Ranging method and device based on UWB digital key

Abstract

The invention provides a distance measuring method and device based on an ultra wide band (UWB) digital key, and a distance measuring system applied to the UWB digital key, the distance measuring system comprises a UWB label and a plurality of UWB anchor points, and the distance measuring method comprises the following steps: determining whether there is an obstacle between the UWB label and the plurality of UWB anchor points; when an obstacle exists between a target anchor point in the plurality of UWB anchor points and the UWB tag, obtaining an anchor point distance calculation model; obtaining distance values between other anchor points, which do not have obstacles with the UWB tag, in the plurality of UWB anchor points and the UWB tag; and inputting the distance value into an anchor point distance calculation model to calculate a target distance between the target anchor point and the UWB tag. The technical problem that when a UWB three-point positioning model is achieved through an existing automobile digital key, if an obstacle exists between the UWB tag and the UWB anchor point, the distance between the UWB anchor point and the UWB tag cannot be measured is solved.

Description

Technical Field

[0001] The present application relates to the field of automobile technology, and in particular to a ranging method and device based on an ultra-wideband (UWB) digital key. Background Art

[0002] With the evolution of smart cars, the development of car keys has entered the era of digital keys. A perfect car digital key system should be able to achieve high-precision positioning between the key and the car, deploy high-reliability anti-attack security encryption technology, and be able to perform sustainable over-the-air upgrades. Usually, the car digital key system will assign digital key operation scenarios based on the area where the user is located. When the digital key is in the sensing area, the vehicle can flash the horn to remind the user. When the digital key is in the control area, the vehicle can automatically unlock the car. When the digital key enters the cockpit, the keyless system can be started with one click. Therefore, precise positioning between the digital key and the anchor point is the key to the car digital key.

[0003] The problem is that when the current car digital key implements the ultra-wide band (UWB) three-point positioning model, if there is an obstacle between the UWB tag and the UWB anchor point, the distance measurement from the UWB anchor point to the UWB tag cannot be achieved. Summary of the invention

[0004] This application solves the technical problem that when the current car digital key implements the UWB three-point positioning model, if there is an obstacle between the UWB tag and the UWB anchor point, the distance measurement from the UWB anchor point to the UWB tag cannot be achieved. This application determines whether there are obstacles between the UWB tag and each UWB anchor point of the vehicle, obtains an anchor point distance calculation model, and inputs the distance values ​​between other anchor points and the UWB tag among the multiple UWB anchor points obtained without obstacles between the UWB tag and the UWB tag into the anchor point distance calculation model to obtain the target distance between the target anchor point and the UWB tag.

[0005] To solve the above problems, the present application provides a ranging method based on an ultra-wideband UWB digital key, which is applied to a ranging system of a UWB digital key. The ranging system includes a UWB tag and multiple UWB anchor points. The ranging method includes: determining whether there is an obstacle between the UWB tag and the multiple UWB anchor points; when there is an obstacle between a target anchor point among the multiple UWB anchor points and the UWB tag, obtaining an anchor point distance calculation model; obtaining distance values ​​between other anchor points among the multiple UWB anchor points that do not have obstacles between them and the UWB tag and the UWB tag; and inputting the distance value into the anchor point distance calculation model to calculate a target distance between the target anchor point and the UWB tag.

[0006] Compared with the prior art, the technical effect achieved by adopting this technical solution is as follows: by determining whether there are obstacles between the UWB tag and multiple UWB anchor points, it is possible to timely discover and resolve ranging obstacles. By obtaining the distance values ​​between other anchor points among multiple UWB anchor points that do not have obstacles between them and the UWB tag, the function of multi-point ranging is realized, thereby providing more data support. When there is an obstacle between the target anchor point and the UWB tag, the penetration ranging of the obstacle is realized through the obtained multi-point ranging information and the anchor point distance calculation model, which improves the reliability and accuracy of ranging, and increases the flexibility and applicability of ranging.

