Cross-region accurate indoor positioning method

Abstract

The invention relates to the technical field of indoor positioning and communication, in particular to a cross-regional accurate indoor positioning method, which utilizes a 6G micro base station, an adjustable metamaterial reflector, a voxel type laser radar and a quantum inertial measurement unit to cooperatively work to realize accurate indoor positioning in multiple regions (such as a house, a corridor, an activity hall, a stair and the like). The core process comprises the steps that multi-source data are included in a hypersurface factor fusion model for continuous calculation, cross-regional behaviors of prisoners are recognized in combination with a digital twin map, and then wireless coverage is changed in a self-adaptive mode through a dynamic phased array mechanism of an adjustable metamaterial reflector. According to the method, centimeter-level precision and millisecond-level response are kept in corner, multipath and base station switching scenes, positioning jump or interruption during area switching in the traditional technology can be avoided, and the method is suitable for accurate monitoring of high-safety scenes such as prisons.

Description

Technical Field

[0001] The present invention relates to the field of indoor positioning and communication technology, and in particular to a cross-regional precise indoor positioning method. Background Art

[0002] Accurate indoor positioning across regions is of great significance in prison management, especially when prisoners need to be tracked to centimeter-level accuracy without delay, which places strict requirements on the rapid switching and continuity of the positioning system. The current common method is to use multiple base stations in conjunction with prisoner bracelets to resolve their locations by sending signals to the bracelets through the base stations. However, when prisoners are constantly moving in different areas (such as cells, corridors, activity halls, stairs, etc.), the number of base stations available in each area and the signal coverage mode are often quite different, resulting in the base station switching speed and positioning mode being unable to adapt to environmental changes in real time. If the switching is not sensitive enough or the positioning mode transition is delayed for a few seconds, tracking deviations or even position loss will occur. Existing technologies often compensate by combining independent base stations or adding blind spot neural networks locally, but due to the failure to effectively solve the problems of high floors, corner occlusions, and real-time data fusion, there are still problems such as instantaneous positioning disorder across regions, multipath interference that cannot be corrected in time, or inability to maintain centimeter-level accuracy at the moment of regional switching.

[0003] Some existing solutions rely only on a fixed number of base stations and use a separate positioning algorithm in each area. When a prisoner walks out of the original area and enters a new area, it takes a long time to switch to another set of base stations or a specific "blind spot compensation model", resulting in positioning gaps of several seconds or even longer. Other solutions rely too much on a single wireless measurement method, which is prone to error drift when encountering corridor obstructions or metal door multipath. Due to the inability to dynamically adjust channel coverage and quickly perceive regional changes, existing technologies are difficult to ensure continuous and accurate positioning in complex environments such as across floors, corners, and narrow passages in prisons. Summary of the invention

[0004] In view of the many problems existing in the above-mentioned prior art, the present invention provides a cross-regional precise indoor positioning method, which uses 6G micro base stations, adjustable metamaterial reflectors, voxel-based laser radars, and quantum inertial measurement units to work together, uses a hypersurface factor fusion model to uniformly solve multi-source data, combines digital twin maps to quickly determine the cross-regional actions of prisoners, and realizes the reconstruction of wireless channels under the dynamic phased array mechanism of adjustable metamaterial reflectors. In this way, centimeter-level accuracy and millisecond-level response can be maintained at all times when switching between different floors and different functional areas in the prison, avoiding the interruption or significant deviation of traditional solutions in instantaneous positioning across regions.

[0005] A cross-regional precise indoor positioning method comprises the following steps: Deploy 6G micro base stations, adjustable metamaterial reflectors, and voxel-based laser radars in various areas of the prison, and build a quantum inertial measurement unit into the wristband; obtain wireless measurement data from the 6G micro base station, obtain point cloud data from the voxel-based laser radar, and obtain motion data from the wristband, and form multi-source data for subsequent processing after time synchronization and noise filtering; Based on the multi-source data, the position of the wristband, the phase distribution of the adjustable metamaterial reflector, and the point cloud calibration information of the voxel-based laser radar are simultaneously incorporated into the hypersurface factor fusion model, and the bidirectional thrust iteration is used to perform nonlinear collaborative solution on each observation quantity to obtain the continuous coordinates of the wristband at different times; Mapping the continuous coordinates of the wristband to the digital twin map of the prison, identifying cross-regional behavior based on the coordinate changes across the regional boundaries, and adjusting the wireless signal coverage based on the phase distribution of the adjustable metamaterial reflector so that the wristband maintains continuous coordinate updates during the cross-region period; After obtaining the continuous coordinates of the wristband, the phase distribution of the adjustable metamaterial reflector is further corrected in combination with the dynamic obstacle information identified by the voxel-based lidar to expand and maintain the prison positioning system, thereby achieving accurate indoor positioning in various areas.

[0006] Preferably, the steps of deploying 6G micro base stations, adjustable metamaterial reflectors and voxel-based laser radars in various areas of the prison include: Additional adjustable metamaterial reflectors are installed in areas with corners or stairs to reduce multipath effects caused by obstructions; The voxel-based laser radar is installed at a higher position in the prison so that it covers at least one main activity channel, which facilitates the subsequent acquisition of point cloud data containing human-shaped targets.

[0007] Preferably, the motion data of the quantum inertial measurement unit also includes real-time measurements of acceleration, angular velocity and posture changes, and is synchronized with the wireless measurement data obtained by the 6G micro base station under the same time reference, thereby ensuring the time alignment accuracy of multi-source data.

[0008] Preferably, the process of incorporating the bracelet position, the phase distribution of the adjustable metamaterial reflector, and the voxel-based laser radar point cloud calibration information into the hypersurface factor fusion model based on multi-source data includes: The motion increment provided by the quantum inertial measurement unit and the arrival time difference and arrival angle obtained by the 6G micro base station are input into the factor graph together; The point cloud data output by the voxel-based lidar is segmented to extract the human body contour voxels, and the center coordinates of the human body contour are used as the observation factor of the bracelet position.

[0009] Preferably, when the hypersurface factor fusion model adopts bidirectional thrust iteration for nonlinear collaborative solution, the propagation characteristics of the wireless signal path are corrected in real time according to the phase distribution of the adjustable metamaterial reflector, and different observation residuals are weighted to improve the positioning accuracy of the bracelet in corners or partially blocked areas.

[0010] Preferably, the bidirectional thrust iteration includes: Forward solution: Solve the factor graph of the observations at the current moment to obtain a preliminary estimate of the bracelet's position; Backward traction: trace back the wristband position at the previous moment in a short time window, and further correct the initial estimate of the wristband position according to the human body center coordinates recognized by the voxel-based laser radar in subsequent frames.

