A DV-hop positioning method and system based on hop count and hop distance optimization

Abstract

The application discloses a DV-Hop positioning method and system based on hop count and hop distance optimization, and relates to the technical field of wireless sensor network positioning. The method comprises the following steps: an anchor node broadcasts by using multiple communication radii to obtain an anchor node distribution degree variable and determine a hop count correction coefficient; the minimum hop count is corrected by using the hop count correction coefficient to obtain an optimized average hop distance of the anchor node; the average hop distance of an unknown node is calculated according to the optimized average hop distance of the anchor node; the estimated distance between the unknown node and the anchor node is calculated according to the calculated average hop distance of the unknown node and the corrected minimum hop count; and the position coordinates of the unknown node are calculated by using the least square method according to the estimated distance. The application can solve the problem that the node positioning error is relatively large in a network area with uneven distribution (such as a C-shaped or Z-shaped irregular network area), and meets the actual application requirements.

Description

Technical Field

[0001] This invention relates to the field of wireless sensor network positioning technology, specifically a DV-Hop (Distance Vector-Hop) positioning method and system based on hop count and hop distance optimization. Background Technology

[0002] Node localization is one of the key supporting technologies for wireless sensor networks. Based on the ranging method, it is mainly divided into ranging-based localization algorithms and ranging-free localization algorithms. Ranging-based localization algorithms estimate the location by directly measuring the distance and angle information between nodes, resulting in small positioning errors, but requiring high hardware costs. Ranging-free localization algorithms estimate the location of unknown nodes mainly through network connectivity or training a matching model, with lower hardware dependence and costs, but lower positioning accuracy. Considering the influence of sensor node power consumption, lifespan, line-of-sight conditions, deployment environment, and other factors, equipping every sensor node in a wireless sensor network with a GPS positioning module is impractical. Therefore, many researchers have proposed ranging-free wireless sensor network localization schemes to address this problem.

[0003] Among them, the DV-Hop localization algorithm is a vector routing-based localization algorithm with advantages such as low hardware cost and ease of implementation. The DV-Hop localization algorithm mainly determines the location of unknown nodes based on hop count information and distance information between nodes.

[0004] Currently, most localization algorithms assume that nodes are deployed in regular areas. However, in real-world applications, node distribution is often irregular, containing holes or obstacles, causing communication paths between nodes to be tortuous. Traditional DV-Hop localization algorithms use a simple hop count multiplied by the average hop distance to estimate distance. All nodes within the node's communication radius are defined as one hop, without considering that the actual hop distance between nodes is not necessarily equal. This error is particularly pronounced when node density is high, leading to a deviation in the actual distance from the unknown node to the anchor node. Furthermore, the higher the node's hop count, the greater the error. Additionally, unknown nodes use the average hop distance of the nearest anchor node as their estimated average hop distance, ignoring the network distribution around the anchor node. The error in the anchor node's average hop distance affects the unknown node's localization error. In unevenly distributed areas, the distance differences between nodes vary with the distribution, resulting in larger multi-hop distance errors and decreased localization accuracy. Summary of the Invention

[0005] The purpose of this invention is to provide a DV-Hop positioning method and system based on hop count and hop distance optimization, which can solve the problem of large node positioning errors in unevenly distributed network areas (such as irregular network areas such as C-shaped or Z-shaped networks) and meet the needs of practical applications.

[0006] To achieve the above objectives, in a first aspect, embodiments of the present invention provide a DV-Hop localization method based on hop count and hop distance optimization, the method comprising:

[0007] Anchor nodes broadcast using multiple communication radii to obtain anchor node distribution degree variables and determine hop count correction coefficients; the minimum hop count is corrected using the hop count correction coefficients to obtain the optimized average hop distance of anchor nodes;

[0008] Calculate the average jump distance of the unknown node based on the optimized average jump distance of the anchor node.

[0009] Based on the calculated average jump distance of the unknown node and the corrected minimum number of jumps, calculate the estimated distance between the unknown node and the anchor node; and based on the estimated distance, calculate the position coordinates of the unknown node using the least squares method.

[0010] As a preferred embodiment, the anchor node uses multiple communication radii for broadcasting, specifically including:

[0011] The node region within the maximum communication distance R is divided into multiple levels p, p = 1, 2, 3...N, where N is a positive integer; the communication radius corresponding to each level is...