[0007] In one possible design, determining whether there are obstacles between a UWB tag and multiple UWB anchor points includes: based on ultra-wideband ranging, measuring received signal strength values ​​and first-path signal estimation values ​​between the UWB tag and multiple UWB anchor points; comparing the difference between the received signal strength value and the first-path signal estimation value with an obstacle determination threshold, and if the difference corresponding to a target anchor point is greater than the obstacle determination threshold, determining that there is an obstacle between the UWB tag and the target anchor point.

[0008] Compared with the prior art, the technical effect achieved by adopting this technical solution is as follows: by measuring the received signal strength value and the first path signal estimation value between the UWB tag and multiple UWB anchor points, and performing a difference comparison, it is possible to determine in real time whether there is an obstacle between the UWB tag and the target anchor point, thereby improving the timeliness of obstacle detection. By comparing with the obstacle determination threshold, the automatic determination of the difference is realized, the need for manual intervention is reduced, and the intelligence level of the system is improved. By comparing the received signal strength value and the first path signal estimation value, it is possible to more accurately determine whether there is an obstacle, thereby improving the accuracy and reliability of the ranging system.

[0009] In one possible design, the method used for ultra-wideband ranging includes flight ranging method or bilateral two-way ranging method.

[0010] Compared with the prior art, the technical effect achieved by adopting this technical solution is that the distance value from the digital key to each anchor point of the vehicle can be measured more accurately through the flying distance measurement method or the bilateral two-way distance measurement method, thereby improving the accuracy of distance measurement and reducing errors. In addition, the flying distance measurement method or the bilateral two-way distance measurement method can provide a more stable distance measurement structure, reduce the influence of external environmental factors on distance measurement, and make the distance measurement result more reliable and stable.

[0011] In one possible design, the received signal strength value is determined based on the channel impulse response power pulse value and the preamble code value.

[0012] Compared with the prior art, the technical effect achieved by adopting this technical solution is as follows: by determining the channel pulse response power pulse value and the preamble code value, the received signal strength value can be calculated more accurately, thereby improving the measurement accuracy of the ranging system for the signal strength, and can improve the stability of the received signal strength value, reduce measurement errors, and improve data reliability.

[0013] Furthermore, in one example, the received signal strength value is specifically determined by the following calculation formula: in, is the received signal strength value; is the channel impulse response power pulse value; is the leading code value; is a constant.

[0014] Compared with the prior art, the technical effect achieved by adopting this technical solution is: introducing the channel impulse response power pulse value, the preamble value and the constant Factors such as the received signal strength value make the calculation more precise and accurate, and improve the calculation accuracy of the received signal strength. The received signal strength value calculation formula can more reliably evaluate the signal strength between the UWB tag and each UWB anchor point of the vehicle, so as to more accurately determine whether there are obstacles between the UWB tag and each UWB anchor point of the vehicle, thereby improving the reliability of the system.

[0015] In one possible design, the first path signal estimation value is determined based on power values ​​and preamble code values ​​of the signals from the three first detected target anchor points to the UWB tag.

[0016] Compared with the prior art, the technical effect achieved by adopting this technical solution is as follows: by using the signal power values ​​and preamble code values ​​from the three first detected target anchor points to the UWB tag, the value of the first path signal can be estimated more accurately, thereby improving the accuracy of the ranging system in estimating the first path signal. This can reduce the impact of external interference on the first path signal estimation, improve the anti-interference ability of the system, and make the ranging result more stable and reliable. By selecting the signals of the three first detected target anchor points for estimation, fast signal processing and ranging response can be achieved, thereby improving the real-time performance and response speed of the system.

[0017] Furthermore, in one example, the first path signal estimation value is specifically determined by the following calculation formula: in, is the estimated value of the first path signal; , , are the power values ​​of the signals from the three first detected target anchor points to the UWB tag; is the leading code value; is a constant, a constant The value of is determined according to the pulse repetition rate of the received signal of the UWB tag.

