Dynamic adaptive communication positioning method and system based on UWB

Abstract

The invention discloses a UWB-based dynamic adaptive communication positioning method and system, and the method comprises the steps: setting a positioning platform and a positioning region, determining the positions and number of UWB positioning base stations, and introducing BitMap and HashMap to obtain improved UWB positioning base stations; adding a byte in a Poll signal frame of the tag as a control identifier; bytes used for storing the time slot threshold value, the time slot value and the positioning mode are added in a response frame of the base station; setting a time slot threshold value and a time slot allocation strategy; setting a positioning mode distribution strategy corresponding to the time slot distribution strategy; the label sends a Poll request to the base station through a Poll signal frame, and receives a time slot and a positioning mode allocated to the label by the positioning platform to realize communication with the base station; the system comprises a UWB positioning label, an improved UWB positioning base station and a UWB positioning platform. The positioning mode and the communication mode can be dynamically switched according to the number of the labels in the positioning area, the positioning precision and the bearing capacity of the labels in the area are effectively improved, and the power consumption of the labels is reduced.

Description

Technical Field

[0001] The present invention relates to the technical field of UWB communication and positioning, and particularly to a dynamic adaptive communication and positioning method and system based on UWB. Background Art

[0002] Ultra-wideband (UWB) is a wireless communication technology. UWB uses an extremely wide spectrum bandwidth, so that it can communicate using ultra-short pulse signals at the nanosecond level. Since UWB uses ultra-short pulses for communication, the position can be calculated by measuring the time difference of ultra-short pulses or the time of flight (TOF) between two devices, and using the TDOA or TWR algorithm.

[0003] The principle of the TWR positioning algorithm is to calculate the two-way time of flight of UWB information between the positioning tag and the base station, and use the speed of light to calculate the distance between the tag and the base station. Knowing the distances between the positioning tag and at least three base stations, and the accurate coordinates of the three base stations, the accurate distance of the positioning tag can be calculated through formulas. When the positioning tag receives signals, to prevent conflicts, the base station replies need to be carried out in different time periods. Such a time period is a channel. Usually, a positioning system generally uses 4 channels. The TWR positioning has high accuracy, and through two-way communication, commands can be sent to the positioning tag. The disadvantage is that multiple interactions are time-consuming, the system capacity is limited, and the power consumption of the positioning tag is relatively large.

[0004] The principle of TDOA positioning is that the positioning tag sends UWB signals, and the base station uploads the timestamps of the received signals to the positioning server. The positioning server calculates the accurate position of the positioning tag based on the time when each base station receives the signal and the time difference of the signal arriving at each base station. The advantage of TDOA positioning is that the positioning tag only needs to broadcast signals, and the base station does not need to reply, which reduces the time spent on measurement. The disadvantage is that the positioning accuracy is slightly worse, and the base station cannot communicate with the positioning tag.

[0005] In traditional UWB positioning scenarios, TWR or TDOA positioning is adopted according to the number of tags in the area. When using TWR positioning, once the number of tag data in the area increases, it will lead to problems such as regional signal conflicts, positioning signal loss, and jitter. If TDOA positioning is used, because the tag cannot communicate with the base station, there is a problem of difficult command issuance. At the same time, the positioning accuracy of TDOA is slightly worse than that of TWR. When there are few tags in the positioning area, the higher-precision TWR positioning cannot be used.

[0006] In summary, it is necessary to design a method that can meet the positioning and communication requirements in such a highly variable scenario. Summary of the Invention

[0007] The present invention provides a dynamic adaptive communication and positioning method and system based on UWB to overcome the technical problems in UWB positioning that when the number of tags in the positioning area increases, using only TWR positioning is likely to cause signal conflicts and unable to position, and using only TDOA positioning has poor accuracy.

[0008] To achieve the above object, the technical solution of the present invention is:

[0009] A dynamic adaptive communication and positioning method based on UWB, comprising:

[0010] S1: Set the positioning platform and the positioning area, determine the positions and quantities of UWB positioning base stations according to the positioning area, and introduce BitMap in the UWB positioning base stations to store the instruction status of positioning tags and introduce HashMap to store instruction data to obtain improved UWB positioning base stations;

[0011] S2: Add a byte as a control identifier in the Poll signal frame of the UWB positioning tag, and the UWB positioning tag interacts with the improved UWB positioning base station through the control identifier;

[0012] S3: Add bytes for storing the time slot threshold, time slot value, and positioning mode in the response frame of the improved UWB positioning base station. When the UWB positioning tag sends a Poll request to the improved UWB positioning base station through the Poll signal frame, send the corresponding time slot and positioning mode to the UWB positioning tag through the response frame;

[0013] S4: Set the time slot threshold and the time slot allocation strategy, determine whether the number of all UWB positioning tags in the positioning area exceeds the time slot threshold under the condition that each UWB positioning tag is allocated a time slot, and use the positioning platform to determine the time slot of each UWB positioning tag through the time slot allocation strategy according to the judgment result;

[0014] S5: Set the positioning mode allocation strategy corresponding to the time slot allocation strategy, and use the positioning platform to determine a positioning mode corresponding to the time slot of each UWB positioning tag according to the positioning mode allocation strategy; the positioning modes include TWR positioning mode, TDOA positioning mode, or a hybrid positioning mode of TWR and TDOA;

[0015] S6: Control the UWB positioning tag to send a Poll request to the improved UWB positioning base station through the Poll signal frame, and receive the time slot and positioning mode allocated by the positioning platform for the UWB positioning tag and saved in the response frame of the improved UWB positioning base station, and realize communication with the improved UWB positioning base station according to the allocated time slot and positioning mode.

