Geometric constraint based ultra-wideband positioning, orientation tag and method thereof

Abstract

The application discloses a kind of ultra-wide positioning and directional label based on geometric constraint and method thereof, the label, modular in structure, single label is provided with double UWB antenna, can flexibly deploy antenna according to specific environment, install on a variety of complex mobile positioning platform, it is easy to assemble disassembly, deployment flexibility is high;The method is customized for label, with the actual distance len between first and second UWB antenna as geometric constraint condition, first, identify and exclude the base station most affected by non-line-of-sight, second, introduce direction angle auxiliary correction positioning coordinate, finally, obtain the optimal solution of label position and direction by Kalman filtering, gradually decompose the label position and direction problem solved under non-line-of-sight environment into the label position and direction problem solved under line-of-sight environment under four, three or two base station conditions.

Description

Technical Field

[0001] This invention relates to the field of wireless communication positioning technology, and in particular to an ultra-wide positioning and orientation tag and method based on geometric constraints. Background Technology

[0002] In situations where GPS (Global Positioning System) is limited, Ultra-Wideband (UWB) is commonly used for accurate indoor positioning. UWB positioning systems utilize ultra-wideband wireless signals to achieve positioning by measuring the distance between tags (MS, mobile station) and base stations (BS). They are characterized by low complexity, strong anti-interference capabilities, high transmission rates, and low power consumption, making them particularly suitable for densely populated, multipath-interference-prone indoor environments such as warehouses and logistics facilities, as well as for both indoor and outdoor positioning needs. Existing UWB positioning systems have a nominal positioning accuracy of 10cm at line-of-sight, sufficient for personnel and general mobile robot navigation. However, their stability is limited, often resulting in significant positioning deviations or even loss of location due to interference or partial base station obstruction. Furthermore, existing UWB positioning systems generally cannot directly provide orientation information; for robot navigation, additional sensors are required to provide directional information, leading to unsatisfactory results. Therefore, there is an urgent need for a stable and reliable tag and method capable of simultaneously providing positioning and orientation functions.

[0003] Ultra-wideband (UWB) positioning and orientation technology is used in indoor scenarios such as warehousing and logistics. The system's positioning tag uses a single UWB module integrated with a gyroscope, accelerometer, or magnetometer to achieve positioning and orientation functions. Single-tag positioning, equipped with only a single UWB antenna, has a relatively fixed structure and generally suffers from insufficient positioning stability in non-line-of-sight environments where radio waves are blocked.

[0004] Ultra-wideband positioning systems generally use , Methods such as [list of methods] can improve positioning accuracy, but ensuring accuracy requires a sufficient number of base stations and high-quality signals propagating in a straight line. If a base station is blocked, the number of effective base station signals received by the tag will be small, resulting in a large deviation in the radio wave characteristic measurement values. This makes it difficult to meet the positioning reliability requirements, and the reliability is severely reduced.

[0005] In addition, sensors such as gyroscopes, accelerometers or magnetometers have drawbacks when orientation, such as the coordinate system must be defined as the local geographic coordinate system, they are susceptible to accelerometer deviation and noise, and cannot be used in continuous dynamic scenarios. In various real-time complex indoor environments such as warehousing and logistics, there are problems such as difficulty in base station deployment, serious impact of non-line-of-sight propagation, and low and unstable orientation accuracy. Summary of the Invention

[0006] The technical problem to be solved by this invention is to overcome the shortcomings of existing ultra-wideband positioning, orientation tags and methods, such as poor tag deployment flexibility, reduced non-line-of-sight positioning accuracy and significant orientation performance interference. This invention provides an ultra-wideband positioning, orientation tag and method based on geometric constraints, which can achieve high-precision positioning of tags in complex environments such as non-line-of-sight locations.

[0007] To solve the above-mentioned technical problems, the present invention adopts the following technical solution:

[0008] This invention proposes an ultra-wideband positioning and orientation tag based on geometric constraints, comprising a message sensing module and a dual... Antenna module, Positioning module, power module; among which,

[0009] The message sensing module is used to sense four base stations in the surrounding environment and receive signals from the base stations;

[0010] pair Antenna modules are used to improve the communication distance and quality of wireless communication.

