A high-density wireless positioning method based on UWB technology

Abstract

This invention discloses a high-density wireless positioning method based on UWB technology, belonging to the field of wireless positioning technology. The method includes: obtaining the number of selectable time slots for N base stations to obtain a result; based on the result, the N base stations each select different transmission time slots; based on UWB technology and clock synchronization technology, the clock synchronization device controls the N base stations to send broadcast messages to space according to the selected transmission time slots; each of M tags listens to all the broadcast messages sent, obtaining multiple listening results; based on all listening results, the location information of each tag is calculated, realizing simultaneous wireless positioning of multiple tags. Since the tags only perform the task of listening to broadcast messages, theoretically, this invention can achieve simultaneous wireless positioning of an unlimited number of tags, regardless of the number of tags that can be accommodated in space, and has high engineering practical value.

Description

Technical Field

[0001] This invention relates to the field of wireless positioning technology, and more specifically, to a high-density wireless positioning method based on UWB technology. Background Technology

[0002] With the rapid development of communication technology and the Internet of Things (IoT) industry, indoor positioning services have been widely applied in daily life. Indoor positioning is mainly achieved through wireless sensor technologies such as RFID, Wi-Fi, Bluetooth, and ZigBee. However, these technologies cannot simultaneously meet the high accuracy and high reliability requirements of indoor positioning. Ultra-bandwidth wireless positioning technology, with its wide bandwidth, strong penetration, and high multipath resolution, can overcome these shortcomings and has therefore become one of the hot technologies for indoor wireless positioning.

[0003] UWB-based wireless positioning primarily involves two types of devices: base stations and tags. The location information of the base stations is known, while the tags estimate their own location by wirelessly communicating with the base stations. Current research on UWB-based wireless positioning mainly focuses on achieving high-precision positioning and positioning in complex environments, with little attention paid to the number of nodes allowed to access the positioning system. Wireless positioning schemes commonly use algorithms based on Time of Arrival (TOA) and Time Difference of Arrival (TDOA), which require the tag to interact and collaborate with multiple base stations to complete the positioning. However, within the communication range of a base station, both the base station and the tag exchange information on the same physical channel. If multiple devices communicate simultaneously, physical link transmission conflicts can occur, leading to the receiver being unable to correctly interpret the signal and resulting in positioning failure. Furthermore, the more nodes in the positioning system, the higher the probability of conflicts, thus significantly limiting the number of nodes that can access the system. Therefore, increasing the number of nodes that a positioning system can access is crucial, especially for high-density application scenarios such as underground parking garages and tunnels requiring the positioning of a large number of vehicles, and large shopping malls and industrial workshops requiring the positioning of a large number of people.

[0004] To allow for a larger number of nodes and achieve high-density wireless positioning, there are currently two main methods: 1) Designing unique MAC layer protocols for UWB wireless positioning, such as ALOHA and TDMA, to divide channel access into different time slots, thereby reducing the probability of signal collisions and data packet conflicts. However, this method can only theoretically increase the number of nodes for UWB wireless positioning to a certain extent and is not suitable for scenarios requiring a large number of user nodes to access, such as indoor positioning in large shopping malls. Moreover, this method is technically complex and has high R&D costs; 2) Tags actively send broadcast messages into space, and multiple base stations record the time of receiving the messages. Combining this with the base station's own location information, the TDOA algorithm is used to achieve tag positioning. However, because the tag needs to occupy a dedicated time slot during the time between sending the message and the base station receiving it to ensure that there are no physical link conflicts in the environment, the number of tags that can be supported within a fixed positioning period is also limited. Therefore, a high-density wireless positioning method based on UWB technology is urgently needed to solve the above problems. Summary of the Invention

[0005] To address the shortcomings of the existing technology, this invention provides a high-density wireless positioning method based on UWB technology, the method comprising:

[0006] The method is implemented using base stations, tags, and a clock synchronization device. The number of base stations is N, and the number of tags is M. The N base stations only perform the operation of sending broadcast messages into space, and the M tags only listen to the broadcast messages sent by the base stations in space. The clock synchronization device is used to synchronize the system clocks of the N base stations.

