Confidence evaluation method for electromagnetic positioning by using six-degree-of-freedom sensor

Abstract

The invention relates to a confidence evaluation method for electromagnetic positioning by using a 6-degree-of-freedom sensor, which comprises the following steps of: under the condition of no interference, respectively fitting relational expressions between the distance between the 6-degree-of-freedom sensor and a transmitter and between the 6-degree-of-freedom sensor and a sensor included angle and between the 6-degree-of-freedom sensor and the sensor distance by using measurement data; the sensor included angle and the sensor spacing are respectively an included angle and a spacing of two five-degree-of-freedom sensors in the six-degree-of-freedom sensors; under the interference condition, the proportional relation between the measured sensor included angles and the fitting relational expression is calculated, the proportional relation between the sensor distances and the sensor distances calculated according to the fitting relational expression is calculated, and the included angle confidence coefficient and the distance confidence coefficient are obtained through fitting; and evaluating an electromagnetic positioning result by using the fitted included angle confidence coefficient and interval confidence coefficient to calculate the obtained total confidence coefficient. According to the invention, the environmental adaptability of electromagnetic positioning is improved, and the positioning reliability is high under the interference condition.

Description

Technical Field

[0001] This invention relates to the field of electromagnetic positioning technology, and in particular to a confidence assessment method for electromagnetic positioning using a 6-DOF sensor. Background Technology

[0002] Electromagnetic positioning is a technology that uses electromagnetic fields to determine the position and attitude of a target object. It is widely used in virtual reality, medical navigation, biomechanics, and motion analysis. It can obtain not only the position information of the target object but also its angular attitude information. Its key advantages are high accuracy and independence from line-of-sight obstructions. However, in the actual use of medical electromagnetic positioning and tracking equipment, the surrounding environment may contain a certain degree of metallic interference, which can degrade the positioning and angular accuracy of the equipment. To effectively measure the existence and degree of interference during equipment use and whether it affects effective positioning, a sensor confidence parameter needs to be introduced when using a 6-DOF sensor for electromagnetic positioning. Summary of the Invention

[0003] Based on the above analysis, the present invention aims to provide a confidence assessment method for electromagnetic positioning using a 6-DOF sensor, so as to improve the environmental adaptability of electromagnetic positioning and have high positioning reliability under interference conditions.

[0004] The objective of this invention is mainly achieved through the following technical solutions:

[0005] This invention discloses a confidence assessment method for electromagnetic positioning using a 6-DOF sensor, comprising:

[0006] Step S1: Under interference-free conditions, use measurement data to fit the relationship between the distance from the 6-DOF sensor to the transmitter and the angle between the sensor and the distance between the sensor; the angle between the sensor and the distance between the sensor are the angle and the distance between the two 5-DOF sensors in the 6-DOF sensor.

[0007] Step S2: Under interference conditions, calculate the ratio of the sensor angle to the sensor spacing and the ratio of the sensor spacing to the sensor spacing calculated from the fitted relationship based on the measured sensor angle and the fitted relationship, and fit the confidence scores of the angle and spacing respectively.

[0008] In the confidence level fitting, a piecewise fitting method is adopted, which divides the confidence level range and the proportional relationship range into segments, and establishes a functional relationship for solving the confidence level through the proportional relationship value in each segment.

[0009] Step S3: Calculate the total confidence score using the fitted angle confidence score and spacing confidence score, and evaluate the electromagnetic positioning results.

[0010] Further, step S1 includes:

[0011] 1) Establish interference-free conditions in the laboratory environment and use a 6-DOF sensor to perform electromagnetic positioning measurements to obtain measurement data;

[0012] The measurement data includes the distance R and attitude angle phi of various 6-DOF sensors relative to the transmitter during the measurement; the measured sensor included angle Atti and spacing dR;

[0013] 2) The function relationship between distance R and sensor angle Atti is fitted using measurement data. During the fitting process, the fitting is performed separately for two cases: the attitude angle phi in the measurement data is in the range of 90° and the range is not in the range of 90°. The range of 90° is 90°±5°.

[0014] 3) The distance R and the sensor spacing dR are fitted using the measurement data.