[0018] Compared with the prior art, the technical effect achieved by adopting this technical solution is that by detecting and comparing multiple first-path signals, the accuracy and reliability of signal detection can be improved. , , The power values ​​of the signals from the three first detected target UWB anchor points reaching the UWB tag are combined with the preamble code value and the constant to calculate the first path signal estimation value, which is more precise and accurate, and improves the estimation accuracy of the first path signal. The first path signal estimation value calculation formula can more effectively process the first path signal estimation, reduce the complexity of signal processing, and improve the efficiency and speed of signal processing. By determining the constant according to the pulse repetition rate of the received signal of the UWB tag The value of the constant can be adjusted according to the specific situation The numerical value is used to determine personalized parameters, thereby improving the flexibility and adaptability of the ranging system.

[0019] Further, in one example, determining whether there is an obstacle between the UWB tag and the multiple UWB anchor points is specifically determined based on the following determination formula: in, is the difference between the received signal strength value and the first path signal estimation value; is the received signal strength value; is the estimated value of the first path signal; when When , it is determined that there is an obstacle between the UWB tag and the target anchor point; among them, The obstacle determination threshold.

[0020] Compared with the prior art, the technical effect achieved by adopting this technical solution is as follows: a determination formula is used to determine whether there is an obstacle between the UWB tag and each UWB anchor point of the vehicle. By comparing the difference between the received signal strength value and the first path signal estimation value with the set obstacle determination threshold, it is possible to more accurately determine whether there is an obstacle, thereby improving the accuracy of the determination.

[0021] In one possible design, the multiple UWB anchor points are three anchor points set on the vehicle, including a first anchor point, a second anchor point and a third anchor point; the method also includes: calculating the position of the UWB tag in the cabin of the vehicle by using the distances from the three anchor points to the UWB tag respectively.

[0022] Compared with the existing technology, the technical effect achieved by adopting this technical solution is as follows: by calculating the distance from the three anchor points to the UWB tag, the position of the UWB tag in the vehicle cabin can be determined more accurately, thereby improving the precision and accuracy of positioning.

[0023] Furthermore, in one example, the position of the UWB tag in the vehicle cabin is calculated by the following calculation formula: in, is the location of the UWB tag in the vehicle cabin; is the length of the vehicle cabin; is the vehicle cabin width; is the distance from the UWB tag to the first anchor point, is the distance from the UWB tag to the second anchor point, is the distance from the UWB tag to the third anchor point.

[0024] Compared with the existing technology, the technical effect achieved by adopting this technical solution is: by considering the length of the vehicle cabin and width , as well as the distance from the UWB tag to each UWB anchor point, the position of the UWB tag in the vehicle cabin is calculated, achieving accurate positioning of the UWB tag. Taking into account the positions of multiple UWB anchor points and the distance from the UWB tag to each UWB anchor point, the calculation formula can more accurately determine the position of the UWB tag in the vehicle cabin when a certain UWB anchor point is blocked by an obstacle, thereby improving the accuracy of positioning. At the same time, the calculation formula for determining the position of the UWB tag in the vehicle cabin enhances the vehicle's ability to identify the position of the UWB tag and increases the performance of the car's digital key positioning system.

[0025] In a possible design, there is a proportional relationship between the volume and side length of the tetrahedron formed by the three anchor points and the UWB tag. The anchor point distance calculation model calculates two result values ​​of the distance between the anchor point and the UWB tag in the presence of obstacles based on the Kelly-Menger determinant formula, where the result value with the smaller error is the final value.

[0026] Compared with the prior art, the technical effect achieved by adopting this technical solution is as follows: by using the Kelly-Menger determinant formula to calculate the anchor point distance, the accuracy of the distance calculation can be improved, thereby improving the accuracy and reliability of the ranging system. By comparing the error size of the two result values ​​and selecting the result with the smaller error as the final value, the error in the calculation can be automatically corrected, thereby improving the accuracy and stability of the ranging result. This reduces the sensitivity of the ranging system to interference and improves the robustness and anti-interference ability of the system.

[0027] In a possible design, the anchor point distance calculation model is implemented as follows: The location of the UWB tag in the vehicle cabin is the measurement point ; First anchor point, second anchor point, third anchor point and measuring point A tetrahedron is formed between them. The tetrahedron has six edges, which are marked as: , the distance from the first anchor point to the second anchor point; , the distance from the first anchor point to the third anchor point; , the distance from the first anchor point to the measuring point M, that is ; , the distance from the second anchor point to the third anchor point; , the distance from the second anchor point to the measuring point M, that is ; , the distance from the third anchor point to the measuring point M, that is ; Among them, the six edges of the simplified tetrahedron are: According to the Kelly-Menger determinant formula, when the order is 5, the volume of the tetrahedron is The relationship with the length of the six sides is as follows: in, is the volume of the tetrahedron.

