Three-dimensional positioning method for personnel in limited space based on multi-data fusion

Abstract

The present application relates to the field of personnel three-dimensional positioning, and relates to a limited space personnel three-dimensional positioning method based on multi-data fusion. The present application deploys low-frequency magnetic field transmitters at the entrances of each floor passage in the limited space, and determines a layer-changing trigger area and an initial three-dimensional positioning point. When the initial three-dimensional positioning point enters the layer-changing trigger area, a strength time sequence corresponding to each signal code is constructed based on the magnetic field signal code and strength received by the positioning terminal, the layer-changing state of the personnel and the floor where the personnel is located are determined based on the strength time sequence, the vertical coordinate range or set is determined in combination with the layer-changing state, the current actual vertical coordinate of the personnel is determined in combination with the initial vertical coordinate, the grid map of the horizontal projection plane at each vertical height in the limited space is obtained, the associated feasible grid of each grid is obtained, the current feasible grid domain at each vertical height is determined, the actual horizontal coordinate is corrected in combination with the initial horizontal coordinate, and the final three-dimensional positioning coordinate is output, thereby improving the positioning reliability and practicability.

Description

Technical Field

[0001] This invention relates to the field of three-dimensional personnel positioning, and specifically to a method for three-dimensional personnel positioning in a confined space based on multi-data fusion. Background Technology

[0002] Confined spaces such as underground utility tunnels, mine roadways, building stairwells, and enclosed factory buildings are characterized by strong enclosure and complex structure. They are also characterized by multiple floors intersecting in three dimensions and severe signal obstruction. Three-dimensional positioning of personnel is a core technical support for safety monitoring, emergency rescue, and intelligent operation and maintenance. It has extremely high requirements for positioning accuracy, continuity, and reliability. There is an urgent need to invent a stable and reliable three-dimensional positioning method for personnel in confined spaces that can fuse multiple data.

[0003] However, the existing technology has the following problems: 1. The existing technology relies on inertial measurement vertical integration or barometer height measurement to determine the floor change, but inertial measurement has cumulative error at the stair landing, and barometer readings in the stairwell fluctuate drastically due to airflow disturbance, making it impossible to accurately determine the switching time when people enter the stairwell from one floor or arrive at another floor, resulting in misjudgment of floor assignment.

[0004] 2. Existing technologies using wireless positioning output often contain isolated outliers. Traditional post-processing smoothing methods still retain some positioning points located in impassable areas such as walls and equipment obstacles. This makes it impossible to guarantee that the output trajectory moves strictly along the passable area and to identify phenomena that do not conform to physical laws, such as passing through walls. Summary of the Invention

[0005] This invention aims to address the shortcomings of existing technologies by providing a three-dimensional positioning method for personnel in confined spaces based on multi-data fusion. This invention utilizes the temporal sequence of low-frequency magnetic field signal intensity to identify floor transitions and determine floor levels. Based on horizontal coordinate correction within a passable grid domain, it achieves high-precision three-dimensional positioning of personnel within a confined space.

[0006] To achieve the above objectives, the present invention adopts the following technical solution: The present invention provides a three-dimensional positioning method for personnel in a confined space based on multi-data fusion, including: deploying low-frequency magnetic field transmitters at the entrances of passageways on each floor of the confined space and determining the floor-changing triggering area; using wireless ranging signals to calculate the horizontal coordinates of the positioning terminal worn by the personnel; calculating the vertical coordinates based on the differential barometric altimetry method; and determining the initial three-dimensional positioning point.

[0007] When the initial three-dimensional positioning point enters the floor change triggering area, the intensity time sequence corresponding to each signal code is constructed based on the magnetic field signal encoding and intensity received by the positioning terminal. Based on the intensity time sequence corresponding to each signal code, the floor change status of the personnel and the floor where the personnel are located are determined.

[0008] The range or set of vertical coordinates is determined based on the floor the person is on and the floor change status. The person's current actual vertical coordinates are then determined by combining the initial vertical coordinates of the initial three-dimensional positioning points.

[0009] Establish a grid diagram of the horizontal projection plane at each vertical height in a limited space, obtain the associated feasible grids of each grid, obtain the grid where the horizontal coordinates of each time point in the historical time window are located, determine the current feasible grid domain, obtain the actual horizontal coordinates by combining the initial horizontal coordinates, and output the final three-dimensional positioning coordinates.

