Positioning method based on positioning reference type terminal, redcap terminal and apparatus

Abstract

This invention provides a positioning method, RedCap terminal, and apparatus based on positioning reference terminals, applicable to positioning reference networks comprising a positioning server, several base stations, and several positioning reference terminals. The method includes: establishing initial connections between each positioning reference terminal and a serving base station in the positioning reference network; establishing a connection with the positioning server based on a positioning protocol via NAS messages and reporting capability information to the positioning server; the positioning server sending positioning management requests to the positioning reference terminals via the positioning protocol based on the capability information and network planning requirements; the positioning reference terminals acquiring their own reference positions and calculating the signal propagation time difference to generate positioning reference information; the positioning server processing each positioning reference information to generate positioning correction information; and generating the location coordinates of the target UE device in response to a positioning request initiated by the target UE device. This invention can achieve high-precision positioning with low cost and low power consumption.

Description

Technical Field

[0001] This invention relates to the field of high-precision positioning technology, and in particular to a positioning method, RedCap terminal, and device based on a positioning reference terminal. Background Technology

[0002] High-precision positioning technology in 5G and its evolved versions is one of the core technologies in the field of modern communication and positioning fusion. This technology uses positioning reference signals between the terminal and the base station to accurately measure key parameters such as time of arrival and angle of arrival, thereby accurately calculating the terminal's location. Its positioning accuracy can reach meter-level or even sub-meter level, making it a core infrastructure supporting precise services in numerous scenarios such as the Internet of Things, intelligent transportation, industrial IoT, and smart parks, greatly expanding the application boundaries and value of 5G technology.

[0003] Currently, the mainstream implementation of 5G high-precision positioning strictly follows the Release 16 / 17 standards released by the 3rd Generation Partnership Project (3GPP). It relies on signal interaction between the terminal and network sides to complete basic positioning calculations. The network side can introduce dedicated positioning reference terminals, which, through their known precise location combined with base station signal measurement data, provide error correction for ordinary terminals, offsetting propagation interference errors. However, these reference terminals are based on fully functional 5G User Equipment (UE), resulting in high hardware costs and high power consumption, making large-scale, dense deployment difficult and severely restricting the widespread availability of high-precision positioning services, failing to meet the needs of a massive number of terminals. To address the cost and power consumption pain points of IoT terminals, 3GPP introduced Reduced Capability (RedCap) terminal technology in Release 17. This terminal's core advantages are low power consumption, low cost, and low complexity. By cutting unnecessary communication functions, it significantly reduces cost and power consumption while ensuring core communication requirements. However, the core role of the RedCap terminal defined by the current 3GPP standard is data consumer. The design focuses on downlink data reception and uplink small data reporting. It has not been optimized for the role of network positioning infrastructure at the protocol or hardware level. At present, the industry lacks dedicated positioning reference terminals that are extremely low cost, extremely low power consumption and can be identified and scheduled by 5G standard protocols. This is also a key bottleneck for the large-scale popularization of 5G high-precision positioning services. Summary of the Invention

[0004] The present invention aims to provide a positioning method, RedCap terminal and device based on a positioning reference terminal to solve the above-mentioned technical problems and achieve high-precision positioning with low cost and low power consumption.

[0005] To address the aforementioned technical problems, this invention provides a positioning method based on a positioning reference terminal, applicable to a positioning reference network comprising a positioning server, several base stations, and several positioning reference terminals, characterized in that it includes: In the positioning reference network, an initial connection is established between each positioning reference terminal and the serving base station; The positioning reference terminal establishes a connection with the positioning server based on the positioning protocol through NAS messages, and reports capability information to the positioning server through the positioning protocol; the capability information includes the positioning measurement capabilities supported by the positioning reference terminal. Based on capability information and network planning requirements, the positioning server sends a positioning management request to the positioning reference terminal via a positioning protocol; the positioning management request carries the configuration parameters of the positioning reference task. The positioning reference terminal obtains its own reference position, calculates the signal propagation time difference based on the actual measurement value of the signal emitted by the base station in the positioning reference network reaching the reference position, generates positioning reference information, and reports it to the positioning server. The positioning server processes the positioning reference information reported by each positioning reference terminal and generates positioning correction information. In response to a location request initiated by the target UE device, the location coordinates of the target UE device are generated based on the location correction information.

[0006] In the above solution, during the access phase, positioning reference terminals are identified and dedicated positioning management requests are issued, enabling precise collaboration between the terminal and the network. Without altering the existing 5G network architecture and protocols, the low-cost, low-power, and wide-coverage characteristics of positioning reference terminals are reused to quickly build a high-density positioning reference source, solving the problems of high deployment cost, limited coverage, and poor scalability of traditional positioning reference stations. Secondly, the positioning reference terminal uses a multi-source fusion positioning engine to generate its own high-precision reference position and uses this as a benchmark to calculate the propagation time difference between the measured and theoretical values ​​of the base station signal, transforming the single-point high-precision position into reference information usable for global correction, thus achieving networked output of the positioning benchmark. Furthermore, the positioning server performs spatiotemporal alignment on data reported by multiple terminals, constructing differential correction fields and enhanced auxiliary data respectively, integrating discrete and heterogeneous terminal data into continuous, global positioning correction resources, improving the reliability and coverage of correction information. Ordinary UEs can achieve high-precision positioning using positioning correction information without hardware upgrades, reducing the barrier to entry and terminal costs associated with high-precision positioning.

[0007] In one implementation, the positioning reference terminal is a RedCap terminal with reduced capabilities.

[0008] In the above scheme, the positioning reference terminal is limited to the reduced-capability RedCap terminal. On the one hand, it can make full use of the inherent advantages of RedCap terminal, such as low cost, low power consumption, small bandwidth, and easy deployment. Under the premise of meeting the requirements for positioning reference data collection and reporting, it can reduce the overall deployment cost of the positioning reference network and the terminal hardware overhead. On the other hand, as a 5G standard terminal, RedCap terminal can directly access the existing 5G network without the need for hardware modification of base stations and core networks. It can quickly build a wide-coverage, high-density positioning reference network, while reducing terminal power consumption and complexity, and improving the stability and maintainability of the positioning reference network.

[0009] In one implementation, the positioning reference terminal obtains its own reference position, including any of the following methods: Method 1: By using a multi-source sensor fusion positioning engine, observation data from different location sources are collected, and a recursive estimation filtering algorithm is used to fuse and solve the observation data to generate the reference position of the reference positioning terminal itself; wherein, the types of location sources include one or more of the following: GNSS multi-frequency multi-mode receiver chip, 5G NR positioning signal receiving link, IMU, and storage module of pre-stored calibration map; Method 2: Read the reference position of the positioning reference terminal itself from the locally stored calibration map or the pre-configured precise coordinates; Method 3: Receive the pre-stored location information of the positioning reference terminal from the positioning server or other network elements on the network side, and use the location information that has passed the consistency verification as the reference position of the positioning reference terminal itself.

[0010] The above scheme provides three flexible and selectable methods for obtaining reference positions for positioning reference terminals, which can effectively adapt to different deployment scenarios, hardware configurations and network conditions. The multi-source sensor fusion positioning engine combined with the recursive estimation filtering algorithm can autonomously generate high-precision continuous reference positions in dynamic or complex environments. The method of pre-storing calibration coordinates locally is suitable for fixed deployment scenarios and does not require real-time calculation and has lower power consumption. The method of receiving position information from the network side and performing consistency verification can still obtain reliable reference positions when the terminal sensors are limited or malfunctioning. The three methods complement each other and can significantly improve the applicability, reliability and robustness of the positioning reference terminal in obtaining high-precision reference positions.

[0011] In one implementation, a positioning management request is sent to the positioning reference terminal via a positioning protocol, specifically including: The location server generates an LPP request message containing location reference task configuration parameters and sends it to the AMF; AMF encapsulates the LPP request message in a NAS protocol data unit and sends it to the serving base station; The serving base station transmits the NAS PDU containing the LPP request message to the positioning reference terminal.

[0012] In the above scheme, by using standardized LPP messages and NAPDU encapsulation and transparent transmission processes between the positioning server, AMF, and serving base station, and strictly following the 5G core network control plane transmission mechanism, reliable delivery and accurate delivery of positioning management requests can be achieved without modifying the existing network architecture and interface protocols. The AMF performs NAS encapsulation of LPP request messages, and the serving base station only performs transparent forwarding. This ensures the security and integrity of the positioning configuration information transmission without increasing the parsing burden on the access network. It ensures that the positioning reference task configuration parameters are efficiently, stably, and in a standardized manner transmitted to the positioning reference terminal, thereby improving the standardization and compatibility of the positioning process.

[0013] In one implementation, The signal propagation time difference is calculated based on the actual measured value of the signal transmitted by the base station in the positioning reference network reaching the positioning reference terminal, and positioning reference information is generated, specifically including: The base stations corresponding to the PRS signals detected by the positioning reference terminal at the same time are paired with the serving base stations to construct several base station pairs. The theoretical RSTD value for each base station pair is calculated based on the base station location coordinates within the base station pair and the reference position of the positioning reference terminal itself. Obtain the actual RSTD measurement value for each base station pair, and generate the signal propagation time difference between the positioning reference terminal and each base station pair based on the actual RSTD measurement value and the theoretical RSTD value; Based on the type of location reference information in the location management request, the encapsulation strategy is invoked to generate location reference information and report it to the location server.

[0014] In the above scheme, by constructing base station pairs, calculating theoretical RSTD values, obtaining actual RSTD measurement values ​​and generating signal propagation time difference, and encapsulating and reporting according to the strategy, the complete process can accurately extract the common errors introduced by the signal during propagation based on the high-precision reference position of the terminal itself. The original measurement data is transformed into positioning reference information that can be used for network correction, realizing the quantification and standardized output of positioning errors. At the same time, it is consistent with the RSTD measurement mechanism subsequently adopted by the target UE, ensuring the effectiveness and universality of the correction data, and providing high-quality and high-reliability raw data support for the positioning server to generate high-precision positioning correction information.

[0015] In one implementation, the positioning server processes the positioning reference information reported by each positioning reference terminal to generate positioning correction information, specifically including: The validity of the positioning reference information reported by each positioning reference terminal is verified based on signal quality indicators and consistency principles. The verified positioning reference information is spatiotemporally aligned based on the timestamp and the reference position of each positioning reference terminal. Depending on the type of positioning reference information, the aligned data are processed to generate differential correction fields or augmentation auxiliary data, which serve as positioning correction information.

[0016] In the above scheme, the positioning reference information is validated, spatiotemporally aligned, and categorized to generate differential correction fields or enhanced auxiliary data. This can eliminate abnormal data, unify the spatiotemporal reference of multi-terminal data, and fuse discrete and heterogeneous positioning reference data into full-coverage, high-precision positioning correction information. This effectively solves the problems of asynchronous, inconsistent, and uneven quality of data reported by multiple terminals, improves the accuracy and usability of positioning correction information, and thus significantly improves the accuracy and robustness of the overall positioning system.

