Ultra-wideband calibration systems, methods, and apparatuses

Abstract

Systems, devices, and methods for calibrating UWB sensing and ranging systems are disclosed. In one aspect, a method of calibrating at least one UWB device is disclosed. In one embodiment, the method includes receiving a first packet using a first power level; estimating a first channel impulse response from the first packet, wherein the first channel impulse response includes at least one tap; and determining tap saturation in the first channel impulse response. The method can also include, based on the determination, receiving a second packet; estimating a second channel impulse response from the second packet, wherein the second channel impulse response includes a first path location; and storing the first path location.

Description

[0001] Cross-reference to related applications

[0002] This application claims the benefit of U.S. Provisional Application No. 63 / 566,510, filed March 18, 2024, entitled “Ultra-Wideband Calibration Systems, Methods, and Devices,” the entire contents of which are incorporated herein by reference. Technical Field

[0003] This disclosure relates generally to ultra-wideband wireless communication technologies, and more specifically to systems, methods and apparatus for ultra-wideband sensing and two-way ranging. Background Technology

[0004] In ultra-wideband (UWB) sensing and two-way ranging (TWR) applications, precise time-of-flight (ToF) information between the transmitting and receiving antennas is typically desired for highly accurate distance, position, velocity, or localization determination. If the distance between the transmitting and receiving antennas is not considered, the ToF information and the associated determinations of various related quantities, such as distance, can become inaccurate. The distance between the transmitting and receiving antennas affects ToF and associated determinations, leading to inaccurate sensing and TWR applications. Therefore, calibrating sensing or TWR systems to account for the direct path distance between the antennas may be important.

[0005] A dedicated calibration system that operates with an external target at a known distance can be used to determine a direct path reference. However, when using a dedicated calibration system, each device must typically be calibrated during production testing, and this calibration can be quite expensive in terms of time, cost, and resources. Furthermore, due to hardware (HW) degradation, calibration may need to be repeated over time, which may not always be feasible and / or convenient.

[0006] Therefore, effective methods are still needed to calibrate UWB sensing and TWR systems. Summary of the Invention

[0007] Embodiments of this disclosure include systems, apparatus, and methods for calibrating UWB sensing and ranging systems.

[0008] In an exemplary aspect, a method for calibrating at least one UWB device is disclosed. In one embodiment, the method includes: receiving a first packet using a first power level; estimating a first channel impulse response from the first packet, wherein the first channel impulse response includes at least one tap; and determining tap saturation in the first channel impulse response. The method may further include: based on the determination, receiving a second packet; estimating a second channel impulse response from the second packet, wherein the second impulse response includes a first path location; and storing the first path location. In some embodiments, the second packet may be received using a second power level lower than the first power level.

[0009] In another exemplary aspect, a UWB communication device is disclosed, comprising a receiver and a memory. In one embodiment, the receiver is configured to: receive a first packet using a first power level; estimate a first channel impulse response from the first packet, wherein the first channel impulse response includes at least one tap; determine tap saturation in the first channel impulse response; and based on the determination, receive a second packet; and estimate a second channel impulse response from the second packet, wherein the second impulse response includes a first path location. The memory is configured to store the first path location. In some embodiments, the second packet may be received using a second power level lower than the first power level.

[0010] In another exemplary aspect, a UWB chip is disclosed, wherein the UWB chip includes a receiver. In one embodiment, the receiver is configured to: receive a first packet using a first power level; estimate a first channel impulse response from the first packet, wherein the first channel impulse response includes at least one tap; determine tap saturation in the first channel impulse response; and based on the determination, receive a second packet; and estimate a second channel impulse response from the second packet, wherein the second impulse response includes a first path localization. In some embodiments, the second packet may be received using a second power level lower than the first power level.

[0011] Additional aspects, features, and advantages of this disclosure will become apparent from the following detailed description. Attached Figure Description

[0012] The accompanying drawings, which are incorporated in and form a part of this specification, illustrate several aspects of this disclosure and, together with the description of the drawings, serve to explain the principles of this disclosure.

[0013] Figure 1 The operation of a UWB device in a sensing application is illustrated according to some aspects of this disclosure.

[0014] Figure 2An example graph illustrating the magnitude of the preamble channel impulse response (CIR) as a function of time according to some aspects of this disclosure is shown.