[0010] Compared with the prior art, the present invention has the following beneficial effects: (1) The present invention deploys low-frequency magnetic field transmitters at the passage entrances of each floor in a limited space, determines the floor change triggering area, uses wireless ranging signals to calculate the horizontal coordinates of the positioning terminal worn by the personnel, calculates the vertical coordinates based on the differential barometric altimetry, and determines the initial three-dimensional positioning point, providing a reliable initial value for subsequent coordinate correction.

[0011] (2) When the initial three-dimensional positioning point enters the floor change triggering area, the present invention constructs the intensity time sequence corresponding to each signal code based on the magnetic field signal encoding and intensity received by the positioning terminal, and determines the floor change status and the floor where the person is located based on the intensity time sequence corresponding to each signal code, so as to realize the accurate determination of the floor change time and the floor affiliation, and solve the defect of the traditional method that cannot capture the switching time.

[0012] (3) The present invention determines the range or set of vertical coordinates based on the floor where the person is located and the floor change status, and determines the current actual vertical coordinates of the person by combining the initial vertical coordinates of the initial three-dimensional positioning point, thereby realizing the binding of the floor with the vertical coordinates, solving the problem of inaccurate vertical positioning, and realizing accurate vertical coordinate positioning.

[0013] (4) This invention establishes a grid diagram of the horizontal projection surface at each vertical height in a limited space, obtains the associated feasible grid of each grid, obtains the grid where the horizontal coordinates of each time point in the historical time window are located, determines the current feasible grid domain, obtains the actual horizontal coordinates by combining the initial horizontal coordinates, and outputs the final three-dimensional positioning coordinates, eliminates unreasonable behaviors such as passing through walls, ensures that the output three-dimensional coordinates are in the passable area, and improves the reliability and practicality of positioning. Attached Figure Description

[0014] To more clearly illustrate the technical solutions of the embodiments of the present invention, the accompanying drawings used in the description of the embodiments will be briefly introduced below. Obviously, the drawings described below are only some embodiments of the present invention. For those skilled in the art, other drawings can be obtained based on these drawings without creative effort.

[0015] Figure 1 This is a schematic diagram of the method steps of the present invention;

[0016] Figure 2 This is a schematic diagram illustrating the specific steps of the method for determining the personnel's layer change status in this invention;

[0017] Figure 3 This is a flowchart illustrating the steps of the method for obtaining the current actual vertical coordinates in this invention. Detailed Implementation

[0018] Various exemplary embodiments of the present invention will now be described in detail with reference to the accompanying drawings. It should be noted that, unless otherwise specifically stated, the relative arrangement, numerical expressions, and values ​​of the components and steps set forth in these embodiments do not limit the scope of the invention. Furthermore, it should be understood that, for ease of description, the dimensions of the various parts shown in the drawings are not drawn to actual scale.

[0019] The following description of at least one exemplary embodiment is merely illustrative and is in no way intended to limit the invention or its application or use. Techniques, methods, and apparatus known to those skilled in the art may not be discussed in detail, but where appropriate, such techniques, methods, and apparatus should be considered part of the specification.

[0020] In all examples shown and discussed herein, any specific values ​​should be interpreted as merely exemplary and not as limitations. Therefore, other examples of exemplary embodiments may have different values.

[0021] Please see Figure 1 As shown, the present invention provides a three-dimensional positioning method for personnel in a limited space based on multi-data fusion, including: S1, deploying a low-frequency magnetic field transmitter and determining the layer-changing triggering area, and determining the initial three-dimensional positioning point.

[0022] Considering the complex floor structure of confined spaces, strong wireless signal obstruction, and large fluctuations in air pressure due to airflow disturbances, relying solely on a single barometer or wireless positioning is insufficient to accurately distinguish floor boundaries, easily leading to floor jumps and vertical drift. Low-frequency magnetic fields, with their strong penetrating power and good anti-interference capabilities, can form stable boundary signals in floor corridors, serving as the basis for triggering floor changes. Simultaneously, wireless ranging provides initial horizontal values, and differential air pressure provides initial vertical values; merging these provides a reliable initial three-dimensional positioning point, offering a benchmark for subsequent floor change identification and coordinate correction.

[0023] Based on this, the specific implementation steps of S1 include: S11, deploying low-frequency magnetic field transmitters at the entrances of passageways on each floor in the confined space, and determining the floor-changing trigger area. The specific implementation steps include: S111, the method for determining the floor-changing trigger area includes: deploying low-frequency magnetic field transmitters with different magnetic field signal codes at the center of the top of the stairwell entrance on each floor, recording their signal codes as floor signal codes, and associating them with the corresponding floors. In this embodiment, the low-frequency magnetic field transmitter is a coil-type magnetic field generator with a working frequency of 20kHz, a transmission power of 20W, and an effective coverage radius of 10m.

