Bluetooth beacon with double positioning mode and positioning method

Abstract

The application discloses a Bluetooth beacon with double positioning modes and a positioning method. The Bluetooth beacon comprises a battery, a power management module, an SoC chip and a PCB antenna. The SoC chip is configured to periodically send a Bluetooth low-power broadcast data packet containing a double-mode identifier at a preset broadcast interval in a default state, so that a receiving end realizes rough positioning through RSSI. When a connection request of a receiving end device supporting channel sounding is received, the connection is established, the role is switched to a reflection end, a channel sounding process is executed to realize high-precision ranging, and the default state is automatically restored after the ranging is completed. The double-mode identifier is used to indicate that the Bluetooth beacon supports a rough positioning mode based on RSSI and a precise positioning mode based on channel sounding. The application switches the double modes on demand, and compatibility of the device and positioning precision are considered.

Description

Technical Field

[0001] This invention relates to the field of wireless communication and positioning technology, and in particular to a Bluetooth beacon with dual positioning modes and a positioning method. Background Technology

[0002] Bluetooth Low Energy (BLE) beacon technology is a positioning technique based on the periodic broadcast of specific format data packets. Traditional Bluetooth beacons periodically broadcast BLE signals containing specific identification information. The receiving end (such as a smartphone or tablet) estimates the distance to the beacon based on the strength of the received signal's RSSI value, and then uses triangulation or fingerprint matching algorithms to achieve positioning. Due to its advantages such as low cost, low power consumption, and simple deployment, RSSI positioning has been widely used in indoor positioning, asset tracking, smart retail, and smart parking.

[0003] However, RSSI values ​​are significantly affected by environmental factors, including multipath effects, co-channel interference, human body occlusion, and obstacle penetration loss, resulting in low ranging accuracy, typically ranging from several meters to tens of meters. In certain applications requiring high positioning accuracy (such as precise navigation, close-range object retrieval, and high-precision asset tracking), RSSI positioning is insufficient.

[0004] To address these issues, the Bluetooth Special Interest Group (Bluetooth SIG) introduced Channel Sounding technology in Bluetooth Core Specification version 6.0. Channel Sounding achieves sub-meter or even centimeter-level ranging accuracy by transmitting phase measurement signals on different frequency channels and combining this with round-trip time (RTT) measurements, while also exhibiting strong robustness against environmental multipath interference. However, Channel Sounding requires the receiving device (such as a smartphone) to support the Bluetooth 6.0 specification, and many existing devices on the market only support Bluetooth 4.x / 5.x versions, making them unable to use Channel Sounding.

[0005] Therefore, the existing technology has the following shortcomings: (1) Pure RSSI positioning accuracy is low and cannot meet the high-precision positioning requirements; (2) Pure Channel Sounding positioning has poor compatibility and cannot cover old devices that do not support Bluetooth 6.0; (3) Existing beacon products usually only support a single working mode and cannot simultaneously take into account compatibility and accuracy. Summary of the Invention

[0006] This invention provides a Bluetooth beacon with dual positioning modes and a positioning method, which automatically adapts the positioning mode according to the capabilities of the receiving device, achieving seamless switching from coarse area positioning to precise distance / direction positioning, while maintaining extremely low power consumption and long battery life.

[0007] To achieve the above-mentioned technical objectives, the present invention adopts the following technical solution: A first aspect of the present invention provides a Bluetooth beacon with dual positioning modes, comprising: A battery, used to provide operating voltage for the Bluetooth beacon; A power management module, connected to the battery, is used to convert the battery voltage into the operating voltage required by the SoC chip and to achieve low-power power management. The SoC chip is connected to the power management module and configured to execute dual positioning logic; The PCB antenna is connected to the radio frequency port of the SoC chip and is used to transmit and receive Bluetooth signals; The SoC chip is configured to perform the following dual-location logic: In the default state, Bluetooth Low Energy broadcast data packets containing a dual-mode identifier are periodically sent at preset broadcast intervals so that the receiving device can achieve coarse positioning by receiving the broadcast data packets and measuring the RSSI value; wherein, the dual-mode identifier is used to indicate that the Bluetooth beacon supports both RSSI-based coarse positioning mode and ChannelSounding-based fine positioning mode. When a connection request is received from a receiving device that supports Channel Sounding, a Bluetooth Low Energy connection is established, and the system switches to a Channel Sounding-based precision positioning mode to perform a channel detection process with the receiving device to achieve high-precision ranging and positioning. After the channel detection process is completed or the connection is lost, the system automatically returns to the default state.