[0011] Preferably, the step of mapping the continuous coordinates of the wristband to the digital twin map of the prison and identifying cross-regional behavior according to the coordinate changes across regional boundaries includes: Demarcate the geometric boundaries of cells, corridors, and activity halls in the digital twin map; When the continuous coordinates of the wristband enter from one geometric boundary area into another geometric boundary area, it is determined that the prisoner has completed the cross-area movement and a region switching instruction is generated.

[0012] Preferably, the process of adjusting the wireless signal coverage based on the phase distribution of the adjustable metamaterial reflector includes: When cross-region behavior is detected, a command is sent to the adjustable metamaterial reflector to change the phase combination of the phased array units, so that the signal weight of the base station in the newly entered area is improved; When the wristband approaches a corner or an area with many obstacles, the phase distribution of the phased array unit is further fine-tuned to keep the wristband position observation error within the expected range.

[0013] Preferably, the step of enabling the wristband to maintain continuous coordinate updates during the cross-region period further comprises: Quantum inertial measurement units are used for short-term autonomous navigation. When the voxel lidar or adjustable metamaterial reflector is in a temporary switching state resulting in insufficient observation data, the position increment of the quantum inertial measurement unit is preferentially used for positioning transition.

[0014] Preferably, the step of further correcting the phase distribution of the adjustable metamaterial reflector in combination with the dynamic obstacle information identified by the voxel-based laser radar after obtaining the continuous coordinates of the wristband to expand and maintain the prison positioning system includes: When the voxel-based lidar detects a new obstacle or channel modification, the structural information of the corresponding area in the digital twin map is updated; The phase distribution of the adjustable metamaterial reflector is reset according to the updated structural information so that the 6G micro base station measurement data still has a low multipath error in the new environment, thereby maintaining effective coverage of the prison positioning system.

[0015] Compared with the prior art, the advantages and beneficial effects of the present invention are: Dynamically reshape the wireless signal path through adjustable metamaterial reflectors to achieve low-error coverage in multipath environments such as corners and metal doors; The quantum inertial measurement unit and voxel-based lidar form complementary observations, achieving the effect of providing continuous centimeter-level positioning when the base station signal is insufficient or switching transitions; Through the hypersurface factor fusion model, the wristband position, reflector phase distribution and lidar observation are incorporated in a single iteration process, overcoming the delay or drift caused by changes in the environment or reflector state; After determining that the prisoner has crossed regions through the digital twin map, real-time scheduling of coverage strategies is carried out, achieving rapid identification of cross-regional behavior and seamless switching of positioning modes. BRIEF DESCRIPTION OF THE DRAWINGS

[0016] Figure 1 It is a schematic diagram of the process of the present invention; Figure 2 It is a schematic diagram of the principle of implementing the logic of the present invention. DETAILED DESCRIPTION

[0017] Hereinafter, embodiments of the present disclosure will be described with reference to the accompanying drawings. However, it should be understood that these descriptions are exemplary only and are not intended to limit the scope of the present disclosure. In the following detailed description, for ease of explanation, many specific details are set forth to provide a comprehensive understanding of the embodiments of the present disclosure. However, it is obvious that one or more embodiments may also be implemented without these specific details. In addition, in the following description, descriptions of known structures and technologies are omitted to avoid unnecessary confusion of the concepts of the present disclosure.

[0018] The terms used herein are only for describing specific embodiments and are not intended to limit the present disclosure. The terms "comprise", "include", etc. used herein indicate the existence of the features, steps, operations and / or components, but do not exclude the existence or addition of one or more other features, steps, operations or components.

[0019] All terms (including technical and scientific terms) used herein have the meanings commonly understood by those skilled in the art unless otherwise defined. It should be noted that the terms used herein should be interpreted as having a meaning consistent with the context of this specification and should not be interpreted in an idealized or overly rigid manner.

[0020] like Figure 1-Figure 2 As shown, a cross-region precise indoor positioning method includes the following steps: Deploy 6G micro base stations, adjustable metamaterial reflectors, and voxel-based laser radars in various areas of the prison, and build a quantum inertial measurement unit into the wristband; obtain wireless measurement data from the 6G micro base station, obtain point cloud data from the voxel-based laser radar, and obtain motion data from the wristband, and form multi-source data for subsequent processing after time synchronization and noise filtering; 6G micro base stations, adjustable metamaterial reflectors, and voxel-based laser radars are deployed in various areas of the prison, and a quantum inertial measurement unit is built into the wristband; wireless measurement data is obtained from the 6G micro base station, point cloud data is obtained from the voxel-based laser radar, and motion data is obtained from the wristband, and after time synchronization and noise filtering, multi-source data is formed for subsequent processing.

[0021] 6G micro base stations refer to base station units that use the sixth-generation communication protocol or its terahertz extended frequency band. Although 6G is still in the research and development stage, "quasi-6G" experimental equipment for terahertz and high millimeter wave bands has appeared, which can be provided by communication equipment manufacturers (such as China Telecom, China Mobile, China Unicom Laboratory, etc.); in academia, research institutions have conducted prototype verification of 300GHz-1THz segment communications. These experimental base stations can achieve higher bandwidth and shorter coverage radius, and cooperate with multiple-input multiple-output (MIMO) antenna arrays for ranging (TOF / TDoA) and angle measurement (AOA). 6G micro base stations are generally installed in locations such as prison walls, ceilings or corridors. Through higher bandwidth and more dense deployment methods, they provide centimeter-level ranging, angle measurement and communication capabilities for indoor areas. TOF (Time of Flight) or TDoA (Time Difference of Arrival) measurements, as well as AOA (Angle of Arrival) measurements, can be achieved to sense data such as the distance, direction and signal strength between the bracelet and the base station.

[0022] An adjustable metamaterial reflector refers to a device that arranges a large-scale phased array microstructure on a dielectric surface or a thin film, and dynamically adjusts the reflection characteristics of electromagnetic waves by controlling the phase distribution of the microstructure. A metamaterial reflector (or adjustable metasurface) is a type of device that uses artificial microstructures to reconstruct the bandwidth, phase or scattering of electromagnetic waves. Related phased reflector test platforms have appeared in university laboratories and some startups (such as Kymeta, Meta Materials Inc., etc.). In the higher frequency band (millimeter wave / terahertz) range, an adjustable panel with a phased array microstructure is made, which can change the reflection path and direction according to the electric control signal. In a prison environment, the reflector can be installed near corners, stairs or blind spots, and the reflection direction, amplitude or focal area can be adjusted by the electric control array to improve the multipath phenomenon or make up for the base station coverage blind spot. For example, if the signal attenuation at a corner of a corridor is severe, the adjustable metamaterial reflector can automatically change the phase unit combination to form a directional reflection according to the relative position of the current base station and the bracelet, and concentrate the main beam to the area where the bracelet is located, reducing the interference of complex reflection paths caused by walls, metal facilities, etc.