[0016] Further, the time slot allocation strategy includes:

[0017] Judge the number of current UWB positioning tags u in the positioning area, and the judgment conditions are as follows:

[0018] When u ≤ m, adopt the fixed time slot allocation method, that is, allocate one time slot for each UWB positioning tag, where m is the time slot threshold;

[0019] When m < u ≤ q, divide each time slot equally. Each time slot is divided into n parts, forming n*m first divided time slots and the corresponding serial numbers of the first divided time slots in the corresponding time slots, and allocate one first divided time slot for each UWB positioning tag according to the preset allocation order; among them, q = n*m, which is the threshold of the first divided time slot;

[0020] When q < u ≤ w, divide each first divided time slot equally to form n*m*j second divided time slots, and allocate one second divided time slot for each UWB positioning tag; among them, w = n*m*j, which is the threshold of the second divided time slot.

[0021] Furthermore, the allocation order includes:

[0022] Under the condition that one UWB positioning tag is allocated to all time slots, when the (m + 1)-th positioning tag appears in the positioning area, the positioning platform allocates the second first divided time slot of the first time slot to this positioning tag;

[0023] When the (m + 2)-th positioning tag appears in the positioning area, the positioning platform allocates the second first divided time slot of the second time slot to this positioning tag;

[0024] When the (m + 3)-th positioning tag appears in the positioning area, the positioning platform allocates the third first divided time slot of the third time slot to this positioning tag;

[0025] And so on, when the (m*n)-th positioning tag appears in the positioning area, the positioning platform allocates the last first divided time slot of the m-th time slot to this positioning tag.

[0026] Furthermore, the positioning mode allocation strategy includes:

[0027] When u ≤ m, the UWB positioning tag uses the TWR positioning mode;

[0028] When m < u ≤ q, the UWB positioning tag uses the hybrid positioning mode of TWR and TDOA;

[0029] When q < u ≤ w, the UWB positioning tag uses the TDOA positioning mode.

[0030] Furthermore, the hybrid positioning mode of TWR and TDOA specifically includes:

[0031] In each time slot, for each UWB positioning tag, every time a TWR positioning is performed, N TDOA positionings are carried out, and the TDOA positioning data is calibrated using the TWR positioning data through the Kalman filtering algorithm; where N = u;

[0032] The timing for each UWB positioning tag to send TDOA signals is as shown in formula (1),

[0033] T = TS + Tr + (ST * l) (1)

[0034] where T is the timing for the UWB positioning tag to send TDOA signals, TS is the time for positioning in the time slot where each UWB positioning tag is located, Tr is the TWR signal period, ST is the serial number of the first divided time slot corresponding to each UWB positioning tag in the time slot it is in, and l is the duration of the corresponding first divided time slot.

[0035] Furthermore, calibrating the TDOA positioning data using the TWR positioning data through the Kalman filtering algorithm includes:

[0036] Based on the result of each TDOA positioning, use the preset uniform motion model to predict the position of the UWB positioning tag, as shown in formula (2),

[0037]

[0038] In the formula, represents the predicted value of the current state based on the state estimate value of the previous moment, represents the state estimate value of the previous moment, k represents the discrete time step, F represents the state transition matrix, as shown in formula (3),

[0039]

[0040] where Δt represents the time interval;

[0041] When the positioning platform receives the TWR positioning data of the UWB positioning tag, update the position of the corresponding UWB positioning tag using the TWR positioning data, as shown in formulas (4) and (5),

[0042] K k = P k|k-1 × H T × (H × P k|k-1 × H T + R TWR ) -1 (4)

[0043]

[0044] where H is the observation matrix, R TWRRepresents the TWR noise covariance, P k|k-1 Represents the prediction error covariance direction matrix, K k Represents the Kalman gain, Z TWR Represents the TWR positioning data Represents the predicted state Represents the updated optimal position estimate

[0045] Based on the same inventive concept, a dynamic adaptive communication positioning system based on UWB is also provided, including:

[0046] A UWB positioning tag, which is installed on the target to be positioned and sends real-time positioning information to the improved UWB positioning base station in real time;

[0047] An improved UWB positioning base station, which is used to receive the positioning information sent by the UWB positioning tag, and every four improved UWB positioning base stations form a positioning area;

[0048] A UWB positioning platform, which is connected to the improved UWB positioning base station through a network, allocates time slots and positioning modes for the UWB positioning tags in each positioning area according to the time slot allocation strategy and the positioning mode allocation strategy, and collects and processes the positioning data received by the improved UWB positioning base station in real time to update the positions of the UWB positioning tags.

[0049] Beneficial effects: By expanding the UWB communication protocol, the present invention saves the information of the tags, realizes the fast communication between the tags and the base station, sets the time slot allocation strategy and the positioning mode allocation strategy, and can dynamically switch the positioning mode and the communication mode according to the number of positioning tags in the positioning area. When only TWR positioning and communication are used for the positioning tags in the area, the positioning accuracy of the system is improved; when the number of positioning tags increases, the frequency of TWR positioning is dynamically reduced when using the hybrid mode of TWR and TDOA, and when only TDOA positioning is used for the tags, a fast communication method is used to keep the communication between the positioning tags and the base station. Therefore, the positioning accuracy and the bearing capacity of the positioning tags in the area are effectively improved, and the power consumption of the tags is reduced. Description of the Drawings

[0050] In order to more clearly illustrate the technical solutions in the embodiments of the present invention or the prior art, the following will briefly introduce the drawings required for the description of the embodiments or the prior art. Obviously, the drawings in the following description are some embodiments of the present invention. For those of ordinary skill in the art, other drawings can be obtained based on these drawings without creative efforts.

