Method, device, medium and equipment for locating failure area of wireless sensor network

Abstract

The present invention discloses a method, device, medium and terminal device for locating a failure area of a wireless sensor network, including constructing a positioning model with a communication base station in the wireless sensor network as the origin of the coordinate system; obtaining the relative coordinates of network nodes, as well as the distance measurement deviation value and the multipath propagation deviation; establishing a basic equation of the failure area and the actual sensing distance and propagation time according to the relative coordinates of any network node with the failure area as the unknown coordinate; taking any network node as the reference node, and taking the difference between the relevant parameters between the unknown coordinate and the ordinary node and the relevant parameters between the unknown coordinate and the reference node correspondingly; substituting the difference of the relevant parameters into the basic equation correspondingly to obtain the failure area positioning equation; and solving the failure area positioning equation according to the limit value of the multipath propagation deviation to obtain the coordinates of the failure area. The failure area positioning of the present invention occupies relatively little communication resources, can adapt to the conditions of limited communication resources, and meets the actual requirements in this scenario.

Description

Technical Field

[0001] The present invention relates to the technical field of wireless sensor network positioning, and in particular to a positioning method, device, medium and terminal device for a failure area of a wireless sensor network. Background Art

[0002] A wireless sensor network (Wireless Sensor Network, WSN) can collaboratively sense, collect, process, and transmit information of sensed objects within the geographical area covered by its network through wireless sensors, and is widely used in environmental monitoring, target tracking and other scenarios. In some application scenarios, such as emergency scenarios with harsh environments like floods, earthquakes, fires, and explosions, wireless network communication methods and facilities may be damaged, and the network nodes of the wireless sensor network may shift or fail, resulting in the failure of information transmission in some areas of the wireless sensor network, with great uncertainty. Therefore, it is necessary to locate the failure area of the wireless sensor network. To solve this problem, the prior art provides a regional investigation method based on GPS positioning of wireless sensors, which uses the GPS positioning function of wireless sensors to globally locate the network nodes in the application scenario, and then gradually analyzes whether the area fails according to the global positioning to determine the location of the failure area.

[0003] In the above application scenarios, wireless network communication methods and facilities may be damaged. Among them, the communication facilities include regional servers, and the damage of the regional servers will lead to a sharp reduction in communication resources, resulting in greater limitations of communication resources. However, the prior art's failure area positioning method based on GPS positioning of wireless sensors requires a large amount of communication resources and cannot adapt to the communication resource conditions in this application scenario. Therefore, the existing failure area positioning methods are difficult to meet the actual needs in scenarios with limited communication resources. Summary of the Invention

[0004] The present invention provides a positioning method, device, medium and terminal device for a failure area of a wireless sensor network. By solving the relative coordinates of network nodes and the limit constraints of multipath propagation deviation, it is possible to locate the failure area of wireless sensor network nodes in emergency scenarios using less communication resources.

[0005] To solve the above technical problems, the present invention provides a positioning method for a failure area of a wireless sensor network, including:

[0006] Taking a communication base station in the wireless sensor network as the origin of the coordinate system, a positioning model for the failure area is constructed;

[0007] Based on the positioning model, the relative coordinates of the network nodes, the distance measurement deviation value and the multipath propagation deviation when the network nodes transmit information are obtained;

[0008] Taking the failure area as the unknown coordinates, based on the relative coordinates of any of the network nodes, the coordinate distance between the unknown coordinates, the distance measurement deviation value, the multipath propagation deviation, and the propagation speed of radio waves, establish a basic equation between the failure area and any of the network nodes regarding the actual sensing distance and the propagation time;

[0009] Taking any of the network nodes as the reference node and the network nodes other than the reference node as ordinary nodes; taking the difference between the relevant parameters between the unknown coordinates and the ordinary nodes and the relevant parameters between the unknown coordinates and the reference node correspondingly to form the difference corresponding to the relevant parameters; wherein, the relevant parameters include the coordinate distance, the distance measurement deviation value, the multipath propagation deviation, the actual sensing distance, and the propagation time;

[0010] Substitute the difference of the relevant parameters into the basic equation correspondingly to obtain the failure area positioning equation;

[0011] Solve the failure area positioning equation according to the limit value of the multipath propagation deviation to obtain the coordinates of the failure area.

[0012] Preferably, taking the failure area as the unknown coordinates, based on the relative coordinates of any of the network nodes, the coordinate distance between the unknown coordinates, the distance measurement deviation value, the multipath propagation deviation, and the propagation speed of radio waves, establishing a basic equation between the failure area and any of the network nodes regarding the actual sensing distance and the propagation time specifically includes:

[0013] Taking the failure area as the unknown coordinates, assuming that there are n + 1 network nodes, which are the 0th, 1st, …, nth network nodes respectively, then the basic equation between the failure area and the mth network node regarding the actual sensing distance and the propagation time is:

[0014]

[0015] wherein, m is an integer belonging to [0, n], r m represents the actual sensing distance between the failure area and the mth network node; v represents the propagation speed of radio waves; d m represents the coordinate distance between the unknown coordinates and the relative coordinates of the mth network node; n m represents the distance measurement deviation value; e m represents the multipath propagation deviation; t m represents the propagation time of radio waves.