[0008] Furthermore, the Bluetooth Low Energy Broadcast data packet contains multiple standard fields and one vendor-specific data field, and the dual-mode identifier is set in the vendor-specific data field; The dual-mode identifier includes a vendor ID and a dual-mode capability flag, which indicates that the Bluetooth beacon supports a precise positioning mode based on Channel Sounding.

[0009] Furthermore, the channel detection process includes: The receiving device serves as the channel sounding initiator, and the beacon serves as the reflector. The initiating end sequentially sends channel probe request signals on multiple preset frequency channels; After receiving the request signal, the reflecting end sends a response signal on the corresponding frequency channel; The initiating end measures the signal phase difference and / or round-trip time on each frequency channel, and calculates the precise distance between itself and the reflecting end using a multi-frequency point phase difference algorithm.

[0010] Furthermore, the multi-frequency phase difference algorithm includes: Let the phase measured at the initiating end at the i-th frequency fi be φi, and the phase measured at the j-th frequency fj be φj. Then, the phase ranging distance d1 is calculated according to the following formula: d1 = c × Δφ / (4π × Δf) Where c is the speed of light, Δφ = |φi - φj| is the phase difference, and Δf = |fi - fj| is the frequency difference; Furthermore, based on the round-trip time (RTT) measurement, the RTT ranging distance d2 = c × RTT / 2 is calculated. The final ranging distance is obtained by weighting the phase ranging distance d1 and the RTT ranging distance d2.

[0011] Furthermore, the power management module is configured to dynamically switch the low-power operating mode of the SoC chip according to the operating stage of the SoC chip; wherein the low-power operating mode of the SoC chip includes at least: system shutdown mode, system power-on mode, RF transmission mode, RF reception mode and CPU active mode; In the default state, the power management module controls the SoC chip to switch cyclically according to the following timing sequence: enter the RF transmit mode to send broadcast data packets, enter the system power-on mode to keep RAM and wait for timed wake-up after the transmission is completed, enter the RF receive mode at intervals during the broadcast interval to listen for connection requests, and return to the system power-on mode when no connection request is received. When the connection request is received during a broadcast interval, the power management module controls the SoC chip to switch to CPU active mode to perform the channel detection process, and restores the low-power operating mode timing to the default state after completion; When the preset deep sleep conditions are met, the power management module controls the SoC chip to enter the system shutdown mode. In the system shutdown mode, the current consumption is less than 0.5μA, and only the GPIO wake-up function is retained.

[0012] Furthermore, the battery is a disposable lithium battery, which is one of CR2032 button cell batteries, CR2450 button cell batteries, lithium-ion batteries, or alkaline batteries; The SoC chip is a Nordic nRF54L15 SoC chip, which integrates an ARM Cortex-M33 application processor, a 2.4GHz RF transceiver, Flash memory, RAM memory, and various peripheral interfaces.

[0013] Furthermore, the preset broadcast interval is 100ms to 1s, and the preset broadcast interval is adjustable.

[0014] Furthermore, the PCB antenna is an onboard inverted-F antenna or a serpentine antenna, and copper plating and metal devices are prohibited in the area around the antenna.

