined in any suitable manner with a "reference path signature," or may include or may be combined in any suitable manner with information used to determine a "reference path signature" or any information on which a "reference path signature" is based, as described in PCT International Application No. PCT / US2021 / 071497, entitled "Location Recognition Using Inertial Measurement Unit," filed September 17, 2021, which is incorporated by reference herein in its entirety.For example, readings or signals from an inertial measurement unit (IMU), such as an accelerometer, gyroscope, and / or magnetometer, or information based on such signals or readings, can be concatenated or combined with one or more UWB measurements using any sequencing algorithm or mathematical combination to provide additional velocity and / or orientation information that can serve as a reference time signature and / or can also be used to determine intent.

[0045] In some examples, collecting reference time signatures for one or more reference approaches / paths (e.g., 502, 504, 506, 508, 510, 512) to an access point 105 and / or reader 102 may be completed collectively by multiple users 114 and / or using multiple devices 116. Similarly, collecting reference time signatures for one or more reference approaches / paths to each of multiple access points and / or readers in a given environment may be completed collectively by multiple users 114 and / or using multiple devices 116. Each reference time signature may be stored with an identifier and label associating the reference time signature with a given access point 105 and / or reader 102. The reference time signatures may be stored with any other suitable information. For example, the reference time signature may be stored along with data indicating whether the reference time signature relates to a reference approach / route on a secured side or an unsecured side of the access point 105 and / or reader 102.

[0046] In some examples, software or applications (or “apps”) running on device 116 or other UWB-enabled devices can guide user 114 through calibration of environment 500 (i.e., through collection of reference time signatures). For example, such apps may guide user 114 to traverse a typical path starting near access point 105 and / or reader 102, moving away from the access point / reader (toward either the secured or unsecured side), and then returning to the access point / reader. The speed at which user 114 moves and / or the distance the user traverses can be monitored, for example, by device 116, and appropriate prompts can be provided to the user, if desired, such as via, but not limited to, prompts instructing the user to go slower / faster, move farther away from the reader, return to the reader, etc. The velocity information for the user may be, but need not be, based on UWB readings or signals, for example, may additionally or alternatively be based on readings or signals from one or more IMU sensors on the device 116 (or other UWB-enabled device), such as an accelerometer and / or gyroscope. Such a guidance process may be repeated for several routes, such as the most common route, for both the secured and unsecured sides of the access point 105 and / or reader 102.

[0047] Steps 604-608 of the example method of FIG. 6 may be performed by and / or are described as being performed by the device 116. However, in other examples, some, or a portion of all, of steps 604-608 of the example method of FIG. 6 may be performed by the reader 102 or a combination of the device 116 and the reader 102. For example, and not limited by such example, steps 606 and 608 may instead be performed by the reader 102 or a combination of the device 116 and the reader 102. Also, for example, the reference time signature may instead be stored in the reader 102, or both the device 116 and the reader 102, or a combination thereof. In yet another example, some, or a portion of the steps, of steps 604-608 may be performed by the control panel 108 and / or the host server 112, and / or the reference time signature may be stored in the control panel 108 and / or the host server 112.

[0048] In another example, collecting one or more reference temporal signatures may be performed during a training or learning period and may be referred to as training-type collection or learning-type collection of reference temporal signatures. For example, in step 610, a training period for the reader 102 may be initiated. In one example, during the training period, the reader may be in a UWB listen-only mode, in which access control decisions regarding the access point 105 are not based on UWB location sensing signals, and UWB signals are used solely or primarily to calibrate the access point and / or the reader. The training period may be initiated, for example, upon installation or startup of the reader 102. However, the training period may be initiated at any suitable time, such as, but not limited to, upon a reader 102 update, pursuant to an instruction received at the reader to initiate the training period, or the like. In several examples, the training period may be a predetermined length of time, such as, but not limited to, several hours, days, or weeks. In some examples, the training period may be extended indefinitely or until an end trigger-event occurs. The termination trigger event may include, but is not limited to, the reader 102 receiving an instruction to end the training period, reaching a certain or predetermined number of reference time signatures, reaching a reader limitation such as a certain memory capacity, etc. During the training period, a user may use one or more conventional methods to access (e.g., pass through) the access point 105, such as, but not limited to, entering credential data (e.g., PIN, biometric data, etc.) using a keypad or other interface of the reader 102 and / or manually activating the access point using the credential device 116, such as via an app on the credential device.Once the training period is over, the reader 102 may switch to a normal operating mode in which, in addition to or as an alternative to conventional methods for accessing the access point 105, various methods may be used to determine the location and / or intent of a user (or device) based on UWB readings or signals transmitted by, received by, or communicated with a UWB-enabled device held, carried, worn, or carried by the user (or device), as described herein.

[0049] In step 612, during a training period, while the device 116 is carried within UWB range of the reader 102 throughout the environment 100, 500, such as by the user 114, the reader may monitor or record transient UWB readings or signals transmitted to or from the reader 102, or between the device 116 and the reader. The UWB readings or signals may be monitored and / or recorded at any suitable intervals, such as substantially continuously, periodically, randomly, or according to any other repeating or non-repeating pattern or algorithm.