[0011] The positioning module is used to observe the relationship between each base station and the dual-channel system. The distance between antenna modules;

[0012] Power supply module, used for message sensing module and Power supply for the positioning module;

[0013] As a further optimization scheme for ultra-wideband positioning and orientation tagging based on geometric constraints as described in this invention, the message sensing module includes... main control unit and antenna, Main control unit and Antenna connection, before indoor positioning. The main control unit scans the Bluetooth identifiers of four base stations deployed in the surrounding environment and receives and parses the positioning commands from the base stations to perform positioning. During indoor positioning... Main control unit control Positioning module observation base station and dual The distance between antenna modules allows each base station to obtain distance information;

[0014] As a further optimization scheme for the ultra-wideband positioning and orientation tag based on geometric constraints described in this invention, dual Antenna module, including the first Antenna, Second Antenna, First Antenna and Second The antennas are spaced a certain distance apart on the movable platform to be positioned. Arrangement, first Antenna, Second The antenna automatically adjusts its position according to the environment of the mobile platform to be located, thereby changing the distance. The value of this effectively alleviates the problem of poor tag deployment flexibility in existing ultra-wideband positioning and directional tags.

[0015] As a further optimization scheme for the ultra-wideband positioning and orientation tag based on geometric constraints described in this invention, The positioning module is used to realize the ranging function, including the first Unit 2 Unit, respectively with the first Antenna, Second The antennas are connected, and the first one is calculated separately. Antenna, Second Time difference between antenna and base station antenna This allows each base station to obtain distance information.

[0016] An ultra-wideband localization and orientation method based on geometric constraints includes the following steps:

[0017] step , obtain the first and second measurements at the current time The observation distance information between the antenna and the four base stations, where the current time is the [number]th [time]. The time is recorded as: First antenna: ,second antenna: ;

[0018] Calculate the current time of the four base stations and the first, second, and third base stations respectively. The difference in observation distance between antennas, where the current time is the nth time. The time is recorded as follows: ;in, , , middle For antenna identification, For base station identification, For time markers;

[0019] The first base station and the first and second The antennas form a triangle, at normal line-of-sight. In the propagation case, the resulting triangle satisfies the geometric constraint that the difference between any two sides of the triangle is less than the third side. It must be less than the first and second Actual distance between antennas Considering The inherent ranging error , Should be smaller The same logic applies to the second, third, and fourth base stations. Based on the constraints of the triangle, it is possible to effectively distinguish whether the four base stations are in line-of-sight propagation. Under what circumstances?

[0020] step If steps Each All less than Then it is judged as pure Environment; if steps There exists greater than of If the value is true, then it is judged as true. environment;

[0021] For pure The environment was analyzed using a quadrilateral positioning algorithm to obtain the first and second... Antenna estimated coordinates , ;

[0022] for Environment, elimination steps middle The base station corresponding to the maximum value, this base station is affected The most affected approach is to treat the remaining three base stations as line-of-sight base stations and retain them. Then, using a trilateration algorithm, the first and second... Antenna estimated coordinates , ;in, middle For antenna identification, Used as a time marker.

[0023] By excluding non-line-of-sight (NOS) base stations and retaining NOS base stations, the problem of large ranging errors caused by NOS base stations can be directly avoided. The positioning that was originally affected by NOS base station interference can be converted into positioning in a pure NOS base station environment. It is also applicable to scenarios where the ranging error is large due to base station loss, effectively improving the positioning accuracy.

[0024] step Calculation steps First and second Antenna coordinates , The distance difference between them is recorded as:

[0025] ;

[0026] like and The difference Greater than If the location result is unreliable, then the location result is considered unreliable. Less than If the location result is "first" or "second", then the location result is considered reliable. The antenna position result is , ;

[0027] step If steps The mid-positioning result is considered reliable, and the steps are... First and second The antenna position is recorded as follows , If steps If the positioning result is considered unreliable, then the base station most affected by non-line-of-sight interference will be further filtered out, taking into account the steps. The number of line-of-sight base stations remaining after the first exclusion of non-line-of-sight base stations is equal to the number of line-of-sight base stations remaining after further filtering of non-line-of-sight base stations. Then, the trilateration algorithm is used to solve the first and second... Antenna location, if the number of line-of-sight base stations is less than Then, the first and second line-of-sight base stations are used to solve the problem. Antenna location;