[0007] Specifically, the following steps are included:

[0008] The number of available time slots for N base stations is obtained to obtain the acquisition result. Based on the acquisition result, the N base stations select different transmission time slots respectively.

[0009] Based on UWB technology and clock synchronization technology, the clock synchronization device controls N base stations to send broadcast messages to space based on selected transmission time slots;

[0010] Each of the M tags listens to all broadcast messages sent, obtains multiple listening results, and calculates the location information of each tag based on all listening results, thereby enabling multiple tags to be wirelessly located simultaneously.

[0011] This invention is achieved through the following technical solution: This solution involves base stations, tags, and clock synchronization devices. In this positioning scenario, base stations and tags can communicate with each other. N base stations only perform the operation of sending broadcast messages into space, and M tags only listen to the broadcast messages sent by the base stations in space. The clock synchronization device is used to synchronize the clocks of multiple base stations. Specifically, it is achieved through the following steps: First, obtain the number of selectable time slots for N base stations. Then, select different transmission time slots for each base station from the selectable time slots. Each base station then sends broadcast messages into space based on the selected transmission time slot. The M tags listen to all broadcast messages sent by the base stations in space and obtain multiple listening results for each tag. Based on all listening results, calculate the location information of each tag to achieve simultaneous wireless positioning of multiple tags.

[0012] As an optional technical solution, obtaining the number of selectable time slots for N base stations includes:

[0013] In a positioning cycle T position In this context, the number of time slots that a base station can select when sending a broadcast message is N. slot = T slot To ensure the minimum time interval without physical channel collisions during communication between the base station and the tag, the symbol This means rounding x down to the nearest integer.

[0014] As an optional technical solution, based on the obtained results, the N base stations select different transmission time slots, including:

[0015] N base stations respectively from N slot If a time slot is selected from the available time slots to send a broadcast message, then the time slot at which the i-th base station sends the broadcast message is... 0≤s i ≤N slot ―1, 0≤i≤N―1,T base This indicates the start time of the current positioning cycle.

[0016] As an optional technical solution, N base stations sending broadcast messages to space includes:

[0017] Any base station Anchor i At any moment Send a broadcast message, and this broadcast message only needs to carry the location information p of the corresponding base station. i =[x i y i , z i ] T .

[0018] As an optional technical solution, the M tags monitoring the broadcast messages include:

[0019] Any tag j Within a positioning period, listen for broadcast messages in the space and record the time of receiving the broadcast message as vector Tr and the location information carried in the broadcast message as vector P;

[0020] Tr T = [t0, t1, ..., t N―1 ], P T = [p0, p1, ..., p N―1 ], Tr T P is the transpose of vector Tr. T The vector Tr is the transpose of vector P, and the k-th element of vector Tr represents the tag. j At the moment the k-th message is received, the k-th element of vector P represents the tag. j The location information carried in the kth received message.

[0021] As an optional technical solution, based on all monitoring results, the location information of each tag is calculated, including:

[0022] Calculate tags j The first calculation result is obtained based on the relative time of receiving the broadcast message;

[0023] Based on the first calculation result and T slot Calculate the broadcast message from each base station to the tag. j The arrival time difference is used to obtain the second calculation result;

[0024] Based on the second calculation result and vector P, the tag is calculated using a preset algorithm. j Location information.

[0025] As an optional technical solution, the preset algorithm is the TDOA algorithm.

[0026] As an optional technical solution, computational tagging j The relative time of receiving a broadcast message includes:

[0027] T R =Tr―Tr0

[0028] Tr0 represents the first element in vector Tr, T R Tag j The relative time of receiving the broadcast message.

[0029] As an optional technical solution, the calculation of broadcast messages from each base station to the tag... j The arrival time difference includes:

[0030]

[0031] T tof This indicates that broadcast messages travel from each base station to the tag. j The time difference of arrival.

[0032] As an optional technical solution, based on the second calculation result and vector P, a preset algorithm is used to calculate the tag. j Location information includes:

[0033] United T tof And P, use the TDOA algorithm to calculate the tag. j Location information.