[0015] Furthermore, in steps 2) and 3), polynomial fitting is used to obtain the corresponding fitted polynomial relations:

[0016] First relation: Atti_Z = a1*R + b1;

[0017] Second relation: Atti_X = a2*R + b2;

[0018] Third relation: dR = a³ * R + b³;

[0019] Where Atti_Z is the sensor angle fitted according to the first relation when the sensor pitch attitude angle is in the range of 90°; Atti_X is the sensor angle fitted according to the second relation when the sensor pitch attitude angle is not in the range of 90°; dR is the sensor spacing fitted according to the third relation; R is the distance vector from the sensor to the transmitter; a1, a2, a3 are polynomial coefficient vectors, and b1, b2, b3 are polynomial constants.

[0020] Furthermore, the angle confidence fitting process included in step S2 includes:

[0021] 1) Determine the sensor angle judgment threshold; during the measurement process, determine whether the sensor posture is within the range of 90°; if yes, use the first relational formula to calculate Atti_Z as the sensor angle judgment threshold Atti_th for whether there is interference; if no, use the second relational formula to calculate Atti_X as the sensor angle judgment threshold Atti_th for whether there is interference.

[0022] 2) Divide the measured sensor angle Atti_d by the sensor angle judgment threshold Atti_th to calculate the first proportional relationship value.

[0023] 3) Using a piecewise fitting method, the confidence level of the included angle is divided into four segments: 100%, 80%-100%, 50%-80%, and 0%-50%. Corresponding first proportional relationship values ​​are set for each of the four segments: less than 1.1, 1.1-1.4, 1.4-1.8, and greater than 1.8. Corresponding functional relationships are established between the included angle confidence level and the first proportional relationship value within each segment, ensuring that the function curve is continuous within the 0-100% confidence level range, and that the functional relationship in each segment conforms to the relationship that the greater the deviation between the measured sensor included angle and the sensor included angle judgment threshold, the lower the confidence level.

[0024] 4) Calculate the first proportional relationship value obtained in step 2). Substitute the function relationship established in step 3) into the corresponding segment to calculate the confidence level of the included angle.

[0025] Furthermore, during the fitting process of the included angle confidence score, the corresponding function relationship is established as follows:

[0026] The first proportional relationship value segment is less than 1.1, and the angle confidence segment is 100%. The corresponding angle confidence function relationship is:

[0027] Con_Level_A = 1;

[0028] The first proportional relationship value is segmented from 1.1 to 1.4, and the confidence level of the included angle is segmented from 80% to 100%. The corresponding confidence level function relationship for the included angle is:

[0029]

[0030] Where c1 and d1 are coefficients; satisfying the formula

[0031] The first proportional relationship value is segmented from 1.4 to 1.8, and the confidence level of the included angle is segmented from 50% to 80%. The corresponding confidence level function relationship for the included angle is as follows:

[0032]

[0033] Where c2 and d2 are coefficients; satisfying the formula

[0034] The first proportional relationship value segment is greater than 1.8, and the confidence level segment of the included angle is 0%-50%. The corresponding confidence level function relationship of the included angle is:

[0035]

[0036] Among them, That is, c3 = 0.9.

[0037] Further, the spacing confidence fitting included in step S2 includes:

[0038] 1) During the measurement process, determine whether the distance between the sensor and the transmitter is less than the voltage saturation threshold. If yes, set the distance confidence level to 0: Con_Level_R = 0; otherwise, proceed to the next step.

[0039] 2) The sensor spacing at the current distance is calculated using the third relation, and this serves as the threshold dR_th for judging whether there are interference factors.

[0040] 3) Divide the measured sensor spacing dR_Cal by the sensor spacing judgment threshold dR_th to calculate the second proportional relationship value.

[0041] 4) Divide the spacing confidence level into 4 segments: 100%, 80%-100%, 50%-80%, and 0%-50%. Set corresponding second proportional relationship values ​​for each of the 4 segments: less than 1.1, 1.1-1.4, 1.4-1.8, and greater than 1.8. Establish corresponding functional relationships between the spacing confidence level and the second proportional relationship value within each segment, so that the function curve is continuous within the 0-100% confidence level range, and the functional relationship in each segment conforms to the relationship that the greater the deviation between the measured sensor spacing and the sensor spacing judgment threshold, the lower the confidence level.

[0042] 5) Calculate the second proportional relationship value obtained in step 2). Substitute the function relationship established in step 3) into the corresponding segment to calculate the interval confidence level.