[0051] Figure 1 Is a flowchart of a dynamic adaptive communication positioning method based on UWB provided by the present invention;

[0052] Figure 2 Schematic diagram of a networking architecture of a positioning system provided by an embodiment of the present invention;

[0053] Figure 3 Distribution diagram of label time slots provided by an embodiment of the present invention;

[0054] Figure 4 Poll signal frame structure diagram provided by an embodiment of the present invention;

[0055] Figure 5 Poll signal response frame structure diagram provided by an embodiment of the present invention;

[0056] Figure 6 Processing flow chart after the positioning label is powered on provided by an embodiment of the present invention;

[0057] Figure 7 Processing flow chart of the positioning label in the TWR mode provided by an embodiment of the present invention;

[0058] Figure 8 Processing flow chart of the positioning label in the hybrid mode of TWR and TDOA provided by an embodiment of the present invention;

[0059] Figure 9 Processing flow chart of the positioning label in the TDOA mode provided by an embodiment of the present invention;

[0060] Figure 10 System block diagram of a dynamic adaptive communication positioning system based on UWB provided by the present invention. Specific implementation manner

[0061] To make the objectives, technical solutions and advantages of the embodiments of the present invention clearer, the technical solutions in the embodiments of the present invention will be clearly and completely described below with reference to the accompanying drawings in the embodiments of the present invention. Apparently, the described embodiments are some, but not all, of the embodiments of the present invention. All other embodiments obtained by those of ordinary skill in the art based on the embodiments of the present invention without creative efforts shall fall within the protection scope of the present invention.

[0062] This embodiment provides a dynamic adaptive communication positioning method based on UWB, as Figure 1 shown, including:

[0063] S1: Set a positioning platform and a positioning area, determine the positions and quantities of UWB positioning base stations according to the positioning area, and introduce a BitMap in the UWB positioning base stations to store the instruction status of positioning labels and introduce a HashMap to store instruction data, so as to obtain an improved UWB positioning base station;

[0064] S2: Add a byte as a control identifier in the Poll signal frame of the UWB positioning tag. The UWB positioning tag interacts with the improved UWB positioning base station through the control identifier.

[0065] S3: Add bytes for storing the time slot threshold, time slot value, and positioning mode in the response frame of the improved UWB positioning base station. When the UWB positioning tag sends a Poll request to the improved UWB positioning base station through the Poll signal frame, send the corresponding time slot and positioning mode to the UWB positioning tag through the response frame.

[0066] S4: Set the time slot threshold and time slot allocation strategy. Judge whether the number of all UWB positioning tags in the positioning area exceeds the time slot threshold under the condition that each UWB positioning tag is allocated a time slot, and use the positioning platform to determine the time slot of each UWB positioning tag through the time slot allocation strategy according to the judgment result.

[0067] S5: Set the positioning mode allocation strategy corresponding to the time slot allocation strategy, and use the positioning platform to determine a positioning mode corresponding to the time slot of each UWB positioning tag according to the positioning mode allocation strategy; the positioning mode includes the TWR positioning mode, the TDOA positioning mode, or the hybrid positioning mode of TWR and TDOA.

[0068] S6: Control the UWB positioning tag to send a Poll request to the improved UWB positioning base station through the Poll signal frame, and receive the time slot and positioning mode allocated by the positioning platform for the UWB positioning tag saved in the response frame of the improved UWB positioning base station, and implement communication with the improved UWB positioning base station according to the allocated time slot and positioning mode.

[0069] Specifically, set the positioning platform and the positioning area, determine the positions and quantities of the UWB positioning base stations according to the positioning area, and introduce BitMap in the UWB positioning base station to store the positioning tag instruction status, and introduce HashMap to store the instruction data to obtain the improved UWB positioning base station. Introducing BitMap and HashMap in the UWB positioning base station can store the status and instructions of all tags in the area. Introducing BitMap can reduce invalid data search and improve the processing speed. Using HashMap to save the instruction data can reduce memory occupancy. Through Hash calculation, the data storage address can be directly located, improving the efficiency of data search.

[0070] Secondly, add a byte as a control identifier in the Poll signal frame of the UWB positioning tag. The UWB positioning tag interacts with the improved UWB positioning base station through the control identifier. By adding the control identifier, the base station can adjust the positioning frequency of the positioning tag, adjust the grouping and frequency band of the positioning tag, set the number of channels of the positioning tag, enter the fast communication mode with the positioning tag. Using the fast communication mode, compared with communicating through TWR, it reduces one data interaction with the base station and can save power. Compared with TDOA which cannot receive data sent by the base station, in this mode, instructions sent by the base station can be received at any time, enabling a faster response;

[0071] Add bytes for storing the time slot threshold, time slot value, and positioning mode in the response frame of the improved UWB positioning base station. When the UWB positioning tag sends a Poll request to the improved UWB positioning base station through the Poll signal frame, the corresponding time slot and positioning mode are sent to the UWB positioning tag through the response frame. Through the extension of two bytes, the base station can issue instructions in real time to control the time slot parameters of each tag, achieving efficient dynamic control;