[0050] In step 614, one or more UWB measurements or UWB calculations may be determined based on the monitored and / or recorded UWB readings or UWB signals. As indicated above, the one or more UWB measurements may include any type of measurement based on the UWB readings or UWB signals, such as, but not limited to, a radial distance (D), an angle of arrival (AoA), a signal-to-noise ratio (SNR), and / or a line-of-sight (LoS) measurement. In one example, the UWB measurements may include only a single type of UWB measurement, such as one of the radial distance (D), angle of arrival (AoA), signal-to-noise ratio (SNR), or line-of-sight (LoS) measurements, while in other examples, the UWB measurements may include two or more types of UWB measurements, such as two or more of the radial distance (D), angle of arrival (AoA), signal-to-noise ratio (SNR), or line-of-sight (LoS) measurements. In particular examples, the UWB measurements include pairs of radial distance (D) and angle of arrival (AoA), or other mathematical combinations thereof. In some examples, the UWB measurements additionally include or are mathematically combined with SNR and / or LoS measurements. The UWB measurements may be determined at any suitable interval of the UWB readings or UWB signals, such as substantially continuously, periodically, randomly, or according to any other repeating or non-repeating pattern or algorithm. The UWB measurements need not be determined for or based on all UWB readings or UWB signals monitored and / or recorded in step 612, but may be determined for or based in part on a portion of the UWB readings or UWB signals.

[0051] In step 616, upon detection of an access event (e.g., access through the access point) to the access point 105, such as access based on one or more conventional access methods, the reader 102 may store at least a portion of one or more UWB measurements preceding the access event as a reference temporal signature corresponding to the access point and / or the reader. Any portion or sub-portion of the one or more UWB measurements preceding the access event may be stored as a reference temporal signature, although it is not required that all consecutive UWB measurements corresponding to such portion or sub-portion be included as part of the stored reference temporal signature. As mentioned above, in some examples, if the UWB measurements determined in each interval consist of two or more UWB measurements, such as a radial distance (D) and an angle of arrival (AoA), the two or more UWB measurements in each interval may be concatenated or combined in any manner, such as using any ordering algorithm or mathematical combination. Such a concatenated or combined set of UWB measurements for at least a portion of the interval may be stored as a reference temporal signature. In some examples, at least a portion of the one or more UWB measurements preceding the access event may be further processed according to any suitable algorithm or method, the output of which may alternatively or additionally be stored as a reference time signature. In yet another example, as described above, the reference time signature may include or be combined with a “reference path signature,” or may include or be combined in any suitable manner with information used to determine or any information on which a “reference path signature” is based, as described in PCT International Application No. PCT / US2021 / 071497, previously incorporated by reference, entitled “Location Recognition Using Inertial Measurement Unit.”For example, readings or signals from an IMU, such as from an accelerometer, gyroscope, and / or magnetometer, or information based on such signals or readings, can be concatenated or combined with one or more UWB measurements using any sequencing algorithm or mathematical combination to provide additional speed and / or orientation information that can serve as a reference temporal signature and / or also be used to determine intent. Step 616 can be repeated or performed for multiple access events, or in some examples, for each access event, during a training period, thereby collecting multiple reference temporal signatures.

[0052] Similar to the guided collection of reference time signatures, in the trained or learned collection of reference time signatures, the collection of reference time signatures for an access point 105 and / or reader 102 may be completed collectively by multiple users 114 and / or using multiple devices 116. Similarly, the collection of reference time signatures for each of multiple access points and / or multiple readers in a given environment may be completed collectively by multiple users 114 and / or using multiple devices 116. Each reference time signature may be stored with an identifier and label associating the reference time signature with a given access point 105 and / or reader 102. The reference time signature may be stored with any other suitable information. For example, the reference time signature may be stored with data indicating whether the reference time signature relates to a reference approach / path on a secured side or an unsecured side of the access point 105 and / or reader 102. Classifying a reference time signature as being on the secure or unsecured side of the access point 105 and / or reader 102 may be determined at least in part from the type of access event. For example, an access event that requires credential authentication (e.g., entering a room) may indicate that the reference time signature is on the unsecured side of the access point 105 and / or reader 102, and an access event that does not involve credential authentication (e.g., leaving a room) may indicate that the reference time signature is on the secure side of the access point and / or reader.

[0053] In some examples, steps 614 and 616, or portions thereof, may be performed substantially simultaneously, or at least a portion of step 616 may be performed before step 614. For example, an access event for the access point 105 may be detected before determining one or more UWB measurements based on monitored and / or recorded UWB readings or UWB signals. Waiting until the detection of an access event before determining any UWB measurements based on monitored and / or recorded UWB readings or UWB signals may conserve processing power of the reader 102, for example, by deferring the determination of any UWB measurements until such UWB measurements are actually desired or needed.

[0054] Steps 610-616 of the example method of FIG. 6 may be performed by and / or are described as being performed by the reader 102. However, in other examples, some, or a portion of all, of steps 610-616 of the example method of FIG. 6 may be performed by the device 116 or a combination of the reader 102 and the device 116. For example, and not limited by such example, steps 612 and 614 may instead be performed by the device 116 or a combination of the reader 102 and the device 116. Also, for example, the reference time signature may instead be stored on the device 116, or on both the reader 102 and the device 116, or a combination thereof. In yet another example, some, or a portion of the steps, of steps 610-616 may be performed by the control panel 108 and / or the host server 112, and / or the reference time signature may be stored on the control panel 108 and / or the host server 112.

