Signal dynamic occlusion error reduction method and system

Abstract

The present application relates to a kind of signal dynamic shielding error reduction method and system.This method constructs the ranging model about the projection of Fresnel zone to two-dimensional plane according to the UWB device of Anc and Tag, and the wearer Wearer of label Tag;The blocking degree index DFO of Wearer is calculated by ranging model, and ranging model is optimized using DFO to reduce shielding error;In the optimized ranging model, when Wearer is in the Fresnel zone ellipse, the actual blocking length of Wearer to the Fresnel zone ellipse is calculated;The range of truncated relative heading angle RHA is calculated in combination with blocking length.The present application establishes mathematical model by projecting the UWB device of Tag and Anc, wearer and Fresnel zone to two-dimensional plane, and is optimized in combination with index DFO, effectively reduces the error in positioning process.

Description

Technical Field

[0001] This invention relates to the field of signal processing technology for wearable ultra-wideband devices, specifically to a method and system for reducing dynamic signal occlusion errors. Background Technology

[0002] With the rapid development of the Internet of Things (IoT) technology, sensor devices have been widely used in daily life and industry, and various indoor positioning methods have been adopted, such as Wi-Fi, Bluetooth, UWB (Ultra-Wide Band), and other positioning methods. Among them, UWB is a wireless carrier communication technology that has attracted widespread attention in indoor positioning, near-field communication, and IoT fields due to its high transmission speed, low power consumption, high accuracy, and strong anti-interference capabilities.

[0003] For pedestrian positioning services, UWB-based pedestrian positioning systems offer the highest positioning accuracy among existing radio frequency technologies. However, in pedestrian positioning scenarios, under non-line-of-sight (NLOS) conditions, the pedestrian's body can obstruct the direct path between the wearable sensor and the base station, leading to significant fluctuations in ranging results. Therefore, the main challenge is analyzing the wearer's influence on ranging results within the positioning system. Theoretically, the wearer's influence on ranging results can be divided into two parts: the pedestrian's own radiation and the influence of the human body's unique structural composition; and human shadow occlusion. Experiments show that the human body's influence on experimental results almost entirely stems from the shadow effect. In recent research, researchers have incorporated the relative heading angle (RHA), considered in vehicle positioning, into pedestrian ranging models, introducing new research opportunities for UWB wearable device positioning. However, there are still many problems in the current research on pedestrian localization, such as the adaptability of the models proposed by researchers to different scenarios, and the static nature of localization training / test data. One of the main reasons for the slow progress of UWB localization research is that most researchers summarize and analyze experiments, but fail to notice that even in the same indoor scene with the same experimental configuration, there will be unevenness in the experimental scene. The conclusions drawn from the data obtained under such circumstances are always biased.

[0004] Therefore, there is an urgent need for a method to correct errors in application scenarios to verify the performance of positioning algorithms and models. Summary of the Invention

[0005] The purpose of this invention is to provide a method and system for reducing dynamic signal occlusion errors, in order to solve the current problem of lacking methods for correcting errors in application scenarios and thus verifying the performance of positioning algorithms and models.

[0006] To achieve the above objectives, the technical solution adopted by the present invention is as follows:

[0007] A method for reducing signal dynamic occlusion error, the method comprising:

[0008] Based on the UWB devices of base station Anc, the UWB devices of tag, and the wearer of tag's UWB devices, a ranging model is constructed regarding the Fresnel band projection onto a two-dimensional plane.

[0009] The Wearer Obstruction Index (DFO) is calculated using a ranging model, and the ranging model is then optimized using the DFO to reduce occlusion error.

[0010] In the optimized ranging model, when Wearer is in the Fresnel zone ellipse, the actual blocking length of Wearer on the Fresnel zone ellipse is calculated.

[0011] Calculate the range of the cut-off relative heading angle (RHA) based on the blocking length.

[0012] Furthermore, based on the UWB device of base station Anc, the UWB device of tag, and the wearer of tag's UWB device, a ranging model is constructed regarding the Fresnel band projection onto a two-dimensional plane, including:

[0013] Establish a rectangular coordinate system with the midpoint of the line connecting Tag and Anc as the origin;

[0014] By placing the center of the Fresnel zone ellipse at the origin of the rectangular coordinate system, we obtain a distance measurement model that projects the Fresnel zone onto a two-dimensional plane.