[0072] Thirdly, set the time slot threshold and time slot allocation strategy. Judge whether the number of all UWB positioning tags in the positioning area exceeds the time slot threshold under the condition that each UWB positioning tag is allocated a time slot, and use the positioning platform to determine the time slot of each UWB positioning tag according to the time slot allocation strategy based on the judgment result. By using time slots and sub - time slots (the first split time slot), the utilization rate of the time period is greatly improved. Through time - sharing operation, the probability of signal conflict between tags is effectively reduced, and the capacity of positioning tags in the area is increased;

[0073] Set the positioning mode allocation strategy corresponding to the time slot allocation strategy. Use the positioning platform to determine a positioning mode corresponding to the time slot of each UWB positioning tag according to the positioning mode allocation strategy; the positioning modes include TWR positioning mode, TDOA positioning mode, or a hybrid positioning mode of TWR and TDOA. When there are fewer positioning tags in the area, use TWR for positioning and communication to improve the positioning accuracy of the system; when the number of tags increases, dynamically reduce the frequency of TWR positioning and use TDOA for assisted positioning; when the number of tags further increases, use TDOA for all positioning and adjust the TODA mode, and use the fast communication method to keep the positioning tag in communication with the base station, effectively improving the positioning accuracy and bearing capacity of the positioning tags in the area and reducing the power consumption of the tags;

[0074] Finally, control the UWB positioning tag to send a Poll request to the improved UWB positioning base station through the Poll signal frame, and receive the time slot and positioning mode allocated by the positioning platform for the UWB positioning tag in the response frame of the improved UWB positioning base station. Communicate with the improved UWB positioning base station according to the allocated time slot and positioning mode, effectively improving the positioning accuracy and bearing capacity of the positioning tags in the area and reducing the power consumption of the tags.

[0075] In a specific embodiment, set the positioning platform and the positioning area, determine the positions and quantities of the UWB positioning base stations according to the positioning area, and introduce a BitMap in the UWB positioning base station to store the instruction status of the positioning tags and a HashMap to store the instruction data. The solution for the improved UWB positioning base station is as follows:

[0076] S11, as Figure 2 shown, first set the positioning platform and the positioning area, determine the positions and quantities of the UWB positioning base stations according to the positioning area. Each positioning area consists of one master base station and three slave base stations. Place the base stations at the designated positions for subsequent communication;

[0077] S12, introduce a BitMap in the UWB positioning base station to store the instruction status of the positioning tags and a HashMap to store the instruction data: The BitMap and the HashMap are associated through the memory address. In the RAM of one base station, the status and instructions of all positioning tags in the area can be saved simultaneously.

[0078] In this solution, introducing the BitMap can reduce the search for invalid data and improve the processing speed. Using the HashMap to save the instruction data reduces the memory occupancy. Through the Hash calculation, the data storage address can be directly located, improving the efficiency of data search.

[0079] In a specific embodiment, add a byte as a control identifier in the Poll signal frame of the UWB positioning tag. The solution for the UWB positioning tag to interact with the improved UWB positioning base station through the control identifier is as follows:

[0080] Expand the Poll signal frame of the UWB positioning, add a byte as a control identifier, and the positioning tag can use this control identifier to negotiate with the base station. Its structure is as Figure 3 shown, including:

[0081] [0 - 2]: Request instruction: 0: None 1: UWB configuration request 2: UWB obtain configuration

[0082] [3 - 7]: seq for receiving the response, only valid when the request instruction is 2

[0083] In this solution, a control identifier is added, and the base station can adjust the positioning frequency of the positioning tag, adjust the grouping and frequency band of the positioning tag, set the number of channels of the positioning tag, and enter the fast communication mode with the positioning tag. The fast communication mode means that in the pure TDOA mode, all tags perform a cycle of signal reading. Specifically: send poll -> receive (1 cycle) resp. Compared with TWR positioning, the receiving cycle of the tag is shorter, reducing power consumption. Compared with pure TDOA positioning, there is one more reception, which can respond more quickly to the instructions sent by the server; when using the fast communication mode, compared with communicating through TWR, there is one less data interaction with the base station, which can save power. Compared with TDOA where the data sent by the base station cannot be received, in this mode, the instructions sent by the base station can be received at any time, enabling a faster response.

[0084] In a specific embodiment, bytes for storing the time slot threshold, time slot value, and positioning mode are added to the response frame of the improved UWB positioning base station. When the UWB positioning tag sends a Poll request to the improved UWB positioning base station through the Poll signal frame, the scheme for sending the corresponding time slot and positioning mode to the UWB positioning tag through the response frame is as follows:

[0085] As Figure 4 shown, expand the UWB positioning response frame signal, and add two bytes (16 bits) as the system mode extension:

[0086] [0 - 6] bits: Time slot sequence number, supporting up to 127 time slots

[0087] [7 - 9] bits: Operation instruction: 0: None, 1: TWR mode, 2: Hybrid mode, 3: TDOA mode

[0088] [10 - 13] bits: Time slot sub - sequence number, 0 - 16, cooperating with 127 time slots, up to 2032 communications

[0089] [14 - 15] bits: Time slot value

[0090] The positioning platform allocates time slots starting from 0 for each positioning area, increasing by 1 in sequence each time. At the same time, the corresponding relationship between the tag and the time slot is saved, and the time slot value is set to 0;

[0091] After the positioning platform sends an instruction to the improved UWB positioning base station, the positioning mode of all tags in this area is set to 1. When the positioning mode is 1, the platform only uses the TWR positioning data and communicates with the tag through TWR;

[0092] When the number of tags in the positioning area increases and the time slots allocated by the positioning platform for this area increase to 127, the allocation starts from 0 again. The first split time slot is allocated to the subsequent tags starting from the first time slot. Correspondingly, the sub-sequence number of the time slot starts from 0 and increases, and the time slot value is set to 1. At this time, the positioning platform issues an instruction to set the positioning mode of all tags in this positioning area to 2.