[0055] In a further example of collecting one or more reference time signatures, which is similar to the trained collection of reference time signatures, the reference time signatures may generally be collected at any time after installation of the reader 102 and may be added as additional reference time signatures or may replace previously stored reference time signatures corresponding to the access point 105 and / or the reader. Such a method may be referred to as on-the-fly collection of reference time signatures. Such an on-the-fly method may include steps similar to steps 612 and 614. However, such steps need not be performed during a training period as described above. Rather, steps 612 and 614 may occur at any time in accordance with the on-the-fly collection of reference time signatures. The on-the-fly collection of reference time signatures may include steps similar to step 616. Specifically, upon detection of an access event to an access point 105 (e.g., access through the access point), the reader 102 may store at least a portion of one or more UWB measurements preceding the access event as a reference temporal signature corresponding to the access point and / or reader. As indicated above, the reference temporal signature may be stored as an additional reference temporal signature corresponding to the access point 105 and / or reader 102, or may replace a previously stored reference temporal signature corresponding to the access point and / or reader. As described with respect to step 616, any portion or subportion of one or more UWB measurements preceding the access event may be stored as a reference temporal signature, although it is not required that all consecutive UWB measurements corresponding to such portion or subportion be included as part of the stored reference temporal signature. In some examples, when the UWB measurements determined at each interval consist of two or more UWB measurements, such as a radial distance (D) and an angle of arrival (AoA), the two or more UWB measurements at each interval may be concatenated or combined in any manner, such as using any ordering algorithm or mathematical combination.Such a concatenated or combined set of UWB measurements for at least a portion of the interval may be stored as a reference time signature. In some examples, at least a portion of the one or more UWB measurements preceding the access event may be further processed according to any suitable algorithm or method, the output of which may alternatively or additionally be stored as a reference time signature. Again, in some examples, the reference time signature may include or be combined with a “reference path signature,” or may further include or be combined in any suitable manner with information used to determine or on which the “reference path signature” is based, as described in PCT International Application No. PCT / US2021 / 071497. Each reference time signature may be stored with an identifier and label associating the reference time signature with a given access point 105 and / or reader 102. As mentioned above, the reference time signature may be stored with any other suitable information. For example, the reference time signature may be stored with data indicating whether the reference time signature relates to a reference approach / path on a secure side or an unsecured side of the access point 105 and / or reader 102. As mentioned above, the classification of the reference time signature as being on a secure or unsecured side of the access point 105 and / or reader 102 may be determined at least in part from the type of access event.

[0056] As an example, on-the-fly collection of a reference time signature may be desirable if UWB-based location and / or intent detection for a particular user fails and the user has to use a backup method of accessing the access point 105, such as, but not limited to, entering credential data (e.g., a PIN, biometric data, etc.) using a keypad or other interface of the reader 102 and / or manually activating the access point using the credential device 116, such as via an app on the credential device. Subsequent access by the user may indicate that the approach / route just taken by the user to the access point 105 does, in fact, represent at least one approach / route that could be taken by the user to reach the access point and / or represents the user's intent to access the access point.

[0057] Any of the exemplary methods for collecting one or more reference temporal signatures associated with one or more access points and / or readers in an environment may be used alone or in combination with one another. That is, while any of the aforementioned exemplary methods for collecting one or more reference temporal signatures may be used alone, these methods are not mutually exclusive and may be used in any combination to collect reference temporal signatures in the environment 100, 500. Furthermore, although the flowchart of FIG. 6 depicts the exemplary method as including sequential steps or processes having a particular order of operations, some or many of the steps or operations in the flowchart may be performed in parallel or simultaneously, and the flowchart should be read in the context of various exemplary embodiments of the present disclosure. Similarly, the order of the method steps or process operations depicted in FIG. 6 may be rearranged in some embodiments. Similarly, the method depicted in FIG. 6 may have additional steps or operations not included therein or may have fewer steps or operations than those depicted.

[0058] Once one or more reference temporal signatures for the environment 100, 500 have been collected, the reference temporal signatures may be used to determine the location and / or intent of a user (or device) (such as, but not limited to, intent to access an access point 105) based on UWB readings or signals transmitted by, received by, or communicated to a UWB-enabled device held, carried, worn, or carried by the user (or device). Figure 7 is a flow chart that schematically illustrates an example method 700 for determining the location and / or intent of a user (or device), with reference to the environment 500 of Figure 5. At step 702, a user 114 holding, carrying, or wearing a UWB-enabled device 116 (or carrying a UWB-enabled device 116, in examples where the user 114 is a device) enters the environment 500. The users 114 and / or devices 116 may, but need not, be the same users and / or devices used to calibrate the environment 500, as described above with respect to FIG.

[0059] In step 704, while device 116 is carried throughout environment 500 and within UWB range of reader 102, such as by user 114, the reader and / or device may monitor or record temporal UWB readings or signals transmitted to or from reader 102, or between the device and reader. The UWB readings or signals may be monitored and / or recorded at any suitable intervals, such as substantially continuously, periodically, randomly, or according to any other repeating or non-repeating pattern or algorithm.

