Ultra-wideband distributed many-to-many ranging method

Abstract

The invention relates to an ultra-wideband distributed many-to-many distance measurement method, which comprises the following steps: S1, each distance measurement node sends a distance measurement signal frame in a fixed time slot of the distance measurement node, and receives distance measurement signal frames sent by neighbor nodes in other time slots; and S2, the ranging node carries out time slot synchronous updating and ranging calculation by recording the timestamps of sending and receiving ranging signal frames and receiving the timestamps carried in the ranging signal frames of the neighbor nodes, so that a distance value is obtained, and distance estimation is realized. According to the ultra-wideband distributed many-to-many ranging method, TDMA is used as a ranging scheduling strategy to solve the problem of signal collision, information interaction in the ranging process is simplified, the whole ranging process has only one signal frame, the capacity and ranging efficiency of distributed ranging nodes are improved through a signal multiplexing mode, and the ranging efficiency is improved. The method is suitable for a many-to-many ultra-wideband ranging system.

Description

Technical Field

[0001] The invention belongs to the technical field of ultra-wideband wireless communication, and in particular relates to an ultra-wideband distributed many-to-many ranging method. Background Art

[0002] Ultra-wideband (UWB) technology transmits data through extremely narrow pulses rather than traditional carriers, resulting in extremely high data transmission speeds. In addition, UWB technology has the advantages of low system complexity, high information security, and strong resistance to multipath fading, making it a highlight in the field of wireless LAN communications.

[0003] The commonly used ultra-wideband ranging method is difficult to efficiently obtain complete distance information between nodes in scenarios with a large number of nodes. There are two main reasons: First, if the random Aloha method is used, each node randomly initiates a ranging request, then as the number of nodes increases, the collision probability of UWB signals between nodes will increase rapidly, which will lead to the failure of ranging between nodes and reduce the success rate of ranging; second, if the time division multiplexing (TDMA) method is used to solve the collision problem of UWB signals, the traditional UWB one-to-one ranging method requires multiple interactions between nodes to complete a ranging, and the channel utilization rate and time slot capacity are relatively low. Therefore, a simple and efficient many-to-many ranging method is needed to improve the capacity of distributed ranging nodes and ranging efficiency.

[0004] Chinese patent document CN 112612000 A discloses an intelligent configuration platform suitable for rapid deployment of UWB positioning systems, including a data acquisition module, a data preprocessing module, a time slot automatic allocation module and a base station coordinate solution module base station, the data acquisition module, the data preprocessing module, the time slot automatic allocation module and the base station coordinate solution module base station are sequentially connected according to the process mode of the base station configuration to form an intelligent integrated configuration platform, and are all deployed on a cloud server or a local server; the data acquisition module collects communication data between base stations through the network; the data preprocessing module classifies and organizes the original communication data collected by the data acquisition module; the time slot automatic allocation module automatically allocates time slots to all base stations through a centralized time slot allocation algorithm; the base station coordinate solution module obtains the coordinate values ​​of each base station according to the information processed by the data preprocessing module, and automatically writes the solution results into the corresponding base station. This technical solution only applies the distance values ​​between base stations for many-to-many ranging, and the method mentioned in this technical solution is aimed at the base station topology network is fixed, the position of the base station does not change after installation, and during the period of data collection, as long as there is one packet of ranging values ​​​​during the period of data collection, the demand can be met. Therefore, the many-to-many method used in this technical solution is based on the random Aloha method, and there are no strict requirements for packet loss and capacity.

[0005] Therefore, it is necessary to provide an ultra-wideband distributed many-to-many ranging method, use TDMA as the ranging scheduling strategy to solve the signal collision problem, simplify the information interaction during the ranging process, and improve the capacity and ranging efficiency of distributed ranging nodes through signal multiplexing. Summary of the invention

[0006] The present invention provides an ultra-wideband distributed many-to-many ranging method, which uses TDMA as a ranging scheduling strategy to solve the signal collision problem, simplifies information interaction during the ranging process, and improves the capacity and ranging efficiency of distributed ranging nodes by signal multiplexing.