[0028] Compared with the prior art, the technical effect achieved by adopting this technical solution is as follows: by combining the volume of the tetrahedron and using the Kelly-Menger determinant formula, the distance between non-visual anchor points can be accurately calculated, thereby improving the accuracy of distance calculation. The Kelly-Menger determinant formula can simplify the process of calculating the volume of the tetrahedron, reduce the complexity of the calculation, and improve the calculation efficiency. By calculating the volume of the tetrahedron and the Kelly-Menger determinant formula, the position of the digital key in the vehicle cabin can be determined more accurately, thereby improving the precision and accuracy of positioning.

[0029] Furthermore, in one example, in the anchor point distance calculation model, the distance between the anchor point with obstacles and the UWB tag is calculated based on the following calculation formula: as well as: in, is the distance between the anchor point where there is an obstacle and the UWB tag; .

[0030] Compared with the existing technology, the technical effect achieved by adopting this technical solution is: Calculation formula and The calculation formula can accurately calculate the distance between the target anchor point and the UWB tag , which improves the accuracy of distance calculation. By adopting the formula of the distance between the target anchor point and the UWB tag, the calculation process is simplified, the calculation complexity is reduced, and the calculation efficiency is improved.

[0031] In a possible design, the result value with a smaller error is used as the final value, specifically including: comparing the absolute values ​​of the two calculated result values ​​with the absolute value of the distance value between the vehicle anchor point and the UWB tag measured last time, and the result value with a smaller difference is used as the final value of the distance between the vehicle anchor point and the digital key where there is an obstacle.

[0032] Compared with the prior art, the technical effect achieved by adopting this technical solution is as follows: by dynamically comparing the calculated result value with the distance value of the previous measurement, the result with a small difference is selected as the obstacle distance value, so as to realize adaptive obstacle distance judgment and improve the intelligence and accuracy of the distance measurement system. By selecting the result value with a small difference as the obstacle distance value, the distance calculation error caused by measurement error or other factors can be reduced, and the accuracy and reliability of the distance value can be improved. The method of dynamically selecting the result value with a small error can improve the stability of the system for obstacle distance and reduce the misjudgment caused by measurement fluctuations or interference.

[0033] The present application also provides a distance measuring device based on an ultra-wideband UWB digital key, and the distance measuring device based on the ultra-wideband UWB digital key implements a distance measuring method based on the ultra-wideband UWB digital key.

[0034] Compared with the prior art, the technical effect achieved by adopting this technical solution is as follows: the ranging device based on ultra-wideband UWB digital key of the present application includes the ranging method based on ultra-wideband UWB digital key of any technical solution of the present application. Therefore, it has all the beneficial effects of the ranging method based on ultra-wideband UWB digital key of any technical solution of the present application, which will not be repeated here. BRIEF DESCRIPTION OF THE DRAWINGS

[0035] Figure 1 A flow chart of a ranging method based on an ultra-wideband UWB digital key provided in an embodiment of the present application; Figure 2 A UWB tag scene diagram provided in an embodiment of the present application; Figure 3A schematic diagram of three-point positioning based on ultra-wideband ranging provided in an embodiment of the present application; Figure 4 A schematic diagram showing obstacles between the UWB tag and each UWB anchor point provided in an embodiment of the present application; Figure 5 A schematic diagram of the distance from the target anchor point to the UWB tag measurement point provided in an embodiment of the present application. DETAILED DESCRIPTION

[0036] In order to make the above-mentioned objects, features and advantages of the present application more obvious and easy to understand, the specific embodiments of the present application are described in detail below with reference to the accompanying drawings.