[0060] In step 706, one or more UWB measurements or calculations may be determined based on the monitored and / or recorded UWB readings or UWB signals. As indicated above, the one or more UWB measurements may include any type of measurement based on the UWB readings or UWB signals, such as, but not limited to, a radial distance (D), an angle of arrival (AoA), a signal-to-noise ratio (SNR), and / or a line-of-sight (LoS) measurement. In one example, the UWB measurements may include only a single type of UWB measurement, such as one of the radial distance (D), angle of arrival (AoA), signal-to-noise ratio (SNR), or line-of-sight (LoS) measurements, while in other examples, the UWB measurements may include two or more types of UWB measurements, such as two or more of the radial distance (D), angle of arrival (AoA), signal-to-noise ratio (SNR), or line-of-sight (LoS) measurements. In particular examples, the UWB measurements include pairs of radial distance (D) and angle of arrival (AoA), or other mathematical combinations thereof. In some examples, the UWB measurements additionally include or are mathematically combined with SNR and / or LoS measurements. The UWB measurements may be determined at any suitable interval of the UWB readings or UWB signals, such as substantially continuously, periodically, randomly, or according to any other repeating or non-repeating pattern or algorithm. The UWB measurements need not be determined for or based on all UWB readings or UWB signals monitored and / or recorded in step 704, but may be determined for or based in part on a portion of the UWB readings or UWB signals.

[0061] In step 708, at any time t corresponding to the current location of the user 114, at least a portion of the UWB measurements preceding time t can be used as or represent a current time signature for the current approach or path 518 prior to the user's location at time t (e.g., the user's current location 520 represented by the device in the virtual line). In one example, any portion or sub-portion of the UWB measurements preceding time t can be used as or represent a current time signature for the user 114, although it is not required that all consecutive UWB measurements corresponding to such portion or sub-portion be included as part of the current time signature. Similarly, multiple current time signatures for the approach / path 518 prior to the user's current location 520 can be determined or generated from different portions or time periods of UWB measurements preceding time t. As mentioned above, in some examples, when the UWB measurements determined in each interval consist of two or more UWB measurements, such as a radial distance (D) and an angle of arrival (AoA), the two or more UWB measurements in each interval may be concatenated or combined in any manner, such as using any ordering algorithm or mathematical combination. The set of UWB measurements so concatenated or combined for at least a portion of the time preceding time t may be included as a current time signature. In some examples, at least a portion of the UWB measurements preceding time t may be further processed according to any suitable algorithm or method, the output of which may alternatively or additionally be used as or represent a current time signature.Additionally, in some examples, the current time signature may further include or be combined with a “current path signature,” or may further include or be combined in any suitable manner with information used to determine or on which a “current path signature” is based, as described in PCT International Application No. PCT / US2021 / 071497, previously incorporated by reference, entitled “Location Recognition Using Inertial Measurement Units.” For example, readings or signals from an IMU, such as an accelerometer, gyroscope, and / or magnetometer, or information based on such signals or readings, can be concatenated or combined with one or more UWB measurements using any ordering algorithm or mathematical combination to provide additional speed and / or orientation information that may serve as a current time signature and / or also be used to determine intent.

[0062] In step 710, the current temporal signature may be compared or analyzed with one or more reference temporal signatures stored for environment 500 to determine whether the current temporal signature substantially matches, substantially matches, or corresponds to any reference temporal signatures or any portions of the reference temporal signatures. In one example, the current temporal signature may be compared or analyzed with one or more reference temporal signatures or any one or more portions of the reference temporal signatures stored for environment 500 to determine whether the current temporal signature matches or matches any reference temporal signatures or portions thereof within a predefined or predetermined tolerance. Determining whether the current temporal signature substantially matches, substantially matches, or corresponds to a reference temporal signature or portion thereof may be performed using any suitable method(s), algorithm(s), or combination thereof. For example, determining whether the current temporal signature substantially matches, substantially aligns with, or corresponds to a reference temporal signature or portion thereof may be performed using one or more methods or algorithms such as decision tree(s) or ensemble(s) of decision trees, neural network(s), support vector machine(s), logistic regression, Bayesian statistics or methods, k-nearest neighbors (k-NN), principal component analysis (PCA), Mahalanobis distance measure(s) (directly or after decomposition, e.g., by PCA), dynamic time warping (DTW), etc.

[0063] For example, in some examples, a similarity metric between the current time signature and one or more stored reference time signatures corresponding to the access point 105 and / or the reader 102 may be calculated using methods such as, but not limited to, k-NN or PCA with or without Mahalanobis distance scaling. The similarity metric represents the similarity between the current time signature and the respective reference time signature. In some examples, one or more similarity metrics may be used to classify the current time signature. For example, one or more similarity metrics may be used to classify the current time signature as being on a secured or unsecured side of the access point 105. In additional or alternative examples, one or more similarity metrics may be used to classify the current time signature as more than just on a secured or unsecured side of the access point 105. For example, a third class (e.g., “other”) may be used to classify cases where a user is within UWB range of the reader 102 but is motionless, standing still, turning around, or engaging in some other similar behavior that does not necessarily indicate the user's intent to pass through the access point 105. In an algorithm that calculates a similarity metric as described above, in one example, a case may be classified into such a third class (e.g., “other”) by applying a predefined threshold to the similarity metric. If the similarity metric does not meet the predefined threshold, the current temporal signature may be classified into the third class. In another example, a case may additionally or alternatively be classified into such a third class by applying one or more predefined thresholds to one or more UWB measurements, alone or in combination, or to their temporal patterns, such as, but not limited to, the temporal patterns of changing radial distance (D).In yet another example, cases may additionally or alternatively be classified into such a third class by using velocity information generated from one or more IMU sensors, such as an accelerometer and / or gyroscope, that may be embedded in device 116.