[0015] A second aspect of the present invention provides a positioning method based on the aforementioned Bluetooth beacon, comprising the following steps: Step S1: The Bluetooth beacon powers on and starts up, the system initializes and configures broadcast parameters; Step S2: The Bluetooth beacon enters the normal RSSI broadcast mode and periodically sends BLE broadcast data packets containing dual-mode identifiers at preset broadcast intervals; wherein, the Bluetooth beacon enters a low-power sleep state during the broadcast intervals, waiting for the next broadcast timer to wake it up or for an external interrupt; Step S3: Determine whether the Bluetooth beacon has received a connection request from a receiving device that supports Channel Sounding. If not, return to step S2. Step S4: If a connection request is received, the Bluetooth beacon establishes a BLE connection and switches to Channel Sounding reflective mode; Step S5: The Bluetooth beacon and the receiving device perform the Channel Sounding ranging process. The receiving device, as the initiator, measures the phase difference and round-trip time to calculate the precise distance. Step S6: After ranging is completed, the receiving device disconnects, the Bluetooth beacon returns to the normal RSSI broadcast mode, and returns to step S2.

[0016] Further, in step S5, the Channel Sounding ranging process includes: The initiating end sequentially sends channel probe request signals on multiple preset frequency channels; After receiving the request signal, the reflector sends a response signal on the corresponding frequency channel; The initiating end measures the signal phase difference on each frequency channel and calculates the phase ranging distance d1 using a multi-frequency point phase difference algorithm. The initiating end simultaneously measures the round-trip time (RTT) and calculates the RTT ranging distance d2 based on the RTT measurement value. The final ranging distance is obtained by weighting the phase ranging distance d1 and the RTT ranging distance d2. Compared with the prior art, the present invention has the following beneficial effects: (1) This embodiment of the invention enables the beacon to simultaneously support traditional RSSI coarse positioning and Bluetooth 6.0 Channel Sounding high-precision positioning by setting a dual-mode identifier in the broadcast data packet. Ordinary Bluetooth devices (which only support RSSI) can still achieve positioning at the meter level, while devices supporting Bluetooth 6.0 can automatically trigger the high-precision mode to achieve sub-meter or even centimeter-level positioning. This solution does not require modification of existing infrastructure, is compatible with new and old devices, and allows for smooth upgrades.

[0017] (2) In this embodiment of the invention, the Bluetooth beacon is in RSSI broadcast mode by default, with an average current of less than 10µA. It is only temporarily woken up to CPU active mode to perform high-precision ranging when a device supporting Channel Sounding requests a connection. After completion, it automatically returns to sleep mode. Compared with the solution that always keeps high-precision positioning on, this invention greatly extends battery life. It can work for 1-2 years with a CR2032 battery and 3-5 years with a CR2450 battery.

[0018] (3) In the Channel Sounding mode, the Bluetooth beacon of this embodiment adopts a multi-frequency phase differential ranging and round-trip time (RTT) ranging weighted fusion algorithm to effectively suppress the multipath effect in complex indoor environments and achieve sub-meter / centimeter-level positioning accuracy to meet the needs of high-end applications such as precise navigation and asset tracking.

[0019] (4) The Bluetooth beacon in this embodiment of the invention is powered by a disposable lithium battery, requiring no wiring or charging facilities; the hardware is based on a low-power SoC chip and an onboard PCB antenna, and the overall size is small (e.g., 20mm×30mm×5mm), which can be easily attached to various assets, vehicles or employee ID cards. No additional base station or infrastructure is required, and it can be used immediately after being attached. Attached Figure Description

[0020] Figure 1 A schematic diagram illustrating the working principle of a Bluetooth beacon with dual positioning modes, provided for the first embodiment of the present invention; Figure 2 A schematic diagram of a Bluetooth beacon with dual positioning modes provided in the first embodiment of the present invention; Figure 3 This is a schematic diagram of low-power power management powered by battery in the first embodiment of the present invention; Figure 4 This is a schematic diagram of the structure of a broadcast data packet in the first embodiment of the present invention; Figure 5This is a schematic diagram of the Channel Sounding ranging principle in the first embodiment of the present invention; Figure 6 A flowchart of a positioning method provided in the second embodiment of the present invention; Figure 7 The diagram shows several typical application scenarios of Bluetooth beacons according to embodiments of the present invention.