[0017] In one implementation, in response to a positioning request initiated by the target UE device, the location coordinates of the target UE device are generated based on positioning correction information, specifically including: In response to a location request initiated by the target UE device, the location server obtains the RSTD measurement value of the target UE device relative to a preset base station pair; The positioning server extracts the corresponding signal propagation time difference from the pre-generated differential correction field based on the coarse position coordinates of the target UE device; The positioning server calculates and generates high-precision location coordinates of the target UE device based on RSTD measurements, signal propagation time difference, and the location coordinates of a preset base station.

[0018] In the above scheme, the RSTD measurement value of the target UE is centrally obtained by the positioning server. The signal propagation time difference of the corresponding area is extracted from the differential correction field for error correction. The position is calculated by combining the base station coordinates. This can achieve high-precision positioning calculation on the network side, reduce the requirements on the computing power and positioning capabilities of the target UE terminal, and enable ordinary UEs to obtain sub-meter or even higher precision positioning results without upgrading hardware. At the same time, the centralized processing of positioning calculation facilitates unified network scheduling and optimization, and improves the consistency and reliability of positioning results.

[0019] In one implementation, in response to a positioning request initiated by the target UE device, generating the location coordinates of the target UE device based on positioning correction information further includes: In response to a location request initiated by the target UE device, the location server extracts the location correction information within the area where the target UE device is located and sends it to the target UE device via the LPP protocol; The target UE device measures the actual RSTD value of the preset base station pair and obtains the corresponding signal propagation time difference or enhanced auxiliary data from the sent positioning correction information; The target UE device calculates and generates its own high-precision position coordinates on the terminal side based on the actual RSTD value, signal propagation time difference, or enhanced auxiliary data.

[0020] In the above scheme, the positioning server sends regional positioning correction information to the target UE, and the UE autonomously completes RSTD measurement, error compensation and location calculation on the terminal side. This can distribute the positioning calculation pressure to the terminal side, greatly improve the system's ability to support the concurrent positioning of massive UEs, reduce the computing load of the positioning server and the network transmission pressure, and the terminal-side calculation has the advantages of lower latency and higher real-time performance. It can directly correct using the signal propagation time difference, or combine with enhanced auxiliary data to achieve multi-source fusion positioning, further improving positioning accuracy and scene adaptability.

[0021] Secondly, this application also provides a positioning reference type RedCap terminal, applicable to the positioning method based on the positioning reference terminal described above, wherein the RedCap terminal is configured as follows: During the establishment of an RRC connection with the serving base station, the first capability information is reported to the serving base station via RRC signaling. The first capability information includes a dedicated identifier for identifying the RedCap terminal as a positioning reference type terminal. The dedicated identifier is an enumerated value added in the RedCap type field of the UE capability information element in the RRC protocol to indicate the positioning reference, or a dedicated indication information added in the RRC connection establishment completion message.

[0022] In the above scheme, during the RRC connection process of the RedCap terminal, the first capability information containing a dedicated identifier is reported using RRC signaling to explicitly identify the terminal as a positioning reference RedCap terminal. This dedicated identifier is implemented by adding an enumeration value or dedicated indication information to the UE capability information element in the existing RRC protocol, without requiring significant changes to the protocol framework. The network side can quickly and accurately identify the positioning reference terminal type and perform differentiated configuration and management, which improves the network's identification efficiency and scheduling accuracy of reference terminals, ensures the decoupling of the positioning reference process from ordinary service processes, and enhances the manageability and scalability of the positioning reference network.

[0023] Thirdly, the present invention also provides a positioning device based on a positioning reference terminal, applicable to a positioning reference network comprising a positioning server, several base stations, and several positioning reference terminals, including: The initial connection establishment module is used to establish the initial connection between each positioning reference terminal and the serving base station; The LPP protocol execution module is used to establish a connection with the positioning server based on the positioning protocol through NAS messages, and to report capability information to the positioning server through the positioning protocol; the capability information includes the positioning measurement capabilities supported by the positioning reference terminal. The management request sending module is used to enable the positioning server to send a positioning management request to the positioning reference terminal through the positioning protocol based on capability information and network planning requirements; wherein the positioning management request carries the configuration parameters of the positioning reference task; The reference information generation module is used to enable the positioning reference terminal to obtain its own reference position, calculate the signal propagation time difference based on the actual measured value of the signal emitted by the base station in the positioning reference network reaching the reference position, generate positioning reference information, and report it to the positioning server. The positioning information generation module is used to enable the positioning server to process the positioning reference information reported by each positioning reference terminal and generate positioning correction information. The location request response module is used to respond to a location request initiated by the target UE device and generate the location coordinates of the target UE device based on the location correction information. Attached Figure Description

[0024] Figure 1 This is a flowchart illustrating a positioning method based on a positioning reference terminal provided in one embodiment of the present invention. Figure 2 This is a schematic diagram of a positioning device based on a positioning reference terminal provided in one embodiment of the present invention. Detailed Implementation

[0025] The specific embodiments of the present invention will be described in further detail below with reference to the accompanying drawings and examples. The following examples are for illustrative purposes only and are not intended to limit the scope of the invention.

[0026] The terms "first" and "second," etc., in the specification, claims, and drawings of this application are used to distinguish different objects, not to describe a specific order. Furthermore, the terms "comprising" and "having," and any variations thereof, are intended to cover non-exclusive inclusion. For example, a process, method, system, product, or apparatus that includes a series of steps or units is not limited to the listed steps or units, but may optionally include steps or units not listed, or may optionally include other steps or units inherent to such processes, methods, products, or apparatus.

[0027] In this document, the term "embodiment" means that a particular feature, structure, or characteristic described in connection with an embodiment may be included in at least one embodiment of this application. The appearance of this phrase in various places throughout the specification does not necessarily refer to the same embodiment, nor is it a separate or alternative embodiment mutually exclusive with other embodiments. It will be explicitly and implicitly understood by those skilled in the art that the embodiments described herein can be combined with other embodiments.

[0028] First, some of the terms used in this application will be explained to facilitate understanding by those skilled in the art.

[0029] (1) NAS message: Non-Access Stratum message, which is the control signaling that is directly interacted between the 5G terminal UE and the 5G core network.

[0030] (2) IMU (Inertial Measurement Unit): An inertial measurement unit is a sensor component based on the principle of inertia that can acquire the motion state of a carrier in real time. Its core function is to output the three-dimensional acceleration and three-dimensional angular velocity of the carrier. (2) AMF (Access and Mobility Management Function): It is a core network element of the control plane in the 5G core network. It follows standard protocols such as 3GPP TS23.501 and focuses on the access control, mobility management and signaling coordination of UE devices. It is the signaling hub for UE devices to access the 5G network.

[0031] (3) LPP (LTE Positioning Protocol) is the core positioning protocol standardized by 3GPP. Its core function is to transparently transmit positioning-related signaling and data between the positioning server and the UE, and realize the full-process coordination of positioning configuration, measurement and result feedback.

[0032] (4) NAS PDU: (Non-Access Stratum Protocol Data Unit) is a core network signaling data encapsulation format defined in the 3GPP standard. It refers to the signaling data block transmitted between the UE and the 5G core network control plane network element at the NAS layer.

[0033] (5) RSTD: (Reference Signal Time Difference) is a key positioning measurement parameter defined by 3GPP standards (TS 38.331, TS 36.355). It refers to the time difference between the positioning reference signals (PRS) sent by two base stations (usually the serving base station + neighboring base stations) received by the UE (such as RedCap terminals and ordinary mobile phones) and the arrival time of the terminal.

[0034] (6) LMF (Location Management Function): This is a key network function in the 5G core network defined in 3GPP R16 and later versions. It is the core control and computing entity of the entire 5G positioning system. Its core responsibility is to calculate, manage, and deliver services to the UE's geographical location based on the measurement data reported by the radio side and the terminal, through standardized protocols and positioning algorithms.

[0035] See Figure 1 , Figure 1 This is a flowchart illustrating a positioning method based on a positioning reference terminal according to an embodiment of the present invention. The embodiment of the present invention provides a positioning method based on a positioning reference terminal, applicable to a positioning reference network comprising a positioning server, several base stations, and several positioning reference terminals, including steps 101 to 106, each step being as follows: Step 101: In the positioning reference network, establish the initial connection between each positioning reference terminal and the serving base station.

[0036] In this embodiment of the invention, after the terminal powers on, it performs a cell search, identifies the synchronization signals of base stations within the positioning reference network, and selects the base station with the best signal quality. It then establishes an initial physical layer connection with this base station through a random access procedure, selecting it as the serving base station. The terminal initiates an RRC connection establishment request to the serving base station, completing the construction of a higher-layer signaling channel. During the RRC connection phase, the terminal sends UE capability information to the serving base station using a pre-configured UE-specific capability identifier, declaring its own positioning reference terminal identity. By selecting a serving base station in the positioning reference network, establishing an initial connection between the positioning reference terminal and the base station, and sending UE capability information containing a unique identifier to the base station, the terminal clearly identifies itself as a positioning reference terminal, distinguishing it from ordinary terminals. This reuses the standardized terminal access process, ensuring compatibility with existing 5G networks without requiring additional network modifications. The unique capability identifier enables accurate identification of the positioning reference terminal, laying the foundation for subsequent targeted configuration on the network side. It should be noted that the positioning reference network in this embodiment of the invention is not a dedicated network independent of the existing mobile communication network, but rather an enhanced positioning network based on the existing 5G network infrastructure. It is composed of several base stations and positioning servers within the 5G network, as well as several positioning reference terminals deployed within the coverage area of ​​the 5G network. It represents a functional extension of the 5G network in high-precision positioning scenarios. This positioning reference network uses existing 5G network base station equipment and wireless transmission links as its basic carriers, requiring no modification to the 5G network's hardware architecture or protocol system. The positioning server is the LMF defined by the 3GPP standard; the base station is the 5G base station gNB or the evolved next-generation base station; the positioning reference terminal, as a special terminal with positioning reference capabilities, accesses the existing 5G network along with ordinary 5G terminals and IoT terminals, following the standardized network access, signaling interaction, and data transmission rules of the 5G network. The positioning method provided in this embodiment of the invention is fully compatible with and applicable to the 5G network architecture defined by 3GPP or next-generation mobile networks possessing the aforementioned network element characteristics. In one embodiment, the positioning reference terminal is a RedCap terminal with reduced capabilities.

[0037] In this invention, a positioning reference terminal refers to a terminal device with high-precision positioning capabilities that can provide positioning correction information to other terminals. Besides RedCap terminals with reduced capabilities, this type of terminal can also be a regular 5G terminal or an IoT terminal. Its core features are the ability to obtain its own high-precision reference position, the ability to measure base station signals and calculate signal propagation time differences, and the ability to report the generated positioning reference information to a positioning server for constructing positioning correction information.