[0015] Figure 3 Examples of sensing operation methods according to some aspects of this disclosure are provided.

[0016] Figure 4 This is a block diagram of an example communication device based on some aspects of this disclosure.

[0017] Figure 5 This is a more detailed block diagram of a receiver in an example communication device according to some aspects of this disclosure.

[0018] Figure 6 Four examples of packet configurations, such as those currently defined in the IEEE 802.15.4z standard, are illustrated according to some aspects of this disclosure. Detailed Implementation

[0019] To facilitate understanding of the principles of this disclosure, embodiments illustrated in the accompanying drawings will be discussed, and specific terminology will be used in the description. Nevertheless, it should be understood that this is not intended to limit the scope of this disclosure. Any changes and further modifications to the described apparatus, systems, and methods, as well as any further application of the principles of this disclosure, are fully considered and included within this disclosure, as would normally occur to those skilled in the art to which this disclosure pertains. Specifically, upon careful consideration, features, components, and / or steps described with respect to one embodiment may be combined with features, components, and / or steps described with respect to other embodiments of this disclosure. However, for the sake of brevity, multiple repetitions of these combinations will not be described separately.

[0020] This document discloses systems, methods, and apparatus for determining a direct path reference in a UWB sensing and ranging system. Such a direct path reference between two antennas may also be referred to herein as a “zero-meter reference.” A zero-meter reference can be determined between two antennas residing in a single UWB device or on different UWB devices. In some embodiments, an iterative zero-meter calibration method for UWB sensing or TWR can transmit and receive one or more packets until a first path (FP) index can be recorded without clipping in the channel impulse response (CIR). Therefore, this disclosure allows for potentially more efficient zero-meter reference determination for both transmitting and receiving antennas or for at least two UWB devices performing TWR.

[0021] The disclosed implementations are applicable to a wide variety of sensing and TWR use cases and a wide variety of sensing and TWR configurations. In some implementations, the terms "sensing" and "radar" are used herein in accordance with the UWB field to refer to Time-of-Flight (ToF), distance, ranging, angle of arrival (AoA), and / or velocity calculations using some form of light wave (typically radio waves). For example, in some contexts, "sensing" and "radar" may have different meanings. In some contexts, "sensing" and "radar" are used interchangeably.

[0022] In some implementations, a zero-meter reference can generally refer to a distance or time interval used to determine errors and / or delays in ranging applications that include at least co-located transmit and receive antennas. In some implementations, a zero-meter reference can be considered synonymous with a first path index and / or a first path. In some implementations, a zero-meter reference can be considered synonymous with a direct path (DP). In some implementations, a direct path can be used to calculate the zero-meter reference. For example, by comparing the Time of Flight (ToF) required for a packet to travel along a direct path with the Time of Flight (ToF) required for a packet to travel along a target path, the device can calculate the Time of Flight (ToF) required for a packet to travel along a target path if the transmit and receive antennas are theoretically located at the same position (i.e., zero meters apart). Therefore, the transmit and receive antennas can be located in different positions without substantially affecting sensing operation.

[0023] In some implementations, at least one transmit antenna and at least one receive antenna are co-located. The term "co-located" in the UWB field can refer to a true monolithic configuration (where the transmit and receive antennas are located in exactly the same location) or a pseudo-monolithic configuration (where the transmit and receive antennas are relatively close together). In a pseudo-monolithic configuration, zero-meter calibration can be used to determine and account for the distance between the transmit and receive antennas during calibration. In some implementations, the transmit and receive antennas are not co-located; this is often referred to as a bi-site configuration. In a bi-site configuration, zero-meter calibration can be used to determine the distance between the transmit and receive antennas. Zero-meter calibration can be similarly applied to multi-site configurations, where multiple transmit and / or receive antennas are in operation to determine the distance between the individual antennas. In some implementations, the transmit and receive antennas may be part of the same UWB device (e.g., a single-source configuration). In some implementations, the transmit and receive antennas may be part of different UWB devices (e.g., a multi-source configuration). In some implementations, a UWB device may have more than one transmit antenna and / or more than one receive antenna. For example, a UWB device may have one transmit antenna and two receive antennas. In some implementations, multiple UWB devices may each have more than one transmit antenna and / or more than one receive antenna, either individually or in combination. For example, some or all of the UWB devices from a group of UWB devices may each have one transmit antenna and two receive antennas.