[0024] S112. Deploy low-frequency magnetic field transmitters with different magnetic field signal codes at the intermediate platform of the stairwell between adjacent floors. Record the signal code of the transmitter signal as the intermediate layer signal code, and associate the signal code with the corresponding two adjacent floors. In this embodiment, the deployment height of the low-frequency magnetic field transmitter is set to 1.5m from the intermediate platform, and the power and frequency are consistent with those of the transmitter at the entrance of the stairwell.

[0025] S113. Using the low-frequency magnetic field transmitter at the entrance of the stairwell on each floor as the geometric center, and a preset distance as the radius, a first area is determined, which together with the stairwell area forms a floor-changing trigger area.

[0026] In this embodiment, the preset distance is set to 5m, and the stair passage area is all the space area with the stair treads and the middle platform as the horizontal coordinates.

[0027] S12. Calculate the horizontal coordinates of the positioning terminal worn by the person using wireless ranging signals, and calculate the vertical coordinates based on the differential barometric altimetry method to determine the initial three-dimensional positioning point. The specific implementation steps include: S121. Utilize a wireless positioning base station deployed in a limited space to conduct ranging communication with the positioning terminal worn by the person, and calculate the initial horizontal coordinates of the terminal based on the time difference of arrival method.

[0028] In a specific embodiment of the present invention, at least three base stations are deployed on each floor to form a triangulation network, and the time difference of arrival (TDOA) calculation formula is as follows: ;

[0029] in For the terminal horizontal coordinates, Let i be the coordinates of the i-th base station. At the speed of light, Let be the time difference between the terminal and base station i and base station j; this is solved iteratively using the least squares method. This is existing technology, and will not be described in detail here.

[0030] S122. Measure the current air pressure value using the built-in barometric pressure sensor of the positioning terminal, and simultaneously obtain the real-time air pressure value and altitude of the reference point within the limited space. Calculate the relative vertical height of the terminal using the differential barometric altimeter formula, and obtain the initial vertical coordinates of the terminal by combining the altitude of the reference point.

[0031] Specifically, the barometric pressure sensor has an accuracy of ±1 Pa and a sampling frequency of 1 Hz; reference points are deployed at the entrance of each staircase to upload barometric pressure and altitude data in real time. The differential barometric altimeter formula is as follows: ;

[0032] in For reference point altitude, To determine the altitude of the positioning terminal, Reference point pressure, The actual measured air pressure at the terminal, of which and These are formula coefficients, which are existing technologies and will not be described in detail here. The initial horizontal coordinates are obtained based on the mapping relationship between altitude and vertical coordinates.

[0033] S123. Determine the initial three-dimensional positioning point based on the initial horizontal and initial vertical coordinates.

[0034] This invention deploys low-frequency magnetic field transmitters at the entrances of passageways on each floor in a confined space, determines the floor-changing trigger area, uses wireless ranging signals to calculate the horizontal coordinates of the positioning terminal worn by the personnel, and calculates the vertical coordinates based on the differential barometric altimetry method to determine the initial three-dimensional positioning point, providing a reliable initial value for subsequent coordinate correction.

[0035] S2. Construct the intensity time sequence corresponding to each signal code to determine the personnel's floor change status and the floor where the personnel are located.

[0036] Considering the continuous changes in magnetic field strength when people go up and down stairs, the intensity value at a single point is easily misjudged due to obstruction and posture, making it impossible to capture the complete floor-changing process. By constructing an intensity time series, the state of going upstairs, going downstairs, and floor-changing completion can be distinguished by trend changes. According to the different magnetic field characteristics corresponding to different floors and intermediate floors, the floor can be bound to the floor, avoiding floor misjudgment caused by traditional air pressure jumps.

[0037] The specific implementation steps of S2 based on this include: S21, when the initial three-dimensional positioning point enters the layer-changing triggering area, constructing the intensity time sequence corresponding to each signal code based on the magnetic field signal encoding and intensity received by the positioning terminal. The specific implementation steps include: S211, the positioning terminal worn by the personnel receives the analog voltage signal induced by the coil in real time, and converts the analog voltage signal induced by the coil at each time point into a digital sampling sequence through an analog-to-digital converter.

[0038] S212. Demodulate the digital sampling sequence, identify the signal code, and obtain the peak value of the digital sampling sequence, which is used as the signal strength value of the corresponding signal code.