[0007] In order to solve the above technical problems, the technical solution adopted by the present invention is that the ultra-wideband distributed many-to-many ranging method comprises the following specific steps:

[0008] S1: Each ranging node sends a ranging signal frame in its own fixed time slot and receives ranging signal frames sent by neighboring nodes in other time slots;

[0009] S2: The ranging node records the timestamps of its own sending and receiving ranging signal frames and the relevant timestamps carried in the ranging signal frames received from neighboring nodes to perform time slot synchronization update and ranging calculation to obtain the distance value, thereby realizing distance estimation.

[0010] The above technical solution is adopted, and the nodes are all mobile, and the topology is changed in real time. At the same time, the requirement is that each node needs to be able to perform real-time distance estimation, and the neighboring nodes around the node are changed in real time. There are strict requirements for the ranging node capacity and packet loss rate. Therefore, each ranging node only needs to send a ranging signal in its own fixed time slot, and receive the ranging signal sent by the neighboring node in other time slots. The node records the timestamps of its own sending and receiving ranging signals and the related timestamps carried in the ranging signals of the neighboring nodes for time slot synchronization update and distance estimation. And TDMA is used as a ranging scheduling strategy to solve the signal collision problem, and at the same time, the information interaction in the ranging process is simplified. There is only one signal frame in the entire ranging process, and the capacity and ranging efficiency of the distributed ranging nodes are improved by signal multiplexing. Compared with the traditional TDMA distributed UWB TOF ranging method, the present invention simplifies the information interaction in the ranging process, and improves the capacity and ranging efficiency of the distributed ranging nodes by signal multiplexing.

[0011] Preferably, each of the ranging nodes has a unique node ID, and the node IDs of each ranging node are different; the node ID is bound to the time slot number; the node ID value range is 1, 2, ..., N, and the ranging node with ID i is called node i. Each ranging node has the same role and runs the same firmware, the only difference is that each ranging node has a unique node ID number.

[0012] Preferably, the ranging signal frame in step S1 includes: a frame number, a node ID, i.e., a time slot, a system transmission time, a UWB transmission time, and a receiving neighbor node list.

[0013] Preferably, the specific steps of step S1 are:

[0014] S11: Node i sends a ranging signal frame at the start of time slot i and records its own UWB transmission time tx(i);

[0015] S12: Neighbor node j receives the ranging signal frame of node i in time slot i and records the UWB time rx(j,i) of receiving neighbor node i;

[0016] S13: When the neighbor node j reaches the start time of the time slot j, the neighbor node j sends a ranging signal frame, and the neighbor node j ranging signal frame includes the UWB transmission time tx(j) of the neighbor node j and the neighbor node list {i, rx(j, i)};

[0017] S14: Node i receives the ranging signal frame of neighbor node j in time slot j, and records the UWB time rx(i,j) of receiving neighbor node j.

[0018] Preferably, the neighbor node list in step S13 includes node IDs and corresponding UWB reception times.

[0019] Preferably, in step S13, if the node i sends a ranging signal frame at the start of a time slot, and if the node i does not receive any signal from any neighboring node at this time, the list of received neighboring nodes is empty.

[0020] Preferably, the specific steps of step S2 are:

[0021] S21: Node i performs ranging calculation by recording the ultra-wideband timestamp of the ranging signal frame sent and received by itself and the relevant ultra-wideband timestamp carried in the ranging signal frame received from the neighboring node, and obtains the distance value;

[0022] S22: Node i performs time slot synchronization update by recording the system receiving timestamp of the received ranging signal frame and the system sending timestamp carried in the received ranging signal frame of the neighboring node.

[0023] Preferably, the specific steps of step S21 are:

[0024] S211: Assume that the neighbor nodes of node i include: node j, node k, node l and node m;

[0025] S212: First, calculate the distance d(i,j) between node i and its neighbor node j. The calculation formula is:

[0026]

[0027] Where c is the propagation speed of electromagnetic waves, which is equal to 3×10 ^ 8m / s;

[0028] S213: Use the calculation formula in step S212 to obtain the distance values ​​d(i,k), d(i,l) and d(i,m) between node i and other neighboring nodes.