[0023] Voxel-based LiDAR uses multi-beam or phase scanning to detect the three-dimensional environment inside the prison, and outputs three-dimensional point cloud data or voxel data (dividing fine grids under XYZ coordinates to determine whether there are objects in each grid unit). Most existing three-dimensional LiDAR products (such as Velodyne, Ouster, RoboSense, Innoviz, etc.) use multi-beam or rotation scanning to generate three-dimensional point clouds; some manufacturers and research institutions are also exploring the conversion of output data into real-time stereoscopic detection at the voxel level. Although "voxel-based" radar is not yet popular in the commercial field, similar effects can be achieved based on high-resolution solid-state LiDAR or multi-beam LiDAR. The original point cloud is rasterized through the back-end software algorithm, and voxel units are divided to detect the spatial position of people or obstacles. When a humanoid target is detected, the radar can extract the center position of the humanoid point cloud, which is then used to match and fuse with the ranging results of the 6G micro base station, ensuring that the prisoner can still be located by LiDAR when the base station is partially blocked or the signal is attenuated.

[0024] The quantum inertial measurement unit (Quantum IMU) uses ultracold atomic interference, atomic spin or other quantum-level effects to significantly reduce the random drift of acceleration and angular velocity measurements, making the cumulative error in a short time (seconds to tens of seconds) much lower than that of traditional MEMS IMU. Quantum IMUs currently appear mostly in laboratories or military levels. Companies (such as iXblue, Muquans, ColdQuanta, etc.) and research institutions have developed "atom interferometers" or "ultracold atomic accelerometers" prototypes, which can be used for high-precision requirements in environments without satellite signals, such as submarine navigation and underground positioning. In prison applications, simplified versions of quantum gyroscopes or quantum accelerometers can be used to reduce the overall size and power consumption, achieving lower random drift than traditional MEMS IMUs. The quantum IMU is integrated in a bracelet, which can maintain the prediction of the target person's position in the event of a temporary interruption of cross-regional or micro-base station signals, and align and correct with base station and radar measurements after the signal is restored.

[0025] Through a unified clock or communication protocol, the time alignment of the outputs of 6G micro base stations, voxel lidar and quantum IMU is achieved, and then the multipath error, optical noise or the measurement noise of the quantum sensor itself is uniformly filtered, so that the multi-source data formed has higher confidence and consistency in subsequent processing.

[0026] The present invention deploys 6G micro base stations in major prison areas such as cells, corridors, stairs, and activity halls to obtain wireless measurement data that can reflect the distance, angle, or channel quality between prisoners and base stations; through adjustable metamaterial reflectors, directional reflection or phase control of electromagnetic waves in severely blocked areas (such as corners or near metal doors) is achieved to reduce the multipath effect to a lower level; voxel-based laser radar is used to obtain point cloud data containing the prisoner's moving position in three-dimensional space, and combined with the acceleration, angular velocity, and attitude information of the quantum inertial measurement unit in the bracelet to compensate for the continuous positioning in the case of short-term attenuation or blind spots of the base station signal. After time synchronization and noise filtering of all collected data, it can be used as the input of the subsequent fusion algorithm to maintain stable and high-precision indoor positioning in cross-regional scenarios in prison environments (such as walking across floors or corners).

[0027] In one embodiment, if a prisoner walks through a corridor into a stairwell and temporarily loses part of the base station's line of sight, the quantum inertial measurement unit can be used to calculate the displacement increment. Then, when the base station coverage is restored on the other side of the stairwell, the base station measurement value is merged with the lidar point cloud data to quickly correct the bracelet positioning coordinates for seamless connection.

[0028] Preferably, the steps of deploying 6G micro base stations, adjustable metamaterial reflectors and voxel-based laser radars in various areas of the prison include: Additional adjustable metamaterial reflectors are installed in areas with corners or stairs to reduce multipath effects caused by obstructions; The voxel-based laser radar is installed at a higher position in the prison so that it covers at least one main activity channel, which facilitates the subsequent acquisition of point cloud data containing human-shaped targets.

[0029] The additional adjustable metamaterial reflectors at corners or staircases can reshape the beam of 6G band electromagnetic waves through their internal phased array microstructures to achieve directional reflection or phase adjustment, thereby significantly reducing the multiple scattering paths caused by channel obstruction; In a specific embodiment, if there is a metal guardrail or concrete wall at the corner of the prison corridor, an adjustable metamaterial reflector can be mounted on the corner wall, and a small controller can be used to dynamically change the phase unit combination to focus or refract the base station RF signal to the other side channel where the bracelet may appear; in this process, the reflection attenuation coefficient can also be corrected by adjusting the microstructure arrangement to increase the effective signal strength. The voxel-based laser radar is installed at a higher position in the prison (such as the ceiling or high wall). By dividing the fine grid voxels in the XYZ coordinate system, point cloud data containing the prisoner's body, surrounding obstacles, etc. is output. If a large-scale human voxel movement is identified, the base station distance measurement can be combined to determine the prisoner's specific position in the corridor, activity hall or staircase, thereby avoiding obvious positioning deviations when there is no direct line of sight at corners or stair corners.

[0030] In one embodiment, if a prisoner moves quickly in a long and narrow corridor, the lidar scans at a frequency of 10 Hz or higher and can detect the position changes of the human outline within a distance of 10 meters. With the help of an adjustable metamaterial reflector, the wireless signal can maintain a certain quality at the corners, and finally achieve centimeter or decimeter level dynamic positioning accuracy in the data fusion link.

[0031] Preferably, the motion data of the quantum inertial measurement unit also includes real-time measurements of acceleration, angular velocity and posture changes, and is synchronized with the wireless measurement data obtained by the 6G micro base station under the same time reference, thereby ensuring the time alignment accuracy of multi-source data.

[0032] The quantum inertial measurement unit can significantly reduce random drift in a short period of time through ultracold atomic interference or quantum spin sensing, and record the wristband's three-axis acceleration. , , With three-axis angular velocity , , The IMU measurement value and the base station measurement data can be mapped to the same timestamp in conjunction with the programmable clock or the synchronization frame sent by the base station.