[0034] One or more technical solutions provided by this invention have at least the following technical effects or advantages:

[0035] This invention discloses a high-density wireless positioning method based on UWB technology. Based on UWB and clock synchronization technology, multiple base stations are controlled by a clock synchronization device to send broadcast messages into space in time slots. Multiple tag nodes then only listen to the broadcast messages sent by the base stations in space. Based on the listening results, the function of simultaneously wirelessly positioning multiple tag nodes is achieved. Since the tags only complete the listening work of broadcast messages, if the number of tags that can be accommodated in space is not considered, this invention can theoretically achieve simultaneous wireless positioning of an unlimited number of tags. That is, it can achieve simultaneous wireless positioning in high-density environments, and has high engineering practical value. Attached Figure Description

[0036] The accompanying drawings, which are provided to further illustrate embodiments of the invention and constitute a part of this invention, are not intended to limit the scope of the invention.

[0037] Figure 1 This is a schematic diagram of a high-density wireless positioning method based on UWB technology in this invention;

[0038] Figure 2 This is a schematic diagram of a high-density wireless positioning scenario in this invention;

[0039] Figure 3 This is a schematic diagram of message interaction based on transmission time slots in this invention. Detailed Implementation

[0040] To better understand the above-mentioned objectives, features, and advantages of the present invention, the present invention will be further described in detail below with reference to the accompanying drawings and specific embodiments. It should be noted that, where there is no conflict, the embodiments of the present invention and the features thereof can be combined with each other.

[0041] Many specific details are set forth in the following description in order to provide a full understanding of the invention. However, the invention may also be practiced in other ways different from those described herein, and therefore the scope of protection of the invention is not limited to the specific embodiments disclosed below.

[0042] Example

[0043] Please refer to Figures 1-3 , Figure 1 This is a schematic diagram of a high-density wireless positioning method based on UWB technology in this invention; Figure 2 This is a schematic diagram of a high-density wireless positioning scenario in this invention; Figure 3 This is a schematic diagram of message interaction based on transmission time slots in this invention. A high-density wireless positioning method based on UWB technology is implemented through base stations, tags, and a clock synchronization device. The number of base stations is N, and the number of tags is M. The N base stations only perform the operation of sending broadcast messages into space, and the M tags only listen to the broadcast messages sent by the base stations in space. The clock synchronization device is used to synchronize the system clocks of the N base stations.

[0044] Specifically, the following steps are included:

[0045] The number of available time slots for N base stations is obtained to obtain the acquisition result. Based on the acquisition result, the N base stations select different transmission time slots respectively.

[0046] Based on UWB technology and clock synchronization technology, the clock synchronization device controls N base stations to send broadcast messages to space based on selected transmission time slots;

[0047] Each of the M tags listens to all broadcast messages sent, obtains multiple listening results, and calculates the location information of each tag based on all listening results, thereby enabling multiple tags to be wirelessly located simultaneously.

[0048] Furthermore, obtaining the number of selectable time slots for N base stations includes:

[0049] In a positioning cycle T position In this context, the number of time slots that a base station can select when sending a broadcast message is: T slot To ensure the minimum time interval without physical channel collisions during communication between the base station and the tag, the symbol This means rounding x down to the nearest integer.

[0050] Furthermore, based on the obtained results, the N base stations each select different transmission time slots, including:

[0051] N base stations respectively from N slot If a time slot is selected from the available time slots to send a broadcast message, then the time slot at which the i-th base station sends the broadcast message is... 0≤s i ≤N slot ―1, 0≤i≤N―1,T base This indicates the start time of the current positioning cycle.