[0043] Furthermore, in the process of fitting the interval confidence score, the corresponding function relationship is established as follows:

[0044] The second proportional relationship value segment is less than 1.1, and the interval confidence level segment is 100%. The corresponding interval confidence level function is:

[0045] Con_Level_R = 1;

[0046] The second proportional relationship value is segmented from 1.1 to 1.4, and the interval confidence level is segmented from 80% to 100%. The corresponding interval confidence level function is as follows:

[0047]

[0048] Where e1 and f1 are coefficients; satisfying the formula

[0049] The second proportional relationship value is segmented from 1.4 to 1.8, and the interval confidence level is segmented from 50% to 80%. The corresponding interval confidence level function is as follows:

[0050]

[0051] Where e2 and f2 are coefficients; satisfying the formula

[0052] The second proportional relationship value segment is greater than 1.8, and the interval confidence level segment is 0%-50%. The corresponding interval confidence level function is:

[0053]

[0054] Among them, That is, e3 = 0.9.

[0055] Furthermore, step S3 includes:

[0056] 1) Determine whether either the confidence level of the included angle or the confidence level of the spacing is less than 0.5. If so, the total confidence level is the minimum of the two confidence levels. If not, proceed to step 2).

[0057] 2) The confidence scores of the included angle and the spacing are weighted and summed to obtain the total confidence score;

[0058] 3) Based on the confidence interval of the total confidence level, determine the interference situation in the workspace and the reliability of the positioning results.

[0059] Furthermore, in the weighted summation,

[0060] If the confidence level of the included angle (Con_Level_A) is greater than the confidence level of the interval (Con_Level_R), then the total confidence level is:

[0061] Con_Level=h*Con_Level_A+j*Con_Level_R;

[0062] If the confidence level of the included angle (Con_Level_A) is less than the confidence level of the interval (Con_Level_R), then the total confidence level is:

[0063] Con_Level=j*Con_Level_A+h*Con_Level_R;

[0064] In the formula, h and j are weighting coefficients, and h+j=1, h>j.

[0065] Furthermore, based on the confidence interval of the total confidence level, the interference situation within the workspace and the reliability of the positioning results are determined; during the process,

[0066] When the total confidence level is between 80% and 100% of the confidence interval, it is considered that there is no interference or the degree of interference is weak in the workspace, and the positioning result is reliable.

[0067] When the total confidence level is between 50% and 80% of the confidence interval, it is considered that there is an interference source in the workspace, and the localization result has a certain degree of deviation.

[0068] When the total confidence level is within the confidence interval of 0% to 50%, it is considered that there is a strong interference source in the workspace, and the localization result is unreliable.

[0069] The beneficial effects of this invention are as follows:

[0070] This invention discloses a confidence assessment method for electromagnetic positioning using a 6-DOF sensor. It employs a total confidence score comprised of angle confidence and distance confidence to assess the presence of interference sources in the workspace and the reliability of the electromagnetic positioning results. This improves the environmental adaptability of electromagnetic positioning, enhances the system's anti-interference capability, and maintains high positioning reliability. Furthermore, a piecewise fitting method is used to fit the angle confidence and distance confidence scores, making the confidence values ​​closer to the actual situation and improving the accuracy of the confidence data. Attached Figure Description

[0071] The accompanying drawings are for illustrative purposes only and are not intended to limit the invention. Throughout the drawings, the same reference numerals denote the same parts.

[0072] Figure 1 This is a flowchart of a confidence assessment method for electromagnetic positioning using a 6-DOF sensor, according to an embodiment of the present invention. Detailed Implementation

[0073] Preferred embodiments of the present invention will now be described in detail with reference to the accompanying drawings, which form part of this application and, together with the embodiments of the present invention, serve to illustrate the principles of the present invention.

[0074] This embodiment discloses a confidence assessment method for electromagnetic positioning using a 6-DOF sensor, such as... Figure 1 As shown, it includes:

[0075] Step S1: Under interference-free conditions, use measurement data to fit the relationship between the distance from the 6-DOF sensor to the transmitter and the angle between the sensor and the distance between the sensor; the angle between the sensor and the distance between the sensor are the angle and the distance between the two 5-DOF sensors in the 6-DOF sensor.

[0076] Step S2: Under interference conditions, calculate the ratio of the sensor angle to the sensor spacing and the ratio of the sensor spacing to the sensor spacing calculated from the fitted relationship based on the measured sensor angle and the fitted relationship, and fit the confidence scores of the angle and spacing respectively.

[0077] In the confidence level fitting, a piecewise fitting method is adopted, which divides the confidence level range and the proportional relationship range into segments, and establishes a functional relationship for solving the confidence level through the proportional relationship value in each segment.