[0016] Preferably, taking any of the network nodes as the reference node and the network nodes other than the reference node as ordinary nodes; taking the difference between the relevant parameters between the unknown coordinate and the ordinary nodes and the relevant parameters between the unknown coordinate and the reference node to form the difference of the relevant parameters; wherein, the relevant parameters include the coordinate distance, the distance measurement deviation value, the multipath propagation deviation, the actual sensing distance, and the propagation time; substituting the difference of the relevant parameters into the basic equation correspondingly to obtain the failure area positioning equation, specifically including:

[0017] Taking the 0th network node as the reference node and the ith network node as the ordinary node, where i is a positive integer belonging to (0, n], then the failure area positioning equation is:

[0018]

[0019] wherein, r i,0 represents the difference of the actual sensing distance; d i,0 represents the difference of the coordinate distance; n i,0 represents the difference of the distance measurement deviation value; e i,0 represents the difference of the multipath propagation deviation.

[0020] Preferably, the limit value of the multipath propagation deviation includes the upper limit value of the multipath propagation deviation and the lower limit value of the multipath propagation deviation; wherein, the upper limit value of the multipath propagation deviation is obtained from the attenuation rate of the multipath propagation.

[0021] Preferably, the lower limit value of the multipath propagation deviation is 0.

[0022] Preferably, according to the limit value of the multipath propagation deviation, solving the failure area positioning equation to obtain the coordinates of the failure area, specifically including:

[0023] Let the unknown coordinates of the failure area be x(x x , y x , z x ), and the relative coordinates of the ith network node be Performing a square operation on the failure area positioning equation to obtain Equation (3):

[0024]

[0025] Rewriting Equation (3) to obtain Equation (4):

[0026]

[0027] wherein, A i =(S1, S2,..., Si ), ΔA i = (S1, S2, …, S i ) T ,

[0028] B i = ((r 1，0 - e 1，0 ), (r 2，0 - e 2，0 ), …, (r i，0 - e i，0 ))), ΔB1 = (-d1, -d2, …, -d i ));

[0029] Omit the high-order small quantities from formula (4) to obtain formula (5):

[0030]

[0031] where N is a positive integer greater than 1;

[0032] According to the difference of the said limit values, rewrite formula (5) into formula (6):

[0033]

[0034] where the difference ρ of the said limit values i,0 is determined by ρ i,0 = ρ i - ρ0, and ρ i is the upper limit value of the multipath propagation deviation of the i-th said network node;

[0035] Solve formula (6) to obtain the coordinates of the said failure region.

[0036] Preferably, the solving formula (6) to obtain the coordinates of the said failure region specifically includes:[[]]

[0037] Substitute the expressions of ΔA i and ΔB i into formula (6) to obtain formula (7):

[0038]

[0039] Scale formula (7) through the absolute value inequality to obtain formula (8):

[0040]

[0041] Define the variable λ = [λ1, λ2, …, λ n T , and transform formula (8) into formula (9) and formula (10): ​

[0042]

[0043] Express the variable θ as formula (11):

[0044] θ * = θθ T ≥ 0 (11)

[0045] where, θ * ≥ 0 indicates that the eigenvalues of matrix θ * are greater than or equal to 0;

[0046] Convert formula (11) into formula (12):

[0047]

[0048] According to formula (9), formula (10), and (12), obtain the optimized positioning model (13):

[0049]

[0050] Use the mathematical toolbox to solve the optimized positioning model (13) to obtain the coordinates of the failure area. The present invention also provides a positioning device for a wireless sensor network node area, including:

[0051] A model establishment unit, configured to construct a positioning model of the failure area with the communication base station in the wireless sensor network as the origin of the coordinate system;

[0052] A node data acquisition unit, configured to obtain the relative coordinates of the network nodes and the distance measurement deviation value and multipath propagation deviation when the network nodes transmit information based on the positioning model;

[0053] A calculation and processing unit, including an equation set establishment module and an equation set calculation module;

[0054] The equation set establishment module is configured to establish a basic equation between the failure area and any of the network nodes regarding the actual sensing distance and the propagation time with the failure area as the unknown coordinates, according to the relative coordinates of any of the network nodes, the coordinate distance between the unknown coordinates, the distance measurement deviation value, the multipath propagation deviation, and the propagation speed of radio waves;

[0055] The system of equations calculation module is used to take any of the network nodes as the reference node, and the network nodes other than the reference node as ordinary nodes; calculate the differences between the relevant parameters between the unknown coordinates and the ordinary nodes and the relevant parameters between the unknown coordinates and the reference node respectively, to form the differences corresponding to the relevant parameters; wherein, the relevant parameters include the coordinate distance, the distance measurement deviation value, the multipath propagation deviation, the actual sensing distance, and the propagation time.