[0038] Step 102: The positioning reference terminal establishes a connection with the positioning server based on the positioning protocol through NAS messages, and reports capability information to the positioning server through the positioning protocol; wherein, the capability information includes the positioning measurement capabilities supported by the positioning reference terminal.

[0039] In this embodiment of the invention, the positioning reference terminal establishes a signaling connection with the positioning server based on a standardized positioning protocol by sending a NAS message containing positioning measurement capabilities. After the connection is established, the terminal reports its own positioning measurement capability information to the positioning server in full through the positioning protocol, so that the positioning server can clearly understand the positioning function boundary and performance level of the terminal, and provide accurate basis for subsequent customized issuance of positioning management requests.

[0040] Step 103: The positioning server sends a positioning management request to the positioning reference terminal through the positioning protocol based on the capability information and network planning requirements; the positioning management request carries the configuration parameters of the positioning reference task.

[0041] In this embodiment of the invention, after receiving and parsing the positioning measurement capability information reported by the positioning reference terminal, the positioning server, in conjunction with the overall planning requirements of the positioning reference network, such as the positioning accuracy requirements and coverage of the terminal deployment area, and the network's reporting requirements for positioning reference information, formulates an appropriate positioning reference task by matching the terminal's capabilities with network requirements. Subsequently, through the LPP standardized positioning protocol, a positioning management request is sent to the positioning reference terminal. The request carries a complete set of configuration parameters for the positioning reference task, including the type of location source to be collected, multi-source fusion strategy, signal measurement parameters and accuracy requirements, the type of positioning reference information, and the reporting triggering mechanism and format, clarifying the specific standards and requirements for the terminal to execute the positioning reference task. The positioning management request defines the terminal's positioning reference task configuration parameters. The positioning server customizes the configuration of the positioning reference terminal, ensuring that the terminal's positioning reference behavior matches the network's positioning planning requirements. Standardized request commands enable unified scheduling and management of a massive number of positioning reference terminals, adapting to large-scale networking scenarios.

[0042] In one embodiment, sending a positioning management request to a positioning reference terminal via a positioning protocol specifically includes: the positioning server generating an LPP request message containing positioning reference task configuration parameters and sending it to the AMF; the AMF encapsulating the LPP request message in a NAS protocol data unit and sending it to the serving base station; and the serving base station transparently transmitting a NASPDU containing the LPP request message to the positioning reference terminal.

[0043] Specifically, after receiving the UE capability information containing a dedicated capability identifier reported by the positioning reference terminal, the serving base station identifies the terminal as a positioning reference terminal and then triggers the establishment of a positioning session between the terminal and the core network positioning server (LMF). The terminal establishes an LPP connection with the LMF through a non-access stratum (NAS) message and reports second capability information to the LMF via the LPP protocol. This information includes detailed positioning measurement capabilities supported by the terminal, such as supported positioning methods and measurement accuracy. This LPP message, as part of a NAS PDU, is sent by the terminal to the serving base station. The serving base station transparently transmits this NAS PDU to the Access and Mobility Management Function (AMF), which then forwards it to the LMF. Throughout this process, the serving base station only performs the transparent transmission function and does not parse the LPP message content. After receiving the terminal's positioning capability information, the LMF, combined with network planning requirements and real-time positioning service requirements, such as reporting frequency and accuracy requirements, generates a dedicated positioning management request for the terminal. The request, in the form of an LPP protocol message, includes the following configuration parameters: (1) the type of positioning reference information (differential correction information or raw observation dataset); (2) the location source type and fusion strategy (such as the fusion weight of GNSS / 5G NR / IMU); (3) the number of signal parameters to be measured and the accuracy requirements (such as RSTD measurement of PRS signals, with an accuracy ≤0.1μs); and (4) the reporting triggering mechanism and format (such as periodic reporting, event-triggered reporting, etc.). The LMF sends the generated LPP request message to the AMF, which encapsulates it in a NAS protocol data unit and sends it to the serving base station. The serving base station transmits the NAS PDU to the positioning reference terminal through the established RRC connection. After decapsulation, the terminal obtains the LPP request content and initializes the positioning engine according to the configuration parameters therein, and executes the subsequent positioning reference task.

[0044] For example, after the serving base station gNB2 receives the UE capability information of the positioning reference terminal, it forwards the information directly to the campus positioning server LMF through the NG-RAN interface. After parsing the information, the LMF identifies the terminal as a positioning reference terminal and the terminal is deployed in the underground parking lot of the campus. Based on the network positioning plan and real-time positioning requirements of the parking lot, a customized positioning management request is generated for the terminal. The request specifies that: (1) the positioning reference information type is differential correction information; (2) the location source type and fusion strategy is GNSS+5G NR+pre-stored parking lot calibration location, with an initial weight of 60%:30%:10%; (3) the measurement signal parameter is the RSTD (Reference Signal Time Difference) of 5G NR PRS (Positioning Reference Signal), with an accuracy of ≤0.1μs; (4) the reporting triggering mechanism and format is periodic reporting every 10 seconds. The campus LMF sends the generated location management request to the serving base station gNB2 through the NG-RAN interface. gNB2 encapsulates the request into a Request Location Information message of the standard LPP location signaling and uses the RRC signaling connection established with the location reference terminal to send the LPP signaling to the terminal.

[0045] Step 104: The positioning reference terminal obtains its own reference position, calculates the signal propagation time difference based on the actual measurement value of the signal emitted by the base station in the positioning reference network reaching the reference position, generates positioning reference information, and reports it to the positioning server.

[0046] In this embodiment of the invention, the positioning reference terminal first initializes the positioning engine based on the positioning management request. It generates its own high-precision reference position by Kalman filtering multi-source fusion of observation data from multiple location sources such as GNSS, 5G NR, and IMU. Then, using this reference position as a benchmark, it pairs base stations that detect PRS signals at the same time with the serving base station to form base station pairs. It calculates the theoretical RSTD value of each base station pair and obtains the actual RSTD measurement value of the base station pair. It calculates the signal propagation time difference ΔRSTD, which includes the common propagation error, by using the difference between the measured value and the theoretical value. Finally, according to the positioning management request, it encapsulates ΔRSTD into differential correction information or combines its own reference position with the original observation data to encapsulate it into an original observation dataset, forming standardized positioning reference information. This information is then forwarded by the serving base station within a preset uplink time slot and reported to the positioning server.

[0047] In one embodiment, the positioning reference terminal obtains its own reference position in any of the following ways: Method 1: By using a multi-source sensor fusion positioning engine, observation data from different location sources are collected, and a recursive estimation filtering algorithm is used to fuse and solve the observation data to generate the reference position of the reference positioning terminal itself; wherein, the types of location sources include one or more of the following: GNSS multi-frequency multi-mode receiver chip, 5G NR positioning signal receiving link, IMU, and storage module of pre-stored calibration map; Method 2: Read the reference position of the positioning reference terminal itself from the locally stored calibration map or the pre-configured precise coordinates; Method 3: Receive pre-stored location information of the positioning reference terminal from the LMF or other network elements on the network side, and use the location information that has passed the consistency verification as the reference position of the positioning reference terminal itself; preferably, it also includes: the positioning reference terminal obtains the verification position through other positioning methods, and uses the verification position to perform consistency verification on the accurate location information received from the network side; if the verification passes, the accurate location information is confirmed to be valid.

[0048] In this embodiment of the invention, the positioning reference terminal can obtain its own reference position through three independent methods, adapting to different deployment scenarios, hardware conditions, and network environments, all of which can ensure the high accuracy and effectiveness of the reference position. Method one is multi-source fusion autonomous calculation. The terminal uses a pre-deployed multi-source sensor fusion positioning engine to connect to one or more location sources such as GNSS, 5G NR, IMU, and pre-stored calibration maps. After collecting standardized observation data, it uses a recursive estimation filtering algorithm for multi-source fusion calculation. Inertial navigation ensures continuity, and external signals correct drift errors, autonomously generating a high-precision reference position, adapting to scenarios where the terminal is moving or has no pre-stored coordinates. Method two is local pre-stored information reading, a simple and low-power method for static deployment scenarios. For fixed-installation terminals, it directly reads the precise coordinates configured during the pre-deployment stage from the local storage module, or matches the corresponding position with a pre-stored high-precision calibration map, without the need for real-time data collection and calculation, significantly reducing terminal computing power and power consumption, adapting to the requirements of low-cost, low-power fixed deployment. Method 3 is network-side location authorization + local verification, which is a network-assisted method. The terminal receives its own precise location information from the LMF or other network elements in the core network, and at the same time obtains the verification location through its other positioning methods. It performs consistency verification on the network-side location information. If the verification passes, it is used as the reference location; if the verification fails, it re-requests or switches to other methods. Through the dual mechanism of network-side location authorization + local verification, the error risk of single network data is avoided, and it is suitable for scenarios where the terminal sensor is faulty or has no pre-stored information but can still communicate normally.

[0049] Specifically, in the first scenario, the multi-source sensor fusion positioning engine is used to adapt to scenarios where the terminal needs to dynamically update its location or where there are no pre-stored coordinates. The terminal uses a pre-deployed multi-source sensor fusion processing unit to connect to one or more location sources, such as a GNSS multi-frequency multi-mode receiver chip, a 5G NR positioning signal receiving link, an IMU, and a storage module for pre-stored calibration maps, via a low-speed bus. It collects corresponding raw observation data, such as GNSS satellite signals, 5G NR PRS signals, and IMU acceleration / angular velocity data, and adds timestamps and location source identifiers to the data for standardized preprocessing. Subsequently, a recursive estimation filtering algorithm is used to fuse and solve the formatted observation data. IMU high-frequency data triggers state prediction to ensure positioning continuity. Prediction errors are corrected by combining GNSS / 5G NR signal observations, dynamically suppressing sensor drift and environmental interference. Finally, a high-precision, high-continuity reference position for the terminal is calculated. This method combines autonomy and dynamic adaptability, making it the preferred approach for mobile or complex scenarios. The second method is a simple and efficient approach for static positioning scenarios, suitable for fixed deployments of positioning reference terminals where the location does not need to change dynamically, such as terminals permanently installed in industrial parks or smart buildings. During deployment, the precise coordinates of the terminal's actual installation location or a high-precision calibration map of the area where the terminal is located are pre-stored in the local storage module. When a reference position is needed, the terminal does not need to perform complex multi-source data acquisition and fusion calculations; it directly reads the pre-stored calibration map coordinates from the local storage module or directly retrieves the pre-configured precise coordinates as its reference position. This method eliminates the real-time calculation process, significantly reducing the terminal's computing power and power consumption. Furthermore, the accuracy of the reference position is determined by pre-stored calibration information, ensuring high stability and adapting to low-cost, low-power deployment requirements. Method three relies on network-side network elements to provide a location reference, adapting to scenarios where the terminal's own sensors are faulty or lack pre-stored calibration information, but it can still communicate with the network. The core of this method is the dual guarantee of network authorization and local verification, ensuring the validity of the reference position. The terminal first initiates a location information acquisition request to the positioning server or other network elements in the 5G core network, receiving the terminal's precise location information pre-stored by the network. To avoid data transmission or storage errors on the network side, the terminal obtains a verification position through its other positioning methods, such as simple GNSS measurement or coarse positioning of base station cells. This verification position is then compared with the location information received from the network side to check for consistency, such as comparing whether the coordinate deviation between the two is within a preset threshold. If the verification passes, the network-side location information is confirmed to be valid and used as its own high-precision reference position. If the verification fails, the location information is determined to be invalid, and the terminal will request the location information from the network side again, or switch to mode one for autonomous calculation. The verification process avoids the error risk of single network location authorization and ensures the accuracy of the reference position.