[0024] In some implementations, zero-meter calibration can be used to determine the antenna delay of a UWB device. In some implementations, zero-meter calibration can be used to determine the distance and / or time delay in a TWR. For example, zero-meter calibration can be used to determine the distance and / or time delay between a first ranging UWB device and a second ranging UWB device. Then, zero-meter calibration can be used to determine the distance and / or time delay between the second UWB device and the first UWB device. For another example, zero-meter calibration can be used to perform a TWR synchronously or serially between more than two UWB devices.

[0025] Zero-meter calibration is particularly useful in configurations where the transmit and receive antennas are co-located in the same device and / or in nearly the same position relative to other objects in the environment. In such configurations, the transmitted signal typically has a relatively high amplitude due to the high transmit power distribution. This high amplitude can cause clipping in the CIR when the analog-to-digital converter (ADC) receives the signal at the receive antenna. In some implementations, zero-meter calibration can effectively and systematically alter the transmit power distribution until the CIR can be analyzed without clipping.

[0026] The terms “packet” and “frame” are used in this document, consistent with the UWB domain, to refer to the basic unit of transmission. For example, in some contexts, a packet may refer to a physical layer unit of transmission, and a frame may refer to a media access control (MAC) layer unit of transmission. In some contexts, “packet” and “frame” are used interchangeably.

[0027] In some implementations, at least one device can provide a separate on-chip calibration with a zero-meter reference at the transmitting antenna, thereby mitigating or eliminating the need for a dedicated calibration system or method with an external target in production testing. In some implementations where a separate on-chip calibration is performed, at least one zero-meter calibration can be run in any sensing session, potentially providing an accurate zero-meter reference for virtually any session, and thus potentially allowing for more stable and more accurate estimation of the target's distance over time.

[0028] In some implementations, at least one UWB device can provide independent on-chip zero-meter calibration for the UWB sensing system. In some implementations, zero-meter calibration reduces or eliminates the need for a dedicated calibration system or method with at least one external target during production testing. In some implementations, zero-meter calibration can be performed in any sensing session.

[0029] In some implementations, at least one UWB device can analyze the quality of the FP positioning of the preamble CIR. In some implementations, at least one UWB device defines the zero-meter reference as the FP positioning of the unsaturated preamble CIR. In some implementations where the antenna of the UWB device is relatively isolated from other objects, calibration may be more successful, more efficient, and / or more convenient. In some implementations, at least one UWB device can combine FP positioning detected in different UWB packet fields or sequences to improve the accuracy of the zero-meter reference. In some implementations, at least one UWB device can probe the channel at the preamble of a packet and possibly at at least one other packet field in the same packet with a number of different transmit power levels, thereby potentially extracting more channel information. In some implementations, calibration includes antenna delay calibration for ranging applications, including UWB sensing, single-sided TWR (SS-TWR), and double-sided TWR (DS-TWR).

[0030] Figure 1 An example UWB sensing system 100 according to some aspects of this disclosure is illustrated. The UWB sensing system 100 includes a transmitting antenna 101 and a receiving antenna 102. A typical sensing scenario is illustrated where a signal (such as packets) is transmitted, and a direct path 104 exists between the transmitting antenna 101 and the receiving antenna 102 (in... Figure 1(Labeled as "DP" in the figure). In some embodiments, transmitting antenna 101 can transmit at least one packet. As shown in a sensing application in which object 108 exists in the same environment as transmitting antenna 101, multiple versions of the transmitted packet are received at receiving antenna 102. For example, the receiving antenna receives the transmission on direct path 104 and also receives the reflection from object 108 along target path 106. Note that "overflow path" is a term used interchangeably with "direct path" in related art.

[0031] In some implementations, a zero-meter reference can be determined using a signal received on the direct path. For example, by comparing the Time of Flight (ToF) required for a packet to travel along the direct path with the Time of Flight required for a packet to travel along the target path, the device can determine the Time of Flight required for a packet to travel along the target path if the transmitting and receiving antennas are theoretically located at the same point (i.e., zero meters apart). Thus, sensing operations (e.g., for determining the distance of a target from the device) can take into account the distance between the transmitting and receiving antennas.