[0028] After further excluding non-line-of-sight base stations, the trilateration algorithm is used to solve the first and second... The antenna position is recorded as follows: , ;

[0029] After further excluding non-line-of-sight base stations, dual-line-of-sight base stations are used to solve the first and second... The location of the antenna, then each The antenna will generate two coordinate values, and the first and second coordinates can be obtained based on the direction estimated from the tag. The antenna's unique coordinates are recorded as follows: , ; where, direction angle The calculation formula is as follows:

[0030] ;

[0031] in, middle This indicates the result after further excluding non-line-of-sight base stations; the label orientation is first and second. The antenna coordinate line perpendicular to the direction of Angular deviation in the positive direction of the axis;

[0032] Dual-line-of-sight base stations complete the orientation function, enabling them to provide orientation information without the need for other sensors; dual-line-of-sight base stations, supplemented by azimuth angles, complete the orientation of the first and second lines of sight. Antenna position correction can be applied to scenarios such as positioning failure caused by base station loss;

[0033] step According to the steps middle , Solve for the estimated position of the label at the current time step. and direction angle , where the current time is the th At that moment, the estimated position of the label was first or second. The center coordinates of the antenna. Wherein, The calculation formula is as follows:

[0034] ;

[0035] step 1. Construct a Kalman filter, set the parameters of the Kalman filter, and follow the steps. middle , Perform Kalman filter processing to find and output the optimal solution for the tag's position and direction at the current time, where the current time is the [i, j]. At time, the label position is recorded after solving. The label direction is recorded as ; will the first The time will be postponed to the next At that moment, return to the previous step. The process is repeated to obtain the label position and label orientation at each time step.

[0036] The technical effects and advantages of this invention are: overcoming the limitations of existing ultra-wideband positioning technology in non-line-of-sight applications. To address the shortcomings of localization in various environments, this paper proposes an ultra-wideband localization and orientation tag and its method based on geometric constraints. The tag is structurally modularized, with each tag equipped with two... The antenna can be flexibly deployed as an ultra-wideband antenna according to specific environments and installed on various complex mobile positioning platforms; in addition, positioning and orientation methods are customized for tags, using the first and second... Actual distance between antennas As a geometric constraint, the base stations most affected by non-line-of-sight (NOS) conditions are first identified and excluded. Next, an orientation angle is introduced to assist in correcting the positioning coordinates. Finally, Kalman filtering is used to obtain the optimal solution for the tag position and orientation, thus mitigating NOS. The problem of determining label position and orientation in an environment is gradually decomposed into line-of-sight distance. This method solves the tag position and orientation problem in environments with four, three, or two base stations. It significantly improves the accuracy of positioning and orientation in indoor non-line-of-sight environments. Specifically, it offers the following benefits:

[0037] To identify non-line-of-sight base stations and exclude those most affected by non-line-of-sight conditions;

[0038] A single tag, in addition to achieving localization, also enables orientation observation;

[0039] Introducing and integrating azimuth angle-assisted implementation for the first and second line-of-sight base stations with only two base stations. Position coordinate correction of module antenna;

[0040] There is no limit to the number of base stations that can be deployed indoors, and the number of base stations that can be moved is [number missing]. In various indoor non-line-of-sight positioning and orientation scenarios. Attached Figure Description

[0041] 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 drawings can be obtained based on these drawings without creative effort.

[0042] picture This is a diagram of the label structure of the present invention;

[0043] picture This is a schematic diagram illustrating the label position and label orientation of the present invention.

[0044] picture This is a schematic diagram of the installation of the label of the present invention on a mobile platform;

[0045] picture The schematic diagram shows other necessary modules of the present invention;

[0046] picture This is a schematic diagram of the ultra-wideband tag positioning method based on distance geometry constraints of the present invention;

[0047] picture This is a flowchart of an ultra-wideband tag localization and orientation method based on geometric constraints according to the present invention; Detailed Implementation

[0048] The technical solutions of this invention will now be clearly and completely described with reference to the accompanying drawings. Obviously, the described embodiments are only some, not all, of the embodiments of this invention. All other embodiments obtained by those skilled in the art based on the embodiments of this invention without creative effort are within the scope of protection of this invention.