[0039] S213. Obtain the signal strength value of the same signal code at each time point within the historical set time window, and combine it with the current signal strength value of the corresponding signal code to form the intensity time sequence corresponding to each signal code.

[0040] In a specific implementation of the present invention, the historical time window is set to 20 seconds. This time can cover the time required for a person to walk half a floor, ensuring that the intensity time series contains the complete process of the magnetic field signal rising to the peak and then falling, thereby accurately extracting the local maximum point. The implementer can also set other specific values, but they should not be too small to avoid missing the local maximum point of a certain intensity time series, which may lead to misjudgment or omission.

[0041] S22. Determine the personnel's floor-changing status and the floor they are on based on the intensity time sequence corresponding to each signal code. For example, Figure 2 As shown, the method for determining the personnel's floor-changing status includes: S221, when the initial three-dimensional positioning point is located within the stairwell area, if a local maximum value appears in the intensity time sequence corresponding to the signal code of a certain floor, it is determined that the floor-changing phase is in its initial stage. The local maximum value is defined as a sampling point whose intensity value is greater than the intensity values ​​of the three sampling points before and after it, and whose intensity value is not lower than a preset stairwell signal strength threshold. The preset stairwell signal strength threshold is obtained by collecting the minimum signal strength value of the corresponding floor signal code when the personnel pass through the stairwell during the floor-changing process, and recording this minimum value as the preset stairwell signal strength threshold.

[0042] S222. Obtain the lower floor among the floors associated with the intermediate layer signal code that has the highest current signal strength value. If the lower floor is equal to the floor associated with the signal code of that floor, then the floor change state is determined to be starting to go upstairs; otherwise, the floor change state is determined to be starting to go downstairs. Specifically, for example, if the intermediate layer code 1001 is associated with floors 1 and 2, if the current floor is floor 1, then it is determined to start going upstairs; if the current floor is floor 2, then it is determined to start going downstairs.

[0043] S223. If a local maximum point appears in the intensity time series corresponding to the current intermediate layer signal code, and the initial three-dimensional positioning point is located in the stairwell area, then it is determined that the area is at the end of a floor change. The method for determining the local maximum point is the same as the method for determining the local maximum point in the intensity time series corresponding to a floor signal code in S221 above; it must also meet the requirement of being no less than a preset intermediate layer signal strength threshold. The method for obtaining the preset intermediate layer signal strength threshold is as follows: when the data acquisition personnel pass through the intermediate layer platform during the floor change process, the minimum signal strength value corresponding to the intermediate layer signal code is recorded as the preset intermediate layer signal strength threshold.

[0044] S224. Obtain the associated floor of the floor with the highest current signal strength value. If it is equal to the higher floor among the associated floors of the intermediate floor signal strength value, it is determined to be the end of the upper floor; otherwise, it is determined to be the end of the lower floor.

[0045] For example, if the middle layer code 1001 is associated with floors 1 and 2, and the current signal strength value corresponding to the floor code associated with floor 2 is the highest, then it is determined to be the end of the upper floor; if the current signal strength value corresponding to the floor code associated with floor 1 is the highest, then it is determined to be the end of the lower floor.

[0046] S225. When the initial 3D positioning point is only located in the first area but not in the stairwell, update the floor where the person is located based on the intensity time series corresponding to the floor signal code and the intermediate floor signal code. The specific implementation steps include: S2251. When a local maximum point appears in the intensity time series corresponding to a certain floor signal code, obtain the initial 3D positioning points of each historical time point before the time point corresponding to the local maximum point.

[0047] It should be noted that the method for determining this local maximum point is the same as the method for determining the local maximum point of the intensity time sequence corresponding to the signal encoding of a certain floor in S221 above.

[0048] S2252. If the initial 3D positioning points at each historical time point are located within the stairwell area, then it is determined that the current floor change is complete. Floor change completion indicates that the person has left the stairwell and entered a new floor area, at which point the person's current floor needs to be updated. After the floor update, the current floor is locked until the next floor change is completed and a new floor update is performed.

[0049] S2253. Update the current floor of the person based on the associated floor code of the floor where a local maximum point appears in the intensity time series.

[0050] When the initial three-dimensional positioning point enters the floor-changing triggering area, this invention constructs an intensity time sequence corresponding to each signal code based on the magnetic field signal encoding and intensity received by the positioning terminal. Based on the intensity time sequence corresponding to each signal code, the floor-changing status of the personnel and the floor where the personnel are located are determined, thereby achieving accurate determination of the floor-changing time and floor affiliation, and solving the defect of traditional methods that cannot capture the switching time.