[0021] In the accompanying drawings, the reference numerals indicate: 100. Bluetooth beacon; 200. RSSI receiver; 300. CS receiver; 1. Battery; 2. Power management module; 3. SoC chip; 4. PCB antenna. Detailed Implementation

[0022] To make the objectives, features, and advantages of this invention more apparent and understandable, the technical solutions of the embodiments of this invention will be clearly and completely described below with reference to the accompanying drawings. Obviously, the described embodiments are only a part of the embodiments of this invention, and not all of them. All other embodiments obtained by those skilled in the art based on the embodiments of this invention without creative effort are within the scope of protection of this invention.

[0023] This invention provides a Bluetooth beacon with dual positioning modes. Its core concept lies in: on the same low-power Bluetooth beacon platform, it announces its simultaneous support for coarse positioning based on RSSI and high-precision positioning based on Bluetooth 6.0 Channel Sounding by broadcasting a "dual-mode identifier" in the data packet. For example... Figure 1 As shown, in its default state, the Bluetooth beacon 100 periodically broadcasts this data packet with extremely low power consumption for the RSSI receiver 200 to perform RSSI ranging. Only when it receives a connection request initiated by a CS receiver 300 that supports Channel Sounding (e.g., a high-end mobile phone supporting BLE 6.0) based on this identifier does the Bluetooth beacon 100 temporarily switch to high-precision ranging mode, and automatically return to the default state after ranging is completed. Thus, through this on-demand switching mechanism, the present invention balances device compatibility, positioning accuracy, and ultra-long battery life.

[0024] The Bluetooth beacon 100 of the present invention will be described in detail below based on its structure and cooperative working process: First embodiment: like Figure 2As shown, a Bluetooth beacon 100 with dual positioning modes is provided in the first embodiment of the present invention. The Bluetooth beacon 100 mainly consists of a battery 1, a power management module 2, a SoC chip 3, and a PCB antenna 4. Specifically, the battery 1 is preferably a disposable lithium battery (e.g., CR2032, CR2450, lithium-ion battery, or alkaline battery), which directly provides a raw voltage of approximately 3.0V to the power management module 2. The power management module 2 converts this voltage into the operating voltage required by the SoC chip 3 (e.g., 1.8V or 3.3V), and dynamically switches its internal low-power operating mode according to the current operating stage of the SoC chip 3. The SoC chip 3 (preferably Nordic nRF54L15, but not limited to) integrates an application processor, a 2.4GHz RF transceiver, memory, and various peripheral interfaces. Its internal firmware implements the Bluetooth protocol stack and the dual positioning logic of the present invention. The PCB antenna 4 (e.g., an onboard inverted-F antenna or a serpentine antenna) is connected to the RF port of the SoC chip 3, and is located on the edge of the circuit board with no copper plating or metal components placed around it to ensure radiation efficiency.

[0025] The following details the collaborative working process of the four-part structure: After the Bluetooth beacon powers on, SoC chip 3 completes system initialization and configures broadcast parameters, including setting the broadcast interval to a value between 100ms and 1s (typically 1s). The beacon then enters its default state—RSSI broadcast mode. Figure 3 As shown, in this mode, the power management module 2 controls the SoC chip 3 to cycle through low-power operating modes according to a fixed timing sequence: First, enter RF transmit mode (i.e., Radio TX mode). Specifically, transmit a BLE broadcast data packet at approximately 0dBm transmit power. For example... Figure 4 As shown, the structure of this broadcast data packet conforms to the Bluetooth core specification, including a preamble (1 byte), access address (4 bytes), protocol data unit header (2 bytes), broadcast address (6 bytes), broadcast data (0-31 bytes), and cyclic redundancy check (3 bytes). The broadcast data includes: Flags, LocalName, Service UUID, and Manufacturer Specific Data. The Manufacturer Specific Data field contains a "dual-mode identifier," specifically including a manufacturer ID and a dual-mode capability flag. In this embodiment, this flag is set to 1 to declare that the beacon supports Channel Sounding fine positioning mode (and implicitly supports RSSI coarse positioning mode). The data packet transmission process lasts only a few hundred microseconds and consumes approximately 4.5mA of power.