[0012] Each anchor node has a communication radius corresponding to its different levels. Multiple broadcasts are performed. During each broadcast, the anchor node carries a data packet containing its own location coordinates, current communication radius, and hop count information initialized to 0. After receiving the data packet, other nodes record the current communication radius, mark neighboring nodes, count the number of neighboring nodes, increment the hop count in the data packet by 1, save the contents of the data packet, and then forward the data packet to the neighboring nodes.

[0013] If a node receives a data packet originating from the same anchor node, it compares and saves the hop count information with the smaller hop value as the minimum hop count from that anchor node to this node.

[0014] As a preferred embodiment, obtaining the anchor node distribution degree variable and determining the jump number correction coefficient specifically includes:

[0015] After all broadcasts have finished, each anchor node obtains the node distribution information within its various communication ranges and defines the anchor node distribution degree variable as follows:

[0016] Each anchor node is determined by the degree of anchor node distribution. And the total number of neighboring nodes C within the maximum communication distance R. i (R), calculate the jump number correction factor δ i The calculation formula is:

[0017]

[0018] The calculated jump number correction coefficient δ i Conduct flood broadcasts.

[0019] As a preferred embodiment, the step of correcting the minimum number of jumps to obtain the optimized average jump distance of the anchor node specifically includes:

[0020] Each anchor node corrects for the number of hops it receives from broadcasts by other anchor nodes using a correction factor δ. i The node hop of the corresponding anchor node contained in the data packet is corrected, and the corresponding minimum hop number is corrected accordingly.

[0021] Each anchor node is used to calculate its optimized average hop size using its position coordinates and the corrected minimum hop count. i And broadcast the optimized average hop size to other nodes. i .

[0022] As a preferred implementation, hopsize i The calculation formula is:

[0023]

[0024] In the formula, (x i y i ), (x u y u ) are the coordinates of anchor nodes i and u, respectively, and h is the coordinate of anchor node i. iu This represents the minimum number of hops from anchor node i to anchor node u after correction.

[0025] As a preferred implementation, the step of calculating the average jump distance of the unknown node based on the optimized average jump distance of the anchor node is carried out in the following way: first, determine the set of possible anchor nodes for the unknown node, and then select different calculation methods in segments according to the minimum jump number to calculate the average jump distance of the unknown node.

[0026] As a preferred implementation, the step of first determining the set of possible anchor nodes for the unknown node, and then selecting different calculation methods in segments based on the minimum hop count to calculate the average hop distance of the unknown node, specifically includes:

[0027] Set a minimum hop count threshold H for anchor nodes and unknown nodes, and select anchor nodes that meet the minimum hop count threshold H to form a set of possible anchor nodes for unknown nodes;

[0028] The unknown node is divided based on the minimum hop count between it and the anchor node in the set. If the minimum hop count is less than or equal to 1, the average hop distance of the anchor node is selected as the average hop distance of the unknown node. If the minimum hop count is greater than 1, the average hop distance of the unknown node is calculated by weighting the distribution coefficient, average hop distance and communication radius.

[0029] As a preferred implementation, when setting the minimum hop count threshold H between the anchor node and the unknown node, the following requirements are met:

[0030]

[0031] Where R is the maximum communication distance, P is the anchor node ratio, L is the area side length, M is the minimum number of anchor nodes that can be used to locate unknown nodes, and N is the total number of nodes in the area.

[0032] As a preferred embodiment, the step of calculating the average hop distance of unknown nodes by weighting the relationship between the distribution coefficient, average hop distance, and communication radius specifically includes:

[0033] Calculate the average connectivity C of the anchor node avg The calculation formula is: Where q is the total number of anchor nodes that satisfy the minimum hop count threshold H, and C i (R) represents the total number of neighboring nodes within the maximum communication distance R;

[0034] Calculate the distribution coefficient ε i The calculation formula is:

[0035] Calculate the weight coefficient ω of the anchor node i The calculation formula is: Among them, hopsize i The optimized average jump distance of the anchor node;

[0036] Calculate the average hop size of unknown nodes. k The calculation formula is:

[0037] In a second aspect, embodiments of the present invention also provide a DV-Hop positioning system based on hop count and hop distance optimization using the method in the first aspect embodiment, comprising:

[0038] The broadcast and correction coefficient determination module is used to control anchor nodes to broadcast using multiple communication radii, obtain anchor node distribution degree variables, and determine the hop number correction coefficient.