[0093] In this solution, through the extension of two bytes, the improved UWB positioning base station can issue instructions in real time to control the time slot parameters of each tag, achieving efficient dynamic control.

[0094] In a specific embodiment, a time slot threshold and a time slot allocation strategy are set. It is judged whether the number of all UWB positioning tags in the positioning area exceeds the time slot threshold under the condition that each UWB positioning tag is allocated a time slot, and according to the judgment result, the scheme for the positioning platform to determine the time slot of each UWB positioning tag through the time slot allocation strategy is as follows:

[0095] The time slot allocation strategy includes:

[0096] When u ≤ m, a fixed time slot allocation method is adopted, that is, a time slot is allocated to each UWB positioning tag, where m is the time slot threshold;

[0097] In this solution, to ensure that all tags complete all positioning cycles within 1 s, the value of m is set to 127, that is, there are a total of 127 time slots;

[0098] When m < u ≤ q, each time slot is equally divided. Each time slot is equally divided into n parts, forming n * m first split time slots and the serial numbers corresponding to the first split time slots in the corresponding time slots. A first split time slot is allocated to each UWB positioning tag according to the preset allocation order; where q = n * m, which is the threshold of the first split time slot;

[0099] In this solution, each time slot is equally divided into 8 parts, that is, at most 8 tags can share a time slot;

[0100] When q < u ≤ w, each first split time slot is equally divided to form n * m * j second split time slots, and a second split time slot is allocated to each UWB positioning tag; where w = n * m * j, which is the threshold of the second split time slot;

[0101] In this solution, j = 2, that is, at most 16 tags share a time slot;

[0102] Specifically, the positioning area defaults to the fixed time slot allocation method, and time slots are allocated according to the tag access order, supporting up to 127 time slots; when the number of tags exceeds 127, the first split time slot is enabled, and up to 8 tags share one time slot; when the number of tags further increases and the first split time slot is used up, the first split time slot is further divided equally, and up to 16 tags share one time slot;

[0103] The allocation order includes:

[0104] Under the condition that a UWB positioning tag is allocated to all time slots, when the (m + 1)-th positioning tag appears in the positioning area, the positioning platform allocates the second first split time slot of the first time slot to this positioning tag;

[0105] When the (m + 2)-th positioning tag appears in the positioning area, the positioning platform allocates the second first split time slot of the second time slot to this positioning tag;

[0106] When the (m + 3)-th positioning tag appears in the positioning area, the positioning platform allocates the third first split time slot of the third time slot to this positioning tag;

[0107] And so on. When the (m * n)-th positioning tag appears in the positioning area, the positioning platform allocates the last first split time slot of the m-th time slot to this positioning tag.

[0108] As Figure 5 shown, it takes 8 ms for a positioning tag to send a TWR signal once and 1 ms to send a TDOA signal once. When one of the positioning tags in this time slot sends a TWR signal, the remaining positioning tags send TDOA;

[0109] In this solution, by using time slots, the first split time slot, and the second split time slot, the utilization rate of the time period is greatly improved. Through time-sharing operation, the probability of signal conflicts between tags is effectively reduced, and the capacity of positioning tags in the area is increased.

[0110] In a specific embodiment, a positioning mode allocation strategy corresponding to the time slot allocation strategy is set, and the positioning platform uses the positioning mode allocation strategy to determine a positioning mode corresponding to the time slot of each UWB positioning tag; the positioning mode includes the TWR positioning mode, the TDOA positioning mode, or a hybrid positioning mode of TWR and TDOA. The solution is:

[0111] The positioning mode allocation strategy includes:

[0112] When u ≤ m, the UWB positioning tag uses the TWR positioning mode, and the tag and the improved UWB positioning base station use TWR for ranging and communication. The positioning platform calculates the position of the tag based on the distance between the tag and the improved UWB positioning base station;

[0113] When m < u ≤ q, the UWB positioning tag uses a hybrid positioning mode of TWR and TDOA, and according to the instructions issued by the platform, sends TWR and TDOA signals in proportion;

[0114] In each time slot, each UWB positioning tag performs N TDOA positionings every time it performs a TWR positioning, where N = u, and uses the TWR positioning data to calibrate the TDOA positioning data through the Kalman filtering algorithm:

[0115] Based on the result of each TDOA positioning, use the preset uniform motion model to predict the position of the UWB positioning tag, as shown in formula (6),

[0116]

[0117] In the formula, represents the predicted value of the current state based on the state estimation value of the previous moment, represents the state estimation value of the previous moment, k represents the discrete time step, F represents the state transition matrix, as shown in formula (7),

[0118]

[0119] where Δt represents the time interval;

[0120] When the positioning platform receives the TWR positioning data of the UWB positioning tag, use the TWR positioning data to update the position of the corresponding UWB positioning tag, as shown in formulas (8) and (9),

[0121] K k = P k|k-1 × H T × (H × P k|k-1 × H T + R TWR ) -1 (8)

[0122]

[0123] where H is the observation matrix, R TWR represents the TWR noise covariance, P k|k-1 represents the prediction error covariance matrix, K k represents the Kalman gain, Z TWR represents the TWR positioning data, represents the predicted state, represents the updated optimal position estimate;

[0124] The timing for each UWB positioning tag to send the TDOA signal is as shown in formula (10),

[0125] T = TS + Tr + (ST * l) (10)

[0126] Wherein, T is the timing for the UWB positioning tag to send the TDOA signal, TS is the time for positioning in the time slot where each UWB positioning tag is located, Tr is the TWR signal period, ST is the serial number of the first divided time slot corresponding to each UWB positioning tag in the time slot where it is located, and l is the duration of the corresponding first divided time slot;

[0127] When q < u ≤ w, the UWB positioning tag uses the TDOA positioning mode. In the pure TDOA mode, before the end of the time slot, a cycle of UWB signal reception is performed to read the instruction data sent by the improved UWB positioning base station.