[0033] In one embodiment, the Internally calculate the acceleration measured by the IMU and angular velocity To update the bracelet speed and location , if the base station TDoA is measured at time Get the distance between the bracelet and the base station , then according to the alignment of the time bases of the two, and Residual comparisons are performed and corrections are made in the subsequent fusion steps to ensure that the prisoner's continuous positioning does not jump when crossing different areas in the prison. Combined with the human point cloud position output by the voxel-based lidar, it can assist in detecting certain short-term loss of lock phenomena: if the error between the IMU predicted coordinates and the radar recognition point cloud is too large, the correction process can be triggered to ensure that the final positioning solution is always within the expected accuracy range.

[0034] Based on the multi-source data, the position of the wristband, the phase distribution of the adjustable metamaterial reflector, and the point cloud calibration information of the voxel-based laser radar are simultaneously incorporated into the hypersurface factor fusion model, and the bidirectional thrust iteration is used to perform nonlinear collaborative solution on each observation quantity to obtain the continuous coordinates of the wristband at different times; Under the overall idea of ​​cross-regional precise indoor positioning, the multi-source data generated by 6G micro base stations, adjustable metamaterial reflectors, voxel-based laser radars and quantum inertial measurement units can be used to uniformly solve the wristband position and related observation information using a hypersurface factor fusion model; this model treats the wristband position, adjustable metamaterial reflector phase configuration and voxel-based laser radar point cloud calibration information as multiple mutually coupled high-dimensional factors for the dynamic and complex wireless channels and multi-source perception quantities in the prison environment, and iterates under the same optimization framework to avoid the limitations of traditional single algorithms that are difficult to take into account both the dynamic control of the reflector and the calibration of the laser radar. Through "bidirectional thrust iteration", the forward solution can be used to obtain a preliminary estimate of the real-time wristband coordinates, and the backward traction can be used to correct the estimate of the previous moment within a short time window, so that the wristband position can still be kept smooth and accurate when switching quickly between different areas of the prison or when the reflector beam changes.

[0035] In one embodiment, when a prisoner moves across floors, the quantum inertial measurement unit accumulates low drift in a short period of time, and the adjustable metamaterial reflector transforms the phased array unit at the corner to redirect the beam, and the lidar provides a human point cloud observation of the corridor or staircase space. When these observations are simultaneously incorporated into the hypersurface factor fusion model, a continuous and robust coordinate trajectory can be output through bidirectional thrust iterative solution, which significantly reduces the jump error in the cross-region process.

[0036] In the present invention, the "hypersurface factor fusion model" is used to uniformly integrate multi-source observations and simultaneously include the phase control parameters of the adjustable metamaterial reflector, so as to continuously and accurately solve the three-dimensional position of the bracelet at different times in a prison environment. The principle can be understood as establishing a comprehensive error function in a high-dimensional space, adding the motion increment of the quantum inertial measurement unit, the arrival time difference and arrival angle of the 6G micro base station, the point cloud observation of the voxel-based laser radar, and the reflector phase parameters as "factors" to the same optimization target, and simultaneously estimating the bracelet state and reflector configuration through nonlinear minimization. For ease of explanation, an exemplary calculation embodiment and the corresponding core expression are given below.

[0037] In this model, a discrete time window is first defined ,make Indicates that the bracelet is at the time The state of (including position, optional attitude or velocity), Indicates at time The phase distribution vector of the adjustable metamaterial reflector (e.g. the phase combination of the phased array unit). The point cloud calibration information of the voxel-based lidar can be used as the “target observation coordinates” The motion increment generated by the quantum inertial measurement unit can be regarded as , the arrival time difference obtained by the 6G micro base station is recorded as , the arrival angle is recorded as (If there are multiple base stations, they are recorded as , To describe the effect of reflectors on the channel, a “path correction” function can be added to the model. To show how the theoretically predicted TDoA or AOA changes due to changes in the reflection path or gain of the phased array.

[0038] Incorporate all observations into the same objective function to construct the "comprehensive residual" And minimize it, as shown below (omitting the small amount of noise term in inertial navigation):

[0039] in, represents the wristband displacement difference at adjacent moments, For quantum IMU The motion increment obtained by inner integration; and They are the "theoretical arrival time difference" and "theoretical arrival angle" derived from the wristband position and the reflector phase distribution, which can be calculated by the electromagnetic propagation model or simplified path approximation. If the reflector changes the phased array unit, these theoretical values ​​will also change. renew; is the center coordinate of the human figure extracted by voxel laser radar, Represents a function that matches the bracelet coordinates with the center of the human body (for example, when the bracelet is worn on the waist or wrist, there is a fixed offset, and this offset relationship can be modeled to infer the center of the entire human voxel), , , , It is the weighting coefficient of different observation residuals, which is used to balance the influence of each channel in multi-source fusion.

[0040] The above comprehensive residual As a high-dimensional "hypersurface", When taking different values ​​in space, Also changes accordingly; through nonlinear iterative methods such as Gauss-Newton or Levenberg-Marquardt, , At the same time, the bracelet state and phase distribution are solved and continuously updated until convergence, so as to obtain the overall optimal solution. Once the solution converges, the time Bracelet position , and determine the most suitable reflector phase The distribution is such that the arrival time difference and arrival angle in various areas of the prison (including corners, stairs, etc.) are as closely matched as possible between actual measurements and theoretical predictions, and coincide with the positions of the human figures detected by the voxel-based lidar.

[0041] In specific applications, the dynamic adaptability of the model can also be enhanced through the two-way thrust iteration of "forward solution + backward traction": the forward solution quickly outputs the initial coordinate value based on the observation at the current moment, and the backward traction is based on the observations of the subsequent frames (for example, the center of the human figure recognized by the lidar in the next shot) Backtracking correction is performed to ensure that the entire trajectory remains smooth and accurate when encountering sudden beam switching or personnel quickly crossing areas. For example, when a prisoner enters a new floor and the adjustable metamaterial reflector has not yet switched to the optimal phase, the TDoA measurement error becomes larger. In the subsequent frames, the position of the human figure captured by the lidar will cause the backtracking traction to readjust. and , while ensuring the position accuracy, it also optimizes the reflector configuration, providing continuous robustness for cross-region positioning. Through this joint estimation, the system can simultaneously solve the problems of high-precision positioning and reflector channel maintenance in the complex environment of multiple floors and rooms in the prison, and achieve long-term and stable cross-region tracking of prisoners.

[0042] Preferably, the process of incorporating the bracelet position, the phase distribution of the adjustable metamaterial reflector, and the voxel-based laser radar point cloud calibration information into the hypersurface factor fusion model based on multi-source data includes: The motion increment provided by the quantum inertial measurement unit and the arrival time difference and arrival angle obtained by the 6G micro base station are input into the factor graph together; The point cloud data output by the voxel-based lidar is segmented to extract the human body contour voxels, and the center coordinates of the human body contour are used as the observation factor of the bracelet position.