[0078] Step S3: Calculate the total confidence score using the fitted angle confidence score and spacing confidence score, and evaluate the electromagnetic positioning results.

[0079] Specifically, step S1 includes:

[0080] 1) Establish interference-free conditions in the laboratory environment and use a 6-DOF sensor to perform electromagnetic positioning measurements to obtain a large amount of measurement data;

[0081] The measurement data includes the distance R and attitude angle phi of various 6-DOF sensors relative to the transmitter; the measured values ​​of the sensor included angle Atti and the spacing dR;

[0082] 2) The function relationship between distance R and sensor angle Atti is fitted using the measurement data. During the fitting process, the fitting is performed separately for two cases: when the attitude angle phi is in the range near 90° and when it is not in the range near 90°.

[0083] The range around 90° is 90°±5°.

[0084] 3) The distance R and the sensor spacing dR are fitted using the measurement data.

[0085] More specifically, in steps 2) and 3), polynomial fitting is used to obtain the corresponding fitted polynomial relations:

[0086] First relation: Atti_Z = a1*R + b1;

[0087] Second relation: Atti_X = a2*R + b2;

[0088] Third relation: dR = a³ * R + b³;

[0089] Where Atti_Z is the sensor angle fitted according to the first relation when the sensor pitch attitude angle is around 90°; Atti_X is the sensor angle fitted according to the second relation when the sensor pitch attitude angle is not around 90°; dR is the sensor spacing fitted according to the third relation; R is the distance vector from the sensor to the transmitter; a1, a2, a3 are polynomial coefficient vectors, and b1, b2, b3 are polynomial constants;

[0090] R = {R, R} 2 ,R 3 ,...};a1={a 11 ,a 12 ,a 13 ,...};a2={a 21 ,a 22 ,a 23 ,...};a3={a 31 ,a 32 ,a 33 ,...};

[0091] b1={b 11 ,b 12 ,b 13 ,...};b2={b 21 ,b 22 ,b 23 ,...};b3={b 31 ,b 32 ,b 33 ,...}.

[0092] Specifically, the angle confidence fitting included in step S2 includes:

[0093] 1) Determine the sensor angle judgment threshold; during the measurement process, determine whether the sensor posture is within the range of 90°; if yes, use the first relational formula to calculate Atti_Z as the sensor angle judgment threshold Atti_th for whether there is interference; if no, use the second relational formula to calculate Atti_X as the sensor angle judgment threshold Atti_th for whether there is interference.

[0094] 2) Divide the measured sensor angle Atti_d by the sensor angle judgment threshold Atti_th to calculate the first proportional relationship value.

[0095] 3) A piecewise fitting method was adopted, dividing the angle confidence level into four segments: 100%, 80%-100%, 50%-80%, and 0%-50%. Corresponding first proportional relationship values ​​were set for each of the four segments: less than 1.1, 1.1-1.4, 1.4-1.8, and greater than 1.8. Corresponding functional relationships were established between the angle confidence level and the first proportional relationship value within each segment, ensuring the function curve is continuous within the 0-100% confidence level range. Furthermore, the functional relationship in each segment conformed to the relationship that the greater the deviation between the measured sensor angle and the sensor angle judgment threshold, the lower the confidence level.

[0096] The first proportional relationship value segment is less than 1.1, and the angle confidence segment is 100%. The corresponding angle confidence function relationship is:

[0097] Con_Level_A = 1;

[0098] The first proportional relationship value is segmented from 1.1 to 1.4, and the confidence level of the included angle is segmented from 80% to 100%. The corresponding confidence level function relationship for the included angle is:

[0099]

[0100] Where c1 and d1 are coefficients; satisfying the formula

[0101] The first proportional relationship value is segmented from 1.4 to 1.8, and the confidence level of the included angle is segmented from 50% to 80%. The corresponding confidence level function relationship for the included angle is as follows:

[0102]

[0103] Where c2 and d2 are coefficients; satisfying the formula

[0104] The first proportional relationship value segment is greater than 1.8, and the confidence level segment of the included angle is 0%-50%. The corresponding confidence level function relationship of the included angle is:

[0105]

[0106] Among them, That is, c3 = 0.9;

[0107] 4) Calculate the first proportional relationship value obtained in step 2). Substitute the function relationship established in step 3) into the corresponding segment to calculate the confidence level of the included angle.