[0049] Refer to This paper demonstrates an ultra-wideband positioning and orientation tag based on geometric constraints, including a message-aware module and a dual-channel system. Antenna module Positioning module and power module.

[0050] The message sensing module is used to sense four base stations in the surrounding environment and receive signals from the base stations;

[0051] pair Antenna modules are used to improve the communication distance and quality of wireless communication.

[0052] The positioning module is used to observe the relationship between each base station and the dual-channel system. The distance between antenna modules;

[0053] Power supply module, used for message sensing module and Power supply for the positioning module.

[0054] Refer to It shows the label position and label orientation, including: label, The positioning tag is fixed on a movable platform and sends data periodically. and Signal; base station The positioning base stations are fixedly installed around the environment and periodically measure the dual... Antenna distance; tag location, first and second Coordinates of the geometric center of the positioning module antenna; tag orientation, first and second. The antenna connection of the positioning module is perpendicular to the direction of the antenna. Angular deviation in the axial direction;

[0055] Refer to This paper illustrates the deployment and installation of a geometrically constrained ultra-wideband positioning and orientation tag on a mobile platform, including: a mobile platform, a carrier for the tag; a tag body, fixed at any suitable position on the mobile platform; and dual... Antenna modules, first and second The antennas are fixed at both ends of the movable platform, at a distance of [distance missing]. .

[0056] Refer to The diagram shows other necessary modules, including: four base station modules, which are installed around the surrounding environment and communicate with the tag modules to measure distance information, and are used to connect and transmit distance information to the host module; and the host module, which is used to perform tasks such as calculating the tag position and orientation, building offline maps, and displaying the tag in a two-dimensional plane.

[0057] Refer to This illustrates a localization method based on distance geometry constraints, including:

[0058] step Obtain the first and second respectively The distance from the positioning module antenna to each base station;

[0059] step , with the first Base stations and the first and second Taking the positioning module antenna as an example, the theorem that the sum of any two sides of a triangle is greater than the third side leads to the property that the difference between any two sides of a triangle is less than the third side. Therefore: Taking into account the error, then It can be represented as: ;

[0060] in For double The actual distance (true value) of the positioning module antenna. The ranging accuracy error is generally 100%. The primary purpose of prior distance constraints is to identify larger non-line-of-sight distances during the observation process. After identifying gross errors and excluding the base station with the largest gross error, the line-of-sight distance of the three base stations can be determined. Positioning.

[0061] step In obtaining double After determining the coordinates of the positioning module antenna, the dual antennas can be calculated. Distance between antenna coordinates of the positioning module Calculated value truth value The difference between the two values ​​is defined as the distance residual. The distance residual can be used to further optimize the positioning results. If the distance residual is greater than... If the location result is unreliable, then the system will continue to exclude base stations with significant non-line-of-sight interference and switch to two base stations. Positioning is achieved by combining indoor constraints with directional angles.

[0062] Refer to This paper demonstrates an ultra-wideband localization and orientation method based on geometric constraints, which includes the following steps:

[0063] step , obtain the first and second measurements at the current time The observation distance information between the antenna and the four base stations, where the current time is the [number]th [time]. The time is recorded as: First antenna: ,second antenna: ;

[0064] Calculate the current time of the four base stations and the first, second, and third base stations respectively. The difference in observation distance between antennas, where the current time is the nth time. The time is recorded as follows: ;in, , , middle For antenna identification, For base station identification, For time markers;

[0065] The first base station and the first and second The antennas form a triangle, at normal line-of-sight. In the propagation case, the resulting triangle satisfies the geometric constraint that the difference between any two sides of the triangle is less than the third side. It must be less than the first and second Actual distance between antennas Considering The inherent ranging error , Should be smaller The same logic applies to the second, third, and fourth base stations. Based on this triangular constraint, it is possible to effectively distinguish whether the four base stations are in line-of-sight propagation. Under what circumstances?

[0066] step If steps Each All less than Then it is judged as pure Environment; if steps There exists greater than of If the value is true, then it is judged as true. environment;

[0067] For pure The environment was analyzed using a quadrilateral positioning algorithm to obtain the first and second... Antenna estimated coordinates , ;

[0068] for Environment, elimination steps middle The base station corresponding to the maximum value, this base station is affected The most affected approach is to treat the remaining three base stations as line-of-sight base stations and retain them. Then, using a trilateration algorithm, the first and second... Antenna estimated coordinates , ;in, middle For antenna identification, Used as a time marker.