[0056] Substitute the differences of the relevant parameters into the basic equation correspondingly to obtain the failure area positioning equation.

[0057] Solve the failure area positioning equation according to the limit value of the multipath propagation deviation to obtain the coordinates of the failure area.

[0058] The present invention also provides a computer-readable storage medium, which includes a stored computer program; wherein, when the computer program runs, it controls the device where the computer-readable storage medium is located to execute the positioning method for the failure area of the wireless sensor network described in any one of the above.

[0059] The present invention also provides a terminal device, which includes a processor, a memory, and a computer program stored in the memory and configured to be executed by the processor. When the processor executes the computer program, it implements the positioning method for the failure area of the wireless sensor network described in any one of 1 to 7 above.

[0060] Compared with the prior art, the present invention constructs a positioning model for the failure area, obtains the relative coordinates of the network nodes, the distance measurement deviation value and the multipath propagation deviation when the network nodes transmit information, establishes a basic equation between the failure area and any of the network nodes regarding the actual sensing distance and the propagation time, and performs numerical processing by taking the differences between the relevant parameters between the unknown coordinates and the ordinary nodes and the relevant parameters between the unknown coordinates and the reference node correspondingly, to establish a constrained failure area positioning equation. Therefore, the coordinates of the failure offset area can be obtained by constrained solution according to the limit value of the multipath propagation deviation. Compared with the failure area positioning method based on wireless sensor GPS positioning, obtaining the relative coordinates of the network nodes, the distance measurement deviation value and the multipath propagation deviation when the network nodes transmit information for failure area positioning occupies less communication resources. Therefore, the present invention can adapt to the condition of limited communication resources and meet the actual requirements in this scenario. BRIEF DESCRIPTION OF THE DRAWINGS

[0061] Figure 1 is a schematic flowchart of an embodiment of a method for positioning a node area of a wireless sensor network provided by the present invention;

[0062] Figure 2 Schematic structural diagram of an embodiment of a wireless sensor network node area positioning device provided by the present invention. Detailed implementation manners

[0063] Next, the technical solutions in the embodiments of the present invention will be clearly and completely described in conjunction with the accompanying drawings in the embodiments of the present invention. Obviously, the described embodiments are only a part of the embodiments of the present invention, rather than all the embodiments. Based on the embodiments of the present invention, all other embodiments obtained by those of ordinary skill in the art without creative efforts shall fall within the protection scope of the present invention.

[0064] See Figure 1 , which is a schematic flowchart of an embodiment of a method for positioning a failure area of a wireless sensor network provided by the present invention.

[0065] A method for positioning a failure area of a wireless sensor network provided by an embodiment of the present invention includes steps S1 to S6:

[0066] S1: Taking the communication base station in the wireless sensor network as the origin of the coordinate system, construct a positioning model for the failure area;

[0067] Specifically, taking the communication base station in the wireless sensor network as the origin of the coordinate system, establish a three-dimensional rectangular coordinate system. Then, taking the coordinates of the communication base station as the reference point, any point in the failure area has a determined relative coordinate. Only by calculating the relative coordinates of each point in the failure area can the position of the failure area be determined.

[0068] S2: Based on the positioning model, obtain the relative coordinates of the network nodes, as well as the distance measurement deviation value and multipath propagation deviation when the network nodes transmit information;

[0069] S3: Taking the failure area as the unknown coordinate, according to the relative coordinates of any network node, the coordinate distance between the unknown coordinate, the distance measurement deviation value, the multipath propagation deviation, and the propagation speed of radio waves, establish a basic equation between the failure area and any network node regarding the actual sensing distance and the propagation time;

[0070] It should be noted that the network nodes in the wireless sensor network can communicate with each other and determine the distance between them, and the communication base station. During the process of obtaining the distance between them, due to the influence of factors such as the transceiver of the wireless sensor itself and the environment, there are distance measurement deviations of the sensor itself and multipath propagation deviations related to the propagation path. Among them, the distance measurement deviation of the wireless sensor itself satisfies N(0,σ 2) is a normal distribution and much smaller than the coordinate distances between each other. Based on this, taking the failure area as the unknown coordinate, a basic equation regarding the actual sensing distance can be written between the failure area and any of the network nodes, considering the above two deviations.

[0071] S4: Taking any of the network nodes as the reference node and the network nodes other than the reference node as ordinary nodes; subtracting the relevant parameters between the unknown coordinate and the ordinary nodes and the relevant parameters between the unknown coordinate and the reference node correspondingly to form the difference values corresponding to the relevant parameters; where the relevant parameters include the coordinate distance, the distance measurement deviation value, the multipath propagation deviation, the actual sensing distance, and the propagation time.

[0072] S5: Substituting the difference values of the relevant parameters into the basic equation correspondingly to obtain the failure area positioning equation.