[0043] In the specific implementation of the model, the motion increment of the quantum inertial measurement unit (short-term posture change obtained by integrating acceleration and angular velocity) is combined with the arrival time difference (TDoA) and arrival angle (AOA) of the 6G micro base station through the factor graph to form multiple residuals of the associated wristband position; and the three-dimensional point cloud output by the voxel-based lidar is first segmented, and the voxel clusters that meet the human shape characteristics are detected, and their center coordinates are extracted to form another dimension of observation factors, which are connected to the wristband position. At this time, the phase distribution of the adjustable metamaterial reflector can be set as a parameter that affects the channel propagation characteristics between the "base station-wristband". If the phased array configuration is changed in the corner or staircase area, the corresponding constraints in the factor graph will also be refreshed to ensure that the system can simultaneously correct the wristband coordinates and the reflector state to maintain the positioning continuity across regions.

[0044] In one embodiment, the quantum inertial measurement unit can be used in a time period , Displacement increment within Compared with voxel-based lidar at the moment Output humanoid center Together they serve as residual constraints, and the TDoA or AOA measured by the base station is used to limit the position of the bracelet through another residual term, and finally a relatively consistent optimal coordinate is obtained to avoid positioning errors caused by single observation failure or drift.

[0045] In another embodiment, 6G micro base stations are first deployed in major areas of the prison (such as cells, corridors, stairwells and activity halls). These base stations can obtain arrival time difference and arrival angle data at high frequency. At the same time, adjustable metamaterial reflectors are deployed at key locations, and their internal phased array microstructures are used to achieve dynamic regulation of the wireless signal path; in addition, voxel-based laser radars are installed in the prison to scan and output three-dimensional point cloud data, extract voxel clusters containing the outline of people through algorithm segmentation, and then calculate the center coordinates of these voxel clusters as target observation values; in addition, the bracelets worn by prisoners have built-in quantum inertial measurement units, which obtain acceleration and angular velocity data through quantum interference or ultracold atom technology, and obtain short-term posture increments through integration. All these data are synchronized and noise filtered to form inputs for subsequent multi-source data fusion.

[0046] Specifically, in the discrete time window Inside, order Indicates that the bracelet is at the time The three-dimensional position state of the quantum inertial measurement unit in the period The measured motion increment is recorded as , the arrival time difference obtained by the 6G micro base station is recorded as and the angle of arrival is denoted as , the human center coordinates output by the voxel laser radar are marked as , and the phase distribution of the tunable metamaterial reflector is recorded as the vector In order to jointly solve the above multi-source data in high-dimensional space, a comprehensive residual function is constructed as follows:

[0047] in: Represents the quantum inertial measurement unit in the time period The motion increment obtained by inner integration; Indicates that according to the bracelet position and adjustable metamaterial reflector phase distribution The predicted time difference of arrival, the calculation of which may be based on a radio propagation model; represents the predicted arrival angle based on the wristband position and reflector phase distribution; represents a mapping function used to convert the wristband position into a theoretical value that matches the center coordinates of the human figure extracted by the lidar; , , , is the weight coefficient, which is used to balance the impact of various residuals in the overall optimization.

[0048] In the implementation, the comprehensive residual function A high-dimensional hypersurface is formed, and its optimal solution corresponds to the optimal position of the bracelet at each moment under given observation conditions and the corresponding metamaterial reflector phase distribution. When solving the problem, nonlinear least squares methods such as Gauss-Newton method or Levenberg-Marquardt algorithm can be used for iterative optimization. In order to improve dynamic adaptability, the system introduces a bidirectional thrust iteration mechanism: Forward solution: At each moment Solve the initial position of the bracelet based on all current observation factors (quantum IMU increment, TDoA, AOA, lidar point cloud center) ; Backward traction: using the subsequent moment Or the real-time human center coordinates provided by the lidar in subsequent frames relative to the previous moment position Corrections are made, residual weights are updated, and the solution is iterated again to ensure that the entire continuous trajectory remains smooth when switching across areas or encountering occlusion.

[0049] For example, in one specific embodiment, when a prisoner enters the staircase from the corridor, the motion increment cumulative error provided by the quantum IMU in a short period of time is small, but because the base station signal in the staircase area may be temporarily unstable, the voxel-based lidar detects the change of the human point cloud in the corridor in time, resulting in Compared with the actual measured value If there is a deviation, the backward traction mechanism will adjust the previous estimate of the bracelet position. and the corresponding reflector phase vector , so that the newly calculated residual is minimized, thereby obtaining the corrected optimal position, ensuring continuous and accurate positioning in the cross-region process. Through this joint optimization method, the system can provide stable centimeter-level positioning accuracy in all areas of the prison (including corners, stairs, partitions and other complex environments), while updating the working status of the adjustable metamaterial reflector in real time, realizing dynamic adaptive control of the wireless channel, and thus ensuring the robustness and long-term stability of the entire prison positioning system.

[0050] The advantage of this hypersurface factor fusion model is that it can simultaneously consider the interdependence between multi-source data, avoiding the overall positioning deviation caused by errors in a single measurement channel. Through a two-way iteration mechanism, the system can achieve rapid convergence and self-correction in a dynamic environment, providing strong technical support for real-time positioning in high-security prison environments.

[0051] Preferably, when the hypersurface factor fusion model adopts bidirectional thrust iteration for nonlinear collaborative solution, the propagation characteristics of the wireless signal path are corrected in real time according to the phase distribution of the adjustable metamaterial reflector, and different observation residuals are weighted to improve the positioning accuracy of the bracelet in corners or partially blocked areas.

[0052] During the iterative calculation process, the phase distribution of the adjustable metamaterial reflector will produce directional or amplitude corrections to the main propagation channel between the base station and the bracelet. For example, when the phased array is updated, a reflection path with a low weight may become the main signal path. The bidirectional thrust iteration mechanism allows temporary reliance on the reflector configuration of the previous iteration during forward derivation. When a large residual is detected (such as a sudden change in the TDoA measurement at a corner), the backward traction will trace back to the bracelet coordinates at the previous moment and re-evaluate the observed residual weights in combination with the new phase configuration. In this way, for strong occlusion scenarios near corners or metal doors, the system can compensate for channel attenuation in a timely manner as the adjustable metamaterial reflector is adjusted, reducing positioning errors in blind spots.

[0053] Preferably, the bidirectional thrust iteration includes: Forward solution: Solve the factor graph of the observations at the current moment to obtain a preliminary estimate of the bracelet's position; Backward traction: trace back the wristband position at the previous moment in a short time window, and further correct the initial estimate of the wristband position according to the human body center coordinates recognized by the voxel-based laser radar in subsequent frames.