[0032] In some implementations, in UWB sensing systems, the FP index can typically be detected as the direct path between the transmitting and receiving antennas (e.g., see...). Figure 1 Therefore, the FP index is often used as a zero-meter reference when estimating at least one target distance. In some implementations, if clipping occurs at the ADC, the range deviation may distort the CIR estimate in the accumulator, and thus distort the zero-meter estimate.

[0033] Figure 2 An example graph illustrating the magnitude of the preamble CIR as a function of time according to some aspects of this disclosure is shown. This graph illustrates the magnitude 200 of the accumulated preamble CIR 204 determined from the received packet as a function of time in nanoseconds. At relatively high power, the first tap saturates, resulting in a plateau at peak 206. At relatively low power, the first tap is not saturated, resulting in peak 208. Therefore, some magnitude data above the plateau threshold is lost during plateau 206, while peak 208 may allow analysis of all magnitude data. Therefore, Figure 2 This illustrates how range bias affects FP index estimation in some implementations, potentially leading to inaccurate range estimates. Figure 2 In the example, there is a 1.53 ns offset between the reliable FP index under low transmit power and the reliable FP index under high transmit power, which results in a corresponding 23 cm offset in the distance calculation.

[0034] Figure 3A method 300 for calibrating a UWB sensing system according to some aspects of this disclosure is illustrated. For illustration, the variable "n" represents the transmit power distribution index, the variable "N" represents the maximum transmit power distribution index, the variable "M" represents the number of packets transmitted at transmit power distribution index n, and the variable "M" represents the maximum number of packets transmitted at transmit power distribution index n. In some embodiments, the transmit power level typically decreases as the transmit power distribution index increases (i.e., n = n + 1). However, the transmit power level may also be increased as needed to result in successful packet reception, as discussed further below. The calibration method 300 may be run in each sensing session such that the FP index is determined in each sensing session, or the method 300 may be run periodically at a certain time interval, wherein the FP index is calculated and used for each time interval, regardless of the number of sensing sessions in each time interval, or the method 300 may be run in one sensing session to determine the FP index for subsequent sensing sessions.

[0035] In some implementation schemes, such as Figure 3 As illustrated, in step 302, the transmit power distribution index n can be selected. Then, in step 304, the transmit antenna can transmit packets. Then, if the receive antenna correctly receives packet m in step 306, the accumulator can determine whether any taps in the CIR are saturated in steps 330 and 332. If the receive antenna does not correctly receive packet m in step 306, the calibration can proceed to step 308. If no taps are saturated in steps 330 and 332, the calibration is considered complete, and the FP index can be recorded in step 334. If any taps are saturated in steps 330 and 332, the calibration can proceed to step 308. In step 308, the calibration can determine whether m is equal to M. If m is not equal to M in step 308, m can be incremented by 1 in step 310, and the calibration can return to step 304. If m is equal to M in step 308, the calibration can determine whether n is equal to N in step 320. If n is not equal to N in step 320, then in step 322 n can be incremented by 1, m can be reset to 1, and calibration can be performed again at step 302. If n equals N, then calibration can stop in step 340. Therefore, Figure 3 The method described illustrates at least a portion of the implementation scheme for zero-meter calibration.

[0036] In some implementations, subsets of N transmit power distributions may be identified after TX calibration. In some implementations, the transmit power distribution may be low power. In some implementations, the transmit power distribution may be less than approximately -35 dBm transmitted over an approximately 500 MHz bandwidth.

[0037] In some implementations, the device can transmit a power distribution index 1 packet. In some implementations, the packet can be transmitted in sensing mode. If the receiving antenna correctly receives the packet, the packet can be analyzed to detect saturation taps in the preamble accumulator (of the UWB packet). If the accumulator does not record any saturation taps, the FP index can be recorded, and the routine can be indicated as complete. In some implementations, if the accumulator does record at least one saturation tap, the packet can be transmitted again. That is, the process can be... Figure 3 The process restarts at point 304. In some implementations, the process can be repeated a certain number of times. For example, a certain number of packets (the number is represented by the variable "m") can be sent via the transmit antenna, and correctly received packets can be analyzed (e.g., using an accumulator) to determine if any tap saturation has occurred. Up to M transmissions can be attempted.