[0039] An anchor node jump number correction and jump distance optimization module, which is used to correct the minimum jump number using the jump number correction coefficient to obtain the optimized average jump distance of the anchor node;

[0040] The module for calculating the average jump distance of unknown nodes is used to calculate the average jump distance of unknown nodes based on the optimized average jump distance of anchor nodes.

[0041] The distance estimation and coordinate calculation module is used to calculate the estimated distance between the unknown node and the anchor node based on the calculated average jump distance and the corrected minimum number of jumps; and to calculate the position coordinates of the unknown node using the least squares method based on the estimated distance.

[0042] The beneficial effects of this invention are as follows:

[0043] (1) In this invention, by broadcasting multiple times with different communication radii, the anchor node can obtain the node distribution of other nodes (including other anchor nodes and unknown nodes) in different communication ranges, thereby obtaining the anchor node distribution degree variable; the hop number correction coefficient is determined according to the anchor node distribution degree variable, and the minimum hop number is corrected by the hop number correction coefficient, which can effectively reduce the hop number error, thereby optimizing the average hop distance of the anchor node, improving the positioning accuracy, and meeting the needs of practical applications.

[0044] (2) In this invention, when calculating the average hop distance of an unknown node, the method first determines the set of possible anchor nodes for the unknown node, and then selects different calculation methods in segments according to the minimum hop count to calculate the average hop distance of the unknown node. This calculation method fully considers the influence of node distribution on the average hop distance of the unknown node. By selecting the average hop distance of anchor nodes that meet the hop count requirements and have a relatively uniform node density distribution to calculate the average hop distance of the unknown node, the positioning error of the unknown node can be effectively reduced, thereby further improving the positioning accuracy of the DV-Hop positioning algorithm in irregular areas. Attached Figure Description

[0045] Figure 1 This is a flowchart of the DV-Hop localization method based on hop count and hop distance optimization in an embodiment of the present invention;

[0046] Figure 2 This is a schematic diagram of the node topology within the C-shaped region used in the simulation analysis;

[0047] Figure 3 This is a schematic diagram of the node topology within the Z-shaped region used in the simulation analysis;

[0048] Figure 4 This is a schematic diagram illustrating the impact of different communication radii on positioning errors in a simulation analysis.

[0049] Figure 5 This is a structural block diagram of the DV-Hop positioning system based on hop count and hop distance optimization in an embodiment of the present invention.

[0050] In the diagram: 10 - Broadcast and correction coefficient determination module, 20 - Anchor node jump number correction and jump distance optimization module, 30 - Unknown node average jump distance calculation module, 40 - Distance estimation and coordinate calculation module. Detailed Implementation

[0051] In practical applications, node distribution areas are often irregular, containing holes or obstacles, causing communication paths between nodes to be tortuous and increasing the difficulty of distance estimation. Traditional DV-Hop positioning algorithms fail to consider that the actual hop distance between nodes may not be equal, leading to deviations in the actual distance from unknown nodes to anchor nodes. Furthermore, because unknown nodes use the average hop distance of the nearest anchor node as their estimated average hop distance, they ignore the network distribution around the anchor node. This means that errors in the anchor node's average hop distance affect the unknown node's positioning error, resulting in significant multi-hop distance errors and decreased positioning accuracy. This invention aims to provide a DV-Hop positioning method and system based on hop count and hop distance optimization. This method can solve the problem of large node positioning errors in unevenly distributed network areas (such as irregular network areas with C-shaped or Z-shaped distributions), improving positioning accuracy and meeting practical application needs.

[0052] The main design concept is as follows: anchor nodes use multiple communication radii for broadcasting to obtain the distribution degree variable of anchor nodes and determine the hop number correction coefficient; the minimum hop number is corrected using the hop number correction coefficient to obtain the optimized average hop distance of anchor nodes; the average hop distance of unknown nodes is calculated based on the optimized average hop distance of anchor nodes; the estimated distance between the unknown node and the anchor node is calculated based on the calculated average hop distance of the unknown node and the corrected minimum hop number; and the position coordinates of the unknown node are calculated using the least squares method based on the estimated distance.

[0053] In the above main design scheme, by broadcasting multiple times with different communication radii, the anchor node can obtain the node distribution of other nodes (including other anchor nodes and unknown nodes) in different communication ranges, thereby obtaining the anchor node distribution degree variable; the hop number correction coefficient is determined based on the anchor node distribution degree variable, and the minimum hop number is corrected by using the hop number correction coefficient, which can effectively reduce the hop number error, thereby optimizing the average hop distance of the anchor node, improving the positioning accuracy, and meeting the needs of practical applications.