[0108] Specifically, the spacing confidence fitting included in step S2 includes:

[0109] 1) During the measurement process, determine whether the distance between the sensor and the transmitter is less than the voltage saturation threshold. If yes, set the distance confidence level to: Con_Level_R = 0; otherwise, proceed to the next step.

[0110] 2) The sensor spacing at the current distance is calculated using the third relation, and this serves as the threshold dR_th for judging whether there are interference factors.

[0111] 3) Divide the measured sensor spacing dR_Cal by the sensor spacing judgment threshold dR_th to calculate the second proportional relationship value.

[0112] 4) Divide the spacing confidence level into 4 segments: 100%, 80%-100%, 50%-80%, and 0%-50%. Set corresponding second proportional relationship values ​​for each of the 4 segments: less than 1.1, 1.1-1.4, 1.4-1.8, and greater than 1.8. Establish corresponding functional relationships between the spacing confidence level and the second proportional relationship value within each segment, so that the function curve is continuous within the 0-100% confidence level range, and the functional relationship in each segment conforms to the relationship that the greater the deviation between the measured sensor spacing and the sensor spacing judgment threshold, the lower the confidence level.

[0113] in,

[0114] The second proportional relationship value segment is less than 1.1, and the interval confidence level segment is 100%. The corresponding interval confidence level function is:

[0115] Con_Level_R = 1;

[0116] The second proportional relationship value is segmented from 1.1 to 1.4, and the interval confidence level is segmented from 80% to 100%. The corresponding interval confidence level function is as follows:

[0117]

[0118] Where e1 and f1 are coefficients; satisfying the formula

[0119] The second proportional relationship value is segmented from 1.4 to 1.8, and the interval confidence level is segmented from 50% to 80%. The corresponding interval confidence level function is as follows:

[0120]

[0121] Where e2 and f2 are coefficients; satisfying the formula

[0122] The second proportional relationship value segment is greater than 1.8, and the interval confidence level segment is 0%-50%. The corresponding interval confidence level function is:

[0123]

[0124] Among them, That is, e3 = 0.9.

[0125] 5) Calculate the second proportional relationship value obtained in step 2). Substitute the function relationship established in step 3) into the corresponding segment to calculate the interval confidence level.

[0126] Specifically, step S3 includes:

[0127] 1) Determine whether either the confidence level of the included angle or the confidence level of the spacing is less than 0.5. If so, the total confidence level is the minimum of the two confidence levels. If not, proceed to step 2).

[0128] 2) The confidence scores of the included angle and the spacing are weighted and summed to obtain the total confidence score;

[0129] In weighted summation,

[0130] If the confidence level of the included angle (Con_Level_A) is greater than the confidence level of the interval (Con_Level_R), then the total confidence level is:

[0131] Con_Level=h*Con_Level_A+j*Con_Level_R;

[0132] If the confidence level of the included angle (Con_Level_A) is less than the confidence level of the interval (Con_Level_R), then the total confidence level is:

[0133] Con_Level=j*Con_Level_A+h*Con_Level_R;

[0134] In the formula, h and j are weighting coefficients, and h+j=1, h>j.

[0135] 3) Based on the confidence interval of the total confidence level, determine the interference situation in the workspace and the reliability of the positioning results;

[0136] When the total confidence level is between 80% and 100% of the confidence interval, it is considered that there is no interference or the degree of interference is weak in the workspace, and the positioning result is reliable.

[0137] When the total confidence level is between 50% and 80% of the confidence interval, it is considered that there is an interference source in the workspace, and the localization result has a certain degree of deviation.

[0138] When the total confidence level is within the confidence interval of 0% to 50%, it is considered that there is a strong interference source in the workspace, and the localization result is unreliable.

[0139] In summary, the confidence assessment method for electromagnetic positioning using a 6-DOF sensor in this invention employs a total confidence score comprised of angle confidence and distance confidence to assess the presence of interference sources in the workspace and the reliability of the electromagnetic positioning results. This improves the environmental adaptability of electromagnetic positioning, enhances the system's anti-interference capability, and maintains high positioning reliability. Furthermore, the use of a piecewise fitting method to fit the angle confidence and distance confidence scores makes the confidence values ​​closer to the actual situation, thus improving the accuracy of the confidence data.