[0050] It should be noted that the positioning reference terminal is pre-deployed with a multi-source sensor fusion processing unit at the factory. This unit, as the hardware core of the terminal's positioning engine, is responsible for the unified acquisition, initial synchronization, and transmission of data from multiple location sources. This unit connects to various positioning sources via a low-speed SPI / I2C bus. The connected location sources cover four main categories: satellite, 5G network, inertial navigation, and pre-stored geographic information. Specifically, this includes a GNSS multi-frequency multi-mode receiver chip, a 5G NR positioning signal receiving link, an IMU inertial measurement unit, and a storage module for pre-stored calibration maps. This storage module stores high-precision calibration locations / geographic maps of the terminal's deployment area as an auxiliary positioning source.

[0051] For Method 1, for example, the positioning reference terminal deployed in the underground parking lot of the industrial park has received a positioning management request from the serving base station gNB2. The configuration requirements are: the location source type and fusion strategy are GNSS+5G NR+IMU+pre-stored parking lot calibration location, with an initial weight of 60%:30%:5%:5% and a measurement accuracy of centimeter level. The multi-source sensor fusion processing unit, based on the location source configuration in the positioning management request, simultaneously activates three types of active location sources: GNSS, 5G NR, and IMU, and retrieves the pre-stored calibration location data of the parking lot from the Flash module. During the acquisition process, microsecond-level unified timestamps are added to the pseudorange / carrier phase data of GNSS, the PRS-RSTD / TOA data of 5G NR, and the acceleration / angular velocity data of IMU, and location source identifiers for GNSS, 5G NR, and IMU are added respectively. Simultaneously, the pre-stored calibration location and the acquired data are spatiotemporally calibrated to complete the acquisition of standardized observation data. The terminal's positioning engine then preprocesses the collected observation data: median filtering removes random noise from the GNSS data, mean filtering smooths high-frequency jitter in the IMU data, and all data is converted into a unified three-dimensional spatial observation vector to obtain formatted observation data. After obtaining the formatted observation data, the terminal's positioning engine, according to the fusion strategy specified in the positioning management request, uses a recursive estimation filtering algorithm to fuse and solve the formatted observation data, generating a high-precision reference position for the terminal itself. In a preferred embodiment, the recursive estimation filtering algorithm is specifically implemented using a Kalman filter. The solution process of this Kalman filter includes: (1) State Prediction: State prediction is triggered based on the received IMU data, and the prior state estimate for the current time is generated based on the posterior state estimate of the previous time step. The expression for the prior state estimate is: In the formula for The state prior estimates at each moment include the terminal's three-dimensional position, velocity, attitude, and the predicted values ​​of the sensor zero bias; This is the state transition function of the inertial navigation dynamics model; for The posterior estimate of the state at time 1; for IMU data at any given moment.

[0052] (2) Error covariance prediction: The prior error covariance matrix for updating the state prediction is expressed as: In the formula, for The prior error covariance matrix at time t; Let be the Jacobian matrix of the state transition function; for The posterior error covariance matrix at time t; It is the transpose of the Jacobian matrix; for The noise covariance matrix at each time step.

[0053] (3) Calculation of observation residuals: Based on the received GNSS satellite signals or PRS signals, the observation residuals between the actual observation vectors and the predicted observation vectors are calculated. The expression is as follows: In the formula, for The observation residual at time, for The actual observation vector at time; For observation models; for The predicted observation vector at time.

[0054] (4) Kalman gain calculation: The Kalman gain is calculated based on the updated prior error covariance matrix and the Jacobian matrix of the observation model. The expression is: In the formula, for Kalman gain at time step; To observe the noise covariance matrix.

[0055] (5) State Update: Based on the observation residuals and Kalman gain, the prior state estimate at the current time is corrected to obtain the posterior state estimate at the current time, expressed as: In the formula, for The posterior state estimate at time step includes the terminal's three-dimensional position, velocity, attitude, and the optimal prediction of the sensor's zero bias.

[0056] (6) Error Covariance Update: Based on the Kalman gain and Jacobian matrix, the prior error covariance matrix at the current time is corrected to obtain the posterior error covariance matrix at the current time, expressed as: In the formula, for The posterior error covariance matrix at time t.

[0057] Based on the posterior state estimate at the current moment By extracting the three-dimensional position components, the high-precision reference position of the terminal itself can be obtained.

[0058] It should be noted that Kalman filtering is only one preferred implementation of the recursive estimation filtering algorithm in this invention. In other embodiments, the recursive estimation filtering algorithm can also be extended Kalman filtering (EKF), unscented Kalman filtering (UKF), particle filtering, or other recursive estimation algorithms suitable for multi-source sensor fusion. As long as it can achieve the fusion calculation of multi-source observation data such as GNSS, 5G NR, and IMU, it should be considered as an equivalent implementation of this invention.

[0059] In this embodiment of the invention, the positioning engine of the positioning reference terminal uses high-frequency acquired IMU data as the trigger source. The IMU acquisition frequency is typically 100Hz-500Hz, far higher than GNSS and 5G NR. Even when GNSS or 5G NR signals are blocked, continuous state prediction can still be achieved through the IMU. The state transition function of the inertial navigation dynamics model is used as the basis for the corrected posterior state estimate of the previous time step, combined with the IMU data at time k-1, to calculate the prior state estimate at time k. This prior estimate includes the predicted values ​​of the terminal's core state quantities: three-dimensional position, velocity, and attitude, as well as the predicted values ​​of error states such as IMU accelerometer / gyroscope zero bias. It is a preliminary state result without GNSS / 5G NR correction, which, while ensuring continuity, will have accumulated errors due to IMU drift. The core function is to establish the state transfer relationship of inertial navigation, allowing the terminal to maintain positioning output even without external high-precision observation. Because the inertial navigation dynamics model is a nonlinear function, it needs to be linearized through its Jacobian matrix to describe the transmission law of small state changes. During the calculation, first use the Jacobian matrix. k Posterior error covariance matrix at time 1 and the transpose of the Jacobian matrix The error propagation caused by the state transition is obtained; then the process noise covariance matrix is ​​superimposed. The process noise covariance matrix is ​​used to quantify the uncertainty caused by IMU sensor noise and model error. It is determined by the IMU factory calibration parameters, and finally the prior error covariance matrix at time k is obtained. This matrix is ​​a symmetric positive definite matrix, with the diagonal elements representing the variances of each state variable. A larger variance indicates a less reliable prior estimate of the corresponding state variable. Updating the prior error covariance matrix of the state prediction is crucial for quantitatively transmitting the error, allowing the positioning engine to clearly define the error range of the prior state, thus laying the foundation for subsequent Kalman gain calculation. The calculation of Kalman gain integrates three core parameters: the prior error covariance matrix at time k. Used to quantify the uncertainty of prior states; the transpose of the Jacobian matrix. This is used to linearize the observation model and describe the impact of state changes on the observed values; the observation noise covariance matrix. This is used to quantify the uncertainty of GNSS / 5G NR observations. In the expression for Kalman gain, if... Large value A smaller value indicates a larger Kalman gain, suggesting greater uncertainty in the current prior state and higher reliability of the observations. The positioning engine places more trust in external observations and uses the observation residuals to significantly correct the prior state. If... Small value A large Kalman gain indicates a small Kalman gain, suggesting low uncertainty in the current prior state, low reliability of the observations, and that the positioning engine trusts the IMU's prior state more, making only minor corrections. Adaptive weight allocation of multi-source data is achieved based on the Kalman gain, allowing the fusion result to be dynamically adjusted according to the real-time signal quality of each location source. Then, the state prior estimate is used... Based on this, Kalman gain is used to weight the observed residuals, and the weighted residuals are then added as a correction to the state prior estimate to optimize the prior state. The final state prior estimate is obtained. This includes the 3D position, velocity, and attitude corrected by GNSS / 5G NR, as well as the corrected IMU sensor zero bias and other error states. The 3D position component serves as the terminal's high-precision reference position, combining the continuity of the IMU with the high precision of GNSS / 5G NR, effectively suppressing accumulated IMU drift and ensuring positioning accuracy. The posterior state estimate at time k... In the process, the three-dimensional position component is extracted, which is the high-precision reference position of the positioning reference terminal itself. Furthermore, the prior error covariance matrix is ​​corrected by the expression of the posterior error covariance matrix to obtain the posterior error covariance matrix at time k. , where I is the identity matrix. This matrix quantifies the posterior state estimate. The estimation uncertainty is much lower than that of the prior state because the posterior state is corrected by GNSS / 5G NR. The posterior error covariance matrix is... The diagonal variance value will be significantly reduced. The corrected posterior error covariance matrix is ​​applied to the prediction step at the next time step to realize the iterative loop of Kalman filtering, allowing the multi-source fusion process to continue to execute as new data arrives.

[0060] For method two, namely the verification of the pre-stored location on the network side, for example, when the positioning reference terminal receives pre-stored precise location information from the network side as its own reference location, in order to further ensure the reliability of the location information, the positioning reference terminal can perform the following verification steps: The positioning reference terminal activates its local backup positioning capabilities, such as obtaining single-point positioning through a low-power GNSS receiver or performing a coarse RSTD measurement using a 5G NR signal to obtain a verification position. The accuracy of this verification position may be lower than the final required reference position accuracy and is only used for reasonableness assessment.

[0061] The positioning reference terminal compares the received pre-stored precise location from the network with the verification location, calculating the spatial distance difference or deviation between the two. If the deviation is less than a preset threshold, such as less than 20 meters, the verification is considered successful, confirming the validity of the pre-stored precise location from the network, and using it as a high-precision reference location for subsequent steps. If the verification fails, it indicates that the pre-stored location from the network may not match the current actual deployment scenario. In this case, the terminal can trigger an alarm, request an update of the location information from the network, or fall back to another backup positioning mode.

[0062] In one embodiment, the signal propagation time difference (RSTD) is calculated based on the actual measured value of the signal emitted by the base station in the positioning reference network reaching the positioning reference terminal, and positioning reference information is generated. Specifically, this includes: pairing the base stations corresponding to the PRS signals detected by the positioning reference terminal at the same time with the serving base station to construct several base station pairs; calculating the theoretical RSTD value of each base station pair based on the base station location coordinates within the base station pair and the reference position of the positioning reference terminal itself; obtaining the actual RSTD measurement value of each base station pair, and generating the signal propagation time difference between the positioning reference terminal and each base station pair based on the actual RSTD measurement value and the theoretical RSTD value; and invoking an encapsulation strategy according to the type of positioning reference information in the positioning management request to generate positioning reference information and report it to the positioning server.