[0128] In this solution, when there are fewer positioning tags in the area, TWR positioning and communication are used to improve the positioning accuracy of the system; when the number of tags increases, the frequency of TWR positioning is dynamically reduced, and TDOA-assisted positioning is used; when the number of tags further increases, all use TDOA positioning, and the TODA mode is adjusted, and a fast communication method is used to keep the positioning tag in communication with the improved UWB positioning base station, effectively improving the positioning accuracy and bearing capacity of the positioning tags in the area, and reducing the power consumption of the tags.

[0129] In a specific embodiment, the solution for controlling the UWB positioning tag to send a Poll request to the improved UWB positioning base station through a Poll signal frame and receiving the time slot and positioning mode allocated by the positioning platform for the UWB positioning tag in the response frame of the improved UWB positioning base station and realizing communication with the improved UWB positioning base station according to the allocated time slot and positioning mode is as follows:

[0130] S61. Build the hardware environment:

[0131] 1. Prepare a server, configure the server network information, use a static IP address or domain name, install the positioning platform, and access the same network as all base stations;

[0132] 2. Configure the base station: Use a dedicated configuration software to write the positioning server network address into the base station Flash, and configure the base station IP as a static IP;

[0133] 3. Install the base stations in each positioning area at the specified positions, and turn on the power and network;

[0134] S62. Software configuration:

[0135] 1. After the base station deployment is completed and powered on, read the network address of the positioning platform written in the Flash, establish a connection through the TCP protocol, and report the base station IP and ID information;

[0136] 2. Use the positioning platform configuration module to configure each base station in the positioning area. Each positioning area consists of four base stations, one of which is the master base station (A1) and three are slave base stations. The master base station serves as the clock synchronization source and sends UWB clock synchronization signals at a set synchronization period (not higher than 200 ms). The four base stations are respectively configured with 4 different channels: 1 - 4. Among them, the base station on channel 1 is used not only for TWR positioning but also for issuing instructions.

[0137] 3. The master base station is responsible for sending clock synchronization signals. The slave base stations receive the clock synchronization signals and report the clock signals sent by the master base station and the clock signals when the synchronization signals are received to the positioning platform for clock synchronization. According to the actual positions of the base stations, configure the base station coordinate information in the configuration module. After configuring all the base station information, the positioning platform will send the configuration information to the base stations through the connection.

[0138] The master base station serves as the TDOA clock synchronization signal source. After power - on, it regularly sends UWB clock synchronization signals and uploads the sent timestamp TX Time to the positioning server. When the slave base station receives the time - synchronized UWB signal, it uploads the received timestamp RX Time, the ID of the base station that sent the signal, and its own ID to the positioning platform and uses them for TDOA time synchronization.

[0139] S63. Configure the positioning tag, as Figure 6 shown,

[0140] 1. After the positioning tag is powered on, it loads the default time slot, that is, reads the time slot configuration from the device memory.

[0141] 2. If the time slot is not configured, set the instruction flag bit of the Poll signal frame to 1, send a UWB signal to the improved UWB positioning base station, and read the UWB signal after waiting for one channel period, that is, receive the time slot and positioning mode assigned by the positioning platform for the UWB positioning tag saved in the response frame of the improved UWB positioning base station.

[0142] 3. If the response instruction of this tag is not received, after sleeping for 1 second, repeat the steps until the response information sent by the improved UWB positioning base station is read. Read the response information. If the sent tag ID is not equal to its own ID, repeat this step until the tag IDs are equal. Execute this instruction, synchronize its own clock and Seq with the improved UWB positioning base station that sent the response, save the sent time slot and positioning mode, and perform subsequent communication.

[0143] S64. After the positioning tag enters the positioning area, it communicates with the improved UWB positioning base station according to the assigned time slot and positioning mode:

[0144] 1. After the tag enters the positioning area and the configuration information is read, compare the slot number and UWB device timestamp attached to the instruction with its own timestamp, calculate the next working time T1, the device enters the sleep mode, waits until time T1, and performs real-time positioning according to the positioning mode;

[0145] 2. When the communication between the positioning tag and the improved UWB positioning base station is in the TWR mode, the processing process is as Figure 7 shown. First, the positioning tag calculates the start time of the slot it is in, sleeps before the time arrives, and after the start time of the slot arrives, at the time of sending the TWR signal, sends a Poll signal to the improved UWB positioning base station, reads the Resp signal returned by the improved UWB positioning base station, processes the Resp instruction returned by the improved UWB positioning base station, and generates a Payload, that is, calculates the time difference, and finally constructs a Final frame item to send a Final signal to the improved UWB positioning base station to complete a ranging interaction;

[0146] At this time, the improved UWB positioning base station receives the TWR signal. First, reads the tag's instruction from the memory, records the timestamp, and calculates and generates the corresponding payload. According to the configured channel number, after waiting for the periodic channel number, sends the Resp signal of this tag, puts the received tag positioning data into the message queue, and the network module uploads the data to the positioning platform;