[0073] Specifically, subtract the relevant parameters between the unknown coordinate and each ordinary node and the relevant parameters between the unknown coordinate and the reference node correspondingly, and substitute them into the basic equation correspondingly to obtain a basic equation set regarding each ordinary node, that is, the failure area positioning equation.

[0074] S6: Solving the failure area positioning equation according to the limit value of the multipath propagation deviation to obtain the coordinates of the failure area; where the multipath propagation deviation is caused by radio waves propagating through multiple paths and usually includes two parts: constant and periodic. In practical applications, the limit value can be determined by continuous observation or empirical data.

[0075] In the embodiment of the present invention, by constructing a positioning model of the failure area, obtaining the relative coordinates of the network nodes, the distance measurement deviation value and the multipath propagation deviation when the network nodes transmit information, a basic equation regarding the actual sensing distance and the propagation time is established between the failure area and any of the network nodes, and numerical processing is carried out by taking the way of subtracting the relevant parameters between the unknown coordinate and the ordinary nodes and the relevant parameters between the unknown coordinate and the reference node correspondingly to establish a constrained failure area positioning equation. Therefore, the coordinates of the failure offset area can be obtained by constrained solution according to the limit value of the multipath propagation deviation. Compared with the failure area positioning method based on wireless sensor GPS positioning, obtaining the relative coordinates of the network nodes, the distance measurement deviation value and the multipath propagation deviation when the network nodes transmit information for failure area positioning occupies less communication resources, can overcome the problems of uneven communication resource allocation, slow signal transmission, and communication content distortion and jamming during the node transmission process under the condition of limited communication resources, is beneficial to the improvement of the communication status, provides scientific and high-quality node communication resources for the disaster area communication network, and thus can effectively adapt to the condition of limited communication resources and meet the actual needs of this scenario.

[0076] In some embodiments, when establishing the basic equation, it is assumed that there are n + 1 wireless network signal sensors numbered 0, 1, 2, 3, …, n, where the 0th one is used as the reference sensor in the offset failure location (note that the 0th wireless network signal sensor is randomly selected from the n + 1 sensors). Taking the failure area as the unknown coordinate, assuming that there are n + 1 network nodes, namely the 0th, 1st, …, nth network nodes, the basic equation regarding the actual sensing distance and the propagation time between the failure area and the mth network node is as follows:

[0077]

[0078] where m is an integer belonging to [0, n], and r m represents the actual sensing distance between the failure area and the mth network node; v represents the propagation speed of the radio wave; d m represents the coordinate distance between the unknown coordinate and the relative coordinate of the mth network node; n m represents the distance measurement deviation value; e m represents the multipath propagation deviation; t m represents the propagation time of the radio wave.

[0079] If the 0th network node is used as the reference node and the ith network node is used as the ordinary node, where i is a positive integer belonging to (0, n], the failure area location equation is:

[0080]

[0081] where r i,0 represents the difference in the actual sensing distance; d i,0 represents the difference in the coordinate distance; n i,0 represents the difference in the distance measurement deviation value; e i,0 represents the difference in the multipath propagation deviation.

[0082] The limit values of the multipath propagation deviation include the upper limit value and the lower limit value of the multipath propagation deviation; it should be noted that when selecting the limit values, the following characteristics of the multipath propagation deviation can be preferably considered:

[0083] 1) During the propagation of the radio wave from the failure area to the network node, the sum of the reflection propagation, refraction propagation, and diffraction propagation paths of the radio wave from this area to adjacent nodes is greater than the direct propagation path. Therefore, the multipath propagation deviation is greater than 0. Preferably, the lower limit value of the multipath propagation deviation is 0.

[0084] 2) Considering the limitations of network nodes and propagation attenuation rates, there is an upper bound for the difference obtained by subtracting the direct path from the sum of the reflection path, refraction path, and diffraction path of radio waves from this area to adjacent nodes. Therefore, the upper limit value of the multipath propagation deviation can be obtained from the attenuation rate of multipath propagation.

[0085] In some embodiments, solving the failure area positioning equation according to the limit value of the multipath propagation deviation to obtain the coordinates of the failure area specifically includes the following steps S11 to S15:

[0086] S11: Let the unknown coordinates of the failure area be x(x x , y x , z x ), and the relative coordinates of the i-th network node be Performing a square operation on the failure area positioning equation (2) to obtain equation (3):

[0087]

[0088] S12: Rewrite equation (3) to obtain equation (4):

[0089]

[0090] Where A i =(S1, S2,..., S i ), ΔA i =(S1, S2,..., S i ), T ,

[0091] B i =((r 1，0 -e 1，0 ), (r 2，0 -e 2，0 ),..., (r i，0 -e i，0 ))), ΔB1 = (-d1, -d2,..., -d i );

[0092] S13: Omit the high-order small quantities from formula (4) to obtain formula (5):

[0093]

[0094] Where N is a positive integer greater than 1;

[0095] S14: Rewrite formula (5) into formula (6) according to the difference of the limit value:

[0096]

[0097] Among them, the difference ρ of the limit value i,0 is determined by ρ i,0 = ρ i - ρ0, where ρ i is the upper limit value of the multipath propagation deviation of the i-th network node;

[0098] S15: Solve formula (6) to obtain the coordinates of the failure area.