[0026] After the broadcast data packet is sent, the power management module 2 immediately switches the SoC chip 3 to System ON mode. In this mode, the RAM is retained, the CPU is in sleep mode, and the current consumption is only about 1.5µA. The internal RTC timer is responsible for waking up the chip after the set broadcast interval to perform the next transmission. During the interval between two broadcasts, the power management module 2 will also periodically (e.g., every tens of milliseconds) briefly switch the SoC chip 3 to RF receive mode (i.e., Radio RX mode) for a few milliseconds, with a current consumption of about 3.5mA, to listen for connection requests from external devices.

[0027] If no connection request is detected within the receiving window, the SoC chip 3 returns to system-on mode and continues to sleep until the next broadcast timer arrives. This cycle repeats continuously. The average current consumption of the Bluetooth beacon is less than 10µA, providing 1-2 years of battery life with a CR2032 battery (225mAh) and 3-5 years with a CR2450 battery (620mAh).

[0028] The situation changes when a Bluetooth beacon captures a valid BLE connection request within a receiving window. This connection request typically originates from a receiving device (such as a high-end smartphone) that supports Bluetooth 6.0 Channel Sounding. After scanning the Bluetooth beacon's broadcast data packets, the receiving device parses the dual-mode capability flag as 1 and actively initiates a connection request to the beacon. Upon the beacon's response, the power management module 2 switches the SoC chip 3 from sleep mode to CPU active mode, and the RF section enters transceiver mode. The beacon establishes a BLE connection with the receiving device and switches its role to Channel Sounding Reflector, while the receiving device acts as the initiator.

[0029] Subsequently, both parties perform a channel detection process. The initiating end sequentially sends detection request signals on multiple preset frequencies (e.g., 2402MHz, 2426MHz, 2450MHz, 2474MHz, 2480MHz); upon receiving the signals, the reflecting end immediately replies with a response on the same frequency. The initiating end measures the phase of the signal on each frequency and records the round-trip time, thereby using a multi-frequency phase difference algorithm to calculate the precise distance between the initiating end and the reflecting end.

[0030] Specifically, such as Figure 5 As shown, in this embodiment, the multi-frequency phase difference algorithm includes: Let the phase measured at the initiating end at the i-th frequency fi be φi, and the phase measured at the j-th frequency fj be φj. Then, the phase ranging distance d1 is calculated according to the following formula: d1 = c × Δφ / (4π × Δf) Where c is the speed of light, Δφ = |φi - φj| is the phase difference, and Δf = |fi - fj| is the frequency difference; Furthermore, based on the round-trip time (RTT) measurement, the RTT ranging distance d2 = c × RTT / 2 is calculated. The final ranging distance is obtained by weighting the phase ranging distance d1 and the RTT ranging distance d2 (e.g., each with a weight of 0.5). It is understood that in this embodiment, the ranging error caused by multipath effects is eliminated through the fusion calculation of the phase method and the RTT method, achieving sub-meter positioning accuracy.

[0031] It is understood that this embodiment only uses the weighted algorithm as an example for calculation. In other embodiments, the phase ranging distance d1 can be corrected by the RTT ranging distance d2 to obtain the corrected final ranging distance, and other fusion calculation methods can be used. No specific limitation is made here.

[0032] After ranging is completed, the receiving device actively disconnects. The Bluetooth beacon detects the disconnection event, and the power management module 2 controls the SoC chip 3 to return from the CPU active mode to the default low-power cycle, that is, to restart the "RF transmission → system power-on → RF reception → system power-on" sequence and continue to send broadcast data packets with extremely low power consumption.

[0033] Furthermore, to further extend battery life, the power management module 2 of this invention also supports a deep sleep mode—system OFF mode. When preset conditions are met (e.g., battery voltage below 2.4V, or no connection requests received for several consecutive hours), the power management module 2 switches the SoC chip 3 to system OFF mode. In this mode, all peripherals and RAM are powered off, only the GPIO wake-up function is retained, and the current consumption is less than 0.5µA. The Bluetooth beacon can be woken up by an external button or vibration sensor to return to normal operation.