[0038] In some implementations, if all or more packets transmitted under transmit power index 1 record at least one saturation tap, the device can re-start calibration under a different power index. In some implementations, the different transmit power level can typically be a reduced transmit power level. For example, the adjusted transmit power level might be referred to as transmit power distribution index 2. In some implementations, the transmit power level can be reduced at regular or random intervals. In some implementations, the transmit power level can be reduced by approximately 3 dBm. In some implementations, the device can repeat this process once or multiple times. That is, the device can transmit one or a number of packets at continuously decreasing transmit power levels and can use an accumulator to analyze any correctly received packets to determine if any taps are saturated. In some implementations, the number of times the transmit power level has been reduced can be represented by, for example, the variable "n". In some implementations, the number of reductions (n) can be limited to a finite number, for example, the transmit power level can be reduced at most N times.

[0039] In some scenarios, the power level of the initial power distribution (n=1) may be low enough that none of the M packets transmitted at that power level are successfully received (e.g., as determined in decision box 306). In this case, the power can be increased in subsequent transmissions (e.g., in other power distributions) until packets are received correctly.

[0040] In some implementations, the device detects saturation taps by comparing taps in the accumulator to defined or predefined thresholds. For example, the magnitude of the Ipatov accumulator can be represented by the variable "z", the pulse repetition frequency can be represented by the variable "PRF", and the number of symbols accumulated by the accumulator (adjusted) can be represented by the variable "". The value is indicated by "T", and the detection threshold can be represented by the variable "T". This can vary depending on the grouping format and / or configuration. In some implementations, the detection threshold can be heuristically set to T=0.75. In some implementations, saturation taps can be detected using the following formula:

[0041] In some implementations, the device can normalize the accumulator. The normalized value of the Ipatov accumulator can be determined by the variable " The normalized value of the Ipatov accumulator can be calculated using the following equation:

[0042] In some implementations, the device can determine whether any taps exceed (or are greater than) a threshold or a defined or predefined threshold. For example, this process can be represented by the following formula:

[0043] In some implementations, the device may analyze CIR estimates obtained from any packet field and / or packet sequence, such as the Start-of-Frame Delimiter (SFD), Physical Layer (PHY) header (PHR), PHY payload, and / or Scrambling Timestamp Sequence (STS). In some implementations, the device may combine FP localization obtained from the preamble and / or any other packet field or packet sequence to potentially further improve the accuracy of the zero-meter reference. For example, these implementations may be particularly suitable for direct path distortion caused by strong reflections from objects relatively close to the antenna sensor.

[0044] In some implementations, the device may utilize at least two different transmit power levels to transmit packets. One transmit power level may be applied to the preamble, while the other transmit power level may be applied to any other packet fields and / or packet sequences within the same or different packets. In some implementations, analysis of the corresponding CIR estimates for the different packet fields and / or different packet sequences can provide further channel information.

[0045] In some implementations, a zero-meter calibration routine can be used to calibrate antenna delay in ranging applications such as SS-TWR and DS-TWR applications. Since UWB devices can often be very precise, even the smallest antenna delay can affect ranging calculations. In some TWR implementations, a first device can transmit packets from its transmit antenna to the receive antenna of a second device. After an undefined, defined, or predefined time interval, the second device can transmit packets from its transmit antenna to the receive antenna of the first device. In some implementations, the receive antennas of both the first and second devices may experience clipping in the ADC, thus preventing accurate bidirectional ranging calculations. In some implementations, the first device can transmit packets with a power distribution index n. The second device can then receive and analyze the packets to detect saturation taps in the preamble accumulator. If no taps are saturated, the TWR process can continue normally. If any taps are saturated, the second device can send packets back to the first device, indicating ranging failure. Then, in some implementations, the first device can send another packet or a number of packets to the second device with the same transmit power distribution index n. If any packets do not have saturation taps, the TWR process can continue normally. If all packets have at least one saturation tap, the second device can send that number of packets back to the first device, indicating that ranging for all packets has failed. Then, in some embodiments, the first device can send power distribution index n+1 transmission packets and can continue with the same calibration routine applied to transmission power distribution n. In some embodiments, this process can be repeated for a certain number of transmission power distribution indices until the second device's accumulator no longer receives a saturation tap or until the maximum value of n (i.e., N) is reached.