[0064] As another example, in some instances, DTW may be applied to a current time signature and one or more stored reference time signatures. DTW may be implemented, for example, in a C-family programming language or other common programming language. DTW should generally be fast enough for at least a relatively small number of reference time signatures using a relatively small number of points per signature. Furthermore, DTW accommodates multidimensional data, allowing for the use of different types of UWB signals in the signatures (e.g., D, AoA, SNR, LoS, etc.), as described above. In addition, DTW is robust to different numbers of sample points and different temporal locations. This is desirable because UWB receivers may typically sample at a fixed rate (e.g., 5 Hz), but users 114 (carrying UWB-enabled devices 116) may approach and / or move away from the access point 105 and / or reader 102 at different rates. Furthermore, in some situations, the distance at which a UWB receiver / transceiver (e.g., reader 102) begins to detect a UWB transmitter / transceiver (e.g., device 116) changes from time to time due to power fluctuations, RF attenuation effects, electronic timing variations, and / or various other influences. Thus, it is possible, though unlikely, that the sample points of the current time signature will not exactly align with all of the sample points in any of the stored reference time signatures. While DTW is robust to the number and alignment of sample points of the compared time signatures, DTW generally assumes that at least the start and end points of the compared time signatures are aligned. Thus, in some examples, the current time signature and the stored reference time signature may be pre-aligned. The current time signature and the stored reference time signature may be pre-aligned, for example, using UWB radial distance (D) measurements and / or other relatively reliable UWB outputs or measurements. For example, the current time signature and each stored reference time signature to which the current time signature is to be compared may be trimmed to approximately the same start and end points based on a radial distance (D) measurement determined for each of the start and end points.The trimmed current time signature and the reference time signature may then be used in DTW to generate a similarity metric, which may then be used to determine the user's location and / or intent, as described herein.

[0065] In some examples, the reference temporal signature may include a "reference path signature," or may be combined with a "reference path signature," or may include or be combined with information used to determine a "reference path signature," or any information on which a "reference path signature" is based; the current temporal signature may similarly include a "current path signature," or may include or be combined with information used to determine a "current path signature," or any information on which a "current path signature" is based, as described in PCT International Patent Application No. PCT / US2021 / 071497; any suitable method(s), algorithm(s), or combination thereof may be used to compare such "current path signature" information with such "reference path signature" information, as also described in PCT International Patent Application No. PCT / US2021 / 071497.

[0066] If a “match” is determined in step 712 between the current time signature and the stored reference time signature for the environment 500, then the current location 520 of the user 114 (holding or carrying the device 116) may be identified as being near the access point and / or on a secured or unsecured side of the access point. Additionally or alternatively, if a “match” is determined between the current time signature and the stored reference time signature for the environment 500, then the intent of the user 114 to access the access point 105 may be determined or inferred. Such determined or inferred intent of the user 114 to access the access point 105 may be used, alone or in combination with other information, such as, but not limited to, credential authentication, to make access control decisions for the access point, including so-called “seamless” access control decisions in which the user does not generally need to take any affirmative action other than moving toward the access point in order to be properly authenticated and granted access to the access point.

[0067] In some examples, various steps or combinations of steps in exemplary method 700 may generally be performed continuously or substantially continuously, at predefined times, periodically, upon receiving, detecting, or identifying a trigger event, and / or randomly while user 114 holding or carrying (or carrying) device 116 moves about environment 500. For example, the steps of comparing the current temporal signature to one or more reference temporal signatures or portions thereof (i.e., step 710) and determining whether there is a “match” (i.e., step 712) may generally be performed continuously or substantially continuously. For example, steps 710 and 712 (and / or any other steps of method 700) may be performed after obtaining each UWB reading or a relatively short series of UWB readings, such as, but not limited to, one second of readings, two seconds of readings, etc., so as to give the overall practical effect of occurring continuously or substantially continuously. As another example, steps 710 and 712 (and / or any other steps of method 700) may be performed periodically, such as, but not limited to, every predefined number of seconds (e.g., 10 seconds, 20 seconds, etc.). In yet another example, steps 710 and 712 (and / or any other steps of method 700) may be performed by detecting a trigger event, such as detecting a particular state of device 116, detecting a particular movement or lack thereof of device 116, receiving a particular user input at device 116, or any other suitable detectable or identifiable trigger event. For example, if it is detected that device 116 has come within a predefined threshold distance of reader 102, such as, but not limited to, within 10 feet (3.048 meters), within 6 feet (1.8288 meters), within 2 feet (0.6096 meters), method 700 may identify this as a trigger event, and steps 710 and 712 (and / or any other steps of method 700) may be performed.