[0034] Thus, through the coordinated work of the aforementioned hardware modules, the Bluetooth beacon of the first embodiment of the present invention achieves a complete closed loop of "extremely low power broadcasting under normal conditions, high-precision ranging by wake-up on demand, and automatic recovery after completion".

[0035] Second embodiment: See Figure 6 As shown, based on the first embodiment described above, the second embodiment of the present invention also provides a positioning method, specifically including the following steps: Step S1: The Bluetooth beacon is powered on and started. The system is initialized and broadcast parameters (including broadcast interval, transmission power, etc.) are configured.

[0036] Step S2: The Bluetooth beacon enters normal RSSI broadcast mode and periodically sends BLE broadcast data packets containing a dual-mode identifier at preset broadcast intervals. The dual-mode capability flag in this broadcast data packet is set to 1, indicating that this beacon supports Channel Sounding precise positioning mode.

[0037] After each broadcast is completed, the beacon enters a low-power sleep state (system-on mode, RAM retained) and waits for the next broadcast timer to wake it up. During the sleep period, the beacon periodically opens the radio frequency receiving window briefly to listen for possible connection requests.

[0038] Step S3: The beacon determines whether a connection request has been received. If not, it returns to step S2 and continues the broadcast loop.

[0039] Step S4: If a connection request is received (this request is usually initiated by a receiver device that supports Channel Sounding based on a dual-mode identifier), the beacon establishes a BLE connection and switches its role to a Channel Sounding reflector.

[0040] Step S5: The beacon and receiver equipment perform the Channel Sounding ranging process.

[0041] Specifically, the receiver acts as the initiator, sequentially sending channel sounding request signals on multiple preset frequency channels; the beacon acts as the reflector, receiving the request and sending a response signal on the same frequency; the initiator measures the phase difference of the signals on each frequency and calculates the phase ranging distance d1 using a multi-frequency point phase difference algorithm; simultaneously, it measures the round-trip time (RTT) and calculates the RTT ranging distance d2; then, it performs a weighted average of d1 and d2 to obtain the final accurate distance (sub-meter or centimeter level).

[0042] Step S6: After the ranging is completed, the receiving device actively disconnects the connection, the beacon returns to the normal RSSI broadcast mode, and returns to step S2.

[0043] In the above method, the weighted average fusion algorithm in step S6 effectively suppresses ranging errors caused by multipath effects, enabling high-precision positioning to be maintained even in complex indoor environments. The entire process is automatically executed by the firmware of the SoC chip inside the beacon, requiring no manual intervention.

[0044] Reference Figure 7 The following are some typical application scenarios of Bluetooth beacons according to embodiments of the present invention: Application Scenario 1: Indoor Asset Tracking In locations such as warehouses, factories, and hospitals, beacons are attached to valuable assets or equipment. Regular staff can use ordinary smartphones to quickly locate the approximate area of ​​the asset (e.g., warehouse, floor) using RSSI mode; when precise location is required (e.g., finding an item on a specific shelf), high-end phones supporting BLE 6.0 can achieve sub-meter precision positioning through ChannelSounding mode, directly navigating to the asset's location.

[0045] Application Scenario 2: Smart Parking Beacons are deployed in each parking space in the parking lot. When a vehicle enters the parking lot, the occupancy status of the parking space is detected through RSSI mode; drivers can use a mobile phone that supports BLE 6.0 to accurately navigate to the nearest available parking space through Channel Sounding mode, solving the problem of "difficulty in finding parking spaces" in large parking lots.

[0046] Application Scenario 3: Personnel Positioning In factories, hospitals, nursing homes, and other similar locations, personnel wear name tags or wristbands with integrated beacons. Managers can use regular mobile phones to manage personnel at the regional level via RSSI mode (such as attendance and regional access control); in emergencies (such as finding lost elderly people or rescuing trapped individuals), devices supporting BLE 6.0 can achieve precise location tracking via Channel Sounding mode.