[0054] This iterative process can be divided into two steps: forward and backward. First, in the forward solution phase, the TDoA, AOA, IMU increments and lidar point cloud center observations collected at the current moment are input into the factor graph to output a temporary solution of the wristband coordinates. Then, in the backward traction phase, the observations within a shorter historical window are re-evaluated. If there is a large deviation between the center of the human figure seen by the lidar in the subsequent frame and the wristband coordinates at the previous moment, the solution of the previous moment is updated by backtracking correction, thereby ensuring that the overall trajectory remains smooth under complex spatiotemporal conditions (such as the prisoner passing a corner quickly or the phase switching of the reflector in the middle).

[0055] In a specific embodiment, the sliding window size can be set to a range of 0.5 to 1 second. When the subsequent frame laser radar successfully identifies the position of the criminal's body , and it is different from the previous prediction of the bracelet position If the deviation is too large, Incorporating the backward pulling process and combining it with a tunable metamaterial reflector The phase configuration at each moment is used to redistribute the residual weight of this section, so that the final output trajectory is closer to the actual moving path. In this way, when crossing areas or going up and down stairs in the prison, a high-confidence estimate of the prisoner's position can be maintained, thereby improving the reliability of precise indoor positioning across areas.

[0056] Mapping the continuous coordinates of the wristband to the digital twin map of the prison, identifying cross-regional behavior based on the coordinate changes across the regional boundaries, and adjusting the wireless signal coverage based on the phase distribution of the adjustable metamaterial reflector so that the wristband maintains continuous coordinate updates during the cross-region period; In cross-regional precise indoor positioning applications, in order for the prison management system to grasp the exact location of prisoners from one area (such as a cell) to another area (such as a corridor or activity hall) in real time, it is necessary to map the continuous coordinates of the bracelet to the digital twin map, identify cross-regional behavior by judging when the coordinates cross the pre-calibrated geometric boundaries in the map, and trigger corresponding linkage measures on the monitoring platform. In order to cope with the changes in the demand for wireless signals in different regions, the adjustable metamaterial reflector will schedule the coverage priority according to its phase distribution, so that the base station signal in the newly entered area can be enhanced or redirected, ensuring that the bracelet still has reliable measurement accuracy at the critical moment of cross-regional movement. In addition, if there is a brief signal mismatch at the moment of switching or in a special occlusion area, the quantum inertial measurement unit can be used to maintain short-term autonomous navigation so that the coordinate update will not be interrupted or significantly jumped.

[0057] In one embodiment, when a prisoner leaves his cell and walks into the corridor, the digital twin map detects that his coordinates have crossed the polygonal boundary of the cell and entered the boundary of the corridor, and immediately notifies the adjustable metamaterial reflector to adjust the main beam direction and amplify the base station signal at the other end of the corridor. The bracelet continues to output continuous coordinates during this connection process to ensure that the entire cross-regional positioning process is smooth and reliable.

[0058] In another embodiment, during the forward solution phase, the system calculates the current time All observation data are according to the formula: Input the factor graph and use an iterative optimization algorithm (such as the Gauss-Newton method or the Levenberg–Marquardt algorithm) to solve the current wristband position. and reflector phase parameters Specifically, the system first calculates the difference between the motion increment measured by the quantum IMU and the change in the position of the bracelet as the motion constraint. At the same time, it uses the TDoA and AOA data provided by the 6G micro base station to calculate the theoretical prediction value through the propagation model, and subtracts it from the actual measurement value to form the corresponding residual. After the center coordinates of the human figure extracted by the lidar are added as the position compensation factor, all constraints are integrated to form a high-dimensional nonlinear optimization problem. The optimization goal is to minimize the comprehensive residual. :

[0059] In each iteration, the system calculates the gradient and Hessian matrix approximation and updates the solution until the residual converges. Through forward solution, the system obtains the preliminary continuous coordinate trajectory of the bracelet and records the reflector phase parameters corresponding to each moment to provide a reference for subsequent steps.

[0060] In the backward traction phase, the system uses the subsequent observation data collected after the forward solution, especially the center coordinates of the human figure identified by the voxel-based laser radar in the subsequent frames, to retrospectively correct the position of the bracelet at the previous moment. The center coordinates of the human figure extracted by the laser radar are If there is a large deviation from the predicted position calculated in the forward direction, the deviation is fed back to the time The backward traction process can reconstruct the residual function within the optimization window to estimate the previous position. For example, add the following additional residual term:

[0061] in, is the weight of backward traction. The system combines this term with the original residual function and iterates again to obtain the corrected bracelet position. This forward and backward iterative approach can effectively compensate for the instantaneous error caused by the adjustment of wireless signals or reflector states during large environmental changes or cross-regional processes, ensuring a smooth transition of continuous coordinates.

[0062] Example description: For example, at the junction of a prison corridor and stairs, due to changes in the building structure and the appearance of obstructions (such as metal doors), the TDoA data obtained by the 6G micro base station at time Suddenly, a large deviation occurs, and the wristband position given by the forward solution The center of the human figure identified by the LiDAR There is an obvious error between the two. At this time, the system starts the backward traction mechanism and LiDAR data is used as a reference to Assume that at time , the center coordinates of the human figure detected by the laser radar are , and the corresponding theoretical mapping value and If the residual between is large, then the additional residual This deviation is fed back to the optimization process. After several backward iterations, the updated bracelet position A closer match with lidar observations, while also correcting the phase parameters of the tunable metamaterial reflector This process ensures that even when there are sudden structural changes in the building, the system can still adjust itself in a short time and provide continuous and accurate positioning data.

[0063] Combining forward solution and backward traction, the bidirectional thrust iteration method realizes the efficient fusion of multi-source data, ensuring that the continuous position solution of the bracelet has high robustness and accuracy in the complex and changeable environment of the prison. The final output continuous coordinates not only reflect the real-time position of the prisoner, but also synchronously output the optimal phase parameters of the reflector, so that the entire wireless channel can be adaptively adjusted according to environmental changes to achieve cross-regional continuous positioning. Through the above method, this system can eliminate the positioning error caused by signal obstruction, multipath interference and hardware switching delay in cross-regional scenarios, providing strong technical support for high-security management of prisons.

[0064] Preferably, the step of mapping the continuous coordinates of the wristband to the digital twin map of the prison and identifying cross-regional behavior according to the coordinate changes across regional boundaries includes: Demarcate the geometric boundaries of cells, corridors, and activity halls in the digital twin map; When the continuous coordinates of the wristband enter from one geometric boundary area into another geometric boundary area, it is determined that the prisoner has completed the cross-area movement and a region switching instruction is generated.