[0015] In the ranging model, the straight line connecting Tag and Anc is taken as the baseline, and Wearer is equivalent to a line segment. The angle of the midpoint of Wearer with respect to the baseline is the relative heading angle RHA.

[0016] Furthermore, the Wearer Obstruction Index (DFO) is calculated using a ranging model, including:

[0017] Using the ranging model, calculate the distance R between the k-th Fresnel zone ellipse and any point P on the baseline;

[0018] Calculate the actual blocking length R' of Wearer for the k-th Fresnel zone ellipse;

[0019] Calculate the Wearer Obstruction Index (DFO):

[0020]

[0021] Further, the distance R between the k-th Fresnel zone ellipse and any point P on the baseline is calculated, including:

[0022]

[0023] λ is the wavelength of the UWB signal;

[0024] l1 and l2 are the distances from Anc and Tag to any point P on the baseline, respectively.

[0025] Further, the actual blocking length R' of Wearer for the k-th Fresnel zone ellipse is calculated, including:

[0026]

[0027] in:

[0028] d w The length of the Wearer;

[0029] d is the vertical distance between Wearer and Tag;

[0030] φ c Let (x, y) be the intersection point of the Wearer and Fresnel zone ellipses and Tag(x). c The angle between the line connecting ,0) and the baseline;

[0031] φ c0 For φ c Boundary values ​​when they are the same as RHA;

[0032] φ w The angle between the two ends of the Wearer and the line connecting it to the Tag.

[0033] Furthermore, the Fresnel zone ellipse is selected as the first Fresnel zone ellipse.

[0034] Furthermore, the ranging model is optimized using DFO to reduce occlusion error, including:

[0035] Obtain the error probability distribution model of DFO;

[0036] The probability distribution of DFO is obtained by combining RHA, and a random number is obtained from the probability distribution of DFO. This random number is the ranging error.

[0037] The optimized distance measurement value is obtained by subtracting the distance measurement error from the collected distance measurement value.

[0038] Furthermore, combining the blocking length, the range of the cut-off relative heading angle (RHA) is calculated, including:

[0039] φ is calculated based on the blocking length. c and obtain φ c0 ;

[0040] When φc0 -φ w / 2>0, Wearer's RHA range inside the Fresnel zone ellipse is [φ c0 -φ w / 2,φ c0 +φ w / 2];

[0041] When φ c0 -φ w / 2≤0, Wearer's RHA range inside the Fresnel zone ellipse is [0,φ c0 +φ w / 2].

[0042] On the other hand, a signal dynamic occlusion error reduction system is provided, the system being used to implement the method, including:

[0043] The building module is used to construct a ranging model about Fresnel band projection onto a two-dimensional plane based on the UWB device of the base station Anc, the UWB device of the tag, and the wearer of the UWB device of the tag.

[0044] The error reduction module is used to calculate the Wearer Obstruction Index (DFO) through the ranging model, and to optimize the ranging model using the DFO to reduce occlusion error.

[0045] The blocking length calculation module is used to calculate the actual blocking length of the Wearer on the Fresnel zone ellipse in the optimized ranging model when the Wearer is located on the Fresnel zone ellipse.

[0046] The cutoff range calculation module is used to calculate the cutoff range relative to the heading angle (RHA) by combining the blocking length.

[0047] Compared with the prior art, the beneficial effects of the present invention are as follows:

[0048] This invention provides a method and system for reducing signal dynamic occlusion errors. A mathematical model is established by projecting the UWB device (Tag), Anc (base station), the wearer, and the Fresnel zone onto a two-dimensional plane. Based on controllable variables, all necessary parameters in the model are calculated, and a Degree of Fresnel Zone Obstruction (DFO) index for the degree of obstruction by the wearer is proposed. The model is validated in an indoor scenario using different Restricted Area Habitats (RHA) and different distances between the Tag and Anc as experimental variables. Using existing experimental data, DFO is incorporated into the ranging error probability model, proposing a new error elimination model. A new dataset is collected as a test set in the same scenario to evaluate the performance of the proposed model. Using a model of the wearer in the first Fresnel zone, it is shown that when the pedestrian is relatively close to the Tag and the distance between the Tag and Anc is relatively short, the distance between the Tag and Anc has almost no impact on the degree of obstruction. The proposed ranging model is applied to a positioning model, and corresponding positioning experiments are conducted to verify the performance of the positioning algorithm, effectively reducing errors in the positioning process. Attached Figure Description

[0049] To more clearly illustrate the technical solutions in the embodiments of the present invention or the prior art, the drawings used in the description of the embodiments or the prior art 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 embodiments can be obtained from these drawings without creative effort.