[0054] To make the technical problems, technical solutions, and advantages of this invention clearer, the technical solutions of this invention will be described in detail below with reference to the accompanying drawings and specific embodiments.

[0055] However, it should be noted that the examples described below are merely specific examples and are not intended to limit the embodiments of the present invention to the specific steps, values, conditions, data, order, etc. Those skilled in the art can utilize the concept of the present invention to construct more embodiments not mentioned herein by reading this specification.

[0056] Example 1

[0057] See Figure 1 As shown, this embodiment provides a DV-Hop positioning method based on hop count and hop distance optimization, which can be applied to irregular wireless sensor network areas (such as typical C-shaped or Z-shaped network areas). Within this area, anchor nodes with known location coordinates and unknown nodes whose locations are to be located are randomly deployed, and the maximum communication distance between nodes is set to the communication radius R. The DV-Hop positioning method includes the following steps:

[0058] Step A: The anchor node broadcasts using multiple communication radii to obtain the anchor node distribution degree variable and determine the hop number correction coefficient; the minimum hop number is corrected using the hop number correction coefficient to obtain the optimized average hop distance of the anchor node.

[0059] Understandably, the distribution of nodes affects the minimum number of hops required for anchor nodes, and the higher the number of hops, the greater the deviation. Furthermore, the number of hops between nodes significantly impacts the estimated distance. Therefore, the more accurate the number of hops, the more accurate the estimated distance, and the lower the overall positioning error of the positioning method.

[0060] To address this, in this embodiment, to ensure more accurate hop counts, a hop count correction coefficient is determined based on the distribution degree of other nodes corresponding to the anchor node (i.e., based on the anchor node distribution degree variable). This correction coefficient is then used to adjust the minimum hop count, reducing hop count errors and thus optimizing the average hop distance of the anchor node. Furthermore, to confirm the node distribution, this embodiment employs a multi-communication radius broadcasting method. By introducing a region division mechanism, the node region within the maximum communication distance is divided into multiple levels, with different levels corresponding to different communication radii. Through multiple broadcasts with different communication radii, the anchor node can obtain the node distribution of other nodes within each different communication range.

[0061] For example, as an optional implementation, the anchor node uses multiple communication radii for broadcasting, specifically including:

[0062] 1. Divide the node region within the maximum communication distance into multiple levels p, p = 1, 2, 3...N, where N is a positive integer; the communication radius corresponding to each level is...

[0063] For example, suppose the node region is divided into three levels, i.e., p = 1, 2, 3, then the three communication radii corresponding to the three levels are R, Therefore, when subsequent anchor nodes broadcast using multiple communication radii, they will broadcast according to the communication radius. R broadcasts three times in sequence.

[0064] 2. The communication radius of each anchor node is determined according to its corresponding level. Multiple broadcasts are performed. Each broadcast carries a data packet containing the anchor node's location coordinates, current communication radius, and a hop count initialized to 0. Other nodes (including other anchor nodes and unknown nodes) receive the packet, record the current communication radius, mark neighboring nodes, count the number of neighboring nodes, increment the hop count in the packet by 1, save the packet's content, and then forward the packet to their neighboring nodes. If a node receives a data packet originating from the same anchor node, it compares and saves the smaller hop count as the minimum hop count from that anchor node to itself. In practice, when other nodes count the number of neighboring nodes after receiving a data packet, they do so based on the number of data packets received from the previous node. For example, if node C receives data packets from nodes A and B after one hop, it will mark nodes A and B as neighboring nodes and count them as 2.

[0065] Furthermore, as an optional implementation method, the node distribution degree variable is obtained, and the hop count correction coefficient is determined, specifically including:

[0066] 1. After all broadcasts have finished, each anchor node obtains the node distribution information of other nodes within different communication ranges, and defines the node distribution degree variable as follows: Understandably, in practical applications, when anchor nodes obtain the distribution of other nodes (including other anchor nodes and unknown nodes) within different communication ranges, they can do so based on the number of neighboring nodes counted within each communication range. Specifically, each anchor node obtains the distribution of other nodes based on the number of neighboring nodes counted after its broadcast. The anchor node determines its neighboring node count based on which nodes have marked it as a neighbor. For example, if anchor node A broadcasts a data packet, and nodes B and C receive the broadcast data packet, both nodes B and C will mark anchor node A as a neighbor after receiving the data packet and continue forwarding it (flooding). Anchor node A, being within the broadcast range, will receive data packets from nodes B and C (equivalent to return packets). Therefore, when anchor node A counts its neighboring nodes, it can do so based on the data packets from nodes B and C that have marked it as a neighbor, resulting in a count of 2 neighboring nodes.