[0046] Figure 4 This is a block diagram of an example communication device 400 according to some aspects of this disclosure. The communication device 400 can operate in any sensing configuration proposed herein. For example, the communication device 400 may represent... Figure 1 One or more devices in the device. In this embodiment, communication device 400 includes a receiving antenna 402, a transmitting antenna 410, a transceiver 408, a processor 404, and a memory 406. In this embodiment, transceiver 408 includes a receiver 420 and a transmitter (not shown), wherein the transmitter includes an amplifier 412 or other circuitry controlled by communication device 400 for adjusting the transmission power level to achieve about Figure 3The flowchart discusses the transmit power distribution / level. In some embodiments, transceiver 408 is configured to transmit packets or sets of packets via transmit antenna 410, and transceiver 408 is configured to receive reflected packets or sets of packets via receive antenna 402 and receiver 420. The received packets or sets of packets may be stored in memory 406. Processor 404 may be used to convert packet data into other formats. In some embodiments, other formats may also be stored in memory 406. In some embodiments, transceiver 408 may be implemented using a combination of separate transmitter and receiver circuitry (such as analog circuitry) connected to other circuitry (such as processor 404 or other circuitry) for performing baseband processing. In other embodiments, communication device 400 may include more than two antennas, and the selection of which antennas are used for transmitting and which antennas are used for receiving may be dynamically controlled by processor 404. In such embodiments, using multiple antennas can provide multiple snapshots of reflections from the environment, which are then combined by the processor to obtain a better CIR.

[0047] Transceiver 408 enables UWB communication capabilities, such as sending and / or receiving UWB packets, such as regarding Figure 3 As described, communication device 400 may represent a smartphone or other device that also implements Bluetooth, Wi-Fi, cellular, and / or other communication capabilities (such as via one or more chips or processors that implement these capabilities). Transceiver 408 may be implemented as an integrated circuit or chip.

[0048] Memory 406 may include one or more non-transitory storage devices, which may include local and / or network-accessible storage devices, disk drives, drive arrays, optical storage devices, solid-state storage devices such as random access memory (RAM) and / or read-only memory (ROM), programmable ROM, flash-updatable ROM, etc. Such storage devices may be configured to implement any suitable data storage device, including but not limited to various file systems, database structures, etc. Memory 406 may be used to store programming instructions and other computer code for performing the various steps described herein.

[0049] Figure 5 This is a more detailed block diagram of receiver 420 in an example communication device 400 according to some aspects of this disclosure. Receiver 420 represents an exemplary UWB receiver. Figure 5As illustrated, receiver 420 may include analog radio frequency (RF) and baseband (BB) processing circuitry 502. This BB processing circuitry acquires the received RF signal (e.g., received packets) and provides conventional front-end processing (e.g., amplification, filtering, down-conversion to the BB frequency) and passes the baseband signal to ADC 504. The sampled signal is passed to correlator 506. Correlator 506 correlates the sampled signal with a known sequence (such as a preamble sequence). An example of a preamble sequence is one of the known Ipatov sequences. After correlation, the resulting signal can be accumulated by accumulator 508. This accumulated signal can then be used to provide a channel estimate, from which processor 404 can calculate a first path location, time of arrival (ToA), and / or distance to an object (such as object 108). Alternatively, if the transmitter is not co-located with the receiver, processor 404 can transmit information associated with the accumulated signal back to a separate transmitter, and the transmitter device can perform calculations to obtain the distance. Based on the calculated distance, location-based services can be provided.

[0050] Having such Figure 5 The communication device 400 of the receiver 420 shown can be used to implement communication devices 400 based on the receiver 420. Figure 3 The operations performed by the receiving device are explained. For example, regarding... Figure 3 The accumulator in question can be implemented as part of a receiver (such as receiver 420), and the FP index can be determined within receiver 420 or by a processor (such as processor 404) cooperating with receiver 420. The FP index can be stored in memory (such as memory 406) for later use in ranging applications. For example, the FP index can represent the Time of Flight (ToF) of the direct path between transmit antenna 410 and receive antenna 402.