[0068] Although the flowchart of FIG. 7 depicts an exemplary method as including sequential steps or processes having a particular order of operations, some or many of the steps or operations in the flowchart may be performed in parallel or simultaneously, and the flowchart should be read in the context of various exemplary embodiments of the present disclosure. The order of the method steps or process operations shown in FIG. 7 may be rearranged in some embodiments. Similarly, the method illustrated in FIG. 7 may have additional steps or operations not included therein or fewer steps or operations than those shown. In addition, many of the steps of the exemplary method of FIG. 7 may be performed by reader 102, device 116, or a combination of reader 102 and device 116. In yet another example, some of the steps of the exemplary method of FIG. 7, or a portion of the steps, may be performed by control panel 108 and / or host server 112.

[0069] Additional Cases Example 1 includes subject matter related to a non-transitory computer-readable medium including executable program code that, when executed by one or more processors, causes the one or more processors to perform the steps of monitoring ultra-wideband (UWB) signals between a first device and a second device, where the first device is at a fixed location and the second device is portable; determining a reference time signature associated with the first device based on the UWB signals; and storing the reference time signature on a computer-readable medium, where the reference time signature indicates an intent to access a security asset associated with the first device.

[0070] In Example 2, the subject matter of Example 1 optionally includes wherein the step of determining the reference temporal signature includes determining, based on the UWB signal, UWB measurements for each of a plurality of points along a path traversed by the second device.

[0071] In Example 3, the subject matter of Example 2 optionally includes wherein the UWB measurements include at least one of a radial distance (D) measurement, an angle of arrival (AoA) measurement, a signal-to-noise ratio (SNR) measurement, or a line-of-sight (LoS) measurement.

[0072] In Example 4, the subject matter of Examples 2 or 3 optionally includes wherein the UWB measurements include a combination of at least two of a radial distance (D) measurement, an angle of arrival (AoA) measurement, a signal-to-noise ratio (SNR) measurement, or a line-of-sight (LoS) measurement.

[0073] In Example 5, the subject matter of any of Examples 2-4 optionally includes storing UWB measurements for multiple points along a path traversed by the second device as a reference time signature.

[0074] In Example 6, the subject matter of Example 1 optionally includes wherein determining the reference temporal signature includes determining a plurality of different types of UWB measurements for each of a plurality of points along a path traversed by the second device.

[0075] In Example 7, the subject matter of Example 6 optionally includes wherein the plurality of different types of UWB measurements include at least two of a radial distance (D) measurement, an angle of arrival (AoA) measurement, a signal-to-noise ratio (SNR) measurement, or a line-of-sight (LoS) measurement.

[0076] In Example 8, the subject matter of Examples 6 or 7 optionally includes storing a combination of UWB measurements for multiple points along a path traversed by the second device as a reference time signature.

[0077] In Example 9, the subject matter of any of Examples 2-8 optionally includes, wherein monitoring UWB signals between the first device and the second device includes instructing a user of the second device to traverse a path through the second device.

[0078] In Example 10, the subject matter of any of Examples 2-8 optionally includes the executable program code further causing the one or more processors to initiate a training period before monitoring UWB signals between the first device and the second device.

[0079] In Example 11, the subject matter of Example 10 optionally includes determining a reference temporal signature associated with the first device is performed upon detection of an access event corresponding to the secured asset during a training period.

[0080] In Example 12, the subject matter of any of Examples 2-11 optionally includes, wherein the route is at least one of a route leading to a secured asset or a route leading from a secured asset. Example 13 includes subject matter related to a non-transitory computer-readable medium including executable program code that, when executed by one or more processors, causes the one or more processors to perform the steps of: determining a current time signature for a first device moving within an environment; comparing the current time signature to at least a portion of a stored reference time signature corresponding to a secured asset within the environment; and making an access control decision corresponding to the secured asset based on whether the current time signature is determined to correspond to at least a portion of the stored reference time signature.

[0081] In Example 14, the subject matter of Example 13 optionally includes wherein determining a current time signature for the first device includes monitoring an ultra-wideband (UWB) signal between the first device and a second device, the second device being at a fixed location corresponding to the security asset.

[0082] In Example 15, the subject matter of Example 14 optionally includes wherein determining a current time signature for the first device further includes determining UWB measurements for each of a plurality of points along a path traversed by the first device.

[0083] In Example 16, the subject matter of Example 15 optionally includes wherein the UWB measurements include at least one of a radial distance (D) measurement, an angle of arrival (AoA) measurement, a signal-to-noise ratio (SNR) measurement, or a line-of-sight (LoS) measurement.

[0084] In Example 17, the subject matter of Examples 15 or 16 optionally includes, wherein the UWB measurements include a combination of at least two of a radial distance (D) measurement, an angle of arrival (AoA) measurement, a signal-to-noise ratio (SNR) measurement, or a line-of-sight (LoS) measurement.

[0085] In Example 18, the subject matter of any of Examples 15-17 optionally includes determining UWB measurements for a plurality of points along a path traversed by the first device as the current time signature.

[0086] In Example 19, the subject matter of Example 14 optionally includes wherein determining a current time signature for the first device further includes determining a plurality of different types of UWB measurements for each of a plurality of points along a path traversed by the first device.