[0029] By adopting the above technical solution, the ranging node j receives not only the ranging node i as a neighbor node, but also the ranging signal frame of the corresponding node may be received in other time slots. Then, the number of neighbor node lists in the ranging signal frame sent by the ranging node j increases accordingly with the number of ranging nodes. When the corresponding ranging node j receives the ranging signal frame of the ranging node j in the time slot, the distance value between the ranging node and the ranging node j is also obtained by calculation. Similarly, the ranging signal frame of the ranging node is not only received by the ranging node j.

[0030] Preferably, the specific steps of step S22 are:

[0031] S221: Node i receives the ranging signal frame from neighbor node j, records the system receiving time t(i, j) and extracts the system sending time t(j) in the ranging signal frame of neighbor node j; similarly, the corresponding system time information of node i and neighbor node k is obtained: t(i, k), t(k); the corresponding system time information of node i and neighbor node l is obtained: t(i, l), t(l); the corresponding system time information of node i and neighbor node m is obtained: t(i, m), t(m);

[0032] S222: The time deviation between node i and its neighboring nodes is:

[0033]

[0034] Where c is the propagation speed of electromagnetic waves, which is approximately equal to 3×10^8m / s, Δt(i,j) is the system time deviation between node i and node j, Δt(i,k) is the system time deviation between node i and node k, Δt(i,l) is the system time deviation between node i and node l, and Δt(i,m) is the system time deviation between node i and node m.

[0035] S223: Get the mean value Δt(i) of the system time deviation between node i and all neighboring nodes:

[0036]

[0037] S224: Node i corrects its own system time according to the mean value Δt(i) of the system time deviation between itself and all its neighboring nodes, thereby achieving synchronous update of the system time among all nodes, ie, synchronous update in time slots.

[0038] Preferably, the frame length of the ranging signal frame is set to a fixed frame length or is set to a variable frame length according to the number of neighbor node lists.

[0039] Compared with the prior art, the present invention has the following beneficial effects: the ultra-wideband distributed many-to-many ranging method uses TDMA as a ranging scheduling strategy to solve the signal collision problem, and simplifies the information interaction during the ranging process. The entire ranging process has only one signal frame, and the capacity and ranging efficiency of the distributed ranging nodes are improved by signal multiplexing, which is suitable for many-to-many ultra-wideband ranging systems. BRIEF DESCRIPTION OF THE DRAWINGS

[0040] Figure 1 It is a schematic diagram of the distribution of nodes of the ultra-wideband distributed many-to-many ranging method of the present invention;

[0041] Figure 2 It is a schematic diagram of the signal frame structure of the ultra-wideband distributed many-to-many ranging method of the present invention;

[0042] Figure 3 It is the frame data packet format of the ultra-wideband distributed many-to-many ranging method of the present invention;

[0043] Figure 4 It is an interactive schematic diagram of the ultra-wideband distributed many-to-many ranging method of the present invention. DETAILED DESCRIPTION

[0044] The embodiments of the present invention are described in detail below in conjunction with the accompanying drawings. The following embodiments are only used to more clearly illustrate the technical solutions of the present invention and are not intended to limit the protection scope of the present invention.

[0045] Embodiment: UWB communicates through extremely narrow pulses at the nanosecond level, so it consumes less power and is less affected by multipath effects. In addition, since its time resolution can reach the nanosecond level, it is widely used for high-precision ranging.

[0046] The ultra-wideband distributed many-to-many ranging method comprises the following specific steps:

[0047] S1: Each ranging node sends a ranging signal frame in its own fixed time slot and receives ranging signal frames sent by neighboring nodes in other time slots;

[0048] Each of the ranging nodes has a unique node ID, and the node IDs of each ranging node are different; the node ID is bound to the time slot number; the node ID value range is 1, 2, ..., N, and the ranging node with ID i is called node i; each ranging node has the same role and runs the same firmware, the only difference is that each ranging node has a unique node ID number; node i can perform ranging with neighboring nodes within the communication range;

[0049] The ranging signal frame in step S1 includes: frame number, node ID, i.e., time slot, system transmission time, UWB transmission time, and receiving neighbor node list; the signal frame structure diagram is as follows: Figure 2 As shown in FIG. 1 , a data frame includes two types of time slots: a transmission time slot TX and a reception time slot RX. A data frame consists of N time slots. Taking node i as an example, time slot i is the transmission time slot of the node. Node i only sends ranging signal frames in this time slot. Other time slots are receiving time slots, which are used to receive ranging signal frames from neighboring nodes.