[0037] See also Figures 1 to 5 This embodiment provides a ranging method based on an ultra-wideband UWB digital key, which is applied to a ranging system of a UWB digital key. The ranging system includes a UWB tag and multiple UWB anchor points. The ranging method includes: Determine whether there is an obstacle between the UWB tag and multiple UWB anchor points; when there is an obstacle between a target anchor point among the multiple UWB anchor points and the UWB tag, obtain an anchor point distance calculation model; obtain distance values ​​between other anchor points among the multiple UWB anchor points that do not have obstacles between them and the UWB tag and the UWB tag; input the distance values ​​into the anchor point distance calculation model to calculate a target distance between the target anchor point and the UWB tag.

[0038] Specifically, Figure 4 The schematic diagram shows that there is an obstacle between the UWB tag and the UWB anchor point. When using UWB three-point positioning, if one of the UWB anchor points is blocked by an obstacle and the positioning fails, the distance between the UWB anchor point and the UWB tag cannot be measured, and the position of the UWB tag in the vehicle cabin cannot be determined. Among them, UWB is ultra-wideband ranging. If there is an obstacle between the UWB tag and one of the UWB anchor points of the vehicle, the anchor point distance calculation model can be used to calculate the distance value between the target anchor point and the UWB tag, thereby determining the position between the UWB tag and the vehicle, so that the vehicle can perform specific scene operations, such as Figure 2 The UWB tag scenario diagram shown, for example: when the UWB tag is in the sensing area, the vehicle horn flashes to remind the user; when the UWB tag is in the control area, the vehicle automatically unlocks; when the UWB tag enters the cockpit, the vehicle ignites with one click.

[0039] In one embodiment of the present application, determining whether there is an obstacle between a UWB tag and a plurality of UWB anchor points includes: Based on ultra-wideband ranging, the received signal strength value and the first path signal estimation value between the UWB tag and multiple UWB anchor points are measured; The difference between the received signal strength value and the first path signal estimation value is compared with the obstacle determination threshold. If the difference corresponding to the target anchor point is greater than the obstacle determination threshold, it is determined that there is an obstacle between the UWB tag and the target anchor point.

[0040] Specifically, in this embodiment, it is possible to determine whether there are obstacles between the UWB tag and each UWB anchor point of the vehicle by measuring and calculating the received signal strength value and the first path signal estimation value between the UWB tag and each UWB anchor point of the vehicle. During the propagation process, the signal will be affected by obstacles and attenuated or reflected. When there are obstacles between the UWB tag and each UWB anchor point of the vehicle, the obstacles will cause signal attenuation or reflection, thereby affecting the strength of the received signal and the estimation value of the first path signal. By comparing the actual measured signal value with the ideal value, it can be inferred whether there is an obstacle. If the signal strength value and the first path signal estimation value are not as expected, then there may be obstacles that affect the signal transmission, so it can be determined whether there are obstacles between the UWB tag and each anchor point of the vehicle.

[0041] In one embodiment of the present application, the method used for ultra-wideband ranging includes a flight ranging method or a bilateral two-way ranging method.

[0042] Specifically, ultra-wideband ranging is a method of distance measurement using ultra-wideband technology. Ultra-wideband technology is a wireless communication technology that achieves high-precision time measurement by sending short pulse signals. Its bandwidth is very wide and can provide accurate distance measurement. Flight ranging is an ultra-wideband ranging method that calculates the distance by sending short pulse signals and measuring the time from signal transmission to reception. In the flight ranging method, the flight time of the signal is proportional to the distance. By measuring the flight time, the distance between the UWB tag and the vehicle can be calculated. Bilateral two-way ranging is also an ultra-wideband ranging method. It transmits signals back and forth between the UWB tag and the vehicle, and measures the flight time in two directions to calculate the distance. Two-way ranging can reduce the error introduced by the uncertainty in signal transmission in one-way ranging and improve the accuracy of distance measurement.

[0043] In one embodiment of the present application, the received signal strength value is determined based on the channel impulse response power pulse value and the preamble code value.

[0044] The received signal strength value is specifically determined by the following calculation formula: in, is the received signal strength value; is the channel impulse response power pulse value; is the leading code value; is a constant.