[0063] In this embodiment of the invention, the positioning reference terminal completes the detection and screening of PRS positioning reference signals of base stations within the positioning reference network at the same time node, retaining base stations whose signal quality meets the measurement requirements. Subsequently, using the serving base station it accesses as a fixed reference base station, the remaining neighboring base stations that detected PRS signals are paired one-to-one with the serving base station to form several standardized base station pairs. All subsequent RSTD theoretical value calculations and actual value measurements are based on these base station pairs, avoiding calculation errors caused by inconsistent references, and maintaining consistency with the subsequent measurement base station pair system of ordinary UEs, laying the foundation for global differential correction. The positioning reference terminal retrieves the precise three-dimensional position coordinates of each base station in all base station pairs from the local or network side, and combines them with its own high-precision reference position to calculate the straight-line geometric distance from the terminal to the serving base station and neighboring base stations in the base station pair using a spatial geometric algorithm. Then, based on the physical characteristic of the constant speed of light, the theoretical RSTD value of each base station pair is calculated using the ratio of the geometric distance difference to the speed of light. This value is the signal arrival time difference under ideal interference-free scenarios, without any propagation, equipment, or synchronization errors, and is the core reference for measuring the error of actual measurement values. The expression for the theoretical RSTD value is: ; In the formula, For base station The theoretical RSTD value; For positioning reference terminal to base station geometric distance; For positioning reference terminal to base station The geometric distance; c is the speed of light; Then, by analyzing the difference between the theoretical and measured values, common errors applicable to global correction are extracted. The positioning reference terminal, through its own 5G NR positioning signal receiving link, measures the actual RSTD values ​​of each established base station pair, obtaining actual measured values ​​that include common errors such as non-line-of-sight propagation, multipath interference, inter-base station synchronization residuals, and internal device delays. Subsequently, the actual RSTD measurement value of each base station pair is subtracted from the corresponding theoretical RSTD value to calculate the signal propagation time difference for each pair. This difference retains only the common errors within the positioning reference network and is the core raw data for subsequently generating differential correction information and constructing a global differential correction field. The expression for the signal propagation time difference is: ; In the formula, For base station The signal propagation time difference; For base station The actual RSTD measurement value; Furthermore, the key to transforming raw error data into standardized reference information that is recognizable and usable by the network side lies in strictly adhering to the customized configuration requirements of the positioning server. The positioning reference terminal parses the positioning reference information type specified in the positioning management request and calls a preset standardized encapsulation strategy to encapsulate the data: if it is differential correction information, it encapsulates the signal propagation time difference of all base station pairs in an orderly manner according to dimensions such as base station pair identifiers and timestamps; if it is raw observation dataset, it encapsulates the signal propagation time difference along with its own high-precision reference position, raw observation data from each location source, and measured / theoretical RSTD values. After encapsulation, standardized positioning reference information that meets the network side's requirements is generated, preparing for subsequent reporting to the positioning server and conducting global positioning correction.

[0064] For example, after the positioning reference terminal completes the detection of PRS positioning signals from surrounding 5G base stations at the same time, it first filters out base stations, including the serving base station, whose signal quality meets the positioning requirements, forming a list of valid PRS signal base stations. Then, using the serving base station with which the terminal has established a connection as the reference, denoted as i, the remaining neighboring base stations in the list are denoted as j1, j2, j3, etc., and paired one-to-one with the serving base station, ultimately constructing several standardized base station pairs (i, j1), (i, j2), (i, j3), etc. This pairing rule strictly follows the requirements of the 3GPP positioning protocol, uniformly using the serving base station as the reference base station for RSTD calculation, which can avoid calculation errors caused by chaotic base station pairing references, and at the same time allows the network side to quickly parse the received data without additional reference calibration. Then, the terminal retrieves two core data from local storage: one is the three-dimensional precise geographic coordinates of all participating pairing base stations pre-configured / broadcast by the network side, and the other is the terminal's own high-precision reference position. Subsequently, for each base station pair (i,j), the spatial geometric distance from the terminal to base station i and base station j is calculated. Finally, the theoretical STD value of each base station pair is obtained by substituting it into the expression for the theoretical RSTD value. This theoretical RSTD value is the signal arrival time difference of the base station pair under ideal error-free conditions, determined only by the geometric distance difference, without any propagation, equipment, or synchronization errors. It is the core benchmark for measuring the error of the actual measurement value. By comparing the actual RSTD measurement value of the base station pair with the theoretical RSTD value, the signal propagation time difference ΔRSTD, which includes various common errors, is obtained. This value is the core carrier of differential correction information and the core positioning reference data provided by the positioning reference terminal to the network side. The terminal first retrieves and constructs the actual RSTD measurement value RSTDmeasured(i,j) of each base station pair (i,j) collected at the same time from its own 5G NR positioning signal receiving link. This value is the PRS signal arrival time difference between the serving base station and the neighboring base station directly measured by the terminal. It includes common or modelable errors in the actual scenario, such as synchronization residuals between base stations, non-line-of-sight propagation errors, multipath effects, and internal delays of terminal / base station equipment. Subsequently, the actual RSTD measurement value and the corresponding theoretical RSTD value of each base station pair are substituted into the expression for signal propagation time difference to obtain the signal propagation time difference ΔRSTD for each base station pair. The physical meaning of ΔRSTD is the deviation between the actual signal propagation time and the ideal geometric propagation time of a specific base station pair at that location. The magnitude of the deviation directly reflects the degree of signal propagation error at that location. After being reported, it can be used to correct the RSTD measurement values ​​of surrounding ordinary terminals for the same base station pair. Furthermore, the location reference information type specified in the location management request is parsed, and a preset standardized encapsulation strategy is invoked according to the type.If the type is differential correction information, the signal propagation time difference ΔRSTD of all base station pairs is encapsulated in an orderly manner according to the base station pair identifier, and basic information such as terminal identifier and data acquisition timestamp is added to form a differential correction information packet that can be directly used by the network side for error correction. If the type is raw observation dataset, the terminal's own high-precision reference position and the collected raw observation data such as GNSS satellite signals, PRS signals, and IMU data are encapsulated in an integrated manner, and auxiliary information such as data acquisition time, base station list, and measurement accuracy are added to form a raw observation dataset that can be processed by the network side. Both encapsulation strategies follow the 5G positioning data encapsulation specifications formulated by 3GPP to ensure that the serving base station and positioning server can quickly parse it without compatibility errors. As a 5G low-power terminal, the positioning reference terminal will have a dedicated uplink transmission time slot pre-set by the network side. This time slot is configured according to network resource planning and the reporting frequency of positioning reference information, such as a periodic reporting of one uplink time slot every 10 seconds, which avoids network resource conflicts caused by random reporting by the terminal and reduces the uplink transmission power consumption of the terminal. After the terminal completes the encapsulation of the positioning reference information, it will send the encapsulated positioning reference information to the serving base station via the established RRC signaling connection within a preset uplink time slot. Upon receiving the information, the serving base station will not modify the data and will directly forward the complete positioning reference information to the positioning server in the core network through the NG-RAN interface of the 5G network, laying the data foundation for the subsequent construction of global positioning correction information on the network side.

[0065] Step 105: The positioning server processes the positioning reference information reported by each positioning reference terminal and generates positioning correction information.

[0066] In this embodiment of the invention, the positioning server first verifies the validity of the positioning reference information reported by all accessing positioning reference terminals. Based on signal quality indicators and data consistency principles, it removes low-quality, abnormal, or format-incompatible data, and selects valid positioning reference information. Subsequently, based on the timestamp of the data and the terminal reference location, it performs spatiotemporal alignment on the valid data, unifying the discrete and heterogeneous data collected by different terminals at different times into the same time and spatial grid, forming a standardized global dataset. Finally, it performs queue processing according to the type of positioning reference information. For differential correction information, it generates a differential correction field covering the entire positioning reference network by constructing a spatial variogram and using a Kriging interpolation algorithm. For the original observation dataset, it establishes observation equations and solves for common error states to format it into enhanced auxiliary data. The differential correction field and the enhanced auxiliary data together constitute positioning correction information, providing a global and accurate reference for error correction of subsequent ordinary UE positioning.

[0067] In one embodiment, the positioning server processes the positioning reference information reported by each positioning reference terminal to generate positioning correction information. Specifically, this includes: validating the positioning reference information reported by each positioning reference terminal based on signal quality indicators and consistency principles; spatiotemporally aligning the verified positioning reference information according to the timestamp and the reference position of each positioning reference terminal; and processing the aligned data to generate differential correction fields or augmentation auxiliary data, which are used as positioning correction information, according to the type of positioning reference information.

[0068] In this embodiment of the invention, after receiving the positioning reference information reported by each positioning reference terminal, the positioning server performs verification from two dimensions: signal quality and data consistency. In terms of signal quality, it checks whether the base station PRS signal RSRP / RSRQ, GNSS carrier-to-noise ratio, and other indicators corresponding to the data reported by the terminal reach the preset threshold, and removes low-precision data caused by weak signals. In terms of data consistency, it compares the core data such as signal propagation time difference and reference position continuously reported by the same terminal. If the deviation exceeds the reasonable range, it is judged as abnormal data and removed. Only high-quality, non-abnormal, and valid positioning reference information is retained, laying the data foundation for subsequent accurate processing. Furthermore, due to differences in the data collection time and deployment location of various positioning reference terminals, the reported valid data exhibits characteristics of temporal asynchrony and spatial dispersion. Therefore, the positioning server uses its own high-precision network clock as a reference and maps all valid data to a unified time grid based on the timestamps carried in the data. Data exceeding the time deviation range is interpolated or removed to achieve temporal synchronization. Simultaneously, relying on the high-precision reference positions of each positioning reference terminal, valid data is associated with the standardized spatial grid of the positioning reference network. Data is divided by region, and invalid data outside the network coverage area is removed to achieve spatial regularization. After spatiotemporal alignment, the originally discrete multi-terminal data is transformed into a standardized dataset with unified time and spatial dimensions. Finally, differentiated processing strategies are adopted for different types of positioning reference information to generate positioning correction information adapted to different positioning scenarios. The core output consists of two categories: differential correction fields and augmentation auxiliary data. The positioning server first identifies the type of data after spatiotemporal alignment, and then proceeds to the corresponding processing flow: If it is differential correction information, spatial modeling is performed based on the signal propagation time difference of each base station pair to construct a spatial variogram function reflecting the spatial distribution law of error. Then, the Kriging interpolation algorithm is used to perform error interpolation calculation on the entire grid to generate a differential correction field covering the entire positioning reference network. This correction field can directly provide regional error correction for the RSTD measurement values ​​of ordinary UEs. If it is the original observation dataset, standardized observation equations are established for the terminal's original observation data, reference position, and other information. The algorithm solves for common error states such as base station clock deviation, atmospheric propagation delay, and multipath interference within the network, and encapsulates these error states into enhanced auxiliary data according to the 3GPP standard format. This provides accurate error compensation basis for multi-source fusion positioning of ordinary UEs. The differential correction field and enhanced auxiliary data together constitute positioning correction information, becoming the core network resource for ordinary UEs to achieve high-precision positioning.