[0140] The above description is only a preferred embodiment of the present invention, but the scope of protection of the present invention is not limited thereto. Any changes or substitutions that can be easily conceived by those skilled in the art within the scope of the technology disclosed in the present invention should be included within the scope of protection of the present invention.

Claims

1. A method for confidence assessment of electromagnetic positioning with a 6-DOF sensor, characterized in that, Comprising: Step S1, under the condition of no interference, the measured data is used to fit the relationship between the 6-DOF sensor and the transmitter distance and the sensor angle, and the sensor spacing; the sensor angle and the sensor spacing are the angle and spacing between two 5-DOF sensors in the 6-DOF sensor; Step S2, under the condition of interference, the proportional relationship of the sensor angle is calculated according to the measured sensor angle and the fitting relationship, and the proportional relationship of the sensor spacing is calculated according to the fitting relationship, and the angle confidence and the spacing confidence are fitted respectively; In the confidence fitting, the piecewise fitting method is adopted, the confidence range and the proportional relationship range are segmented and corresponded, and the function relationship for solving the confidence through the proportional relationship value is established in each segment; Step S3, the total confidence calculated by the fitted angle confidence and spacing confidence is used to evaluate the electromagnetic positioning result.

2. The confidence evaluation method for electromagnetic positioning using a 6-DOF sensor according to claim 1, characterized in that, In step S1, comprising: 1) Establishing a non-interference condition in a laboratory environment, and using a 6-DOF sensor to perform electromagnetic positioning measurement to obtain measurement data; The measurement data includes the distance R and the attitude angle phi of the 6-DOF sensor relative to the transmitter during measurement; the measured sensor angle Atti and the spacing dR; 2) The function relationship between the distance R and the sensor angle Atti is fitted using the measurement data, and in the fitting process, according to the measurement data, the attitude angle phi is fitted in the range of 90°±5° and in the range of non-90°; the range of 90° is 90°±5°; 3) The function relationship between the distance R and the sensor spacing dR is fitted using the measurement data.

3. The confidence evaluation method for electromagnetic positioning using a 6-DOF sensor according to claim 2, characterized in that, In steps 2) and 3), the polynomial fitting method is used to obtain the corresponding fitting polynomial relationship: First relationship: Atti_Z=a1*R+b1; Second relationship: Atti_X=a2*R+b2; Third relationship: dR=a3*R+b3; Wherein, Atti_Z is the sensor pitch attitude angle in the range of 90°, which is fitted according to the first relationship; Atti_X is the sensor pitch attitude angle in the range of non-90°, which is fitted according to the second relationship; dR is the sensor spacing fitted according to the third relationship; R is the sensor to transmitter distance vector; a1, a2, a3 are polynomial coefficient vectors, and b1, b2, b3 are polynomial constants.

4. The confidence evaluation method for electromagnetic positioning using a 6-DOF sensor according to claim 3, characterized in that, In the angle confidence fitting process included in step S2, comprising: 1) determining a sensor angle judgment threshold value; determining whether the sensor posture is in the range near 90° during the measurement process; if yes, calculating Atti_Z as the sensor angle judgment threshold value Atti_th whether there is an interference factor by using the first relationship; if no, calculating Atti_X as the sensor angle judgment threshold value Atti_th whether there is an interference factor by using the second relationship; 2) divide the measured sensor included angle Atti_d by the sensor included angle determination threshold Atti_th to calculate a first proportional relationship value 3) using the segmented fitting method, the angle confidence is divided into four segments, which are angle confidence: 100%, 80%-100%, 50%-80%, 0%-50%; the corresponding first proportion relationship value segments are set in the four segments: less than 1.1, 1.1-1.4, 1.4-1.8, and greater than 1.8; the corresponding function relationship between the angle confidence in the segment and the first proportion relationship value in the segment is established, so that the function curve is continuous in the 0-100% confidence range, and the function relationship in each segment conforms to the corresponding relationship that the greater the deviation between the measured sensor angle and the sensor angle judgment threshold value, the lower the confidence; 4) Calculate the first ratio value from step 2) The angle confidence is calculated by the function relationship in the corresponding segment established in step 3).