[0045] Specifically, when calculating the received signal strength value RSS, the channel impulse response refers to the response characteristics of the signal when it is transmitted in the channel, which is usually described by an impulse response function. The power pulse value refers to the power value of the channel impulse response, which indicates the power change of the signal during the transmission process. The preamble is a special code sequence used for synchronization and timing in the communication system, which is usually sent before data transmission. The role of the preamble is to help the receiving end correctly identify and extract the received data to ensure the accuracy and reliability of data transmission. The value of the preamble indicates the specific value and mode of the preamble sequence. The receiving end can perform synchronization and data decoding by detecting the preamble.

[0046] In one embodiment of the present application, the first path signal estimation value is determined based on power values ​​and preamble code values ​​of signals from three first detected target anchor points to the UWB tag.

[0047] The estimated value of the first path signal is specifically determined by the following calculation formula: in, is the estimated value of the first path signal; , , are the power values ​​of the signals from the three first detected target anchor points to the UWB tag; is the leading code value; is a constant, a constant The value of is determined according to the pulse repetition rate of the received signal of the UWB tag.

[0048] Specifically, when calculating the first path signal estimate value FPP, the accuracy and reliability of signal detection can be improved by detecting and comparing multiple first path signals. Since the signal may be affected by the multipath effect during transmission, the signal may arrive on multiple different paths at the receiving end. Therefore, by calculating the arrival power values ​​of multiple first path signals, the transmission path and arrival time of the signal can be better estimated, thereby improving the accuracy of signal detection and reducing the impact of the multipath effect on signal detection. By comparing the arrival power values ​​of multiple first path signals, the strongest signal can be selected as the first path signal estimate value, thereby improving the accuracy and stability of signal detection. In this embodiment, the constant is determined based on the pulse repetition rate of the received signal of the UWB tag. The value of the pulse repetition rate is When, constant ; When the pulse repetition rate When, constant .

[0049] In one embodiment of the present application, determining whether there is an obstacle between the UWB tag and the multiple UWB anchor points is specifically based on the following determination formula: in, is the difference between the received signal strength value and the first path signal estimation value; is the received signal strength value; is the estimated value of the first path signal; when When , it is determined that there is an obstacle between the UWB tag and the target anchor point; among them, The obstacle determination threshold.

[0050] Specifically, in this embodiment, the obstacle determination threshold The reference value is , which is subject to actual calibration. It is a unit used to express power.

[0051] In one embodiment of the present application, the plurality of UWB anchor points are three anchor points set on the vehicle, including a first anchor point, a second anchor point and a third anchor point; the method further comprises: The position of the UWB tag in the vehicle cabin is calculated by the distances from the three anchor points to the UWB tag.

[0052] The position of the UWB tag in the vehicle cabin is calculated using the following formula: in, is the location of the UWB tag in the vehicle cabin; is the length of the vehicle cabin; is the vehicle cabin width; is the distance from the UWB tag to the first anchor point, is the distance from the UWB tag to the second anchor point, is the distance from the UWB tag to the third anchor point.

[0053] Specifically, Figure 3 The schematic diagram of three-point positioning based on ultra-wideband ranging is shown. In this embodiment, the target position is determined by constructing a three-point ranging model and a position calculation formula; wherein, constructing a three-point ranging model refers to the process of calculating the accurate position coordinates of the UWB tag by selecting three UWB anchor points at known positions in space and using the distance information between these UWB anchor points and the UWB tag. Through the distance information between the UWB anchor points and the UWB tag at three different positions, a triangle can be constructed, and the position of the target can be determined using the principle of triangulation. By constructing a three-point ranging model, accurate positioning of the target position can be achieved, which is suitable for various scenarios that require accurate positioning.

[0054] In one embodiment of the present application, there is a proportional relationship between the volume and side length of the tetrahedron formed by the three anchor points and the UWB tag, and the anchor point distance calculation model calculates two result values ​​of the distance between the anchor point and the UWB tag where there is an obstacle based on the Kelly-Menger determinant formula, where the result value with the smaller error is the final value.