[0147] 3. When the communication between the positioning tag and the improved UWB positioning base station is in the TWR+TDOA mode, the processing process is as Figure 8 shown:

[0148] First, obtain the frequency of sending TWR from the configuration, that is, perform N TDOA positionings and one TWR positioning. Use the current sequence number Seq to take the modulo of N to determine whether the ranging, that is, the positioning operation, needs to be performed in the current slot:

[0149] If it is equal to the ID of the sub-slot (the first divided slot), the TWR positioning operation needs to be performed. After the TWR positioning ends, increment the sequence number by 1;

[0150] If it is not equal to the ID of the sub-slot (the first divided slot), at this time, the positioning tag communicates with the improved UWB positioning base station through the TDOA mode, sends a Poll signal to the improved UWB positioning base station to complete the TDOA positioning; subsequently, performs a signal reading for a time period and receives the instructions sent by the platform. After the end, increment the sequence number by 1;

[0151] After the positioning operation is completed, perform a sleep for one slot length. Repeat the above operations.

[0152] 4. When the communication between the positioning beacon and the improved UWB positioning base station is in the TDOA mode, the processing procedure is as follows: Figure 9 as shown below:

[0153] When the time slot starts, calculate the time T1 for sending TDOA by itself according to the sub - time slot ID and the sub - time slot duration. After sleeping for T1, send the TDOA positioning signal. Subsequently, calculate the end time T2 of the current time slot. After sleeping for T2 - 1ms, perform data reading for one signal cycle to read the instructions sent by the platform. Then sleep again and wait for the next time slot;

[0154] At this time, the UWB positioning base station receives the TDOA signal, determines the configured channel number. If it is 1, read the instructions of the tag from the memory, generate the corresponding Payload, wait for one channel cycle, send the Resp signal of the tag, and then put the received tag positioning data into the message queue, and the network module uploads the data to the positioning platform; if it is not 1, do not make any response, and at the same time put the received tag positioning data into the message queue, and the network module uploads the data to the positioning platform;

[0155] 5. The positioning platform receives the tag data reported by the improved UWB positioning base station, first performs TDOA positioning, and determines the positioning area where the tag is located according to the result of the TDOA positioning. Subsequently, determine the instruction status of the tag. If it is a request for a configuration instruction, send the instruction to the base station with channel 1 in the positioning area where the tag is located through a TCP long connection.

[0156] After receiving the tag configuration instruction sent by the platform, the positioning base station with channel 1 will save the tag ID and the instruction content in the memory using BitMap. When the positioning tag sends a Poll signal again, according to the TDOA positioning operation, the base station will reply the instruction to the tag;

[0157] 6. After the tag receives the configuration instruction and configures successfully according to the instruction, it can perform positioning in the system.

[0158] This embodiment also provides a UWB - based dynamic adaptive communication positioning system, as shown in Figure 10 the following figure, including:

[0159] A UWB positioning tag, which is installed on the target to be positioned and sends real - time positioning information to the improved UWB positioning base station;

[0160] An improved UWB positioning base station, which is used to receive the positioning information sent by the UWB positioning tag, and every four UWB positioning base stations form a positioning area;

[0161] UWB positioning platform, which is connected to UWB positioning base stations through a network, allocates time slots and positioning modes for UWB positioning tags in each positioning area according to the time slot allocation strategy and positioning mode allocation strategy, and collects and processes in real time the positioning data received by the improved UWB positioning base stations to update the positions of the UWB positioning tags.

[0162] Specifically, the UWB positioning base stations are configured with WiFi modules, 4G modules and Ethernet modules, supporting multiple network communication methods; a long connection is maintained between the UWB positioning platform and the UWB positioning base stations, and this long connection is used for the improved UWB positioning base stations to report positioning data to the UWB positioning platform, and at the same time supports the positioning platform to send instructions to the base stations through this connection; the UWB positioning platform regularly monitors the status of each positioning node, and can adjust the positioning frequency and positioning mode within the node in real time according to the number of tags of each node to improve the positioning accuracy and stability.

[0163] Finally, it should be noted that: the above embodiments are only used to illustrate the technical solutions of the present invention, rather than to limit it; although the present invention has been described in detail with reference to the foregoing embodiments, those of ordinary skill in the art should understand that: they can still modify the technical solutions described in the foregoing embodiments, or perform equivalent replacements for some or all of the technical features; and these modifications or replacements do not make the essence of the corresponding technical solutions deviate from the scope of the technical solutions of the embodiments of the present invention.