[0067] 2. Each anchor node is determined based on the degree of node distribution. And the total number of neighboring nodes C within the maximum communication distance R. i (R), calculate the jump number correction factor δ i The calculation formula is: The calculated jump number correction coefficient δ i Conduct flood broadcasts.

[0068] Furthermore, as an optional implementation, the minimum number of jumps is modified to obtain the optimized average jump distance of the anchor node, specifically including:

[0069] 1. Each anchor node corrects for the number of hops received from broadcasts by other anchor nodes using a correction coefficient δ. i The node hops of the corresponding anchor nodes contained in the data packet are corrected, and the corresponding minimum hop count is corrected accordingly. It can be understood that, since only the anchor nodes are nodes whose own position coordinates are known, this embodiment only corrects the hops of the anchor nodes contained in the data packet when correcting the minimum hop count, and does not correct the hops of unknown nodes.

[0070] For example, suppose the communication path from anchor node i to anchor node u is: anchor node i — unknown node a — anchor node o — anchor node u, and suppose this communication path is unique. Then, the hop count information in the data packets originating from anchor node i retained by anchor node u is the minimum hop count from anchor node i to anchor node u, which is 1 + 1 + 1 = 3 hops.

[0071] Assume that anchor node u receives the hop count correction coefficient δ broadcast by anchor nodes i and o. i δ o The values ​​are 0.8 and 0.6 respectively. Therefore, after correcting the node hop of anchor node i, the corrected hop is h. i =δ i *1 = 0.8; The node hop of anchor node o is corrected to obtain the corrected hop as h. o =δ o *1 = 0.6. Finally, the minimum hop count h from anchor node i to anchor node u after correction can be obtained. iu =h i +1+h o =0.8 + 1 + 0.6 = 2.4 jumps.

[0072] 2. Using the anchor node's position coordinates and the corrected minimum number of hops, the optimized average hop size of that anchor node is obtained. i And broadcast the optimized average hop size to other nodes. i .

[0073] Among them, the average hop size after anchor node optimization i The calculation formula is:

[0074]

[0075] In the formula, (x i y i ), (x u y u ) are the coordinates of anchor nodes i and u, respectively, and h is the coordinate of anchor node i. iu This represents the minimum number of hops from anchor node i to anchor node u after correction.

[0076] Step B: Calculate the average jump distance of the unknown node based on the optimized average jump distance of the anchor node.

[0077] Understandably, in traditional DV-Hop localization algorithms, unknown nodes use the average hop distance of the nearest anchor node as their estimated average hop distance. However, in irregular networks, node distribution is uneven, and areas with dense node distribution have smaller average hop distances. Simply choosing a single average hop distance cannot accurately reflect the overall network distribution. Furthermore, because the network distribution around anchor nodes is ignored, the error in the average hop distance of anchor nodes affects the localization error of unknown nodes. In unevenly distributed areas, the distance differences between nodes vary with the distribution, leading to larger multi-hop distance errors and decreased localization accuracy.

[0078] Therefore, in order to further improve the positioning accuracy of the DV-Hop positioning algorithm in irregular areas, this embodiment fully considers the influence of node distribution on the average hop distance of unknown nodes when calculating the average hop distance of unknown nodes. By selecting the average hop distance of anchor nodes that meet the hop count requirements and have a relatively uniform node density distribution to calculate the average hop distance of unknown nodes, the positioning error of unknown nodes can be effectively reduced.

[0079] For example, as a preferred implementation, in this embodiment, the average jump distance of the unknown node is calculated based on the optimized average jump distance of the anchor nodes, using the following method: first, the set of possible anchor nodes for the unknown node is determined, and then different calculation methods are selected segment by segment based on the minimum jump number to calculate the average jump distance of the unknown node. Specifically, this includes:

[0080] 1. Set a minimum hop count threshold H for anchor nodes and unknown nodes, and select anchor nodes that meet the minimum hop count threshold H to form a set of possible anchor nodes for unknown nodes.