[0069] For example, after receiving the positioning reference information reported by each positioning reference terminal, the positioning server first extracts the core verification dimensions of each data point: First, signal quality indicators, including base station signal RSRP / RSRQ, GNSS carrier-to-noise ratio, and IMU data stability at the time the terminal reports the data. If these indicators are lower than preset thresholds, such as RSRP < -110dBm or GNSS carrier-to-noise ratio < 25dB-Hz, the data is judged as low-quality and discarded. Second, consistency principle verification, comparing the ΔRSTD value or reference position continuously reported by the same terminal. If the deviation between two adjacent data points exceeds a preset threshold, such as ΔRSTD deviation > 1μs or reference position deviation > 0.5m, the data is judged as abnormal and discarded. Simultaneously, the server verifies whether the data format conforms to 3GPP specifications and whether the terminal identifier is valid, among other basic rules. The valid positioning reference information retained after verification is the first positioning reference information. The positioning server then extracts the collection timestamps of all first positioning reference information. Using the positioning server's high-precision network clock as a reference, it maps all data to a unified time grid. Data within the same time grid is retained, while data exceeding the time grid deviation is interpolated or removed to ensure consistency in the time dimension of all data. Subsequently, based on the self-reference positions reported by each positioning reference terminal, the first positioning reference information is associated with the spatial grid of the positioning reference network. Each spatial grid corresponds to valid data from all terminals within its area, while data from terminals outside the coverage area of ​​the positioning reference network is removed. The second positioning reference information obtained after spatiotemporal alignment is a standardized dataset with unified time and spatial dimensions, solving the problem of data incompatibility caused by asynchronous reporting times and discrete deployment locations of different terminals. The positioning server then identifies the type of the second positioning reference information and distributes it to the corresponding queue for processing. The first processing queue, for second positioning reference information of the differential correction information type, first classifies it by base station pair dimension. For the ΔRSTD value of each base station pair, a spatial variability function is constructed based on the spatial location to quantify the variation of the ΔRSTD value with spatial location and reflect the spatial correlation of the error. Subsequently, the Kriging interpolation algorithm is employed, using the reference positions of each positioning reference terminal as sample points, to perform interpolation calculations on all spatial grids within the positioning reference network, ultimately generating a differential correction field covering the entire positioning reference network. This differential correction field is a gridded distribution of ΔRSTD values, with each spatial grid corresponding to the ΔRSTD correction values ​​of all base station pairs. Ordinary UE devices can directly access the ΔRSTD value of their respective grid to correct their own measured RSTD values, rapidly improving positioning accuracy.The second processing queue handles the second positioning reference information, which is the raw observation dataset. First, it establishes observation equations for each terminal's observation data (GNSS pseudorange, PRS signal, etc.), using the terminal reference position as the true value. It then inversely calculates the common error states in the observation data, such as base station clock offset, atmospheric propagation delay, and IMU zero offset. The common error states of all observation equations are solved using the least squares method, eliminating individual errors and retaining network-wide common errors. Finally, the common error states are encapsulated according to the 3GPP standard format to generate enhanced auxiliary data. This enhanced auxiliary data includes base station clock synchronization parameters, atmospheric delay models, GNSS ephemeris correction values, etc. Ordinary UEs can use this data to optimize their own observation data processing and improve positioning accuracy. The final generated differential correction field and enhanced auxiliary data are collectively referred to as positioning correction information.

[0070] Step 106: In response to the positioning request initiated by the target UE device, generate the location coordinates of the target UE device based on the positioning correction information.

[0071] In this embodiment of the invention, the positioning server responds to the positioning request from a regular UE device, calls the corresponding calculation strategy according to the type of positioning correction information, and performs error correction on the measurement data of the UE device in conjunction with the correction information to calculate and generate high-precision position coordinates for the UE device. Regular UEs can obtain centimeter / sub-meter level positioning capabilities without additional hardware modifications, improving the compatibility and flexibility of the solution and ensuring full compatibility with the 3GP protocol. This eliminates the need to modify regular UE devices, lowering the barrier to entry for using high-precision positioning services.

[0072] In one embodiment, in response to a positioning request initiated by the target UE device, the location coordinates of the target UE device are generated based on positioning correction information. Specifically, in response to the positioning request initiated by the target UE device, the positioning server obtains the RSTD measurement value of the target UE device relative to a preset base station pair; the positioning server extracts the corresponding signal propagation time difference from a pre-generated differential correction field based on the coarse location coordinates of the target UE device; and the positioning server calculates and generates high-precision location coordinates of the target UE device based on the RSTD measurement value, the signal propagation time difference, and the location coordinates of the preset base station.

[0073] In this embodiment of the invention, when a regular UE device such as a mobile phone or IoT terminal initiates a high-precision positioning request within the coverage area of ​​the positioning reference network, the positioning server of the core network first receives and parses the request, confirming basic information such as the UE's network access identifier and the currently accessed serving base station. Then, based on the serving base station currently accessed by the UE, the positioning server matches a list of pre-set positioning base stations for that area in the positioning reference network. This list of positioning base stations is consistent with the benchmark used by the positioning reference terminal to construct base station pairs, both using the serving base station as a benchmark and combining it with surrounding fixed neighboring base stations to determine the combination of base station pairs that the UE needs to measure. Finally, the positioning server sends a standardized 5G positioning signaling message to the UE through the UE's current serving base station. This signaling message explicitly instructs the UE to perform synchronous PRS signal actual RSTD measurement on the pre-set base station pairs and requires the UE to report the measurement results to the positioning server. In this step, the pre-set base station list is completely consistent with the base station system used by the positioning reference terminal to construct base station pairs, ensuring that the UE's RSTD measurement value can accurately match the differential correction field generated by the positioning server, avoiding correction failure due to inconsistencies in base station pairs. After receiving signaling instructions from the positioning server, a regular UE performs actual RSTD measurements on preset base station pairs and reports the measurement results (RSTDmeasured) to the positioning server via the serving base station. Upon receiving the actual RSTD measurement values ​​reported by the UE, the positioning server first obtains the coarse location coordinates of the target UE device through methods such as the signal from the serving base station currently accessed by the UE or the preliminary location reported by the UE. For example, it determines the spatial area where the UE is located based on cell-level positioning and uses this as a spatial index. Then, it calls the generated and stored differential correction field covering this area. This differential correction field is a gridded ΔRSTD value distribution generated by the positioning server based on positioning reference terminal data. Each grid corresponds to the signal propagation time difference (STD) of all preset base station pairs in the corresponding area, i.e., the common error correction amount. Based on the UE's regional range, the positioning server extracts the ΔRSTD value of the corresponding preset base station pair in the differential correction field. This value perfectly matches the common errors contained in the UE's measurement values, such as non-line-of-sight propagation, base station synchronization residuals, and atmospheric delays. The positioning server combines the extracted regional ΔRSTD value with the RSTDmeasured value reported by the UE, and then derives the corrected precise RSTD value through reverse derivation: RSTDcorrect = RSTDmeasured. ΔRSTD is used to eliminate common propagation errors. Then, the pre-stored, precise 3D coordinates of the base stations are retrieved from the network side. Based on the corrected, precise RSTD value and combined with the precise base station coordinates, the classic 5G positioning algorithm of polygonal / hyperbolic positioning is used for geometric calculation: with the location of each base station as the center and the signal propagation distance as the constraint, a system of equations is constructed using the distance difference constraints between multiple base station pairs. The optimal solution of the system of equations is obtained, which is the high-precision 3D position coordinate of the UE. Throughout the calculation process, because the corrected RSTD value eliminates common propagation errors, the accuracy of the calculated coordinates is improved by orders of magnitude compared to the original measurement calculation of the UE, reaching centimeter or sub-meter level.

[0074] In one embodiment, in response to a positioning request initiated by the target UE device, generating the location coordinates of the target UE device based on positioning correction information further includes: in response to a positioning request initiated by the target UE device, a positioning server extracts positioning correction information within the area where the target UE device is located and sends it to the target UE device via the LPP protocol; the target UE device measures the actual RSTD value of a preset base station pair and obtains the corresponding signal propagation time difference or enhanced auxiliary data from the sent positioning correction information; the target UE device calculates and generates its own high-precision location coordinates on the terminal side based on the actual RSTD value, signal propagation time difference, or enhanced auxiliary data.

[0075] In this embodiment of the invention, when a regular UE initiates a high-precision positioning request, the positioning server first determines the spatial area range of the UE by using the serving base station currently accessed by the UE and the coarse positioning information of the cell. Then, according to the storage logic of the positioning correction information, it extracts the exclusive positioning correction information of the area from the local cache, removes the correction data of irrelevant areas, and realizes on-demand data filtering; finally, the positioning server encapsulates the extracted regional positioning correction information into 3GPP standard LPP positioning signaling through the serving base station of the UE and sends it to the UE device that initiated the request. (1) When the UE receives the differential correction field sent by the positioning server, it first performs actual RSTD measurement on the PRS signal of the preset base station pair according to the positioning signaling requirements to obtain its own RSTD measured value; then, it extracts the signal propagation time difference ΔRSTD corresponding to the base station pair measured by itself from the differential correction field, and then the UE performs error correction on the actual measurement value by formula RSTDcorrect=RSTDmeasured. ΔRSTD, to obtain the accurate RSTD value to eliminate common errors; finally, the UE retrieves the preset base station accurate coordinates attached in the signaling, and uses the hyperbolic positioning / polygonal positioning algorithm to complete the geometric calculation locally, converting the accurate RSTD value into the distance difference between base stations, constructing a geometric constraint equation system based on the base station coordinates, and solving the optimal solution of the equation system, which is the high-precision position coordinates of the UE itself. The core of this calculation strategy is that the terminal side processes autonomously, and the network side is only responsible for sending correction information, thereby supporting the simultaneous positioning requests of a large number of UEs. (2) When the UE receives the enhanced auxiliary data sent by the positioning server, it first clarifies that the core content of the data is the network-wide common error status calculated by the positioning server based on the original observation dataset of the positioning reference terminal, including base station clock deviation, atmospheric propagation delay model parameters, GNSS ephemeris correction values, IMU zero bias compensation parameters, etc. Subsequently, the UE collects its own multi-source positioning observation data, such as 5G PRS signal measurements, GNSS pseudorange / carrier phase values, and IMU inertial data. It then uses enhanced auxiliary data to correct these observation data for pre-errors, such as correcting the time error of PRS signal measurements based on base station clock deviation parameters, correcting signal propagation time based on atmospheric delay models, and optimizing satellite position calculations based on GNSS ephemeris correction values. Finally, the UE calls its pre-set high-precision positioning calculation algorithms, such as Kalman filtering, particle filtering, and compact combination positioning fusion algorithms, inputting the corrected observation data into the algorithms. Through iterative optimization, the algorithms eliminate individual measurement errors and environmental interference errors, ultimately generating the UE's high-precision position coordinates. The core of this calculation strategy is to optimize observation data and improve algorithm calculation performance through enhanced auxiliary data. Enhanced auxiliary data essentially provides a network-wide error benchmark for the UE's positioning calculation, transforming the UE's calculation process from benchmark-less single-terminal calculation to benchmark-based network-wide collaborative calculation, thereby improving positioning accuracy and stability. In terminal-side calculation mode, the positioning server LMF sends differential correction field or enhanced auxiliary data within the area where the target UE is located to the UE via the LPP protocol. The UE measures the actual RSTD value of the preset base station pair and extracts the corresponding ΔRSTD value from the sent correction information. It then calculates its own position locally using hyperbolic positioning or polygonal positioning algorithms. This mode is suitable for scenarios with limited network-side processing capabilities or where signaling overhead needs to be reduced.