[0050] Figure 1 A two-dimensional mathematical model diagram of the Wearersystem in the signal dynamic occlusion error reduction method provided in an exemplary embodiment of this application.

[0051] Figure 2 A mathematical model diagram of the first scenario in the Wearersystem of the signal dynamic occlusion error reduction method provided in an exemplary embodiment of this application.

[0052] Figure 3 A mathematical model diagram of the second scenario in the Wearersystem of the signal dynamic occlusion error reduction method provided in an exemplary embodiment of this application.

[0053] Figure 4 A mathematical model diagram of the third scenario in the Wearersystem of the signal dynamic occlusion error reduction method provided in an exemplary embodiment of this application.

[0054] Figure 5This is a distribution diagram of the distance between different tags and Anc, and the DFO corresponding to different RHAs, when the wearer is 300mm away from the tag in Embodiment 2 of this application.

[0055] Figure 6 This is a flowchart of the method of the present invention. Detailed Implementation

[0056] To facilitate understanding of the present invention, a more complete description will be given below with reference to the accompanying drawings. Preferred embodiments of the invention are shown in the drawings. However, the invention can be implemented in many different forms and is not limited to the embodiments described herein. Rather, these embodiments are provided to provide a thorough and complete understanding of the disclosure of the invention.

[0057] It should be noted that similar reference numerals and letters indicate similar items; therefore, once an item is defined in one embodiment, it does not need to be further defined and explained in subsequent embodiments. Furthermore, the terms "comprising" and any variations thereof are intended to cover non-exclusive inclusion, for example, a process, method, system, product, or apparatus that includes a series of steps or units is not necessarily limited to those steps or units explicitly listed, but may include other steps or units not explicitly listed or inherent to such processes, methods, products, or apparatus.

[0058] It should also be noted that although the order of steps is mentioned in the method description, in some cases, steps may be performed in a different order than that described here, and this should not be interpreted as a restriction on the order of steps.

[0059] This invention provides a method for reducing signal dynamic occlusion error. It models a two-dimensional model of a UWB device, including the wearer, tags, and anchor, based on Fresnel bands. By using controllable parameters, the required parameters in the model are calculated, and a performance evaluation index—DFO—is proposed. Based on DFO, an error probability model for corresponding scenarios is presented and experimentally implemented. The proposed model is then validated, and finally integrated into a positioning algorithm. Experimental data is used to evaluate the performance of the proposed model.

[0060] This invention derives the distribution of RHA under LOS, QLOS (quasi-line-of-sight), and NLOS channel conditions by linking signal strength with relative heading angle (RHA):

[0061]

[0062] In LOS channel conditions, there is no interference or obstruction on the direct path between Anc and Tag. In NLOS, the human body completely blocks the propagation path, leading to significant attenuation of the main path or even making it undetectable. QLOS is a propagation environment between LOS and NLOS. In the QLOS environment, although there is partial obstruction from the human body, some straight propagation paths are still available. Therefore, the signal transmission quality in the QLOS environment may be between LOS and NLOS. After adding the Wearer, it can be seen that the channel obstruction is symmetrical about the 0° baseline and 180°. Therefore, the specific application scenario of this application is to represent a system including the wearer, Tag, and Anc as a Wearer system, and analyze the situation where the channel obstruction is within [0°, 180°]. The Wearer's standing direction is consistent with the direction of the TAG relative to the fixed base station. In practice, the Wearer and Tag can be regarded as a whole, φ w The angle of the tag relative to the wearer's shoulder width.

[0063] like Figure 6 The method includes:

[0064] S1: Based on the UWB devices of base station Anc, the UWB devices of tag, and the wearer of the UWB devices of tag, construct a ranging model about the Fresnel band projected onto a two-dimensional plane, including:

[0065] S101: Establish a rectangular coordinate system with the midpoint of the line connecting Tag and Anc as the origin;

[0066] S102: Place the center of the Fresnel zone ellipse at the origin of the rectangular coordinate system to obtain a distance measurement model of the Fresnel zone projected onto a two-dimensional plane;

[0067] S103: In the ranging model, the straight line connecting Tag and Anc is taken as the baseline, and Wearer is equivalent to a line segment. The angle of the midpoint of Wearer with respect to the baseline is the relative heading angle RHA.