[0069] By excluding non-line-of-sight (NOS) base stations and retaining NOS base stations, the problem of large ranging errors caused by NOS base stations can be directly avoided. The positioning that was originally affected by NOS base station interference can be converted into positioning in a pure NOS base station environment. This is also applicable to scenarios with large ranging errors caused by base station loss, effectively improving the positioning accuracy.

[0070] step Calculation steps First and second Antenna coordinates , The distance difference between them is recorded as:

[0071] ;

[0072] like and The difference Greater than If the location result is unreliable, then the location result is considered unreliable. Less than If the location result is reliable, the location result is considered to be the first or second. The antenna position result is , ;

[0073] step If steps The mid-positioning result is considered reliable, and the steps are... First and second The antenna position is recorded as follows , If steps If the positioning result is considered unreliable, then the base station most affected by non-line-of-sight interference will be further filtered out, taking into account the steps. The number of line-of-sight base stations remaining after the first exclusion of non-line-of-sight base stations is equal to the number of line-of-sight base stations remaining after further filtering of non-line-of-sight base stations. Then, the trilateration algorithm is used to solve the first and second... Antenna location, if the number of line-of-sight base stations is less than Then, the first and second line-of-sight base stations are used to solve the problem. Antenna location;

[0074] After further excluding non-line-of-sight base stations, the trilateration algorithm is used to solve the first and second... The antenna position is recorded as follows: , ;

[0075] After further excluding non-line-of-sight base stations, dual-line-of-sight base stations are used to solve the first and second... The location of the antenna, then each The antenna will generate two coordinate values, and the first and second coordinates can be obtained based on the direction estimated from the tag. The antenna's unique coordinates are recorded as follows: , ; where, direction angle The calculation formula is as follows:

[0076]

[0077] in, middle This indicates the result after further excluding non-line-of-sight base stations; the label orientation is first and second. The antenna coordinate line perpendicular to the direction of Angular deviation in the positive direction of the axis.

[0078] Dual-line-of-sight base stations complete the orientation function, enabling them to provide orientation information without the need for other sensors; dual-line-of-sight base stations, supplemented by azimuth angles, complete the orientation of the first and second lines of sight. Antenna position correction is applicable to scenarios where positioning fails due to base station loss.

[0079] step According to the steps middle , Solve for the current time (the nth time) (Time) tag estimated location and direction angle The estimated position of the label is the first or second. The center coordinates of the antenna, where, The calculation formula is as follows:

[0080]

[0081] step 1. Construct a Kalman filter, set the parameters of the Kalman filter, and follow the steps. middle , Perform Kalman filter processing to determine the current time (the nth time). The optimal solution for the label position and orientation at time ( ) is calculated and output. The label position is then recorded as follows: The label direction is recorded as ; will the first The time will be postponed to the next At that moment, return to the previous step. The process is repeated to obtain the label position and label orientation at each time step.

[0082] It should be understood that the specific embodiments described above are merely ordinary embodiments of the present invention and are not intended to limit the present invention. Any modifications, equivalent substitutions, improvements, etc., made within the spirit and principles of the present invention should be included within the protection scope of the present invention.