[0050] like Figure 4 As shown, the specific steps of step S1 are:

[0051] S11: Node i sends a ranging signal frame at the start of time slot i and records its own UWB transmission time tx(i); Figure 3 As shown, the content of the ranging signal frame sent by the node in the embodiment of the present invention includes: frame number, node ID (time slot), system sending time, UWB sending time and receiving neighbor node list, and the neighbor node list includes node ID and corresponding UWB receiving time;

[0052] S12: Neighbor node j receives the ranging signal frame of node i in time slot i and records the UWB time rx(j,i) of receiving neighbor node i;

[0053] S13: When the neighbor node j reaches the start time of the time slot j, the neighbor node j sends a ranging signal frame, and the neighbor node j ranging signal frame includes the UWB transmission time tx(j) of the neighbor node j and the neighbor node list {i, rx(j, i)};

[0054] The neighbor node list in step S13 includes node ID and corresponding UWB reception time;

[0055] In the step S13, if the node i sends a ranging signal frame at the start of the time slot, if the node i does not receive any signal from any neighbor node at this time, the received neighbor node list is empty; the frame length of the ranging signal frame is set to a fixed frame length or to a variable frame length according to the number of neighbor node lists;

[0056] When the embodiment is applied, when the ranging signal frame is sent in the first time slot, since no signal from any neighbor node has been received before, the neighbor node list received in the ranging signal frame sent in the time slot is empty. Furthermore, according to the specific application scenario, the frame length of the ranging signal frame can be set to a fixed frame length, or it can be set to a variable frame length according to the number of neighbor node lists. The frame length is mainly determined by the number of elements in the neighbor node list;

[0057] S14: Node i receives the ranging signal frame of neighbor node j in time slot j, and records the UWB time rx(i, j) of receiving neighbor node j. In order to reduce the power consumption of the node and facilitate application in battery-powered products, the length of time for opening the reception in the receiving time slot can be set according to the size of the frame length, and it is not necessary to open the reception in the entire time slot, thereby reducing the power consumption of the node.

[0058] S2: The ranging node records the timestamps of its own sending and receiving ranging signal frames and the relevant timestamps carried in the ranging signal frames received from neighboring nodes to perform time slot synchronization update and ranging calculation to obtain the distance value, thereby realizing distance estimation;

[0059] The specific steps of step S2 are:

[0060] S21: Node i performs ranging calculation by recording the ultra-wideband timestamp of the ranging signal frame sent and received by itself and the relevant ultra-wideband timestamp carried in the ranging signal frame received from the neighboring node, and obtains the distance value;

[0061] The specific steps of step S21 are:

[0062] S211: Assume that the neighbor nodes of node i include: node j, node k, node l and node m; the distribution is as follows: Figure 1 As shown;

[0063] S212: First, calculate the distance d(i,j) between node i and its neighbor node j. The calculation formula is:

[0064]

[0065] Where c is the propagation speed of electromagnetic waves, which is equal to 3×10 ^ 8m / s;

[0066] S213: Using the calculation formula in step S212, obtain the distance values ​​d(i,k), d(i,l) and d(i,m) between node i and other neighboring nodes;

[0067] In this embodiment, the ranging node j receives not only the ranging node i as the neighbor node, but may receive the ranging signal frame of the corresponding node in other time slots. Then, the number of neighbor node lists in the ranging signal frame sent by the ranging node j increases accordingly due to the number of ranging nodes. When the corresponding ranging node j receives the ranging signal frame of the ranging node j in the time slot, the distance value between the ranging node and the ranging node j is also obtained by calculation. Similarly, the ranging signal frame received by the ranging node is not only the ranging node j.