[0068] RHA is defined by the straight line connecting the Tag and Anc as the baseline, clockwise rotation as positive, and the angle between the baseline and the Tag:

[0069]

[0070] in:

[0071] X anc ,Y anc ,X tag ,Y tag These represent the x and y coordinates of Anc and Tag, respectively.

[0072] When pedestrians act as obstacles, the direct channel between Tag and Anc is sometimes not completely blocked, allowing UWB signals to still bypass the obstacle and reach the receiver. This phenomenon can be explained by Fresnel zones, which are concentric ellipsoidal regions between two radio transceivers.

[0073] S2: Calculate the Wearer Obstruction Index (DFO) using the ranging model, and optimize the ranging model using the DFO to reduce occlusion error, including:

[0074] S201: Combining the ranging model, calculate the distance R between the k-th Fresnel zone ellipse and any point P on the baseline, including:

[0075]

[0076] λ is the wavelength of the UWB signal, which is obtained based on the center frequency of the UWB signal;

[0077] l1 and l2 are the distances from Anc and Tag to any point P on the baseline, respectively.

[0078] S202: Calculate the actual blocking length R' of Wearer on the k-th Fresnel zone ellipse, including:

[0079]

[0080] in:

[0081] d w The length of the Wearer;

[0082] d is the vertical distance between Wearer and Tag;

[0083] φ c Let (x, y) be the intersection point of the Wearer and Fresnel zone ellipses and Tag(x). c The angle between the line connecting ,0) and the baseline;

[0084] φ c0 For φ c Boundary values ​​when they are the same as RHA;

[0085] φ w The angle between the two ends of the Wearer and the line connecting it to the Tag.

[0086] S203: Calculate Wearer Obstruction Index (DFO):

[0087]

[0088] The first Fresnel zone ellipse is selected.

[0089] S204: Optimize the ranging model using DFO to reduce occlusion error, including:

[0090] S20401: Obtain the error probability distribution model of DFO;

[0091] S20402: Combine RHA to obtain the probability distribution of DFO, and obtain a random number through the probability distribution of DFO. This random number is the ranging error.

[0092] S20403: Subtract the ranging error from the collected ranging value to obtain the optimized ranging value.

[0093] S3: In the optimized ranging model, when Wearer is in the first Fresnel zone ellipse, calculate the actual blocking length of Wearer on the first Fresnel zone ellipse. The calculation process is the same as in S202.

[0094] S4: Based on the blocking length, calculate the range of the cut-off relative heading angle (RHA), including:

[0095] S401: Calculate φ based on the blocking length c and obtain φ c0 ;

[0096] S402: When φ c0 -φ w / 2>0, Wearer's RHA range inside the Fresnel zone ellipse is [φ c0 -φ w / 2,φ c0 +φ w / 2];

[0097] When φ c0 -φ w / 2≤0, Wearer's RHA range inside the Fresnel zone ellipse is [0,φ c0 +φ w / 2].

[0098] On the other hand, the present invention also provides a signal dynamic occlusion error reduction system, the system being used to implement the above-described method, comprising:

[0099] The construction module is used to construct a ranging model about Fresnel band projection onto a two-dimensional plane based on the UWB device of the base station Anc, the UWB device of the tag, and the wearer of the UWB device of the tag, corresponding to S1 of the above method;

[0100] The error reduction module is used to calculate the Wearer Obstruction Index (DFO) through the ranging model, and to optimize the ranging model using the DFO to reduce occlusion error, corresponding to S2 of the above method.

[0101] The blocking length calculation module is used to calculate the actual blocking length of the Wearer on the Fresnel zone ellipse in the optimized ranging model when the Wearer is in the Fresnel zone ellipse, corresponding to S3 of the above method;

[0102] The cutoff range calculation module is used to calculate the cutoff range relative to the heading angle (RHA) by combining the blocking length, corresponding to S4 of the above method.