[0065] In the digital twin map, the plane and three-dimensional structure information of the prison can be pre-loaded or manually drawn to set corresponding geometric boundaries for each main functional area (including cell units, stairs, public corridors, activity halls, etc.), such as polygons, polyhedrons or grid areas, so as to perform coordinate collision detection in the subsequent positioning system. When crossing from one internal area of ​​a boundary to another boundary area, it can be determined that the prisoner has completed the area switch; at this time, the system will generate a "area switch instruction" and synchronize this information to the adjustable metamaterial reflector control module or monitoring platform. If there is a security access control linkage between multiple areas, the access control, video surveillance and other subsequent operations will be triggered according to the instruction to strengthen the security management and traceability of the cross-area process.

[0066] In one embodiment, the activity hall is set as the coordinate boundary , the corridor is set to ,when Instant satisfaction after a certain moment When the prisoner crosses the area, the system determines that the prisoner has completed the cross-area movement and issues an alarm or status update, presenting the prisoner's area change information to the prison guard in real time.

[0067] Preferably, the process of adjusting the wireless signal coverage based on the phase distribution of the adjustable metamaterial reflector includes: When cross-region behavior is detected, a command is sent to the adjustable metamaterial reflector to change the phase combination of the phased array units, so that the signal weight of the base station in the newly entered area is improved; When the wristband approaches a corner or an area with many obstacles, the phase distribution of the phased array unit is further fine-tuned to keep the wristband position observation error within the expected range.

[0068] After determining the cross-region switch, the adjustable metamaterial reflector will automatically update the phase combination of the internal phased array unit according to the priority of the region or real-time needs, thereby reconstructing the wireless channel coverage. If the prisoner enters a more spacious activity hall from the stairwell, the system can increase the phase gain of the base station signal corresponding to the hall or adjust the reflector to an angle that is more conducive to the coverage of the hall to ensure that the bracelet can obtain stronger ranging or angle measurement information in the hall. When the prisoner enters a corner or an area with dense obstacles (such as fixed metal partitions), the signal path can also be bypassed by "phased array fine tuning" to improve the controllability of the observation residual and maintain better accuracy of the overall positioning in this local area.

[0069] In one embodiment, if there is a metal door at the corner at the end of the corridor, when it is detected that a prisoner is about to pass through the door to enter another area, the system will automatically send instructions to the reflector phased array to change the enhancement strategy for the base station signal in the area behind the door and complete the switching within milliseconds to ensure continuous positioning of the prisoner as he crosses the threshold.

[0070] Preferably, the step of enabling the wristband to maintain continuous coordinate updates during the cross-region period further comprises: Quantum inertial measurement units are used for short-term autonomous navigation. When the voxel lidar or adjustable metamaterial reflector is in a temporary switching state resulting in insufficient observation data, the position increment of the quantum inertial measurement unit is preferentially used for positioning transition.

[0071] In order to prevent the temporary loss of observation data due to the incomplete beam redirection of the adjustable metamaterial reflector or the temporary obstruction of the voxel-based lidar line of sight during the cross-region moment, the system can switch to the position increment provided by the quantum inertial measurement unit for short-term autonomous navigation in a very short time. and angular velocity The points can be used to continuously calculate the coordinates of the bracelet , even if external observations are missing, it can maintain low drift accuracy for several seconds. After the voxel lidar and reflector output are stable again, the subsequent fusion algorithm will perform differential correction between the IMU-calculated coordinates and the new external observations to achieve smooth connection.

[0072] In one embodiment, if the voxel laser radar loses part of its point cloud due to the floor structure while the prisoner is walking in a staircase area across floors, and the reflector has not yet switched to the optimal beam mode for this floor, the quantum IMU can maintain continuous coordinate updates; when the prisoner reaches the staircase exit, the radar and base station signals are restored, and the fusion algorithm matches the IMU trajectory with the new TDoA / laser point cloud information to generate a consistent and precise coordinate trajectory without the prisoner having to stop or perform any calibration operations.

[0073] After obtaining the continuous coordinates of the wristband, the phase distribution of the adjustable metamaterial reflector is further corrected in combination with the dynamic obstacle information identified by the voxel-based lidar to expand and maintain the prison positioning system, thereby achieving accurate indoor positioning in various areas.

[0074] In the overall workflow of cross-regional precise indoor positioning, when the continuous coordinates of the bracelet have been obtained through multi-source fusion of 6G micro base stations, adjustable metamaterial reflectors, voxel-based lidars, and quantum inertial measurement units, if new obstacles appear inside the prison (such as temporarily stacked metal utensils) or the layout of the place changes (such as remodeling channels, adding or removing partitions), the positioning system itself needs to be expanded and maintained. The dynamic changes of the prison environment can be identified in real time by voxel-based lidars, and the corresponding structural information can be updated in the digital twin map. At the same time, the beam direction and phase distribution are corrected twice in combination with adjustable metamaterial reflectors, so that even when new obstacles or new channels appear, the wireless signals emitted by the 6G micro base stations can still cover the target area with low multipath errors, thereby maintaining accurate monitoring of prisoners' cross-regional movement.

[0075] In one embodiment, if a temporary iron fence is added in the event hall, the voxel lidar will detect the presence of the fence and output the modified humanoid target point cloud distribution. The digital twin map will simultaneously refresh the physical boundary information of the hall, and then instruct the adjustable metamaterial reflector to adjust the phased array unit to bypass the signal reflection path brought by the new fence, ultimately continuing to ensure high-precision positioning coverage in the area.

[0076] Preferably, the step of further correcting the phase distribution of the adjustable metamaterial reflector in combination with the dynamic obstacle information identified by the voxel-based laser radar after obtaining the continuous coordinates of the wristband to expand and maintain the prison positioning system includes: When the voxel-based lidar detects a new obstacle or channel modification, the structural information of the corresponding area in the digital twin map is updated; The phase distribution of the adjustable metamaterial reflector is reset according to the updated structural information so that the 6G micro base station measurement data still has a low multipath error in the new environment, thereby maintaining effective coverage of the prison positioning system.

[0077] In specific implementation, the voxel-based lidar can obtain the three-dimensional point cloud data inside the prison through timed scanning or triggered scanning, and compare the changed area with the existing map. If the newly identified large-area object shape (such as a rectangular iron box or a newly added partition wall) does not match the original information in the database, it will be marked and updated in the digital twin map. Subsequently, the adjustable metamaterial reflector will reallocate the phase combination of the phased array unit by parsing the latest map structure. For example, when the newly added obstacle position blocks the original main propagation path, the system can steer the beam to an auxiliary path or increase the attenuation compensation locally on the reflector surface to minimize the multipath spurious interference caused by the newly added obstacle.