[0051] S3. Determine the range or set of vertical coordinates, and determine the current actual vertical coordinates of the personnel based on the range or set of vertical coordinates.

[0052] Considering that the vertical position is in a transitional range between the initial and final stages of floor replacement, directly using a single point value of air pressure would result in significant errors. Therefore, a reasonable vertical range needs to be determined based on the floor replacement status. After the floor replacement is completed, the floor height is fixed and needs to be matched with the building's floor height model. Constraining and correcting the initial air pressure value against the corresponding vertical range can eliminate the effects of air pressure drift and airflow disturbance, ensuring that the vertical coordinates stably match the actual floor height.

[0053] Based on this, the specific implementation steps of S3 include: S31, determining the vertical coordinate range or set based on the floor the person is on and the floor change status. The specific implementation steps are as follows: S311, when at the end or beginning of a floor change, obtaining the vertical coordinates of the corresponding middle platform from the floor design height data of each floor in the background database of the confined space personnel 3D positioning system, and determining the vertical coordinate range. The background database stores the design height of each floor, such as 3m for floors 1-2, and 1.5m for the vertical coordinate of the middle platform; if the current person is on floor 1, in the initial stage of a floor change, and the floor change status is going up, then the vertical coordinate range is, for example, 0-1.5m; if at the end of a floor change, and the floor change status is going up, then the vertical coordinate range is, for example, 1.5-3m; similarly, if the current person is on floor 2, in the initial stage of a floor change, and the floor change status is going down, then the vertical coordinate range is, for example, 1.5-3m; if at the end of a floor change, and the floor change status is going down, then the vertical coordinate range is, for example, 0-1.5m.

[0054] S312. If the current floor change is completed or the user is outside the floor change trigger area, the set of reachable vertical coordinates corresponding to each horizontal coordinate of the current floor is determined based on the building structure model of the confined space in the background database of the confined space personnel 3D positioning system. For example, if there is an independent 0.5m platform in a certain area on the 2nd floor of the confined space, then the set of vertical coordinates of that area is {3m, 3.5m}.

[0055] S313. Based on the initial horizontal coordinates of the initial three-dimensional positioning points, determine the corresponding vertical coordinate set from the set of reachable vertical coordinates corresponding to each horizontal coordinate.

[0056] S32. Determine the current actual vertical coordinates of the personnel by combining the initial vertical coordinates of the initial three-dimensional positioning points.

[0057] Because the airflow disturbance is severe during the floor change process in the stairwell, the differential barometric altimeter results are prone to large fluctuations. Since the attenuation of the low-frequency magnetic field signal intensity in the vertical direction has a clear spatial correlation, the inverted vertical coordinates based on the magnetic field signal intensity are preferred at the beginning and end of the floor change process to correct the initial vertical coordinates of the barometric altimeter.

[0058] like Figure 3 As shown, the specific implementation steps are as follows: S321. When at the end of the layer change or the beginning of the layer change, if the initial vertical coordinate is within the range of the vertical coordinate, it is determined that the initial vertical coordinate range is normal. If the initial vertical coordinate is outside the range of the vertical coordinate, it is determined that the initial vertical coordinate drift is serious.

[0059] S322. Based on the current signal strength value corresponding to each signal code, the current distance between the person and each low-frequency signal transmitter is obtained through an exponential attenuation model. By substituting into the Euclidean distance calculation formula and combining it with the initial vertical coordinates, the person's current actual vertical coordinates are solved. In a specific embodiment of the present invention, the signal strength of each low-frequency signal transmitter is measured at a predetermined distance within the stairwell, and the correlation function between the attenuation distance and the signal strength is obtained by fitting an exponential attenuation model.

[0060] The specific exponential decay model is as follows: ;

[0061] in For signal strength, and All of these are coefficients to be determined. Let be the attenuation distance from the low-frequency signal transmitter. By substituting the attenuation distance as the independent variable and the signal strength value as the dependent variable into the above model, the unknowns are solved using the least squares method. and The correlation function between the attenuation distance and signal strength of each low-frequency signal transmitter is obtained.

[0062] Based on the current signal strength values ​​corresponding to the signal codes received by the positioning terminal worn by the person, and by inputting the correlation function between the attenuation distance and signal strength of the corresponding low-frequency signal transmitter, the distance between the person and each low-frequency signal transmitter is obtained. This is achieved by setting the person's coordinates (x, y, z). 1 ), and solve for z by simultaneously solving the distances between it and each low-frequency signal transmitter, specifically Solve ,in Let be the distance between the current person and the i-th low-frequency signal transmitter. Considering that multiple solutions can be obtained, therefore, when multiple solutions are obtained... When the coordinates are closest to the initial vertical coordinates, the current actual vertical coordinates are taken.