[0081] Furthermore, as an optional implementation, setting a minimum hop count threshold H can satisfy the following requirements:

[0082]

[0083] Where P is the anchor node ratio (the anchor node ratio is the proportion of the number of anchor nodes in the region to the total number of nodes in the region), L is the side length of the region, M is the minimum number of anchor nodes that can be used to locate unknown nodes (usually greater than or equal to 3, and 3 is selected in this embodiment), and N is the total number of nodes in the region.

[0084] 2. The unknown node is divided according to the minimum hop count of the anchor node in the set; if the minimum hop count is less than or equal to 1, the average hop distance of the anchor node is selected as the average hop distance of the unknown node; if the minimum hop count is greater than 1, the average hop distance of the unknown node is calculated by weighting the distribution coefficient, average hop distance and communication radius.

[0085] Furthermore, as an optional implementation, in this embodiment, the average hop distance of the unknown node is calculated by weighting the relationship between the distribution coefficient, the average hop distance, and the communication radius. Specifically, this may include:

[0086] 2.1 Calculate the average connectivity C of the anchor node. avg The calculation formula is:

[0087]

[0088] Where q is the total number of anchor nodes that satisfy the minimum hop count threshold H.

[0089] 2.2 Calculate the distribution coefficient ε i The calculation formula is:

[0090]

[0091] 2.3 Calculate the weight coefficient ω of the anchor node i The calculation formula is:

[0092]

[0093] 2.4 Calculate the average hop size for unknown nodes. k The calculation formula is:

[0094]

[0095] Therefore, in this embodiment, different calculation methods are selected based on the minimum hop count to calculate the average hop distance of unknown nodes. The calculation formula can be summarized as follows:

[0096]

[0097] Step C: Calculate the estimated distance between the unknown node and the anchor node based on the calculated average jump distance and the corrected minimum jump number; and calculate the position coordinates of the unknown node using the least squares method based on the estimated distance.

[0098] To verify the actual effect of the above method, the following simulation analysis of the DV-Hop positioning method based on hop count and hop distance optimization of the present invention is performed using MATLAB.

[0099] The simulation environment is an irregular wireless sensor network area of ​​100×100㎡, with nodes (anchor nodes and unknown nodes) randomly distributed within the network area. The communication radius of each node is R. All experimental results are based on the average of 100 simulation experiments. Figure 2 , Figure 3 As shown, irregular network regions (C-type and Z-type topologies) are represented. Stars indicate anchor nodes, and circles indicate unknown nodes. The total number of nodes is set to 100, with anchor nodes accounting for 30%. To examine the positioning capability of the proposed positioning method, C-type and Z-type irregular topologies were used. The proposed positioning method (DHDV-Hop) and the traditional DV-Hop positioning method were simulated and tested under different communication radii.

[0100] from Figure 4 The simulation results show that the positioning error exhibits a significant trend when the communication radius is less than 25m. As the communication radius increases, the connectivity of nodes within the network increases, resulting in a smaller positioning error. Under the same network topology, the positioning error of this invention (DHDV-Hop) is smaller than that of the traditional DV-Hop, and the positioning algorithm of this invention has a smaller impact on the positioning error for different irregular network regions.

[0101] Example 2

[0102] See Figure 5 As shown, based on the same inventive concept, this embodiment of the invention also provides a DV-Hop positioning system optimized based on hop count and hop distance, which includes:

[0103] The broadcast and correction coefficient determination module 10 is used to control the anchor node to broadcast using multiple communication radii, obtain the anchor node distribution degree variable, and determine the jump number correction coefficient.

[0104] Anchor node jump number correction and jump distance optimization module 20 is used to correct the minimum jump number using the jump number correction coefficient to obtain the optimized average jump distance of the anchor node.

[0105] The unknown node average jump distance calculation module 30 is used to calculate the average jump distance of the unknown node based on the optimized anchor node average jump distance.

[0106] The distance estimation and coordinate calculation module 40 is used to calculate the estimated distance between the unknown node and the anchor node based on the calculated average jump distance of the unknown node and the corrected minimum number of jumps; and to calculate the position coordinates of the unknown node using the least squares method based on the estimated distance.

[0107] It is understood that, using the system of this embodiment, the anchor node can obtain the node distribution of other nodes in different communication ranges through multiple broadcasts with different communication radii; the hop count correction coefficient is determined based on the obtained anchor node distribution degree variable, and the minimum hop count is corrected using the hop count correction coefficient, which can effectively reduce the hop count error, thereby optimizing the average hop distance of the anchor node, improving the positioning accuracy, and meeting the needs of practical applications.