[0051] Figure 6 Four examples of packet configurations, such as those currently defined in the IEEE 802.15.4z standard, are illustrated according to some aspects of this disclosure. In each configuration, the illustrated arrows indicate the ranging marker (RMARKER) reference positioning. The synchronization (SYNC) field 608 is a known preamble (Ipatov sequence). Several Ipatov sequences are defined in the standard. Ipatov sequences have perfect autocorrelation properties, and their cross-correlation properties are good (but not perfect) because the various Ipatov sequences are not completely orthogonal.

[0052] The SFD (Start of Frame Delimiter) field 610 is a known sequence used to indicate the end of the preamble and the beginning of the frame. Depending on the packet structure, a frame may consist of the following: a PHR (PHY Header) 612, which is a structure that includes information about the PHY payload 614; the PHY payload 614, which is the actual data transmitted by the physical frame; and an STS 616, which is a strong encrypted sequence of pseudo-random pulses generated from a key (STS key).

[0053] The PHY packet structure begins with a synchronization field 608, followed by an SFD 610. In some implementations, as shown in packet configuration 600, synchronization field 608 and SFD 610 are followed by a PHR 612, then a PHY payload 614. In some implementations, as shown in packet configuration 602, synchronization field 608 and SFD 610 are followed by an STS 616, then a PHR 612, then a PHY payload 614. In some implementations, as shown in packet configuration 604, synchronization field 608 and SFD 610 are followed by a PHR 612, then a PHY payload 614, then an STS 616. In some implementations, as shown in packet configuration 606, synchronization field 608 and SFD 610 are followed by an STS 616.

[0054] SP0, SP1, SP2, and SP3 are four examples of packet configurations defined by the 802.15.4z specification. The techniques disclosed herein utilize these existing packet structures, but these techniques are also applicable to other packet structures, such as those defined by IEEE 802.15.4ab or any other packet structure used for UWB transmission, which includes a preamble, SFD, payload, and any other additional content added to the physical packet.

[0055] The estimation and analysis of CIR (which may involve aggregating various responses from the environment) can be used to determine the distance to an object, thereby inferring other information about the object, such as its location and velocity. AoA can also be used to enrich CIR information and enhance the estimation of user location.

[0056] In some sensing implementations, the CIR may be constructed based on the analysis of the Ipatov sequence (located in the preamble). In some implementations, the CIR may be constructed based on the analysis of other parts of the packet and by combining the analyses of the individual parts of the frame. In some implementations, the sensing receiver (such as receiver 420) may use STS 616 or PHY payload 614 to filter the response and determine the desired and unwanted received frames accordingly.

[0057] In this disclosure, "PRF" may be considered an acronym for "Pulse Repetition Frequency", "RTLS" may be considered an acronym for "Real-Time Positioning System", "TX" may be considered an acronym for "Transmitter", and "RX" may be considered an acronym for "Receiver".

[0058] Those skilled in the art will recognize that the apparatus, systems, and methods described above can be modified in various ways. Therefore, those skilled in the art will understand that the embodiments covered by this disclosure are not limited to the specific exemplary embodiments described above. In this regard, although illustrative embodiments have been shown and described, a wide range of modifications, alterations, and substitutions are disclosed in the foregoing with full consideration. It should be understood that such modifications may be made above without departing from the scope of this disclosure. Therefore, the appended claims should be interpreted broadly and in a manner consistent with this disclosure.

Claims

1. A method for calibrating at least one ultra-wideband (UWB) device, the method comprising: The first packet is received using the first power level; Estimate a first channel impulse response from the first group, wherein the first channel impulse response includes at least one tap; Determine tap saturation in the first channel impulse response; Based on the determination, the second packet is received; The second channel impulse response is estimated from the second group, wherein the second channel impulse response includes the first path location; as well as Store the location of the first path.

2. The method of claim 1, wherein determining the tap saturation in the channel impulse response includes determining that the magnitude of the tap exceeds a threshold.

3. The method of claim 1, wherein determining the tap saturation in the first channel impulse response includes analyzing the output of the accumulator.

4. The method of claim 1, wherein the first group comprises a preamble and at least one other field, and wherein determining the at least one tap saturation in the first channel impulse response comprises analyzing the preamble and the at least one other field.