[0063] S323. If the current layer change is completed or the current layer change trigger area is outside the current layer change trigger area, if the initial vertical coordinate of the current initial three-dimensional positioning point is the same as a certain vertical coordinate in the vertical coordinate set, then the initial vertical coordinate is used as the current actual vertical coordinate.

[0064] S324. If the initial vertical coordinate of the current initial three-dimensional positioning point is not the same as any vertical coordinate in the vertical coordinate set, then the vertical coordinate in the vertical coordinate set that is closest to the initial vertical coordinate is taken as the current actual vertical coordinate.

[0065] This invention determines the range or set of vertical coordinates based on the floor a person is on and the floor change status, and determines the person's current actual vertical coordinates by combining the initial vertical coordinates of the initial three-dimensional positioning point, thereby binding the floor with the vertical coordinates, solving the problem of inaccurate vertical positioning, and achieving accurate vertical coordinate positioning.

[0066] S4. Determine the current feasible grid domain, correct it to obtain the actual horizontal coordinates, and output the final three-dimensional positioning coordinates.

[0067] Considering that wireless horizontal positioning often results in outliers and points that pass through walls, which do not match the accessible areas of buildings, traditional smoothing methods cannot eliminate physically inaccessible locations. Therefore, it is necessary to mesh the space, combine historical trajectory connectivity to determine the current feasible grid domain, and forcibly constrain the horizontal coordinates within the accessible area to avoid unreasonable trajectories such as those that pass through walls or cross boundaries, ensuring that the output 3D coordinates conform to spatial physical constraints.

[0068] The specific implementation steps of S4 based on this include: S41, establishing a grid diagram of the horizontal projection surface at each vertical height in the limited space, obtaining the associated feasible grids of each grid, obtaining the grid where the horizontal coordinates of each time point within the historical time window are located, and determining the current feasible grid domain. The specific implementation steps are as follows: S411, obtaining the horizontal projection surface at each vertical height in the limited space, and dividing each horizontal projection surface into square grids of equal size. In a specific embodiment of the present invention, the grid size is set to 0.5m × 0.5m; implementers can also set other values ​​according to actual conditions.

[0069] S412. Based on the building structure model or accessible area calibration data of the limited space, determine the associated feasible grids for each grid.

[0070] S413. Obtain the actual horizontal coordinates of each time point within the historical time window, obtain the associated feasible grids of the grids corresponding to the actual horizontal coordinates of adjacent historical time points, and use the connected domains of the associated feasible grids as the current feasible grid domains.

[0071] S42. Combine the initial horizontal coordinates with corrections to obtain the actual horizontal coordinates, and output the final three-dimensional positioning coordinates. The specific implementation steps are as follows: S421. If the current initial horizontal coordinates are not in the current feasible grid domain, then the coordinates of the geometric center of the grid closest to the current initial horizontal coordinates in the current feasible grid domain are taken as the actual horizontal coordinates.

[0072] S422, Conversely, the current initial horizontal coordinates are set as the actual horizontal coordinates.

[0073] This invention establishes a grid diagram of the horizontal projection surface at each vertical height in a limited space, obtains the associated feasible grids of each grid, obtains the grid where the horizontal coordinates of each time point within the historical time window are located, determines the current feasible grid domain, and obtains the actual horizontal coordinates by combining the initial horizontal coordinates with correction, and outputs the final three-dimensional positioning coordinates. This eliminates unreasonable behaviors such as passing through walls, ensures that the output three-dimensional coordinates are in the passable area, and improves the reliability and practicality of positioning.

[0074] The above embodiments can be implemented, in whole or in part, by software, hardware, firmware, or any other combination thereof. When implemented using software, the above embodiments can be implemented, in whole or in part, in the form of a computer program product.

[0075] Those skilled in the art will recognize that the modules and algorithm steps of the various examples described in conjunction with the embodiments disclosed herein can be implemented in electronic hardware, or a combination of computer software and electronic hardware. Whether these functions are implemented in hardware or software depends on the specific application and design constraints of the technical solution. Those skilled in the art can use different methods to implement the described functions for each specific application, but such implementation should not be considered beyond the scope of this application.