[0108] It should be noted that the various variations and specific examples in the foregoing method embodiments are also applicable to the system of this embodiment. Through the detailed description of the foregoing method, those skilled in the art can clearly understand the implementation method of the device in this embodiment. Therefore, for the sake of brevity, they will not be described in detail here.

[0109] Note: The sequence numbers of the embodiments in this application are for descriptive purposes only and do not represent the superiority or inferiority of the embodiments.

[0110] The terms "comprising" and "having," and any variations thereof, in the specification, claims, and accompanying drawings of this application are intended to cover non-exclusive inclusion. For example, a process, method, system, product, or apparatus that includes a series of steps or units is not limited to the listed steps or units, but may optionally include steps or units not listed, or may optionally include other steps or units inherent to such process, method, product, or apparatus. The terms "first," "second," and "third," etc., are used to distinguish different objects, etc., and do not indicate a sequence, nor do they limit "first," "second," and "third" to different types.

[0111] In the description of the embodiments of this application, terms such as "exemplary," "for example," or "for instance" are used to indicate examples, illustrations, or explanations. Any embodiment or design described as "exemplary," "for example," or "for instance" in the embodiments of this application should not be construed as being more preferred or advantageous than other embodiments or designs. Specifically, the use of terms such as "exemplary," "for example," or "for instance" is intended to present the relevant concepts in a concrete manner.

[0112] In the description of the embodiments of this application, unless otherwise stated, " / " means "or". For example, A / B can mean A or B. The "and / or" in the text is merely a description of the relationship between related objects, indicating that there can be three relationships. For example, A and / or B can mean: A exists alone, A and B exist simultaneously, and B exists alone. In addition, in the description of the embodiments of this application, "multiple" means two or more.

[0113] In some processes described in the embodiments of this application, multiple operations or steps are included in a specific order. However, it should be understood that these operations or steps may not be executed in the order they appear in the embodiments of this application, or they may be executed in parallel. The sequence number of the operation is only used to distinguish different operations, and the sequence number itself does not represent any execution order. In addition, these processes may include more or fewer operations, and these operations or steps may be executed sequentially or in parallel, and these operations or steps may be combined.

[0114] Through the above description of the embodiments, those skilled in the art can clearly understand that the methods of the above embodiments can be implemented by means of software plus necessary general-purpose hardware platforms. Of course, they can also be implemented by hardware, but in many cases the former is a better implementation method. Based on this understanding, the technical solution of this application, in essence, or the part that contributes to the prior art, can be embodied in the form of a software product. This computer software product is stored in a storage medium (such as ROM / RAM, magnetic disk, optical disk) as described above, and includes several instructions to cause a terminal device to execute the methods described in the various embodiments of this application.

[0115] The above are merely preferred embodiments of this application and do not limit the patent scope of this application. Any equivalent structural or procedural transformations made using the content of this application's specification and drawings, or direct or indirect applications in other related technical fields, are similarly included within the patent protection scope of this application.

Claims

1. A DV-Hop positioning method based on hop count and hop distance optimization, characterized in that, The method includes: Anchor nodes broadcast using multiple communication radii to obtain anchor node distribution degree variables and determine hop count correction coefficients; the minimum hop count is corrected using the hop count correction coefficients to obtain the optimized average hop distance of anchor nodes; The average jump distance of unknown nodes is calculated based on the optimized average jump distance of anchor nodes. During the calculation, the set of possible anchor nodes for unknown nodes is determined first, and then different calculation methods are selected in segments according to the minimum number of jumps to calculate the average jump distance of unknown nodes. Based on the calculated average jump distance of the unknown node and the corrected minimum number of jumps, calculate the estimated distance between the unknown node and the anchor node; and based on the estimated distance, calculate the position coordinates of the unknown node using the least squares method. The process of obtaining the anchor node distribution degree variable and determining the jump number correction coefficient includes: After all broadcasts have finished, each anchor node obtains the node distribution information within its various communication ranges and defines the anchor node distribution degree variable as follows: ; Each anchor node is determined by the degree of anchor node distribution. and the total number of neighboring nodes within the maximum communication distance R. Calculate the jump number correction factor The calculation formula is: ； The calculated jump number correction coefficient Conduct flood broadcasts.