[0099] Considering that formula (6) is difficult to solve directly, in this embodiment, the algorithm is improved, that is, formula (6) is first rewritten as a positioning optimization problem, and then solved by a common solution method. Preferably, solving formula (6) to obtain the coordinates of the failure area specifically includes the following steps S16 to S22:

[0100] S16: Substitute the expressions of ΔA i and ΔB i into formula (6) to obtain formula (7):

[0101]

[0102] S17: Formula (7) is scaled by the absolute value inequality to obtain formula (8):

[0103]

[0104] S18: Define the variable λ = [λ1, λ2,..., λ n T , and transform formula (8) into formula (9) and formula (10):

[0105]

[0106] ‖x - s i ‖ = d i

[0107]

[0108] S19: Express the variable θ as formula (11):

[0109] θ * = θθ T ≥ 0 (11)

[0110] Among them, θ * ≥ 0 means that the eigenvalues of the matrix θ * are greater than or equal to 0;

[0111] S20: Transform formula (11) into formula (12): ​

[0112]

[0113] S21: According to formulas (9), (10), and (12), the optimized positioning model (13) is obtained:

[0114]

[0115] S22: Use the mathematical toolbox to solve the optimized positioning model (13) to obtain the coordinates of the failure area.

[0116] By improving the above algorithm, the smooth calculation of the positioning coordinates of the failure area can be realized, so as to screen out the effective communication area, improve the information transmission efficiency and communication capacity under the condition of limited communication resources, and ensure the necessary needs of mobile terminal users in the disaster area.

[0117] See Figure 2 , which is a schematic structural diagram of an embodiment of a wireless sensor network node area positioning device provided by the present invention.

[0118] The embodiment of the present invention also provides a wireless sensor network node area positioning device, including:

[0119] A model establishment unit for constructing a positioning model of the failure area with the communication base station in the wireless sensor network as the origin of the coordinate system;

[0120] A node data acquisition unit for obtaining the relative coordinates of the network nodes and the distance measurement deviation value and multipath propagation deviation when the network nodes transmit information based on the positioning model;

[0121] A calculation and processing unit, including an equation set establishment module and an equation set calculation module;

[0122] The equation set establishment module is used to establish a basic equation between the failure area and any network node regarding the actual sensing distance and the propagation time with the failure area as the unknown coordinates, according to the relative coordinates of any network node, the coordinate distance between the unknown coordinates, the distance measurement deviation value, the multipath propagation deviation, and the propagation speed of radio waves;

[0123] The equation set calculation module is used to take any network node as the reference node and the network nodes other than the reference node as ordinary nodes; perform subtraction on the relevant parameters between the unknown coordinates and the ordinary nodes and the relevant parameters between the unknown coordinates and the reference node respectively to form the difference corresponding to the relevant parameters; wherein, the relevant parameters include the coordinate distance, the distance measurement deviation value, the multipath propagation deviation, the actual sensing distance, and the propagation time;

[0124] Substitute the difference of the relevant parameters into the basic equation to obtain the failure area positioning equation;

[0125] Solve the failure area positioning equation according to the limit value of the multipath propagation deviation to obtain the coordinates of the failure area.

[0126] Preferably, the equation set building module is used to build the basic equation. Taking the failure area as the unknown coordinates, assuming that there are n + 1 network nodes, namely the 0th, 1st, …, nth network nodes, the basic equation between the failure area and the mth network node regarding the actual sensing distance and the propagation time is:

[0127]

[0128] where m is an integer belonging to [0, n], and r m represents the actual sensing distance between the failure area and the mth network node; v represents the propagation speed of the radio wave; d m represents the coordinate distance between the unknown coordinates and the relative coordinates of the mth network node; n m represents the distance measurement deviation value; e m represents the multipath propagation deviation; t m represents the propagation time of the radio wave.

[0129] Preferably, the equation set calculation module takes the 0th network node as the reference node and the ith network node as the ordinary node, where i is a positive integer belonging to (0, n]. Then the failure area positioning equation is:

[0130]

[0131] where r i,0 represents the difference of the actual sensing distance; d i,0 represents the difference of the coordinate distance; n i,0 represents the difference of the distance measurement deviation value; e i,0 represents the difference of the multipath propagation deviation.

[0132] The limit value of the multipath propagation deviation includes the upper limit value and the lower limit value of the multipath propagation deviation; it should be noted that the following characteristics of the multipath propagation deviation can be preferably considered for limit value selection:

[0133] 1) During the propagation of the radio wave from the failure area to the network node, the sum of the reflection propagation, refraction propagation, and diffraction propagation paths of the radio wave from this area to adjacent nodes is greater than the direct propagation path. Therefore, the multipath propagation deviation is greater than 0. Preferably, the lower limit value of the multipath propagation deviation is 0.