[0076] In addition, the functional modules in the various embodiments of this application can be integrated into one processing module, or each module can exist physically separately, or two or more modules can be integrated into one module.

[0077] The above description is merely a specific embodiment of this application, but the scope of protection of this application is not limited thereto. Any variations or substitutions that can be easily conceived by those skilled in the art within the scope of the technology disclosed in this application should be included within the scope of protection of this application. Therefore, the scope of protection of this application should be determined by the scope of the claims.

[0078] Finally, the above description is only a preferred embodiment of the present invention and is not intended to limit the present invention. Any modifications, equivalent substitutions, improvements, etc., made within the spirit and principles of the present invention should be included within the protection scope of the present invention.

Claims

1. A method for three-dimensional positioning of personnel in a confined space based on multi-data fusion, characterized in that, include: Low-frequency magnetic field transmitters are deployed at the entrances of passageways on each floor in a confined space, and the floor-changing triggering area is determined. The horizontal coordinates of the positioning terminal worn by the personnel are calculated using wireless ranging signals, and the vertical coordinates are calculated based on the differential barometric altimetry method to determine the initial three-dimensional positioning point. When the initial three-dimensional positioning point enters the floor change triggering area, the intensity time sequence corresponding to each signal code is constructed based on the magnetic field signal encoding and intensity received by the positioning terminal, and the floor change status and the floor where the person is located are determined based on the intensity time sequence corresponding to each signal code. The range or set of vertical coordinates is determined based on the floor where the person is located and the floor change status. The current actual vertical coordinates of the person are determined by combining the initial vertical coordinates of the initial three-dimensional positioning points. Establish a grid diagram of the horizontal projection plane at each vertical height in a limited space, obtain the associated feasible grids of each grid, obtain the grid where the horizontal coordinates of each time point in the historical time window are located, determine the current feasible grid domain, obtain the actual horizontal coordinates by combining the initial horizontal coordinates, and output the final three-dimensional positioning coordinates.

2. The method for three-dimensional positioning of personnel in a confined space based on multi-data fusion according to claim 1, characterized in that, The method for determining the layer switching trigger region includes: Low-frequency magnetic field transmitters with different magnetic field signal codes are deployed at the top center of the stairwell entrance on each floor. Their signal codes are recorded as floor signal codes and associated with the corresponding floors. Low-frequency magnetic field transmitters with different magnetic field signal codes are deployed at the intermediate platform of the stairwell between adjacent floors. The signal codes of their transmitted signals are recorded as the intermediate layer signal codes, and the signal codes are associated with the corresponding two adjacent floors. Using the low-frequency magnetic field transmitter at the entrance of the stairwell on each floor as the geometric center, and a preset distance as the radius, the first area is determined, and together with the stairwell area, it forms the floor-changing trigger area.

3. The method for three-dimensional positioning of personnel in a confined space based on multi-data fusion according to claim 1, characterized in that, The method for obtaining the initial three-dimensional positioning points includes: The initial horizontal coordinates of the terminal are calculated based on the time difference of arrival method by using a wireless positioning base station deployed in a limited space to conduct ranging communication with the positioning terminal worn by the personnel. The current air pressure value is measured by the barometric pressure sensor built into the positioning terminal. At the same time, the real-time air pressure value and altitude of the reference point in the limited space are obtained. The relative vertical height of the terminal is calculated by the differential barometric altimeter formula. The initial vertical coordinates of the terminal are obtained by combining the altitude of the reference point. The initial three-dimensional positioning point is determined based on the initial horizontal and initial vertical coordinates.

4. The method for three-dimensional positioning of personnel in a confined space based on multi-data fusion according to claim 1, characterized in that, The method for constructing the intensity time sequence corresponding to each signal encoding includes: The positioning terminal worn by the personnel receives the analog voltage signal induced by the coil in real time, and converts the analog voltage signal induced by the coil at each time point into a digital sampling sequence through an analog-to-digital converter; The digital sampling sequence is demodulated, the signal code is identified, and the peak value of the digital sampling sequence is obtained and used as the signal strength value of the corresponding signal code. Obtain the signal strength values ​​of the same signal code at each time point within a historically set time window, and combine them with the current signal strength value of the corresponding signal code to form the intensity time sequence of each signal code.