[0052] Furthermore, the broadcast messages sent by N base stations to space include:

[0053] Any base station Anchor i At any moment Send a broadcast message, and this broadcast message only needs to carry the location information p of the corresponding base station. i =[x i y i , z i ] T

[0054] Furthermore, the M tags monitor the transmitted broadcast messages, including:

[0055] Any tag j Within a positioning period, listen for broadcast messages in the space and record the time of receiving the broadcast message as vector Tr and the location information carried in the broadcast message as vector P;

[0056] Tr T = [t0, t1, ..., t N―1 ], P T = [p0, p1, ..., p N―1 ], Tr T P is the transpose of vector Tr. T The vector Tr is the transpose of vector P, and the k-th element of vector Tr represents the tag. j At the moment the k-th message is received, the k-th element of vector P represents the tag. j The location information carried in the kth received message.

[0057] Furthermore, based on all the monitoring results, the location information for each tag is calculated, including:

[0058] Calculate tags j The first calculation result is obtained based on the relative time of receiving the broadcast message;

[0059] Based on the first calculation result and T slot Calculate the broadcast message from each base station to the tag. j The arrival time difference is used to obtain the second calculation result;

[0060] Based on the second calculation result and vector P, the tag is calculated using a preset algorithm. j Location information.

[0061] Furthermore, the preset algorithm is the TDOA algorithm.

[0062] Among them, the TDOA algorithm is a positioning method that infers the relative position of the object to be located relative to each reference base station by solving a system of nonlinear hyperbolic equations based on the distance difference between each reference base station and the object to be located.

[0063] Furthermore, calculate the tag. j The relative time of receiving a broadcast message includes:

[0064] T R =Tr―Tr0

[0065] Tr0 represents the first element in vector Tr, T R Tag j The relative time of receiving the broadcast message.

[0066] Furthermore, the calculation of broadcast messages from each base station to the tag... j The arrival time difference includes:

[0067]

[0068] T tof This indicates that broadcast messages travel from each base station to the tag. j The time difference of arrival.

[0069] Furthermore, based on the second calculation result and vector P, a preset algorithm is used to calculate the tag. j Location information includes:

[0070] United T tof And P, use the TDOA algorithm to calculate the tag. j Location information.

[0071] Specific embodiments of the present invention are as follows:

[0072] This embodiment involves base stations, tags, and a clock synchronization device. In this positioning scenario, base stations and tags can communicate with each other. N base stations only transmit broadcast messages into space, while M tags only listen to the broadcast messages transmitted by the base stations. The clock synchronization device synchronizes the clocks of multiple base stations. For example, in a high-density wireless positioning scenario, four base stations synchronized with clocks M=4 are placed, along with one tag for listening (N=1). The location information of the four base stations is distributed...

[0073] Don't be p i =[x i y i , z i ] Ti = 0, 1, 2, 3, and the tag is Tag j And N slot T base and T slot All of these are known, then perform the following steps:

[0074] 1) Base station selects transmission time slot: Base station Anchor i Different transmission time slots are selected respectively, i = 0, 1, 2, 3;

[0075] 2) Based on the selected transmission time slot, the base station sends broadcast messages into space: Base Station Anchor i At any moment Send carrying location information p i =[x i y i , z i ] T The broadcast message was sent into space;

[0076] 3) Broadcast messages sent by the base station in the tag listening space: Tag j The received message time is recorded as vector Tr, and the location information carried in the broadcast message is recorded as vector P. T =[T0+tof0, T1+tof1, T2+tof2, T3+tof3], P T = [p0, p1, p2, p3], tof i This indicates that the broadcast message originated from the base station Anchor. i Send to Tag j The receiving time, i = 0, 1, 2, 3;

[0077] 4) Tag-based location information calculation:

[0078] a) Calculate the tag j Relative reception time: T R =Tr―Tr0=[0,T slot +tof1―tof0,2T slot +tof2―tof0,3T slot +tof3―tof0] T ;

[0079] b) Calculate the broadcast messages from each base station to the tag. j Arrival time difference:

[0080] c) Calculate the tag j Location information: Joint T tofGiven a vector P, use the TDOA algorithm to calculate the tag. j Location information.

[0081] This embodiment is based on UWB and clock synchronization technology. It controls multiple base stations to send broadcast messages into space in time slots through a clock synchronization device. Multiple tag nodes then only listen to the broadcast messages sent by the base stations in space. Based on the listening results, the function of simultaneously wirelessly locating multiple tag nodes is realized. Since the tag only completes the listening work of broadcast messages, if the number of tags that can be accommodated in space is not considered, the present invention can theoretically realize the simultaneous wireless positioning of an unlimited number of tags, which has high engineering practical value.