[0076] As an optimized embodiment of the present invention, a positioning reference RedCap terminal is also provided, applicable to the positioning method based on the positioning reference terminal described above. The RedCap terminal is configured as follows: During the establishment of an RRC connection with the serving base station, the first capability information is reported to the serving base station via RRC signaling. The first capability information includes a dedicated identifier for identifying the RedCap terminal as a positioning reference type terminal. The dedicated identifier is an enumerated value added in the RedCap type field of the UE capability information element in the RRC protocol to indicate the positioning reference, or a dedicated indication information added in the RRC connection establishment completion message.

[0077] In this embodiment of the invention, when establishing the initial connection between the RedCap terminal and the serving base station, the RedCap terminal is controlled to send first capability information, i.e., UE capability information, to the serving base station. Specifically, during the RedCap terminal power-on phase, a cell search and random access procedure is executed to select a base station in the positioning reference network to establish a serving base station and establish an initial connection; the RedCap terminal is controlled to initiate an RRC connection establishment request to the serving base station, so that the serving base station can respond to the message of the RedCap terminal based on the RRC connection establishment; during the RRC connection establishment phase, the UE capability information is sent to the serving base station based on the UE-specific capability identifier pre-configured in the RedCap positioning reference terminal.

[0078] Specifically, after the RedCap terminal powers on, it first activates the radio frequency receiving module to scan for radio signals broadcast by base stations in the surrounding 5G positioning reference network, executing a standardized cell search process: by identifying synchronization signal blocks sent by the base station, it completes time and frequency synchronization with the target base station, while simultaneously acquiring core network information such as cell ID, system frame number, and base station coverage area. After completing the cell search and selecting a base station with suitable signal quality, the terminal initiates a random access request to that base station, completing a physical layer handshake and establishing a low-level radio transmission link between the terminal and the base station. At this point, the terminal officially selects that base station as the serving base station, achieving the initial connection between the two. After completing the initial physical layer connection with the serving base station, the RedCap terminal actively initiates an RRC (Radio Resource Control) connection establishment request signaling to the serving base station. This signaling contains basic information such as the terminal's access type and terminal identifier, used to inform the base station of the terminal's signaling connection requirements. Upon receiving this request, the serving base station will determine its own radio resource occupancy. If resources are sufficient, it will return an RRC connection establishment response message to the terminal, containing resource configuration information such as the signaling radio bearer and logical channel allocated to the terminal. Upon receiving the response, the terminal completes the establishment of the RRC connection. At this point, the higher-layer signaling interaction channel between the terminal and the serving base station is established, enabling the transmission of complex protocol signaling. In this invention, the UE-specific capability identifier of the RedCap terminal is a fixed parameter pre-configured at the factory and stored in the terminal's hardware or firmware, which cannot be arbitrarily modified. During the RRC connection establishment phase, the terminal sends a standard UE Capability Information message to the serving base station, simultaneously encapsulating the pre-configured UE-specific capability identifier within this message. For reference-based RedCap terminals, this UE-specific capability identifier is implemented by adding a `positioningReferenceCapability` field or a `positioningReference` option to the `redcap-Type` enumeration value, serving as the unique identifier for the terminal as a location reference RedCap terminal. Upon receiving this message, the serving base station can directly identify the terminal's location reference terminal attribute, providing a core identity basis for subsequently forwarding this information to the location server and implementing customized network-side configurations.

[0079] For example, an industrial park deploys a 5G positioning reference network, which includes three 5G base stations: gNB1, gNB2, and gNB3. All Red Cap terminals deployed within the park have a UE-specific capability identifier pre-configured with a redcap-Type enumeration value of `positioningReference`. Upon powering on, the terminal initiates its radio frequency module to scan for wireless signals within the park's positioning reference network. Through cell search, it identifies the SSB synchronization signal block of gNB2, whose RSRP is -75dBm, indicating optimal signal quality. The terminal then initiates a random access request to gNB2. Following random access preamble transmission, gNB2's random access response, and contention resolution, the terminal completes the initial physical layer connection with gNB2, officially selecting gNB2 as the serving base station. After establishing the initial physical layer connection with gNB2, the terminal immediately initiates an RRC connection establishment request to gNB2, indicating that the terminal's access type is a positioning reference type terminal. After verifying its own radio resources, gNB2 returns an RRC connection establishment response message to the terminal, allocating a dedicated signaling radio bearer and logical channel for the terminal. Upon receiving and parsing this response, the terminal completes the RRC connection establishment with gNB2, and the higher-layer signaling interaction channel is officially opened. During the RRC connection establishment signaling interaction phase with gNB2, the terminal sends a UE Capability Information message to gNB2 according to the 3GPP standard procedure, simultaneously encapsulating the pre-set redcap-Type field value positioningReference into this message, thus completing the reporting of UE capability information. Upon receiving this message, gNB2 immediately confirms that the terminal is a positioning reference type RedCap terminal, rather than a regular RedCap terminal, through field identification. It then forwards the UE capability information to the location management function (LMF) of the campus 5G core network via the NG-RAN interface, laying the foundation for the location server to subsequently issue location management requests.

[0080] This invention provides a positioning reference type RedCap terminal. As a hardware product, the core improvement of this terminal lies in the configuration of the RRC protocol stack. Specifically, the RRC layer of this terminal is configured to generate and send first capability information containing a dedicated identifier during the establishment of an RRC connection with the serving base station. This dedicated identifier is used to indicate to the network side that the terminal has positioning reference functionality and can act as a positioning reference node to provide correction information to other terminals. Further, the specific implementation of this dedicated identifier is as follows: in the UE-NR-Capability information element defined in 3GPP TS 38.331, an enumeration value, such as "positioningReference," is added to the redcap-Type field. The addition of this enumeration value allows the network side (base station / LMF) to identify its positioning reference attribute during the terminal access phase, thereby triggering subsequent positioning session establishment and dedicated configuration distribution. Alternatively, this dedicated identifier can also be implemented by adding a dedicated information element to the RRC connection establishment completion message, which carries indication information of a "positioning reference type terminal." The terminal can be implemented based on the existing RedCap chip solution, requiring only an upgrade to the RRC protocol stack software. Therefore, the terminal inherits the low cost and low power consumption advantages of RedCap, while adding a positioning reference function, enabling the large-scale deployment of low-cost positioning reference nodes.

[0081] In this embodiment of the invention, a positioning device based on a positioning reference terminal is also provided, including a processor, a memory, and a computer program stored in the memory and configured to be executed by the processor. When the processor executes the computer program, it implements the above-described positioning method based on the positioning reference terminal.

[0082] In this embodiment of the invention, a computer-readable storage medium is also provided, which includes a stored computer program, wherein the computer program controls the device where the computer-readable storage medium is located to execute the above-described positioning method based on a positioning reference terminal when it is running.

[0083] For example, a computer program can be divided into one or more modules, one or more of which are stored in memory and executed by a processor to perform the present invention. One or more modules can be a series of computer program instruction segments capable of performing a specific function, which describe the execution process of the computer program in a positioning device based on a positioning reference terminal.

[0084] The positioning device based on the positioning reference terminal can be a computing device such as a desktop computer, laptop, handheld computer, or cloud server. The positioning device of the positioning reference terminal may include, but is not limited to, a processor, memory, and display. Those skilled in the art will understand that the above components are merely examples of the positioning device for the positioning reference terminal and do not constitute a limitation on the positioning device. It may include more or fewer components, combinations of certain components, or different components. For example, the positioning device of the positioning reference terminal may also include input / output devices, network access devices, buses, etc.

[0085] The processor can be a Central Processing Unit (CPU), or other general-purpose processors, digital signal processors (DSPs), application-specific integrated circuits (ASICs), field-programmable gate arrays (FPGAs), or other programmable logic devices, discrete gate or transistor logic devices, discrete hardware components, etc. A general-purpose processor can be a microprocessor or any conventional processor. The processor is the control center of the positioning reference terminal's positioning device, connecting all parts of the positioning reference terminal's positioning device through various interfaces and lines.

[0086] The memory can be used to store computer programs and / or modules. The processor implements various functions of the positioning device for the positioning reference terminal by running or executing the computer programs and / or modules stored in the memory, and by calling the data stored in the memory. The memory can mainly include a program storage area and a data storage area. The program storage area can store the operating system, at least one application program required for a function (such as sound playback function, text conversion function, etc.), etc.; the data storage area can store data created according to the use of the mobile phone (such as audio data, text message data, etc.). In addition, the memory can include high-speed random access memory, and can also include non-volatile memory, such as hard disk, RAM, plug-in hard disk, smart media card (SMC), secure digital (SD) card, flash card, at least one disk storage device, flash memory device, or other volatile solid-state storage device.

[0087] The positioning module based on the positioning reference terminal, if implemented as a software functional unit and sold or used as an independent product, can be stored in a computer-readable storage medium. Based on this understanding, all or part of the processes in the above embodiments of the present invention can also be implemented by a computer program instructing related hardware. The computer program can be stored in a computer-readable storage medium, and when executed by a processor, it can implement the steps of the various method embodiments described above. The computer program includes computer program code, which can be in the form of source code, object code, executable files, or certain intermediate forms. The computer-readable medium can include: any entity or device capable of carrying computer program code, recording media, USB flash drives, portable hard drives, magnetic disks, optical disks, computer memory, read-only memory (ROM), random access memory (RAM), electrical carrier signals, telecommunication signals, and software distribution media, etc. Those skilled in the art can understand and implement this without any inventive effort.