5. The method of claim 1, wherein the second packet is received using a second power level lower than the first power level, and wherein the method further comprises: The target distance is estimated based on the location of the first path.

6. The method of claim 1, wherein the first group includes a first preamble, and wherein the first channel impulse response is based on correlation and accumulation of the first preamble.

7. The method of claim 1, wherein the second channel impulse response includes at least one second tap, and wherein the method further comprises: It is determined that none of the second at least one taps is saturated. The first path positioning is determined based on the determination that none of the second at least one taps is saturated.

8. The method of claim 1, wherein the at least one UWB device includes a UWB device, the UWB device including a transmit antenna and a receive antenna, wherein the first packet and the second packet are received using the receive antenna, and wherein the method further comprises: The first packet is transmitted by the transmitting antenna at the first power level; as well as The second packet is transmitted by the transmitting antenna at the second power level.

9. The method of claim 1, wherein the first group includes a first preamble, wherein estimating the first channel impulse response includes processing the first preamble in an accumulator to generate an output, and wherein the first channel impulse response is based on the output.

10. An ultra-wideband (UWB) communication device, comprising: Receiver, the receiver being configured to: The first packet is received using the first power level; Estimate a first channel impulse response from the first group, wherein the first channel impulse response includes at least one tap; Determine tap saturation in the first channel impulse response; as well as Based on the determination, the second packet is received; as well as The second channel impulse response is estimated from the second group, wherein the second channel impulse response includes the first path location; as well as A memory configured to store the location of the first path.

11. The UWB communication apparatus of claim 10, wherein determining the tap saturation in the first channel impulse response includes determining that the magnitude of the tap exceeds a threshold.

12. The UWB communication apparatus of claim 10, wherein the receiver includes an accumulator, and wherein determining the tap saturation in the first channel impulse response includes analyzing the output of the accumulator.

13. The UWB communication device of claim 10, wherein the second packet is received using a second power level lower than the first power level, and wherein the receiver is further configured to: Receive the third packet; and Estimate the third channel impulse response from the third group, and wherein the UWB communication device further includes: A processor configured to estimate target distance based on the third channel impulse response and the first path localization.

14. The UWB communication device of claim 10, wherein the second channel impulse response includes at least one second tap, and wherein the receiver is further configured to: It is determined that none of the second at least one taps is saturated. The first path positioning is determined based on the determination that none of the second at least one taps is saturated.

15. A wireless communication device, comprising: The UWB communication device as described in claim 10; as well as Cellular communication devices.

16. The UWB communication device as claimed in claim 10, further comprising: antenna; as well as A transmitter, the transmitter being configured to: The first packet is transmitted via the antenna at the first power level; as well as The second packet is transmitted via the antenna at a second power level lower than the first power level.

17. An ultra-wideband (UWB) chip, comprising: Receiver, the receiver being configured to: The first packet is received using the first power level; Estimate a first channel impulse response from the first group, wherein the first channel impulse response includes at least one tap; Determine tap saturation in the first channel impulse response; as well as Based on the determination, the second packet is received; as well as Estimate the second channel impulse response from the second group, wherein the second channel impulse response includes the first path location.

18. The UWB chip as described in claim 17, further comprising: antenna; A transmitter, the transmitter being configured to: The first packet is transmitted via the antenna at the first power level; as well as The second packet is transmitted via the antenna at the second power level.

19. A smartphone, the smartphone comprising: The UWB chip as described in claim 18; A memory configured to store the location of the first path; as well as Cellular communication chip.

20. The smartphone of claim 19, wherein the second packet is received using a second power level lower than the first power level, and wherein the receiver is further configured to: Receive the third packet; and Estimate the third channel impulse response from the third group, and wherein the smartphone further includes: A processor configured to estimate target distance based on the third channel impulse response and the first path localization.

21. The UWB chip of claim 17, wherein the receiver is further configured to: The third packet is received using the third power level; It was determined that the third packet was not successfully received; As a result of determining that the third packet was not successfully received, the fourth packet is received at a fourth power level higher than the third power level; and The third channel impulse response is estimated from the fourth group, wherein the third channel impulse response includes the first path location.

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