[0082] Although preferred embodiments of the invention have been described, those skilled in the art, upon learning the basic inventive concept, can make other changes and modifications to these embodiments. Therefore, the appended claims are intended to be interpreted as including the preferred embodiments as well as all changes and modifications falling within the scope of the invention.

[0083] Obviously, those skilled in the art can make various modifications and variations to this invention without departing from its spirit and scope. Therefore, if these modifications and variations fall within the scope of the claims of this invention and their equivalents, this invention also intends to include these modifications and variations.

Claims

1. A high-density wireless positioning method based on UWB technology, characterized in that, The method is implemented using base stations, tags, and a clock synchronization device. The number of base stations is N, and the number of tags is M. The N base stations only perform the operation of sending broadcast messages into space, and the M tags only listen to the broadcast messages sent by the base stations in space. The clock synchronization device is used to synchronize the system clocks of the N base stations. Specifically, the following steps are included: The number of available time slots for N base stations is obtained to obtain the acquisition result. Based on the acquisition result, the N base stations select different transmission time slots respectively. Based on UWB technology and clock synchronization technology, the clock synchronization device controls N base stations to send broadcast messages to space based on selected transmission time slots; Each of the M tags listens to all broadcast messages sent, obtains multiple listening results, and calculates the location information of each tag based on all listening results, so as to realize the simultaneous wireless positioning of multiple tags; The number of available time slots for N base stations includes: In a positioning cycle In this context, the number of time slots that a base station can select when sending a broadcast message is: , To ensure the minimum time interval without physical channel collisions during communication between the base station and the tag, the symbol express Round down; Based on the obtained results, the N base stations each select different transmission time slots, including: N base stations respectively from If a time slot is selected from the available time slots to send a broadcast message, then the time slot at which the i-th base station sends the broadcast message is... , , , This indicates the start time of the current positioning cycle.

2. The high-density wireless positioning method based on UWB technology according to claim 1, characterized in that, N base stations sending broadcast messages to space include: Any base station At any moment Send a broadcast message, and this broadcast message only needs to carry the location information of the corresponding base station. .

3. The high-density wireless positioning method based on UWB technology according to claim 2, characterized in that, The M tags monitor the broadcast messages sent, including: Any tag Listen for broadcast messages in space within a positioning period and record the time of receiving the broadcast message as a vector. Tr The location information carried in the broadcast message is a vector. P ; , , For vectors Tr transpose, For vectors P transpose of vector The k-th element represents the label. The time of receiving the k-th message, vector P The k-th element represents the label. The location information carried in the kth received message.

4. The high-density wireless positioning method based on UWB technology according to claim 3, characterized in that, Based on all the monitoring results, the location information for each tag is calculated as follows: Calculate labels The first calculation result is obtained based on the relative time of receiving the broadcast message; Based on the first calculation result and Calculate the broadcast messages from each base station to the tag The arrival time difference is used to obtain the second calculation result; Based on the second calculation result and vector P, the label is calculated using a preset algorithm. Location information.

5. A high-density wireless positioning method based on UWB technology according to claim 4, characterized in that, The preset algorithm is the TDOA algorithm.

6. A high-density wireless positioning method based on UWB technology according to claim 4, characterized in that, Calculate labels The relative time of receiving a broadcast message includes: Representing vectors The first element in Indicates label The relative time of receiving the broadcast message.

7. A high-density wireless positioning method based on UWB technology according to claim 4, characterized in that, Calculate broadcast messages from each base station to the tag The arrival time difference includes: This indicates that broadcast messages travel from each base station to the tag. The time difference of arrival.

8. A high-density wireless positioning method based on UWB technology according to claim 5, characterized in that, Based on the second calculation result and vector P, the label is calculated using a preset algorithm. Location information includes: joint And P, the TDOA algorithm is used to calculate the tag. Location information.

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