[0134] 2) Considering the limitations of network nodes and propagation attenuation rates, there is an upper bound for the difference obtained by subtracting the direct path from the sum of the reflection path, refraction path, and diffraction path of radio waves from this area to adjacent nodes. Therefore, the upper limit value of the multipath propagation deviation can be obtained from the attenuation rate of multipath propagation.

[0135] According to the limit value of the multipath propagation deviation, solve the failure area positioning equation to obtain the coordinates of the failure area, specifically including:

[0136] Let the unknown coordinates of the failure area be x(x x , y x , z x ), and the relative coordinates of the i-th network node are Perform a squaring operation on the failure area positioning equation (2) to obtain equation (3):

[0137]

[0138] Rewrite equation (3) to obtain equation (4):

[0139]

[0140] Where A i =(S1, S2,..., S i ), ΔA i =(S1, S2,..., S i ) T ,

[0141] B i =((r 1，0 -e 1，0 ), (r 2，0 -e 2，0 ),..., (r i，0 -e i，0 )), ΔB1 = (-d1, -d2,..., d i );

[0142] Omit the high-order small quantities from formula (4) to obtain formula (5):

[0143]

[0144] Where N is a positive integer greater than 1;

[0145] According to the difference of the limit value, rewrite formula (5) as formula (6):

[0146]

[0147] Among them, the difference ρ of the limit value i,0 is determined by ρ i,0 = ρ i - ρ0, where ρ i is the upper limit of the multipath propagation deviation of the i-th network node;

[0148] Solve formula (6) to obtain the coordinates of the failure area.

[0149] Considering that it is difficult to directly solve formula (6), the equation set calculation module is also used to improve the algorithm, that is, first rewrite formula (6) as a positioning optimization problem, and then use the ordinary solution method to solve it. Preferably, solving formula (6) to obtain the coordinates of the failure area specifically includes:

[0150] Substitute the expressions of ΔA i and ΔB i into formula (6) to obtain formula (7):

[0151]

[0152] Formula (7) is scaled by the absolute value inequality to obtain formula (8):

[0153]

[0154] Define the variable λ = [λ1, λ2,..., λ n T , and transform formula (8) into formula (9) and formula (10):

[0155]

[0156] ‖x - s i ‖ = d i

[0157]

[0158] Express the variable θ as formula (11):

[0159] θ * = θθ T ≥ 0 (11)

[0160] Among them, θ * ≥ 0 means that the eigenvalues of the matrix θ * are greater than or equal to 0;

[0161] Transform formula (11) into formula (12):

[0162]

[0163] ​According to formulas (9), (10), and (12), the optimized positioning model (13) is obtained:

[0164]

[0165] Solve the optimized positioning model (13) using a mathematical toolbox to obtain the coordinates of the failure area. An embodiment of the present invention also provides a computer-readable storage medium, which includes a stored computer program; wherein, when the computer program runs, it controls the device where the computer-readable storage medium is located to execute the positioning method for the failure area of the wireless sensor network described in any one of the above embodiments.

[0166] An embodiment of the present invention also provides a terminal device, including a processor, a memory, and a computer program stored in the memory and configured to be executed by the processor. When the processor executes the computer program, it implements the positioning method for the failure area of the wireless sensor network described in any one of the above embodiments.

[0167] Exemplarily, the computer program can be divided into one or more modules / units. The one or more modules / units are stored in the memory and executed by the processor to complete the present invention. The one or more modules / units can be a series of computer program instruction segments capable of performing specific functions, and these instruction segments are used to describe the execution process of the computer program in the terminal device.

[0168] The terminal device can be a computing device such as a desktop computer, a notebook, a palm computer, and a cloud server. The terminal device may include, but is not limited to, a processor and a memory. Those skilled in the art can understand that the schematic diagram is only an example of the terminal device and does not constitute a limitation on the terminal device. It may include more or fewer components than shown, or combine certain components, or different components. For example, the terminal device may also include input / output devices, network access devices, a bus, etc.

[0169] The so-called processor may be a Central Processing Unit (CPU), or it may also be other general-purpose processors, Digital Signal Processors (DSPs), Application Specific Integrated Circuits (ASICs), Field-Programmable Gate Arrays (FPGAs), or other programmable logic devices, discrete gate or transistor logic devices, discrete hardware components, etc. The general-purpose processor may be a microprocessor or the processor may also be any conventional processor, etc. The processor is the control center of the terminal device and connects all parts of the entire terminal device through various interfaces and lines.