[0103] Example 1:

[0104] NLOS conditions only arise when the first Fresnel zone ellipse is completely blocked, but blocking even a portion of the ellipse will also affect the channel. In this embodiment, Figure 1 The diagram below shows the two-dimensional mathematical model of the Wearer system. Algorithm 1 provides the mathematical model of the system, as shown in the table below:

[0105]

[0106] The calculation process is as follows:

[0107] When the system is within the first Fresnel zone ellipse, the Wearer will directly affect the channel. Establish a Cartesian coordinate system with the midpoint of the direct line connecting Tag-Anc as the origin. Place the center of the first Fresnel zone ellipse at the origin; then the intersection of this ellipse and the right x-axis is (x... c The intersection point on the upper side of the y-axis is (0, yc), and the x-axis is (0, yc). c =L / 2, Consider the Wearer as a strip of length d w The line segment whose center is at an angle of RHA with respect to the baseline. The extension of Wearer intersects the x-axis at (x0,0) and the ellipse at (x,y) and (x',y'), where (x,y) are the desired coordinates, and (x,y) and (x',y') are the intersection points of the x-axis and ellipse. c The angle between the line connecting (,0) and the baseline is φ. c The perpendicular distance d between Wearer and Tag can be used to calculate the distance from (x,y) to (x). c ,0) Draw the distance d between the foot of the perpendicular to the extension of Wearer's line and the perpendicular to Wearer's line. c Through d c d w , φ c The actual blocking length R' of Wearer on the first Fresnel zone ellipse is calculated. l1 It is the slope of the line perpendicular to the Wearer's line from the Tag; when the center frequency of the UWB signal is 3.1 GHz, the corresponding UWB signal wavelength is λ = 97 mm; φ c0 The calculation requires the use of φw This is used to truncate the range of RHA. The specific calculation process and parameter representation are shown in Algorithm 1, and the model diagram is as follows. Figure 2-4 As shown, Figure 2 When half of Wearer's body enters the Fresnel zone, RHA < φ c ; Figure 3 This indicates that Wearer is completely inside the Fresnel zone. In this case, let R' = d. w At this point, DFO reaches its maximum value; Figure 4 If the wearer is completely outside the Fresnel zone, let R' = 0, in which case DFO takes the minimum value of 0. Similarly, the parameters for these three cases can be calculated by the model proposed in Algorithm 1, which also proposes the Degree of Fresnel Zone obstruction (DFO) and its calculation method.

[0108] Example 2:

[0109] like Figure 5 The diagram shows the distribution of DFO (Distribution of Field-Oriented Frames) for different distances from the tag to the anchor (Anc) and for different RHAs (Range-Area-of-Hand) when the wearer is 300mm away from the tag. Because the wearer is very close to the tag, when the distance between the tag and the anchor remains at a normal communication distance, the wearer will not be completely within the Fresnel zone. However, the DFO is zero after RHA > 70°, corresponding to the situation where the wearer is not within the Fresnel zone at all. It can be seen that each curve is almost linear between 5° and 70°, which is consistent with common sense. Another finding is that, in this case, the DFO distribution for different tag-to-anc distances is almost identical.

[0110] Example 3:

[0111] To verify that the DFO model can effectively assess the degree of obstruction by pedestrians in the Fresnel zone between Tag and Anc from a theoretical perspective, a verification experiment was conducted to verify the contents of this application's specification and Examples 1 and 2.

[0112] The UWB device features a casing and external antenna, a built-in rechargeable lithium battery, and is characterized by ease of use, high precision, and compact size. Its center frequency is 3244-4259MHz, bandwidth is 500MHz, refresh rate is up to 100Hz, and communication rate is optional at 110Kbps / 6.8Mbps. This experiment used 110Kbps and employed two UWB devices. One was a Tag, held by the experimenter at approximately 30cm in front of their chest, mimicking the common scenario of pedestrians holding mobile phones. The other was an Anc, mounted on a tripod 1.5m above the ground to eliminate inconvenience caused by the z-axis, with the Anc at the same height as the Tag. The line connecting the Tag and Anc served as the 0° baseline, rotated 90° clockwise to +90°. The wearer stood at different angles to alter the RHA (Range of Harmony). Five Tag points (at varying distances from the Anc) were selected for the experiment: 2m, 4m, 6m, 8m, and 10m, spanning five steps. The wearer's RHA was set to [0°, 180°], with a step size of 30°, for a total of 7 steps. 300 data points were collected for each experiment. A total of 10,500 data points were collected in this experiment. The DFO and mean ranging error were obtained for the distance between the Tag and Anc at 2m, 4m, 6m, 8m, and 10m. The portion before DFO=0, i.e., the portion of DFO calculated by the model, highly overlaps with the actual experimental data, proving the reliability of the model proposed in Algorithm 1. Even after DFO=0, errors below 15cm still occurred. These errors were unrelated to the obstruction of the Fresnel band and exhibited a Gaussian distribution, which could be eliminated using a separate error probability distribution model. The mean was taken as the mean of all errors when DFO=0. DFO＝0 =91.269mm, and the distance between different tags and Anc has little effect on the mean error.