[0068] The key to solving the wireless collision problem based on TDMA time slot scheduling is that each node in the network must maintain time slot synchronization. Master-slave synchronization is a widely used synchronization method. It is based on the hierarchical structure of the network, and the synchronization information of each node comes from the upper node. Master-slave synchronization is easy to implement, but the reliability is not high. When a node fails, all its controlled nodes will achieve the synchronization benchmark. One way to improve synchronization reliability is mutual synchronization, that is, the clocks of each node control each other;

[0069] S22: Node i performs time slot synchronization update by recording the system receiving timestamp of the received ranging signal frame and the system sending timestamp carried in the received ranging signal frame of the neighboring node;

[0070] The specific steps of step S22 are:

[0071] S221: Node i receives the ranging signal frame from neighbor node j, records the system receiving time t(i, j) and extracts the system sending time t(j) in the ranging signal frame of neighbor node j; similarly, the corresponding system time information of node i and neighbor node k is obtained: t(i, k), t(k); the corresponding system time information of node i and neighbor node l is obtained: t(i, l), t(l); the corresponding system time information of node i and neighbor node m is obtained: t(i, m), t(m);

[0072] S222: The time deviation between node i and its neighboring nodes is:

[0073]

[0074] Where c is the propagation speed of electromagnetic waves, which is approximately equal to 3×10^8m / s, Δt(i,j) is the system time deviation between node i and node j, Δt(i,k) is the system time deviation between node i and node k, Δt(i,l) is the system time deviation between node i and node l, and Δt(i,m) is the system time deviation between node i and node m.

[0075] S223: Get the mean value Δt(i) of the system time deviation between node i and all neighboring nodes:

[0076]

[0077] S224: Node i corrects its own system time according to the mean value Δt(i) of the system time deviation between itself and all its neighboring nodes, thereby achieving synchronous update of the system time among all nodes, ie, synchronous update in time slots.

[0078] The commonly used ranging scheme based on UWB technology is the bilateral two-way ranging method (DS-TWR, Double Side-Two_way Ranging). In this method, two nodes need to go through three interactions of ranging request Poll frame, ranging request reply Respond frame and the final Final frame to obtain the distance between the two nodes. In order to simplify the process of information interaction during ranging and improve the utilization rate of the channel, in this embodiment, each ranging node only needs to send ranging signal frames in its own fixed time slots and receive ranging signal frames sent by neighboring nodes in other time slots. The node performs time slot synchronization update and distance estimation by recording the timestamps of its own sending and receiving ranging signal frames and the relevant timestamps carried in the ranging signal frames received from neighboring nodes. The synchronization process of the system time between nodes in the mutual synchronization method gradually converges with the transmission and reception of neighboring nodes. As the ranging proceeds, the time slot synchronization will become more and more stable, and finally the time slot mutual synchronization of the entire network will be achieved.

[0079] The ultra-wideband distributed many-to-many ranging method of the present invention uses TDMA as a ranging scheduling strategy to solve the signal collision problem, and simplifies the information interaction in the ranging process. The entire ranging process has only one signal frame, and the capacity and ranging efficiency of the distributed ranging nodes are improved by signal multiplexing. It is suitable for many-to-many ultra-wideband ranging systems.

[0080] The specific embodiments described above further illustrate the objectives, technical solutions and beneficial effects of the present invention. It should be understood that the above are only specific embodiments of the present invention and are not intended to limit the present invention, such as the types of electronic hardware for implementing units and algorithm steps. Any modifications, equivalent substitutions, improvements, etc. made within the spirit and principles of the present invention should be included in the scope of protection of the present invention.

Claims

1. An ultra-wideband distributed many-to-many ranging method, characterized in that: The specific steps are: S1: Each ranging node sends a ranging signal frame in its own fixed time slot and receives ranging signal frames sent by neighboring nodes in other time slots; S2: The ranging node records the timestamps of its own sending and receiving ranging signal frames and the timestamps carried in the ranging signal frames received from neighboring nodes to perform time slot synchronization updates and ranging calculations to obtain the distance value, thereby achieving distance estimation.