[0170] The memory can be used to store the computer program and / or module. The processor realizes various functions of the terminal device by running or executing the computer program and / or module stored in the memory, and by calling the data stored in the memory. The memory may mainly include a program storage area and a data storage area. Among them, the program storage area can store an operating system, application programs required for at least one function (such as a sound playback function, an image playback function, etc.); the data storage area can store data created according to the use of the mobile phone (such as audio data, phone book, etc.). In addition, the memory may include high-speed random access memory, and may also include non-volatile memory, such as a hard disk, memory, plug-in hard disk, Smart Media Card (SMC), Secure Digital (SD) card, Flash Card, at least one magnetic disk storage device, flash device, or other volatile solid-state storage devices.

[0171] Among them, if the modules / units integrated in the terminal device are implemented in the form of software functional units and sold or used as independent products, they can be stored in a computer-readable storage medium. Based on such an understanding, to implement all or part of the processes in the above-mentioned embodiment methods of the present invention, it can also be completed by a computer program instructing relevant hardware. The computer program can be stored in a computer-readable storage medium. When the computer program is executed by a processor, the steps of the above-mentioned various method embodiments can be implemented. Among them, the computer program includes computer program code, and the computer program code can be in the form of source code, object code, executable file, or some intermediate form, etc. The computer-readable medium can include: any entity or device capable of carrying the computer program code, recording medium, USB flash drive, mobile hard disk, magnetic disk, optical disk, computer memory, read-only memory (ROM, Read-Only Memory), random access memory (RAM, Random Access Memory), electrical carrier signal, telecommunication signal, and software distribution medium, etc. It should be noted that the content included in the computer-readable medium can be appropriately increased or decreased according to the requirements of legislation and patent practice within the jurisdiction. For example, in some jurisdictions, according to legislation and patent practice, the computer-readable medium does not include electrical carrier signals and telecommunication signals.

[0172] In summary, for a method, device, medium, and terminal device for locating a failure area of a wireless sensor network provided by an embodiment of the present invention, by constructing a positioning model of the failure area, obtaining the relative coordinates of network nodes, the distance measurement deviation value and multipath propagation deviation when the network nodes transmit information, establishing a basic equation between the failure area and any of the network nodes regarding the actual sensing distance and the propagation time, and performing numerical processing by taking the difference between the relevant parameters between the unknown coordinates and the ordinary nodes and the relevant parameters between the unknown coordinates and the reference nodes, a constrained failure area positioning model is established. Therefore, the coordinates of the failure offset area can be obtained by performing constrained solution according to the limit value of the multipath propagation deviation. Compared with the failure area positioning method based on wireless sensor GPS positioning, obtaining the relative coordinates of network nodes, the distance measurement deviation value and multipath propagation deviation when the network nodes transmit information for failure area positioning occupies relatively less communication resources. Therefore, the present invention can adapt to the condition of limited communication resources and meet the actual needs in this scenario.

[0173] It should be noted that the device embodiments described above are merely illustrative. The units described as separate components may or may not be physically separated, and the components shown as units may or may not be physical units, that is, they may be located in one place or distributed to multiple network units. Some or all of the modules can be selected according to actual needs to achieve the purpose of the solution of this embodiment. In addition, in the attached drawings of the device embodiments provided by the present invention, the connection relationships between modules indicate that they have communication connections, which can be specifically implemented as one or more communication buses or signal lines. Those of ordinary skill in the art can understand and implement without creative efforts.

[0174] The above is the preferred embodiment of the present invention. It should be pointed out that for those of ordinary skill in the art, without departing from the principle of the present invention, several improvements and refinements can be made, and these improvements and refinements are also regarded as the protection scope of the present invention.