[0113] The distance-to-field error (DFO) at a distance of 300mm from the person to the tag is quasi-linear. Dividing the distance-to-area (RHA) with a resolution of 5°, the mean distance measurement error at RHA = 0° can be used under different distances (L). RHA＝0° Subtract Mean DFO＝0 Divide by the DFO corresponding to RHA = 0°, then calculate the average value to obtain the baseline mean when DFO = 1. DFO＝1 =257.788mm, and the mean error of other RHA values ​​were calculated using the formula:

[0114] Mean DFO＝1 =(Mean RHA＝0° -Mean DFO＝0 ) / DFO RHA＝0°

[0115] Mean(DFO) = DFO·MeanDFO＝1

[0116] The mean distance measurement error value and the corresponding DFO for RHA=0° under different L values ​​are listed below.

[0117]

[0118] The relationship between standard deviation and distance error (DFO) was analyzed. The DFO and standard deviation of distance measurement error were compared at distances of 2m, 4m, 6m, 8m, and 10m between Tag and Anc. The standard deviations were found to be relatively stable, except for a maximum of 30mm at 10m, where the standard deviation remained between 10mm and 20mm. Therefore, the mean of all standard deviations was used. For the experiments in this section, σ was taken as... DFO =14.619mm.

[0119] Based on the obtained mean and standard deviation, a normal distribution model of error probability based on DFO is proposed. The expression of the model is shown in the following equation, where x, f(x), σ DFO ,μ DFO , where represent error, the probability density function of error, the standard deviation based on DFO, and the mean based on DFO, respectively.

[0120]

[0121] The following formula gives μ DFO The expression:

[0122] μ DFO =Mean(DFO)=DFO·Mean DFO＝1 +Mean DFO＝0

[0123] The error probability distribution model calculated using DFO was used to eliminate errors in the existing data, and the distance measurement data before and after error elimination was compared. After applying the proposed model, the original distance measurement error decreased from a maximum of nearly 550 mm to about 100 mm. The error elimination effect was particularly significant in the area with a smaller RHA (Range Hidden Aspect), i.e., the area where the wearer's obstruction was more severe. The table below shows the comparison of distance measurement errors before and after error elimination.

[0124] mean err before eliminated[mm]

[0125]

[0126] mean err after eliminated[mm]

[0127]

[0128] In the table, the parameters Mean_RHA and Improve represent the mean error for different L values ​​under the same RHA, and the ratio of the mean error after model elimination to the original mean error. By observing the value of Improve, it can be seen that the model achieves the best error elimination effect for the most severe obstruction scenario, i.e., RHA = 0°, with the mean error after elimination being only 9.633% of the original value, and the actual mean error decreasing from 449.767 mm to 43.326 mm. For other scenarios, after model error elimination, the maximum mean error is below 100 mm, and the minimum is even close to 0 mm.

[0129] Those skilled in the art will understand that all or part of the functions of the embodiments of the present invention can be implemented by hardware or by computer program. When all or part of the functions in the above embodiments are implemented by computer program, the program can be stored in a computer-readable storage medium, which may include: read-only memory, random access memory, disk, optical disk, hard disk, etc., and the program is executed by a computer to achieve the above functions. For example, the program can be stored in the memory of a device, and when the program in the memory is executed by the processor, all or part of the above functions can be achieved. In addition, when all or part of the functions in the above embodiments are implemented by computer program, the program can also be stored in a storage medium such as a server, another computer, disk, optical disk, flash drive, or portable hard drive, and can be downloaded or copied to the memory of a local device, or the system of the local device can be updated. When the program in the memory is executed by the processor, all or part of the functions in the above embodiments can be achieved.