[0087] In Example 20, the subject matter of Example 19 optionally includes wherein the plurality of different types of UWB measurements include at least two of a radial distance (D) measurement, an angle of arrival (AoA) measurement, a signal-to-noise ratio (SNR) measurement, or a line-of-sight (LoS) measurement.

[0088] In Example 21, the subject matter of Examples 19 or 20 optionally includes determining a combination of UWB measurements for multiple points along a path traversed by the second device as the current time signature.

[0089] In Example 22, the subject matter of any of Examples 13-21 optionally includes determining whether the current path signature corresponds to at least a portion of the stored reference temporal signature includes determining whether the current temporal signature matches at least a portion of the stored reference temporal signature within a predefined tolerance.

[0090] In Example 23, the subject matter of any of Examples 13-22 optionally includes, wherein determining whether the current temporal signature corresponds to at least a portion of the stored reference temporal signature includes analyzing the current temporal signature and at least a portion of the stored reference temporal signature using at least one of a decision tree, a decision tree ensemble, a neural network, a support vector machine, logistic regression, Bayesian statistics or methods, a k-nearest neighbor algorithm (k-NN), principal component analysis (PCA), Mahalanobis distance measure, or dynamic time warping (DTW).

[0091] Example 24 includes subject matter (e.g., a method) for calibrating an environment. The method includes monitoring ultra-wideband (UWB) signals between a first device and a second device, where the first device is at a fixed location and the second device is portable, determining a reference time signature associated with the first device based on the UWB signals, and storing the reference time signature in a computer-readable storage medium, where the reference time signature indicates an intent to access a security asset associated with the first device.

[0092] Example 25 includes subject matter (e.g., a method) for determining a location of a device within an environment. The method includes determining a current time signature for a first device moving within the environment, comparing the current time signature to at least a portion of a stored reference time signature corresponding to a secured asset within the environment, and making an access control decision corresponding to the secured asset based on whether the current time signature is determined to correspond to at least a portion of the stored reference time signature.

[0093] Special Notes The above detailed description includes references to the accompanying drawings, which form a part of the detailed description. The drawings show, for illustrative purposes, specific embodiments that can be practiced. These embodiments may be referred to herein as "examples." Such embodiments or examples may include elements in addition to those shown or described. However, the inventors also contemplate examples in which only the shown or described elements are provided. Moreover, the inventors also contemplate examples that use any combination or permutation of the shown or described elements (or one or more aspects thereof) with respect to a particular example (or one or more aspects thereof), or with respect to other examples (or one or more aspects thereof) shown or described herein. That is, the above-described embodiments or examples, or one or more aspects, features, or elements thereof, can be used in combination with each other.

[0094] As will be appreciated by those skilled in the art, various embodiments of the present disclosure may be embodied as a method (including, e.g., a computer-implemented process, a business process, and / or any other process), an apparatus (including, e.g., a system, a machine, a device, a computer program product, and / or the like), or a combination of the foregoing. Accordingly, embodiments of the present disclosure, or portions thereof, may take the form of an entirely hardware embodiment, an entirely software embodiment (including firmware, middleware, microcode, hardware description languages, etc.), or an embodiment combining software and hardware aspects. Furthermore, embodiments of the present disclosure may take the form of a computer program product on a computer-readable medium or computer-readable storage medium having computer-executable program code embodied therein, that defines the processes or methods described herein. One or more processors may perform the necessary tasks defined by the computer-executable program code. In the context of the present disclosure, a computer-readable medium may be any medium that can store, preserve, transmit, or transport a program for use by or in connection with the systems disclosed herein. As mentioned above, a computer-readable medium may be, for example, but is not limited to, an electronic, magnetic, optical, electromagnetic, infrared, or semiconductor system, apparatus, or device. More specific examples of suitable computer-readable media include, but are not limited to, tangible storage media such as an electrical connection having one or more wires, a portable computer diskette, a hard disk, a random access memory (RAM), a read-only memory (ROM), an erasable programmable read-only memory (EPROM or EEPROM), a compact disc read-only memory (CD-ROM), or other optical, magnetic, or solid-state storage device. As mentioned above, computer-readable media includes, but should not be confused with, computer-readable storage media, which is intended to cover all physical, non-transitory, or similar embodiments of computer-readable media.

[0095] In the foregoing description, various embodiments of the present disclosure have been presented for purposes of illustration and description. They are not intended to be exhaustive or to limit the invention to the precise forms disclosed. Obvious modifications or variations are possible in light of the above teachings. The various embodiments have been chosen and described to provide the best explanation of the principles of the present disclosure and their practical application, and to enable those skilled in the art to utilize the various embodiments, with various modifications, as appropriate for the particular use contemplated. All such modifications and variations are within the scope of the present disclosure, as determined by the appended claims, and are to be interpreted in accordance with the breadth to which they are fairly, legally, and equitably entitled.