5. The method for three-dimensional positioning of personnel in a confined space based on multi-data fusion according to claim 4, characterized in that, The method for determining the personnel's layer change status includes: When the initial three-dimensional positioning point is located in the stairwell area, if a local maximum point appears in the intensity time sequence corresponding to the signal code of a certain floor, it is determined that it is in the early stage of floor change. Get the lower floor among the floors associated with the signal code of the middle layer with the highest current signal strength value. If the lower floor is equal to the associated floor of the signal code of that floor, the floor change state is determined to start going upstairs; otherwise, the floor change state is determined to start going downstairs. If a local maximum point appears in the intensity time sequence corresponding to the signal encoding of a certain intermediate layer, and the initial three-dimensional positioning point is located in the stairwell area, then it is determined that it is at the end of the floor change. Obtain the associated floor of the floor with the highest current signal strength value. If it is equal to the higher floor among the associated floors of the intermediate floor, it is determined to be the end of the upper floor; otherwise, it is determined to be the end of the lower floor. When the initial 3D positioning point is located only in the first area but not in the stairwell, the floor where the person is located is updated based on the intensity time sequence corresponding to the floor signal code and the intermediate floor signal code.

6. The method for three-dimensional positioning of personnel in a confined space based on multi-data fusion according to claim 5, characterized in that, The method for updating the floor number of the personnel includes: When a local maximum point appears in the intensity time sequence corresponding to the signal encoding of a certain floor, the initial three-dimensional positioning points of each historical time point before the time point corresponding to the local maximum point are obtained. If the initial three-dimensional positioning points at each historical time point are located within the stairwell area, then it is determined that the current floor change is complete. The current floor of a person is updated based on the associated floor code of the floor where a local maximum point appears in the intensity time series.

7. The method for three-dimensional positioning of personnel in a confined space based on multi-data fusion according to claim 5, characterized in that, The method for determining the range or set of vertical coordinates includes: When at the end or beginning of a floor change, the vertical coordinates of the corresponding middle platform are obtained from the floor design height data of each floor in the background database of the three-dimensional positioning system for personnel in confined space, and the range of vertical coordinates is determined. If the current floor change is completed or the user is outside the floor change trigger area, the set of reachable vertical coordinates corresponding to each horizontal coordinate of the current floor is determined based on the building structure model of the confined space in the background database of the confined space personnel 3D positioning system. Based on the initial horizontal coordinates of the initial three-dimensional positioning points, the corresponding vertical coordinate set is determined from the set of reachable vertical coordinates corresponding to each horizontal coordinate.

8. The method for three-dimensional positioning of personnel in a confined space based on multi-data fusion according to claim 7, characterized in that, The method for determining the current actual vertical coordinates includes: When at the end or beginning of a layer change, if the initial vertical coordinate is within the range of the vertical coordinate, it is determined that the initial vertical coordinate range is normal; if the initial vertical coordinate is outside the range of the vertical coordinate, it is determined that the initial vertical coordinate drift is serious. Based on the current signal strength value corresponding to each signal code, the current distance between the person and each low-frequency signal transmitter is obtained through the exponential decay model. By substituting into the Euclidean distance calculation formula and combining the initial vertical coordinates, the current actual vertical coordinates of the person are solved. If the current layer change is completed or the current layer change trigger area is outside the current layer change trigger area, if the initial vertical coordinate of the current initial 3D positioning point is the same as a vertical coordinate in the vertical coordinate set, then the initial vertical coordinate will be used as the current actual vertical coordinate. If the initial vertical coordinates of the current initial 3D positioning point are not the same as any vertical coordinate in the set of vertical coordinates, then the vertical coordinate in the set that is closest to the initial vertical coordinates will be taken as the current actual vertical coordinates.

9. The method for three-dimensional positioning of personnel in a confined space based on multi-data fusion according to claim 1, characterized in that, The method for obtaining the currently feasible grid domain includes: Obtain the horizontal projection planes at each vertical height in a finite space, and divide each horizontal projection plane into a square grid of equal size; Based on the building structure model of the limited space or the calibration data of the accessible area, determine the associated feasible grids for each grid. Obtain the actual horizontal coordinates of each time point within the historical time window, obtain the associated feasible grids corresponding to the actual horizontal coordinates of adjacent historical time points, and use the connected domains of the associated feasible grids as the current feasible grid domain.

10. The method for three-dimensional positioning of personnel in a confined space based on multi-data fusion according to claim 9, characterized in that, The method for obtaining the actual horizontal coordinates through correction includes: If the current initial horizontal coordinates are not in the current feasible grid domain, then the coordinates of the geometric center of the grid closest to the current initial horizontal coordinates in the current feasible grid domain will be used as the actual horizontal coordinates. Conversely, the current initial horizontal coordinates are set to the actual horizontal coordinates.

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