[0130] The above examples illustrate the present invention only to aid in understanding it and are not intended to limit the scope of the invention. Those skilled in the art can make various simple deductions, modifications, or substitutions based on the principles of this invention.

Claims

1. A method for reducing dynamic signal blocking error, characterized in that: The method includes: Based on the UWB devices of base station Anc, the UWB devices of tag, and the wearer of tag's UWB devices, a ranging model is constructed regarding the Fresnel band projection onto a two-dimensional plane. The Wearer Obstruction Index (DFO) is calculated using a ranging model, and the ranging model is then optimized using the DFO to reduce occlusion error. In the optimized ranging model, when Wearer is in the Fresnel zone ellipse, the actual blocking length of Wearer on the Fresnel zone ellipse is calculated. Calculate the range of the cut-off relative heading angle (RHA) based on the blocking length; in: Based on the UWB devices of base station Anc, the UWB devices of tag, and the wearer of the UWB devices of tag, a ranging model is constructed regarding the Fresnel band projection onto a two-dimensional plane, including: Establish a rectangular coordinate system with the midpoint of the line connecting Tag and Anc as the origin; By placing the center of the Fresnel zone ellipse at the origin of the rectangular coordinate system, we obtain a distance measurement model that projects the Fresnel zone onto a two-dimensional plane. In the ranging model, the straight line connecting Tag and Anc is taken as the baseline, and Wearer is equivalent to a line segment. The angle of the midpoint of Wearer with respect to the baseline is the relative heading angle RHA. The Wearer Obstruction Index (DFO) is calculated using a ranging model, including: Using the ranging model, calculate the distance R between the k-th Fresnel zone ellipse and any point P on the baseline; Calculate the actual blocking length R' of Wearer for the k-th Fresnel zone ellipse; Calculate the Wearer Obstruction Index (DFO): 。 2. The method for reducing signal dynamic blocking error according to claim 1, characterized in that: Calculate the distance R between the k-th Fresnel zone ellipse and any point P on the baseline, including: The wavelength of the UWB signal; and Let Anc and Tag be the distances from Anc and Tag to any point P on the baseline, respectively.

3. The method for reducing signal dynamic blocking error according to claim 2, characterized in that: Calculating the actual blocking length R' of Wearer for the k-th Fresnel zone ellipse includes: in: The length of the Wearer; The vertical distance between the Wearer and the Tag; The intersection of the Wearer and Fresnel zone ellipse and Tag The angle between the line connecting the two points and the baseline; for Boundary values ​​when they are the same as RHA; The angle between the two ends of the Wearer and the line connecting it to the Tag.

4. The method for reducing signal dynamic blocking error according to claim 3, characterized in that: The first Fresnel zone ellipse is selected.

5. The method for reducing signal dynamic blocking error according to claim 4, characterized in that: Optimize the ranging model using DFO to reduce occlusion error, including: Obtain the error probability distribution model of DFO; The probability distribution of DFO is obtained by combining RHA, and a random number is obtained from the probability distribution of DFO. This random number is the ranging error. The optimized distance measurement value is obtained by subtracting the distance measurement error from the collected distance measurement value.

6. The method for reducing signal dynamic blocking error according to claim 5, characterized in that: Based on the blocking length, calculate the range of the cut-off relative heading angle (RHA), including: Calculated based on the length of the blockage. and obtained ; when Wearer's RHA range within the Fresnel zone ellipse is ; when Wearer's RHA range within the Fresnel zone ellipse is .

7. A signal dynamic blocking error reduction system, characterized in that: The system is used to implement the method according to any one of claims 1-6, comprising: The building module is used to construct a ranging model about Fresnel band projection onto a two-dimensional plane based on the UWB device of the base station Anc, the UWB device of the tag, and the wearer of the UWB device of the tag. The error reduction module is used to calculate the Wearer Obstruction Index (DFO) through the ranging model, and to optimize the ranging model using the DFO to reduce occlusion error. The blocking length calculation module is used to calculate the actual blocking length of the Wearer on the Fresnel zone ellipse in the optimized ranging model when the Wearer is located on the Fresnel zone ellipse. The cutoff range calculation module is used to calculate the cutoff range relative to the heading angle (RHA) by combining the blocking length.

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