[0055] The anchor point distance calculation model is implemented as follows: The location of the UWB tag in the vehicle cabin is the measurement point ; First anchor point, second anchor point, third anchor point and measuring point A tetrahedron is formed between them. The tetrahedron has six edges, which are marked as: , the distance from the first anchor point to the second anchor point; , the distance from the first anchor point to the third anchor point; , the distance from the first anchor point to the measuring point M, that is ; , the distance from the second anchor point to the third anchor point; , the distance from the second anchor point to the measuring point M, that is ; , the distance from the third anchor point to the measuring point M, that is ; Among them, the six edges of the simplified tetrahedron are: According to the Kelly-Menger determinant formula, when the order is 5, the volume of the tetrahedron is The relationship with the length of the six sides is as follows: in, is the volume of the tetrahedron.

[0056] Specifically, Figure 5 The distance diagram from the target anchor point to the UWB tag measurement point, the Kelly-Menger determinant formula is used to calculate In dimensional space The formula for the determinant of the four vectors is the Cayley-Menger determinant formula. The volume of a tetrahedron can be calculated by the coordinates of the four vertices, and the length of the hexagonal side is the distance between the four vertices. In three-dimensional space, the volume of a tetrahedron can be calculated by the coordinates of the four vertices, and the distance between the four vertices can be expressed by the difference in their coordinates. Therefore, when the order is 5, there is a certain relationship between the volume of the tetrahedron and the length of the hexagonal side of the tetrahedron, and the volume of the tetrahedron can be calculated by the Cayley-Menger determinant formula.

[0057] In one embodiment of the present application, in the anchor point distance calculation model, the distance between the anchor point where an obstacle exists and the UWB tag is calculated based on the following calculation formula: as well as: in, is the distance between the anchor point where there is an obstacle and the UWB tag; .

[0058] Specifically, in this embodiment, in order to simplify the expansion of the 5th order determinant, it is assumed that ; then the determinant: Tagged as: Expand and derive the notation as follows: Specifically, if there is an obstacle between the UWB tag and the first anchor point, Cannot be measured accurately, but known , , , , beg , according to the equation: When the measuring point of the tetrahedron The volume of the tetrahedron when it falls on the plane where the three anchor points are located is is zero, and the equation becomes: Then the equation is actually a quadratic equation, notated as: Substituting in: .

[0059] Specifically, if there is an obstacle between the UWB tag and the second anchor point, Cannot be measured accurately, but known , , , , beg , according to the equation: When the measuring point of the tetrahedron The volume of the tetrahedron when it falls on the plane where the three anchor points are located is is zero, and the equation becomes: Then the equation is actually a quadratic equation, notated as: Substituting in: .

[0060] Specifically, if there is an obstacle between the UWB tag and the third anchor point, Cannot be measured accurately, but known , , , , beg , according to the equation: When the measuring point of the tetrahedron The volume of the tetrahedron when it falls on the plane where the three anchor points are located is is zero, and the equation becomes: Then the equation is actually a quadratic equation, notated as: Substituting in: .

[0061] In one embodiment of the present application, the result value with small error is the final value and specifically includes: The absolute values ​​of the two calculated result values ​​are compared with the absolute value of the distance value between the vehicle anchor point and the UWB tag measured last time, and the result value with the smaller difference is taken as the final value of the distance between the vehicle anchor point and the digital key where there is an obstacle.

[0062] Specifically, in this embodiment, two result values ​​are calculated according to the formula of the anchor point distance calculation model distance. In actual application, only one result value can be taken. Therefore, the absolute values ​​of the two calculated result values ​​need to be compared with the absolute value of the distance value between the target anchor point and the UWB tag measured last time, and the smaller difference is taken as the distance value between the target anchor point and the UWB tag. The distance calculation error caused by measurement error or other factors can be reduced, and the accuracy and reliability of the distance value can be improved.

[0063] The present application also provides a distance measuring device based on an ultra-wideband UWB digital key, and the distance measuring device based on the ultra-wideband UWB digital key implements a distance measuring method based on the ultra-wideband UWB digital key.

[0064] Specifically, the ranging device based on ultra-wideband UWB digital key of the present application includes the ranging method based on ultra-wideband UWB digital key of any technical solution of the present application. Therefore, it has all the beneficial effects of the ranging method based on ultra-wideband UWB digital key of any technical solution of the present application, which will not be repeated here.