Claims

1. A geometrically constrained ultra-wideband positioning and orientation tag, including a message sensing module and dual... Antenna module, Positioning module, power module, characterized in that: The message sensing module is used to sense four base stations in the surrounding environment and receive signals from the base stations; pair Antenna modules are used to improve the communication distance and quality of wireless communication. pair Antenna module, including the first Antenna, Second Antenna, First Antenna and Second The antennas are spaced a certain distance apart on the movable platform to be positioned. Arrangement, first Antenna, Second The antenna automatically adjusts its position according to the environment of the mobile platform to be located, thereby changing the distance. The value; The positioning module is used to observe the relationship between each base station and the dual-channel system. The distance between antenna modules; Power supply module, used for message sensing module and Power supply for the positioning module; Solving for the label position and label orientation using the distance constraint method includes the following steps: step , obtain the first and second measurements at the current time The observation distance information between the antenna and the four base stations, where the current time is the [number]th [time]. The time is recorded as: First antenna: ,second antenna: ; Calculate the current time of the four base stations and the first, second, and third base stations respectively. The difference in observation distance between antennas, where the current time is the nth time. The time is recorded as follows: ;in, , , middle For antenna identification, For base station identification, For time markers; The first base station and the first and second The antennas form a triangle, at normal line-of-sight. In the propagation case, the resulting triangle satisfies the geometric constraint that the difference between any two sides of the triangle is less than the third side. It must be less than the first and second Actual distance between antennas Considering The inherent ranging error , Should be smaller The same logic applies to the second, third, and fourth base stations. Based on the constraints of this triangle, it is possible to effectively distinguish whether the four base stations are in line-of-sight propagation. In this case; step If steps Each All less than Then it is judged as pure Environment; if steps There exists greater than of If the value is true, then it is judged as true. environment; For pure The environment was analyzed using a quadrilateral positioning algorithm to obtain the first and second... Antenna estimated coordinates , ; for Environment, elimination steps middle The base station corresponding to the maximum value, this base station is affected The most affected approach is to treat the remaining three base stations as line-of-sight base stations and retain them. Then, using a trilateration algorithm, the first and second... Antenna estimated coordinates , ;in, middle For antenna identification, For time markers; step Calculation steps First and second Antenna coordinates , The distance difference between them is recorded as: ； like and The difference Greater than If the location result is unreliable, then the location result is considered unreliable. Less than If the location result is reliable, the location result is considered to be the first or second. The antenna position result is , ; step If steps The mid-positioning result is considered reliable, and the steps are... First and second The antenna position is recorded as follows , If steps If the positioning result is considered unreliable, then the base station most affected by non-line-of-sight interference will be further filtered out, taking into account the steps. The number of line-of-sight base stations remaining after the first exclusion of non-line-of-sight base stations is equal to the number of line-of-sight base stations remaining after further filtering of non-line-of-sight base stations. Then, the trilateration algorithm is used to solve the first and second... Antenna location, if the number of line-of-sight base stations is less than Then, the first and second line-of-sight base stations are used to solve the problem. Antenna location; After further excluding non-line-of-sight base stations, the trilateration algorithm is used to solve the first and second... The antenna position is recorded as follows: , ; After further excluding non-line-of-sight base stations, dual-line-of-sight base stations are used to solve the first and second... The location of the antenna, then each The antenna will generate two coordinate values, and the first and second coordinates can be obtained based on the direction estimated from the tag. The antenna's unique coordinates are recorded as follows: , ; where, direction angle The calculation formula is as follows: ； in, middle This indicates the result after further excluding non-line-of-sight base stations; the label orientation is first and second. The antenna coordinate line perpendicular to the direction of Angular deviation in the positive direction of the axis; Dual-line-of-sight base stations complete the orientation function, enabling them to provide orientation information without the need for other sensors; dual-line-of-sight base stations, supplemented by azimuth angles, complete the orientation of the first and second lines of sight. Antenna position correction is applicable to scenarios where positioning fails due to base station loss; step According to the steps middle , Solve for the estimated position of the label at the current time step. and direction angle , where the current time is the th At that moment, the estimated position of the label was first or second. The center coordinates of the antenna, where, The calculation formula is as follows: ； step 1. Construct a Kalman filter, set the parameters of the Kalman filter, and follow the steps. middle , Perform Kalman filter processing to find and output the optimal solution for the tag's position and direction at the current time, where the current time is the [i, j]. At time, the label position is recorded after solving. The label direction is recorded as ; will the first The time will be postponed to the next At that moment, return to the previous step. The process is repeated to obtain the label position and label orientation at each time step.

2. According to the claims The aforementioned ultra-wideband positioning and orientation tag based on geometric constraints is characterized by: The message awareness module includes... main control unit and antenna, Main control unit and Antenna connection, before indoor positioning. The main control unit scans the Bluetooth identifiers of four base stations deployed in the surrounding environment and receives and parses the positioning commands from the base stations to perform positioning. During indoor positioning... Main control unit control Positioning module observation base station and dual The distance between antenna modules allows each base station to obtain distance information.

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