Claims

1. A dynamic adaptive communication and positioning method based on UWB, characterized in that, Including: S1: Set the positioning platform and the positioning area, determine the positions and quantities of UWB positioning base stations according to the positioning area, introduce BitMap in the UWB positioning base stations to store the instruction status of positioning tags, and introduce HashMap to store instruction data, so as to obtain improved UWB positioning base stations; S2: Add a byte as a control identifier in the Poll signal frame of the UWB positioning tag, and the UWB positioning tag interacts with the improved UWB positioning base station through the control identifier; S3: Add bytes for saving the time slot threshold, time slot value, and positioning mode in the response frame of the improved UWB positioning base station. When the UWB positioning tag sends a Poll request to the improved UWB positioning base station through the Poll signal frame, send the corresponding time slot and positioning mode to the UWB positioning tag through the response frame; S4: Set the time slot threshold and time slot allocation strategy, judge whether the number of all UWB positioning tags in the positioning area exceeds the time slot threshold under the condition that each UWB positioning tag is allocated a time slot, and use the positioning platform to determine the time slot of each UWB positioning tag according to the judgment result through the time slot allocation strategy; S5: Set the positioning mode allocation strategy corresponding to the time slot allocation strategy, and use the positioning platform to determine a positioning mode corresponding to the time slot of each UWB positioning tag according to the positioning mode allocation strategy; the positioning mode includes the TWR positioning mode, the TDOA positioning mode, or a hybrid positioning mode of TWR and TDOA; S6: Control the UWB positioning tag to send a Poll request to the improved UWB positioning base station through the Poll signal frame, and receive the time slot and positioning mode allocated by the positioning platform for the UWB positioning tag saved in the response frame of the improved UWB positioning base station, and implement communication with the improved UWB positioning base station according to the allocated time slot and positioning mode.

2. The dynamic adaptive communication and positioning method based on UWB according to claim 1, wherein, The time slot allocation strategy includes: Judge the number of the current UWB positioning tag u in the positioning area, and the judgment conditions are as follows: When u ≤ m, adopt the fixed time slot allocation method, that is, allocate a time slot for each UWB positioning tag, and m is the time slot threshold; When m < u ≤ q, divide each time slot equally, each time slot is divided into n parts, forming n * m first divided time slots and the serial numbers corresponding to the first divided time slots in the corresponding time slots, and allocate a first divided time slot for each UWB positioning tag according to the preset allocation order; where q = n * m, which is the threshold of the first divided time slots; When q < u ≤ w, divide each first divided time slot equally, forming n * m * j second divided time slots, and allocate a second divided time slot for each UWB positioning tag; where w = n * m * j, which is the threshold of the second divided time slots.

3. The dynamic adaptive communication and positioning method based on UWB according to claim 2, characterized in that The allocation order includes: Under the condition that a UWB positioning tag is allocated to all time slots, when the (m + 1)th positioning tag appears in the positioning area, the positioning platform allocates the second first divided time slot of the first time slot to this positioning tag; When the (m + 2)th positioning tag appears in the positioning area, the positioning platform allocates the second first divided time slot of the second time slot to this positioning tag; When the (m + 3)-th positioning tag appears within the positioning area, the positioning platform assigns the third first divided time slot of the third time slot to this positioning tag; And so on, when the (m * n)-th positioning tag appears within the positioning area, the positioning platform assigns the last first divided time slot of the m-th time slot to this positioning tag.

4. A dynamic adaptive communication and positioning method based on UWB according to claim 2, characterized in that The positioning mode allocation strategy includes: When u ≤ m, the UWB positioning tag uses the TWR positioning mode; When m < u ≤ q, the UWB positioning tag uses a hybrid positioning mode of TWR and TDOA; When q < u ≤ w, the UWB positioning tag uses the TDOA positioning mode.

5. A dynamic adaptive communication and positioning method based on UWB according to claim 4, characterized in that The hybrid positioning mode of TWR and TDOA specifically includes: In each time slot, each UWB positioning tag performs N TDOA positionings every time it performs a TWR positioning, and uses the TWR positioning data to calibrate the TDOA positioning data through the Kalman filtering algorithm; where N = u; The timing for each UWB positioning tag to send a TDOA signal is shown in formula (1), T = TS + Tr + (ST * l) (1) where T is the timing for the UWB positioning tag to send a TDOA signal, TS is the time for positioning in the time slot where each UWB positioning tag is located, Tr is the TWR signal period, ST is the serial number of the first divided time slot corresponding to each UWB positioning tag in the time slot where it is located, and l is the duration of the corresponding first divided time slot.

6. A dynamic adaptive communication and positioning method based on UWB according to claim 5, characterized in that, Using the TWR positioning data to calibrate the TDOA positioning data through the Kalman filtering algorithm includes: Based on the result of each TDOA positioning, using a preset uniform motion model to predict the position of the UWB positioning tag, as shown in formula (2), wherein, represents the predicted value of the current state based on the state estimation value at the previous moment, represents the state estimation value at the previous moment, k represents the discrete time step, and F represents the state transition matrix, as shown in formula (3). where Δt represents the time interval; When the positioning platform receives the TWR positioning data of the UWB positioning tag, use the TWR positioning data to update the position of the corresponding UWB positioning tag, as shown in formulas (4) and (5), K k = P k|k-1 × H T × (H × P k|k-1 × H T + R TWR ) - 1 (4) Among them, H is the observation matrix, and R TWR represents the TWR noise covariance, and P k|k-1 represents the prediction error covariance matrix, and K k represents the Kalman gain, and Z TWR represents the TWR positioning data, represents the predicted state, represents the updated optimal position estimate.

7. A dynamic adaptive communication and positioning system based on UWB, which applies a dynamic adaptive communication and positioning method based on UWB as described in any one of claims 1-6, characterized in that, including: A UWB positioning tag, which is installed on the target to be positioned and sends real-time positioning information to the improved UWB positioning base station in real time; An improved UWB positioning base station, which is used to receive the positioning information sent by the UWB positioning tag, and every four improved UWB positioning base stations form a positioning area; A UWB positioning platform, which is connected to the improved UWB positioning base station through a network, assigns time slots and positioning modes to the UWB positioning tags in each positioning area according to the time slot allocation strategy and the positioning mode allocation strategy, and collects and processes the positioning data received by the improved UWB positioning base station in real time to update the position of the UWB positioning tag.

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