[0065] Although the present application is disclosed as above, the present application is not limited thereto. Any person skilled in the art can make various changes and modifications without departing from the spirit and scope of the present application. Therefore, the protection scope of the present application shall be subject to the scope defined by the claims.

Claims

1. A ranging method based on an ultra-wideband UWB digital key, applied to a ranging system of the UWB digital key, wherein the ranging system comprises a UWB tag and a plurality of UWB anchor points, characterized in that: The ranging method comprises: Determining whether there is an obstacle between the UWB tag and the plurality of UWB anchor points; When there is an obstacle between a target anchor point among the multiple UWB anchor points and the UWB tag, acquiring an anchor point distance calculation model; Obtaining distance values ​​between other anchor points among the multiple UWB anchor points and the UWB tag where no obstacles exist; The distance value is input into the anchor point distance calculation model to calculate the target distance between the target anchor point and the UWB tag.

2. The distance measurement method based on ultra-wideband UWB digital key according to claim 1 is characterized in that: The determining whether there is an obstacle between the UWB tag and the plurality of UWB anchor points includes: Based on ultra-wideband ranging, measuring the received signal strength value and the first path signal estimation value between the UWB tag and the multiple UWB anchor points; The difference between the received signal strength value and the first path signal estimation value is compared with an obstacle determination threshold. If the difference corresponding to the target anchor point is greater than the obstacle determination threshold, it is determined that there is an obstacle between the UWB tag and the target anchor point.

3. The distance measurement method based on ultra-wideband UWB digital key according to claim 2 is characterized in that: The received signal strength value is determined based on a channel impulse response power pulse value and a preamble code value.

4. The distance measurement method based on ultra-wideband UWB digital key according to claim 3 is characterized in that: The received signal strength value is specifically determined by the following calculation formula: in, is the received signal strength value; is the channel impulse response power pulse value; is the leading code value; is a constant.

5. The distance measurement method based on ultra-wideband UWB digital key according to claim 4 is characterized in that: The first path signal estimation value is determined based on power values ​​of three first detected signals from the target anchor point to the UWB tag and the preamble code value.

6. The distance measurement method based on ultra-wideband UWB digital key according to claim 5, characterized in that: The first path signal estimation value is specifically determined by the following calculation formula: in, is the estimated value of the first path signal; , , are power values ​​of the signals from the target anchor point to the UWB tag detected firstly; is the leading code value; is the constant, the constant The value of is determined according to the pulse repetition rate of the received signal of the UWB tag.

7. The distance measurement method based on ultra-wideband UWB digital key according to claim 6, characterized in that: The determining whether there is an obstacle between the UWB tag and the plurality of UWB anchor points is specifically based on the following determination formula: in, is the difference between the received signal strength value and the first path signal estimation value; is the received signal strength value; is the estimated value of the first path signal; when , it is determined that there is an obstacle between the UWB tag and the target anchor point; wherein, is the obstacle determination threshold.

8. The distance measurement method based on ultra-wideband UWB digital key according to claim 7, characterized in that: The multiple UWB anchor points are three anchor points set on the vehicle, including a first anchor point, a second anchor point and a third anchor point; the method further includes: The position of the UWB tag in the cabin of the vehicle is calculated by respectively calculating the distances from the three anchor points to the UWB tag.

9. The distance measurement method based on ultra-wideband UWB digital key according to claim 8, characterized in that: The calculation of the position of the UWB tag in the cabin of the vehicle is specifically calculated by the following calculation formula: in, is the position of the UWB tag in the vehicle cabin; is the length of the vehicle cabin; is the vehicle cabin width; is the distance from the UWB tag to the first anchor point, is the distance from the UWB tag to the second anchor point, is the distance from the UWB tag to the third anchor point.

10. A distance measuring device based on ultra-wideband UWB digital key, characterized in that: The distance measuring device based on ultra-wideband UWB digital key implements the distance measuring method based on ultra-wideband UWB digital key as described in claims 1-9.

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