[0088] This invention provides a positioning method based on a positioning reference terminal, particularly a RedCap reference positioning terminal. During the access phase, the method identifies the positioning reference terminal and issues a dedicated positioning management request, achieving precise collaboration between the terminal and the network. Without altering the existing 5G network architecture and protocols, it leverages the low-cost, low-power, and wide-coverage characteristics of RedCap positioning reference terminals to rapidly build a high-density positioning reference source, solving the problems of high deployment cost, limited coverage, and poor scalability of traditional positioning reference stations. Secondly, the positioning reference terminal uses a multi-source fusion positioning engine to generate its own high-precision reference position and uses this as a benchmark to calculate the propagation time difference between the measured and theoretical values ​​of the base station signal, transforming the single-point high-precision position into reference information usable for global correction, thus achieving networked output of the positioning benchmark. Furthermore, the positioning server performs spatiotemporal alignment on data reported by multiple terminals, constructing differential correction fields and enhanced auxiliary data respectively, integrating discrete and heterogeneous terminal data into continuous, global positioning correction resources, improving the reliability and coverage of correction information. Ordinary UEs can achieve high-precision positioning using positioning correction information without upgrading hardware, thus reducing the barrier to entry and terminal costs for high-precision positioning.

[0089] Example 2 See Figure 2 , Figure 2This is a schematic diagram of the modules of a positioning device based on a positioning reference terminal provided in one embodiment of the present invention. The present invention provides a positioning device based on a positioning reference terminal, applicable to a positioning reference network including a positioning server, several base stations, and several positioning reference terminals, including an initial connection establishment module 201, an LPP protocol execution module 202, a management request sending module 203, a reference information generation module 204, a positioning information generation module 205, and a positioning request response module 206; The initial connection establishment module 201 is used to establish an initial connection between the positioning reference terminal and the serving base station; LPP protocol execution module 202 is used to establish a connection with the positioning server based on the positioning protocol through NAS messages, and to report capability information to the positioning server through the positioning protocol; wherein, the capability information includes the positioning measurement capabilities supported by the positioning reference terminal. The management request sending module 203 is used to enable the positioning server to send a positioning management request to the positioning reference terminal through the positioning protocol based on capability information and network planning requirements; wherein the positioning management request carries the configuration parameters of the positioning reference task; Reference information generation module 204 is used to enable the positioning reference terminal to obtain its own reference position, calculate the signal propagation time difference based on the actual measurement value of the signal emitted by the base station in the positioning reference network reaching the reference position, generate positioning reference information and report it to the positioning server. The positioning information generation module 205 is used to enable the positioning server to process the positioning reference information reported by each positioning reference terminal and generate positioning correction information. The location request response module 206 is used to respond to a location request initiated by the target UE device and generate the location coordinates of the target UE device based on the location correction information.

[0090] Those skilled in the art will understand that, for the sake of convenience and brevity, the specific working process of the device described above can be referred to the corresponding process in the foregoing method embodiments, and will not be repeated here.

[0091] This invention provides a positioning device based on a positioning reference terminal. During the access phase, it identifies the positioning reference terminal and issues a dedicated positioning management request, achieving precise collaboration between the terminal and the network. Without altering the existing 5G network architecture and protocols, it reuses the low-cost, low-power, and wide-coverage characteristics of positioning references to quickly build a high-density positioning reference source, solving the problems of high deployment cost, limited coverage, and poor scalability of traditional positioning reference stations. Secondly, the positioning reference terminal uses a multi-source fusion positioning engine to generate its own high-precision reference position and uses this as a benchmark to calculate the propagation time difference between the measured and theoretical values ​​of the base station signal, transforming the single-point high-precision position into reference information usable for global correction, realizing the networked output of the positioning benchmark. Furthermore, the positioning server performs spatiotemporal alignment on data reported by multiple terminals, constructing differential correction fields and enhanced auxiliary data respectively, integrating discrete and heterogeneous terminal data into continuous, global positioning correction resources, improving the reliability and coverage of correction information. Ordinary UEs can achieve high-precision positioning using positioning correction information without hardware upgrades, reducing the barrier to entry and terminal costs for high-precision positioning.

[0092] The above are merely preferred embodiments of the present invention. It should be noted that those skilled in the art can make several improvements and substitutions without departing from the technical principles of the present invention, and these improvements and substitutions should also be considered within the scope of protection of the present invention.

Claims

1. A positioning method based on positioning reference terminals, applicable to a positioning reference network comprising a positioning server, a number of base stations and a number of positioning reference terminals, characterized in that, include: In the positioning reference network, an initial connection is established between each positioning reference terminal and the serving base station; The positioning reference terminal establishes a connection with the positioning server based on the positioning protocol via NAS messages, and reports capability information to the positioning server via the positioning protocol; wherein, the capability information includes the positioning measurement capabilities supported by the positioning reference terminal. The positioning server sends a positioning management request to the positioning reference terminal via a positioning protocol based on the capability information and network planning requirements; wherein the positioning management request carries the configuration parameters of the positioning reference task. The positioning reference terminal obtains its own reference position, calculates the signal propagation time difference based on the actual measurement value of the signal emitted by the base station in the positioning reference network reaching the reference position, generates positioning reference information, and reports it to the positioning server. The positioning server processes the positioning reference information reported by each positioning reference terminal and generates positioning correction information. In response to a positioning request initiated by the target UE device, the location coordinates of the target UE device are generated based on the positioning correction information.

2. The positioning method based on the positioning reference type terminal according to claim 1, wherein, The positioning reference terminal is a RedCap terminal with reduced capabilities.

3. The positioning method based on a positioning reference terminal as described in claim 1, characterized in that, The positioning reference terminal obtains its own reference position in any of the following ways: Method 1: By using a multi-source sensor fusion positioning engine, observation data from different location sources are collected, and a recursive estimation filtering algorithm is used to fuse and solve the observation data to generate the reference position of the reference positioning terminal itself; wherein, the type of location source includes one or more of the following: GNSS multi-frequency multi-mode receiver chip, 5G NR positioning signal receiving link, IMU, and storage module of pre-stored calibration map; Method 2: Read the reference position of the positioning reference terminal itself from the locally stored calibration map or the pre-configured precise coordinates; Method 3: Receive the pre-stored location information of the positioning reference terminal from the positioning server or other network elements on the network side, and use the location information that has passed the consistency verification as the reference position of the positioning reference terminal itself.

4. The positioning method based on a positioning reference terminal as described in claim 1, characterized in that, The step of sending a positioning management request to the positioning reference terminal via the positioning protocol specifically includes: The positioning server generates an LPP request message containing positioning reference task configuration parameters and sends it to the AMF; The AMF encapsulates the LPP request message in a NAS protocol data unit and sends it to the serving base station; The serving base station transmits the NAS PDU containing the LPP request message to the positioning reference terminal.

5. The positioning method based on a positioning reference terminal as described in claim 1, characterized in that, The step of calculating the signal propagation time difference based on the actual measured value of the signal emitted by the base station in the positioning reference network reaching the positioning reference terminal, and generating positioning reference information, specifically includes: The base stations corresponding to the PRS signals detected by the positioning reference terminal at the same time are paired with the serving base station to construct several base station pairs. The theoretical RSTD value of each base station pair is calculated based on the base station location coordinates within the base station pair and the reference position of the positioning reference terminal itself. Obtain the actual RSTD measurement value for each base station pair, and generate the signal propagation time difference between the positioning reference terminal and each base station pair based on the actual RSTD measurement value and the theoretical RSTD value; Based on the type of location reference information in the location management request, an encapsulation strategy is invoked to generate location reference information and report it to the location server.

6. The positioning method based on a positioning reference terminal as described in claim 1, characterized in that, The positioning server processes the positioning reference information reported by each positioning reference terminal to generate positioning correction information, specifically including: The validity of the positioning reference information reported by each positioning reference terminal is verified based on signal quality indicators and consistency principles. The verified positioning reference information is spatiotemporally aligned based on the timestamp and the reference position of each positioning reference terminal. Depending on the type of positioning reference information, the aligned data are processed to generate differential correction fields or enhanced auxiliary data, which are used as the positioning correction information.

7. The positioning method based on a positioning reference terminal as described in claim 1, characterized in that, The step of generating the location coordinates of the target UE device in response to a positioning request initiated by the target UE device, based on the positioning correction information, specifically includes: In response to a location request initiated by the target UE device, the location server obtains the RSTD measurement value of the target UE device for a preset base station pair; The positioning server extracts the corresponding signal propagation time difference from the pre-generated differential correction field based on the coarse position coordinates of the target UE device. The positioning server calculates and generates high-precision location coordinates of the target UE device based on the RSTD measurement value, the signal propagation time difference, and the location coordinates of the preset base station.

8. The positioning method based on a positioning reference terminal as described in claim 1, characterized in that, The step of generating the location coordinates of the target UE device based on the location correction information in response to a positioning request initiated by the target UE device further includes: In response to a location request initiated by the target UE device, the location server extracts the location correction information within the area where the target UE device is located and sends it to the target UE device via the LPP protocol; The target UE device measures the actual RSTD value of the preset base station pair and obtains the corresponding signal propagation time difference or enhanced auxiliary data from the sent positioning correction information; The target UE device calculates and generates its own high-precision position coordinates on the terminal side based on the actual RSTD value, the signal propagation time difference, or the enhanced auxiliary data.

9. A positioning reference type RedCap terminal, applicable to the positioning method based on a positioning reference type terminal as described in any one of claims 1 to 8, characterized in that, The RedCap terminal is configured as follows: During the establishment of an RRC connection with the serving base station, the first capability information is reported to the serving base station via RRC signaling; wherein, the first capability information includes a dedicated identifier for identifying the RedCap terminal as a positioning reference type terminal, the dedicated identifier being an enumerated value added in the RedCap type field of the UE capability information element in the RRC protocol to indicate positioning reference, or a dedicated indication information added in the RRC connection establishment completion message.

10. A positioning device based on a positioning reference terminal, applicable to a positioning reference network comprising a positioning server, several base stations, and several positioning reference terminals, characterized in that, include: The initial connection establishment module is used to establish the initial connection between each positioning reference terminal and the serving base station; The LPP protocol execution module is used to establish a connection with the positioning server based on the positioning protocol through NAS messages, and to report capability information to the positioning server through the positioning protocol; wherein, the capability information includes the positioning measurement capabilities supported by the positioning reference terminal. The management request sending module is used to enable the positioning server to send a positioning management request to the positioning reference terminal through a positioning protocol based on the capability information and network planning requirements; wherein the positioning management request carries the configuration parameters of the positioning reference task; The reference information generation module is used to enable the positioning reference terminal to obtain its own reference position, calculate the signal propagation time difference based on the actual measurement value of the signal emitted by the base station in the positioning reference network reaching the reference position, generate positioning reference information, and report it to the positioning server. The positioning information generation module is used to enable the positioning server to process the positioning reference information reported by each positioning reference terminal and generate positioning correction information. The location request response module is used to respond to a location request initiated by the target UE device and generate the location coordinates of the target UE device based on the location correction information.

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