2. The ultra-wideband distributed many-to-many ranging method according to claim 1, characterized in that: Each of the ranging nodes has a unique node ID, and the node ID of each ranging node is different; the node ID is bound to the time slot number; the node ID value range is 1, 2, ..., N, and the ranging node with ID i is called node i.

3. The ultra-wideband distributed many-to-many ranging method according to claim 2, characterized in that: The ranging signal frame in step S1 includes: a frame number, a node ID (ie, a time slot), a system sending time, a UWB sending time, and a receiving neighbor node list.

4. The ultra-wideband distributed many-to-many ranging method according to claim 2, characterized in that: The specific steps of step S1 are: S11: Node i sends a ranging signal frame at the start of time slot i and records its own UWB transmission time tx(i); S12: Neighbor node j receives the ranging signal frame of node i in time slot i and records the UWB time rx(j,i) of receiving neighbor node i; S13: When neighbor node j reaches the start time of time slot j, it sends a ranging signal frame, and the ranging signal frame of neighbor node j includes the UWB transmission time tx(j) of neighbor node j and the neighbor node list {i, rx(j, i)}; S14: Node i receives the ranging signal frame of neighbor node j in time slot j, and records the UWB time rx(i,j) of receiving neighbor node j.

5. The ultra-wideband distributed many-to-many ranging method according to claim 4, characterized in that: The neighbor node list in step S13 includes node IDs and corresponding UWB reception times.

6. The ultra-wideband distributed many-to-many ranging method according to claim 5, characterized in that: In the step S13, if the node i sends a ranging signal frame at the start of the time slot, and if the node i does not receive any signal from any neighboring node at this time, the list of received neighboring nodes is empty.

7. The ultra-wideband distributed many-to-many ranging method according to claim 5, characterized in that: The specific steps of step S2 are: S21: Node i performs ranging calculation by recording the ultra-wideband timestamp of the ranging signal frame sent and received by itself and the ultra-wideband timestamp carried in the ranging signal frame received from the neighboring node to obtain the distance value; S22: Node i performs time slot synchronization update by recording the system receiving timestamp of the received ranging signal frame and the system sending timestamp carried in the received ranging signal frame of the neighboring node.

8. The ultra-wideband distributed many-to-many ranging method according to claim 7, characterized in that: The specific steps of step S21 are: S211: Assume that the neighbor nodes of node i include: node j, node k, node l and node m; S212: First, calculate the distance d(i,j) between node i and its neighbor node j. The calculation formula is: Where c is the propagation speed of electromagnetic waves, which is equal to 3×10 ^ 8m / s; S213: Use the calculation formula in step S212 to obtain the distance values ​​d(i,k), d(i,l) and d(i,m) between node i and other neighboring nodes.

9. The ultra-wideband distributed many-to-many ranging method according to claim 8, characterized in that: The specific steps of step S22 are: S221: Ranging node i receives the ranging signal frame of neighbor node j, records the system receiving time t(i, j) and extracts the system sending time t(j) in the ranging signal frame of neighbor node j; similarly, the corresponding system time information of ranging node i and neighbor node k is obtained: t(i, k), t(k); the corresponding system time information of ranging node i and neighbor node l is obtained: t(i, l), t(l); the corresponding system time information of ranging node i and neighbor node m is obtained: t(i, m), t(m); S222: The time deviation between node i and its neighboring nodes is: Where c is the propagation speed of electromagnetic waves, which is approximately equal to 3×10^8m / s, Δt(i,j) is the system time deviation between node i and node j, Δt(i,k) is the system time deviation between node i and node k, Δt(i,l) is the system time deviation between node i and node l, and Δt(i,m) is the system time deviation between node i and node m. S223: Get the mean value Δt(i) of the system time deviation between node i and all neighboring nodes: S224: Node i corrects its own system time according to the mean value Δt(i) of the system time deviation between itself and all its neighboring nodes, thereby achieving synchronous update of the system time among all nodes, ie, synchronous update in time slots.

10. The ultra-wideband distributed many-to-many ranging method according to claim 9, characterized in that: The frame length of the ranging signal frame is set to a fixed frame length or to a variable frame length according to the number of neighbor node lists.

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