[0047] Application Scenario 4: Logistics Parcel Tracking Beacons are attached to express parcels or logistics pallets. Sorting centers use ordinary scanning equipment to quickly screen and sort parcels in RSSI mode; at the delivery end, couriers use mobile phones that support BLE 6.0 to accurately locate target parcels among densely stacked parcels in Channel Sounding mode.

[0048] In the description of this specification, references to terms such as "one embodiment," "some embodiments," "example," "specific example," or "some examples," etc., indicate that a specific feature, structure, material, or characteristic described in connection with that embodiment or example is included in at least one embodiment or example of the present invention. Furthermore, the specific features, structures, materials, or characteristics described may be combined in any suitable manner in one or more embodiments or examples. Moreover, without contradiction, those skilled in the art can combine and integrate the different embodiments or examples described in this specification, as well as the features of those different embodiments or examples.

[0049] Furthermore, the terms "first" and "second" are used for descriptive purposes only and should not be construed as indicating or implying relative importance or implicitly specifying the number of technical features indicated. Thus, a feature defined as "first" or "second" may explicitly or implicitly include at least one of that feature. In the description of this invention, "a plurality of" means two or more, unless otherwise explicitly specified.

[0050] The above description is merely a specific embodiment of the present invention, but the scope of protection of the present invention is not limited thereto. Any variations or substitutions that can be easily conceived by those skilled in the art within the technical scope disclosed in the present invention should be included within the scope of protection of the present invention. Therefore, the scope of protection of the present invention should be determined by the scope of the claims.

Claims

1. A Bluetooth beacon with dual positioning modes, characterized in that, include: A battery, used to provide operating voltage for the Bluetooth beacon; A power management module, connected to the battery, is used to convert the battery voltage into the operating voltage required by the SoC chip and to achieve low-power power management. The SoC chip is connected to the power management module and configured to execute dual positioning logic; The PCB antenna is connected to the radio frequency port of the SoC chip and is used to transmit and receive Bluetooth signals; The SoC chip is configured to perform the following dual-location logic: In the default state, Bluetooth Low Energy broadcast data packets containing a dual-mode identifier are periodically sent at preset broadcast intervals, so that the receiving device can achieve coarse positioning by receiving the broadcast data packets and measuring the RSSI value; wherein, the dual-mode identifier is used to indicate that the Bluetooth beacon supports both RSSI-based coarse positioning mode and Channel Sounding-based fine positioning mode. When a connection request is received from a receiving device that supports Channel Sounding, a Bluetooth Low Energy connection is established, and the system switches to a Channel Sounding-based precision positioning mode to perform a channel detection process with the receiving device to achieve high-precision ranging and positioning. After the channel detection process is completed or the connection is lost, the system automatically returns to the default state.

2. The Bluetooth beacon as described in claim 1, characterized in that, The Bluetooth Low Energy Broadcast data packet contains multiple standard fields and one vendor-specific data field, and the dual-mode identifier is set in the vendor-specific data field; The dual-mode identifier includes a vendor ID and a dual-mode capability flag, which indicates that the Bluetooth beacon supports a precise positioning mode based on Channel Sounding.

3. The Bluetooth beacon as described in claim 2, characterized in that, The channel detection process includes: The receiving device serves as the channel sounding initiator, and the beacon serves as the reflector. The initiating end sequentially sends channel probe request signals on multiple preset frequency channels; After receiving the request signal, the reflecting end sends a response signal on the corresponding frequency channel; The initiating end measures the signal phase difference and / or round-trip time on each frequency channel, and calculates the precise distance between itself and the reflecting end using a multi-frequency point phase difference algorithm.