Claims

1. A method for locating the failure area of a wireless sensor network, characterized in that, Including: Taking the communication base station in the wireless sensor network as the origin of the coordinate system, a positioning model of the failure area is constructed; Based on the positioning model, the relative coordinates of the network nodes, the distance measurement deviation value and the multipath propagation deviation when the network nodes transmit information are obtained; Taking the failure area as the unknown coordinate, according to the coordinate distance between the relative coordinates of any network node and the unknown coordinate, the distance measurement deviation value, the multipath propagation deviation, and the propagation speed of radio waves, a basic equation regarding the actual sensing distance and the propagation time between the failure area and any network node is established; Taking any network node as the reference node and the network nodes other than the reference node as ordinary nodes; the relevant parameters between the unknown coordinate and the ordinary nodes and the relevant parameters between the unknown coordinate and the reference node are subtracted correspondingly to form the difference corresponding to the relevant parameters; wherein, the relevant parameters include the coordinate distance, the distance measurement deviation value, the multipath propagation deviation, the actual sensing distance, and the propagation time; the difference of the relevant parameters is substituted into the basic equation correspondingly to obtain the failure area positioning equation; According to the limit value of the multipath propagation deviation, the failure area positioning equation is solved to obtain the coordinates of the failure area; Among them, taking the failure area as the unknown coordinate, according to the coordinate distance between the relative coordinates of any network node and the unknown coordinate, the distance measurement deviation value, the multipath propagation deviation, and the propagation speed of radio waves, establishing the basic equation regarding the actual sensing distance and the propagation time between the failure area and any network node specifically includes: Taking the failure area as the unknown coordinate, assuming that there are n + 1 network nodes, which are the 0th, 1st, …, nth network nodes respectively, then the basic equation regarding the actual sensing distance and the propagation time between the failure area and the mth network node is: Wherein, m is an integer belonging to [0, n], and r m represents the actual sensing distance between the failure area and the m-th network node; v represents the propagation speed of the radio wave; d m represents the coordinate distance between the unknown coordinate and the relative coordinate of the m-th network node; n m represents the distance measurement deviation value; e m represents the multipath propagation deviation; t m represents the propagation time of the radio wave; Among them, taking any network node as the reference node and the network nodes other than the reference node as ordinary nodes; the relevant parameters between the unknown coordinate and the ordinary nodes and the relevant parameters between the unknown coordinate and the reference node are subtracted correspondingly to form the difference corresponding to the relevant parameters; wherein, the relevant parameters include the coordinate distance, the distance measurement deviation value, the multipath propagation deviation, the actual sensing distance, and the propagation time; substituting the difference of the relevant parameters into the basic equation correspondingly to obtain the failure area positioning equation specifically includes: Taking the 0th network node as the reference node and the ith network node as the ordinary node, where i is a positive integer belonging to (0, n], then the failure area positioning equation is: where r i,0 represents the difference in the actual sensing distance; d i,0 represents the difference in the coordinate distance; n i,0 represents the difference in the distance measurement deviation value; e i,0 represents the difference in the multipath propagation deviation.

2. The method for locating the failure area of a wireless sensor network according to claim 1, characterized in that, The limit value of the multipath propagation deviation includes the upper limit value and the lower limit value of the multipath propagation deviation; among them, the upper limit value of the multipath propagation deviation is obtained from the attenuation rate of the multipath propagation.

3. The method for locating the failure area of a wireless sensor network according to claim 2, characterized in that, The lower limit value of the multipath propagation deviation is 0.

4. A device for locating the node area of a wireless sensor network, characterized in that, Including: A model establishment unit, configured to take the communication base station in the wireless sensor network as the origin of the coordinate system and construct a positioning model of the failure area; A node data acquisition unit, configured to obtain the relative coordinates of a network node, as well as the distance measurement deviation value and the multipath propagation deviation when the network node transmits information, based on the positioning model. A calculation and processing unit, including an equation set establishment module and an equation set calculation module. The equation set establishment module is configured to establish a basic equation regarding the actual sensing distance and the propagation time between the failure area and any of the network nodes, with the failure area as the unknown coordinates, according to the relative coordinates of any of the network nodes, the coordinate distance between the unknown coordinates, the distance measurement deviation value, the multipath propagation deviation, and the propagation speed of radio waves. The equation set calculation module is configured to use any of the network nodes as a reference node and the network nodes other than the reference node as ordinary nodes; perform a difference operation on the relevant parameters between the unknown coordinates and the ordinary nodes and the relevant parameters between the unknown coordinates and the reference node respectively to form the difference values corresponding to the relevant parameters; where the relevant parameters include the coordinate distance, the distance measurement deviation value, the multipath propagation deviation, the actual sensing distance, and the propagation time; substitute the difference values of the relevant parameters into the basic equation correspondingly to obtain the failure area positioning equation. Solve the failure area positioning equation according to the limit value of the multipath propagation deviation to obtain the coordinates of the failure area. Among them, the equation set establishment module is specifically configured to: With the failure area as the unknown coordinates, assume that there are n + 1 network nodes, which are the 0th, 1st, …, nth network nodes respectively. Then the basic equation regarding the actual sensing distance and the propagation time between the failure area and the mth network node is: where m is an integer belonging to [0, n], and r m represents the actual sensing distance between the failure area and the m-th network node; v represents the propagation speed of the radio wave; d m represents the coordinate distance between the unknown coordinate and the relative coordinate of the m-th network node; n m represents the distance measurement deviation value; e m represents the multipath propagation deviation; t m represents the propagation time of the radio wave; The equation set calculation module is specifically configured to: Use the 0th network node as the reference node and the ith network node as the ordinary node, where i is a positive integer belonging to (0, n]. Then the failure area positioning equation is: where r i,0 represents the difference in the actual sensing distance; d i,0 represents the difference in the coordinate distance; n i,0 represents the difference in the distance measurement deviation value; e i,0 represents the difference in the multipath propagation deviation.

5. A computer-readable storage medium, characterized in that, The computer-readable storage medium includes a stored computer program; wherein, the computer program controls the device where the computer-readable storage medium is located to execute the positioning method for the failure area of the wireless sensor network as described in any one of claims 1 to 3 when running.

6. A terminal device, characterized in that, It includes a processor, a memory, and a computer program stored in the memory and configured to be executed by the processor. The processor implements the positioning method for the failure area of the wireless sensor network as described in any one of claims 1 to 3 when executing the computer program.

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