2. The DV-Hop positioning method based on hop count and hop distance optimization as described in claim 1, characterized in that, The anchor node uses multiple communication radii for broadcasting, specifically including: The node region within the maximum communication distance R is divided into multiple levels. N, where N is a positive integer; the communication radius corresponding to each level is... ; Each anchor node has a communication radius corresponding to its different levels. The anchor node broadcasts multiple times. Each time it broadcasts, the anchor node carries a data packet containing its own location coordinates, current communication radius, and hop count information initialized to 0. After receiving the data packet, other nodes record the current communication radius, mark neighboring nodes, count the number of neighboring nodes, increment the hop count in the data packet by 1, save the contents of the data packet, and then forward the data packet to the neighboring nodes. If a node receives a data packet originating from the same anchor node, it compares and saves the hop count information with the smaller hop value as the minimum hop count from that anchor node to this node.

3. The DV-Hop positioning method based on hop count and hop distance optimization as described in claim 1, characterized in that, The process of correcting the minimum number of jumps to obtain the optimized average jump distance of the anchor node specifically includes: Each anchor node adjusts its hop count based on the hop count broadcast from each other. The node hop of the corresponding anchor node contained in the data packet is corrected, and the corresponding minimum hop number is corrected accordingly. Each anchor node is used to calculate its optimized average jump distance using its position coordinates and the corrected minimum jump number. And broadcast the optimized average hop distance to other nodes. .

4. The DV-Hop positioning method based on hop count and hop distance optimization as described in claim 3, characterized in that, The calculation formula is: ； In the formula, ( ), ( , ) are the coordinates of anchor nodes i and u, respectively. For anchor nodes To anchor node The revised minimum number of hops.

5. The DV-Hop positioning method based on hop count and hop distance optimization as described in claim 1, characterized in that, The process of first determining the set of possible anchor nodes for the unknown node, and then calculating the average hop distance of the unknown node by selecting different calculation methods in segments based on the minimum hop count, specifically includes: Set a minimum hop count threshold H for anchor nodes and unknown nodes, and select anchor nodes that meet the minimum hop count threshold H to form a set of possible anchor nodes for unknown nodes; The unknown node is divided based on the minimum hop count between it and the anchor node in the set. If the minimum hop count is less than or equal to 1, the average hop distance of the anchor node is selected as the average hop distance of the unknown node. If the minimum hop count is greater than 1, the average hop distance of the unknown node is calculated by weighting the distribution coefficient, average hop distance and communication radius.

6. The DV-Hop positioning method based on hop count and hop distance optimization as described in claim 5, characterized in that, When setting the minimum hop count threshold H for anchor nodes and unknown nodes, the following requirements must be met: ； Where R is the maximum communication distance, P is the anchor node ratio, L is the area side length, M is the minimum number of anchor nodes that can be used to locate unknown nodes, and N is the total number of nodes in the area.

7. The DV-Hop positioning method based on hop count and hop distance optimization as described in claim 5, characterized in that, The step of calculating the average hop distance of unknown nodes by weighting the relationship between the distribution coefficient, average hop distance, and communication radius specifically includes: Calculate the average connectivity of anchor nodes The calculation formula is: Where q is the total number of anchor nodes that satisfy the minimum hop count threshold H. This represents the total number of neighboring nodes within the maximum communication distance R. Calculate the distribution coefficient The calculation formula is: ; Calculate the weight coefficient of the anchor node The calculation formula is: ,in, The optimized average jump distance of the anchor node; Calculate the average jump distance of unknown nodes The calculation formula is: .

8. A DV-Hop positioning system based on hop count and hop distance optimization using the method of any one of claims 1 to 7, characterized in that, include: The broadcast and correction coefficient determination module is used to control anchor nodes to broadcast using multiple communication radii, obtain anchor node distribution degree variables, and determine the hop number correction coefficient. An anchor node jump number correction and jump distance optimization module, which is used to correct the minimum jump number using the jump number correction coefficient to obtain the optimized average jump distance of the anchor node; The module for calculating the average jump distance of unknown nodes is used to calculate the average jump distance of unknown nodes based on the optimized average jump distance of anchor nodes. The distance estimation and coordinate calculation module is used to calculate the estimated distance between the unknown node and the anchor node based on the calculated average jump distance and the corrected minimum number of jumps; and to calculate the position coordinates of the unknown node using the least squares method based on the estimated distance.

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