4. The Bluetooth beacon as described in claim 3, characterized in that, The multi-frequency phase difference algorithm includes: Let the phase measured at the initiating end at the i-th frequency fi be φi, and the phase measured at the j-th frequency fj be φj. Then, the phase ranging distance d1 is calculated according to the following formula: d1 = c × Δφ / (4π × Δf) Where c is the speed of light, Δφ = |φi - φj| is the phase difference, and Δf = |fi - fj| is the frequency difference; Furthermore, based on the round-trip time (RTT) measurement, the RTT ranging distance d2 = c × RTT / 2 is calculated. The final ranging distance is obtained by weighting the phase ranging distance d1 and the RTT ranging distance d2.

5. The Bluetooth beacon as described in claim 1, characterized in that, The power management module is configured to dynamically switch the low-power operating mode of the SoC chip according to the operating stage of the SoC chip; wherein the low-power operating mode of the SoC chip includes at least: system shutdown mode, system power-on mode, RF transmission mode, RF reception mode and CPU active mode. In the default state, the power management module controls the SoC chip to switch cyclically according to the following timing sequence: enter the RF transmit mode to send broadcast data packets, enter the system power-on mode to keep RAM and wait for timed wake-up after the transmission is completed, enter the RF receive mode at intervals during the broadcast interval to listen for connection requests, and return to the system power-on mode when no connection request is received. When the connection request is received during a broadcast interval, the power management module controls the SoC chip to switch to CPU active mode to perform the channel detection process, and restores the low-power operating mode timing to the default state after completion; When the preset deep sleep conditions are met, the power management module controls the SoC chip to enter the system shutdown mode. In the system shutdown mode, the current consumption is less than 0.5μA, and only the GPIO wake-up function is retained.

6. The Bluetooth beacon as described in claim 1, characterized in that, The battery is a disposable lithium battery, which is one of CR2032 button cell, CR2450 button cell, lithium-ion battery or alkaline battery; The SoC chip is a Nordic nRF54L15 SoC chip, which integrates an ARM Cortex-M33 application processor, a 2.4GHz RF transceiver, Flash memory, RAM memory, and various peripheral interfaces.

7. The Bluetooth beacon as described in claim 1, characterized in that, The preset broadcast interval is 100ms to 1s, and the preset broadcast interval is adjustable.

8. The Bluetooth beacon as described in claim 1, characterized in that, The PCB antenna is an onboard inverted F antenna or a serpentine antenna. Copper plating and metal devices are prohibited in the area around the antenna.

9. A positioning method based on a Bluetooth beacon according to any one of claims 1-8, characterized in that, Includes the following steps: Step S1: The Bluetooth beacon powers on and starts up, the system initializes and configures broadcast parameters; Step S2: The Bluetooth beacon enters the normal RSSI broadcast mode and periodically sends BLE broadcast data packets containing dual-mode identifiers at preset broadcast intervals; wherein, the Bluetooth beacon enters a low-power sleep state during the broadcast intervals, waiting for the next broadcast timer to wake it up or for an external interrupt; Step S3: Determine whether the Bluetooth beacon has received a connection request from a receiving device that supports Channel Sounding. If not, return to step S2. Step S4: If a connection request is received, the Bluetooth beacon establishes a BLE connection and switches to Channel Sounding reflective mode; Step S5: The Bluetooth beacon and the receiving device perform the Channel Sounding ranging process. The receiving device, as the initiator, measures the phase difference and round-trip time to calculate the precise distance. Step S6: After ranging is completed, the receiving device disconnects, the Bluetooth beacon returns to the normal RSSI broadcast mode, and returns to step S2.

10. The positioning method as described in claim 9, characterized in that, In step S5, the ChannelSounding ranging process includes: The initiating end sequentially sends channel probe request signals on multiple preset frequency channels; After receiving the request signal, the reflector sends a response signal on the corresponding frequency channel; The initiating end measures the signal phase difference on each frequency channel and calculates the phase ranging distance d1 using a multi-frequency point phase difference algorithm. The initiating end simultaneously measures the round-trip time (RTT) and calculates the RTT ranging distance d2 based on the RTT measurement value. The final ranging distance is obtained by weighting the phase ranging distance d1 and the RTT ranging distance d2.

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