Claims

1. 1. A method for calibrating access to security assets in an environment, comprising: monitoring a plurality of ultra-wideband (hereinafter UWB) signals between a first device and a second device, the first device being at a fixed location and the second device being portable; determining a reference temporal signature associated with the first device based on the UWB signals, the reference temporal signature being determined by determining UWB measurements for each of one or more points along a reference path traversed by the second device to a security asset in the environment associated with the first device based on the plurality of UWB signals; storing the reference temporal signature in a computer-readable storage medium; The method, wherein the reference temporal signature is used to classify one or more users as being on an unsecured side or a secured side of a secured asset in the environment based on a similarity metric between the reference temporal signature and a plurality of current temporal signatures, and to classify behavior of one or more users that does not necessarily indicate an intention to access a secured asset in the environment based on the similarity metric and a threshold, wherein each of the plurality of current temporal signatures is determined by determining UWB measurements for each of a plurality of points along a path traversed by an individual device of one of one or more users based on a plurality of UWB signals between the first device and the individual device.

2. 2. The method of claim 1, wherein each UWB measurement comprises at least one of a radial distance (D) measurement, an angle of arrival (AoA) measurement, a signal-to-noise ratio (SNR) measurement, or a line-of-sight (LoS) measurement.

3. 2. The method of claim 1, wherein each UWB measurement comprises a combination of at least two of a radial distance (D) measurement, an angle of arrival (AoA) measurement, a signal-to-noise ratio (SNR) measurement, or a line-of-sight (LoS) measurement.

4. 2. The method of claim 1, wherein determining the reference temporal signature comprises determining a plurality of different types of UWB measurements for each of the plurality of points along the path traversed by the second device.

5. 5. The method of claim 4, wherein the plurality of different types of UWB measurements include at least two of a radial distance (D) measurement, an angle of arrival (AoA) measurement, a signal-to-noise ratio (SNR) measurement, or a line-of-sight (LoS) measurement.

6. The method of claim 4 , wherein a combination of the UWB measurements for the plurality of points along a path traversed by the second device is saved as the reference temporal signature.

7. 2. The method of claim 1, wherein monitoring a plurality of UWB signals between the first device and the second device includes instructing a user of the second device to traverse the path through the second device.

8. The method of claim 1 , further comprising initiating a training period before monitoring the plurality of UWB signals between the first device and the second device.

9. The method of claim 8 , wherein determining a reference temporal signature associated with the first device is associated with detecting an access event corresponding to the security asset during the training period.

10. The method of claim 1 , wherein the route is at least one of a route leading to the security asset or a route leading from the security asset.

11. 1. A method for determining a user's intent in an environment, comprising: determining a current time signature for a first device moving within an environment, wherein ultra-wideband (UWB) measurements for each of a plurality of points along a path traversed by the first device are determined as the current time signature; comparing the current time signature with at least a portion of a stored reference time signature corresponding to a security asset within the environment, wherein UWB measurements for each of a plurality of points along a reference path to the security asset within the environment traversed by a mobile device are stored as the reference time signature; making an access control decision corresponding to the secured asset based on whether the current temporal signature is determined to correspond to at least a portion of the stored reference temporal signature; The method, wherein determining whether the current time signature corresponds to at least a portion of the stored reference time signature includes classifying the user as being on an unsecured side or a secured side of the secured asset based on a similarity metric between the current time signature and the reference time signature, and classifying the user's behavior as not necessarily indicative of an intent to access the secured asset based on the similarity metric and a threshold.

12. 12. The method of claim 11, wherein determining the current time signature for the first device includes monitoring a plurality of UWB signals between the first device and a second device, the second device being at a fixed location corresponding to the security asset.

13. 12. The method of claim 11, wherein each UWB measurement includes at least one of a radial distance (D) measurement, an angle of arrival (AoA) measurement, a signal-to-noise ratio (SNR) measurement, or a line-of-sight (LoS) measurement.

14. 12. The method of claim 11, wherein each UWB measurement comprises a combination of at least two of a radial distance (D) measurement, an angle of arrival (AoA) measurement, a signal-to-noise ratio (SNR) measurement, or a line-of-sight (LoS) measurement.

15. 13. The method of claim 12, wherein determining the current time signature for the first device further comprises determining a plurality of different types of UWB measurements for each of a plurality of points along a path traversed by the first device.

16. 16. The method of claim 15, wherein the plurality of different types of UWB measurements include at least two of a radial distance (D) measurement, an angle of arrival (AoA) measurement, a signal-to-noise ratio (SNR) measurement, or a line-of-sight (LoS) measurement.

17. The method of claim 15 , wherein a combination of multiple UWB measurements for the multiple points along the path traversed by the second device is determined as the current time signature.

18. The method of claim 11 , wherein determining whether the current path signature corresponds to at least a portion of the stored reference temporal signature comprises determining whether the similarity metric is within an acceptable range.

19. 12. The method of claim 11, wherein determining whether the current temporal signature corresponds to at least a portion of the stored reference temporal signature comprises analyzing the current temporal signature and at least a portion of the stored reference temporal signature using at least one of a decision tree, a decision tree ensemble, a neural network, a support vector machine, logistic regression, Bayesian statistics or methods, a k-nearest neighbor algorithm (k-NN), principal component analysis (PCA), a Mahalanobis distance measure, or dynamic time warping (DTW).

20. 20. A non-transitory computer readable medium containing executable program code that, when executed by one or more processors, causes the one or more processors to perform the method of any one of claims 1 to 19.

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