5. The confidence evaluation method for electromagnetic positioning by using the 6-DOF sensor according to claim 4, characterized in that, in the angle confidence fitting process, the corresponding function relationship is: when the first proportion relationship value segment is less than 1.1 and the angle confidence segment is 100%, the corresponding angle confidence function relationship is: Con_Level_A=1; when the first proportion relationship value segment is 1.1-1.4 and the angle confidence segment is 80%-100%, the corresponding angle confidence function relationship is: wherein c1, d1 are coefficients; the formula is satisfied when the first proportion relationship value segment is 1.4-1.8 and the angle confidence segment is 50%-80%, the corresponding angle confidence function relationship is: wherein c2, d2 are coefficients; the formula when the first proportion relationship value segment is greater than 1.8 and the angle confidence segment is 0%-50%, the corresponding angle confidence function relationship is: wherein, wherein i.e. c3= 0.

9.

6. The confidence evaluation method for electromagnetic positioning by using the 6-DOF sensor according to claim 5, characterized in that, in the distance confidence fitting included in step S2, it includes: 1) during the measurement process, determining whether the distance between the sensor and the transmitter is less than the voltage saturation threshold value; if yes, the distance confidence is 0: Con_Level_R=0; if no, the next step is entered; 2) calculating the sensor distance under the current distance as the sensor angle judgment threshold value dR_th whether there is an interference factor by using the third relationship; 3) dividing the measured sensor gap dR_Cal by the sensor gap determination threshold dR_th to calculate a second proportional relationship value 4) dividing the distance confidence into four segments, which are distance confidence: 100%, 80%-100%, 50%-80%, 0%-50%; the corresponding second proportion relationship value segments are set in the four segments: less than 1.1, 1.1-1.4, 1.4-1.8, and greater than 1.8; the corresponding function relationship between the distance confidence in the segment and the second proportion relationship value in the segment is established, so that the function curve is continuous in the 0-100% confidence range, and the function relationship in each segment conforms to the corresponding relationship that the greater the deviation between the measured sensor distance and the sensor distance judgment threshold value, the lower the confidence; 5) Calculate the second proportional value in step 2) The function relationship in the corresponding segment established in step 3) is brought in to calculate the distance confidence.

7. The confidence evaluation method for electromagnetic positioning using a 6-DOF sensor according to claim 6, wherein, In the distance confidence fitting process, the corresponding function relationship is: When the second proportional relationship value is less than 1.1 and the distance confidence is segmented as 100%, the corresponding distance confidence function relationship is: Con_Level_R = 1; When the second proportional relationship value is segmented as 1.1-1.4 and the distance confidence is segmented as 80%-100%, the corresponding distance confidence function relationship is: wherein e1, f1 are coefficients; the formula is satisfied When the second proportional relationship value is segmented as 1.4-1.8 and the distance confidence is segmented as 50%-80%, the corresponding distance confidence function relationship is: where e2, f2 are coefficients; the formula is satisfied When the second proportional relationship value is greater than 1.8 and the distance confidence is segmented as 0%-50%, the corresponding distance confidence function relationship is: wherein, wherein i.e. e3= 0.

9.

8. The confidence evaluation method for electromagnetic positioning using a 6-DOF sensor according to claim 7, wherein, In step S3, the following steps are included: 1) judging whether any of the included angle confidence and the distance confidence is less than 0.5, if so, the total confidence is the minimum of the two confidences, if not, step 2) is performed; 2) performing weighted summation on the included angle confidence and the distance confidence to obtain the total confidence; 3) judging the interference situation in the working space and the confidence degree of the positioning result according to the confidence interval in which the total confidence is located.

9. The confidence evaluation method for electromagnetic positioning using a 6-DOF sensor according to claim 8, wherein, In the weighted summation, If the included angle confidence Con_Level_A is greater than the distance confidence Con_Level_R, the total confidence is: Con_Level = h*Con_Level_A + j*Con_Level_R; If the included angle confidence Con_Level_A is less than the distance confidence Con_Level_R, the total confidence is: Con_Level = j*Con_Level_A + h*Con_Level_R; Wherein h and j are weighting coefficients, and h + j = 1, h > j.

10. The confidence evaluation method for electromagnetic positioning using a 6-DOF sensor according to claim 8, wherein, According to the confidence interval in which the total confidence is located, the interference situation in the working space and the confidence degree of the positioning result are judged; in the process, When the total confidence is located in the confidence interval of 80%-100%, it is considered that there is no interference or weak interference in the working space, and the positioning result is reliable; When the total confidence is located in the confidence interval of 50%-80%, it is considered that there is an interference source in the working space, and the positioning result has a certain degree of deviation; When the total confidence is located in the confidence interval of 0%-50%, it is considered that there is a strong interference source in the working space, and the positioning result is unreliable.

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