[0078] In one embodiment, if a baffle is temporarily added at the end of the stairway, the voxel laser radar updates the map information after detecting the hard baffle, and the adjustable metamaterial reflector immediately makes partial parameter adjustments in the phased array microstructure, so that the signal can bypass the baffle from another side door or a better angle, ensuring that the distance measurement of the 6G micro base station remains credible and avoiding large positioning deviations caused by environmental changes. Thus, the present invention continues to expand and maintain the prison positioning system, so that it can still provide reliable high-precision positioning services for prison guards in situations where personnel frequently cross-regional activities or facilities are constantly changing.

[0079] Those skilled in the art will appreciate that the embodiments of the present application may be provided as methods, systems or computer program products. Therefore, the present application may take the form of a complete hardware embodiment, a complete software embodiment, or an embodiment combining software and hardware.

[0080] The above are only embodiments of the present application and are not intended to limit the present application. For those skilled in the art, the present application may have various changes and variations. Any modification, equivalent replacement, improvement, etc. made within the spirit and principle of the present application should be included in the scope of the claims of the present application.

Claims

1. A cross-regional precise indoor positioning method, characterized in that: The following steps are involved: Deploy 6G micro base stations, adjustable metamaterial reflectors, and voxel-based laser radars in various areas of the prison, and build a quantum inertial measurement unit into the wristband; obtain wireless measurement data from the 6G micro base station, obtain point cloud data from the voxel-based laser radar, and obtain motion data from the wristband, and form multi-source data for subsequent processing after time synchronization and noise filtering; Based on the multi-source data, the position of the wristband, the phase distribution of the adjustable metamaterial reflector, and the point cloud calibration information of the voxel-based laser radar are simultaneously incorporated into the hypersurface factor fusion model, and the bidirectional thrust iteration is used to perform nonlinear collaborative solution on each observation quantity to obtain the continuous coordinates of the wristband at different times; Mapping the continuous coordinates of the wristband to the digital twin map of the prison, identifying cross-regional behavior based on the coordinate changes across the regional boundaries, and adjusting the wireless signal coverage based on the phase distribution of the adjustable metamaterial reflector so that the wristband maintains continuous coordinate updates during the cross-region period; After obtaining the continuous coordinates of the wristband, the phase distribution of the adjustable metamaterial reflector is further corrected in combination with the dynamic obstacle information identified by the voxel-based lidar to expand and maintain the prison positioning system, thereby achieving accurate indoor positioning in various areas.

2. The method for cross-regional precise indoor positioning according to claim 1, characterized in that: The steps of deploying 6G micro base stations, adjustable metamaterial reflectors and voxel-based laser radars in various areas of the prison include: Additional adjustable metamaterial reflectors are installed in areas with corners or stairs to reduce multipath effects caused by obstructions; The voxel-based laser radar is installed at a higher position in the prison so that it covers at least one main activity channel, which facilitates the subsequent acquisition of point cloud data containing human-shaped targets.

3. A cross-regional precise indoor positioning method according to claim 1 or 2, characterized in that: The motion data of the quantum inertial measurement unit also includes real-time measurements of acceleration, angular velocity and posture changes, and is synchronized with the wireless measurement data obtained by the 6G micro base station under the same time reference, thereby ensuring the time alignment accuracy of multi-source data.

4. The method for cross-regional precise indoor positioning according to claim 1, characterized in that: The process of incorporating the wristband position, the phase distribution of the adjustable metamaterial reflector, and the voxel-based laser radar point cloud calibration information into the metasurface factor fusion model based on multi-source data includes: The motion increment provided by the quantum inertial measurement unit and the arrival time difference and arrival angle obtained by the 6G micro base station are input into the factor graph together; The point cloud data output by the voxel-based lidar is segmented to extract the human body contour voxels, and the center coordinates of the human body contour are used as the observation factor of the bracelet position.

5. The method for cross-regional precise indoor positioning according to claim 4, characterized in that: When the hypersurface factor fusion model adopts bidirectional thrust iteration for nonlinear collaborative solution, the propagation characteristics of the wireless signal path are corrected in real time according to the phase distribution of the adjustable metamaterial reflector, and different observation residuals are weighted to improve the positioning accuracy of the bracelet in corners or partially blocked areas.

6. The method for cross-regional precise indoor positioning according to claim 5, characterized in that: The bidirectional thrust iteration includes: Forward solution: Solve the factor graph of the observations at the current moment to obtain a preliminary estimate of the bracelet's position; Backward traction: trace back the wristband position at the previous moment in a short time window, and further correct the initial estimate of the wristband position according to the human body center coordinates recognized by the voxel-based laser radar in subsequent frames.

7. The method for cross-regional precise indoor positioning according to claim 1, characterized in that: The step of mapping the continuous coordinates of the wristband to the digital twin map of the prison and identifying cross-regional behavior based on the coordinate changes across the regional boundaries includes: Demarcate the geometric boundaries of cells, corridors, and activity halls in the digital twin map; When the continuous coordinates of the wristband enter from one geometric boundary area into another geometric boundary area, it is determined that the prisoner has completed the cross-area movement and a region switching instruction is generated.

8. The method for cross-regional precise indoor positioning according to claim 7, characterized in that: The process of adjusting the wireless signal coverage based on the phase distribution of the adjustable metamaterial reflector includes: When cross-region behavior is detected, a command is sent to the adjustable metamaterial reflector to change the phase combination of the phased array units, so that the signal weight of the base station in the newly entered area is improved; When the wristband approaches a corner or an area with many obstacles, the phase distribution of the phased array unit is further fine-tuned to keep the wristband position observation error within the expected range.

9. The method for cross-regional precise indoor positioning according to claim 1, characterized in that: The step of enabling the wristband to maintain continuous coordinate updates during the cross-region period also includes: Quantum inertial measurement units are used for short-term autonomous navigation. When the voxel lidar or adjustable metamaterial reflector is in a temporary switching state resulting in insufficient observation data, the position increment of the quantum inertial measurement unit is preferentially used for positioning transition.

10. The method for cross-regional precise indoor positioning according to claim 1, characterized in that: The steps of further correcting the phase distribution of the adjustable metamaterial reflector in combination with the dynamic obstacle information identified by the voxel-based laser radar after obtaining the continuous coordinates of the wristband to expand and maintain the prison positioning system include: When the voxel-based lidar detects a new obstacle or channel modification, the structural information of the corresponding area in the digital twin map is updated; The phase distribution of the adjustable metamaterial reflector is reset according to the updated structural information so that the 6G micro base station measurement data still has a low multipath error in the new environment, thereby maintaining effective coverage of the prison positioning system.

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