CN-121996902-A - Combined error dynamic correction method based on optical fiber and wireless sensing co-judgment event

CN121996902ACN 121996902 ACN121996902 ACN 121996902ACN-121996902-A

Abstract

The invention discloses a combined error dynamic correction method based on an optical fiber and wireless sensing co-judgment event, which relates to the technical field of distributed optical fiber sensing and comprises the following steps: and (3) correlating the DAS vibration event with the wireless network acoustic event through high-precision time synchronization, generating a co-judgment event instance, defining error parameters to be estimated, establishing a joint observation model, combining the error parameters through an iterative re-weighting least square algorithm, carrying out real-time dynamic correction on the event through final error parameter estimation, and obtaining a result through weighted average. The invention combines modeling and real-time compensation to the positioning error of the DAS host and the wireless sensor network, so that the fusion positioning result is more approximate to the real geographic coordinate of the disturbance event, the limitation of the traditional method is overcome, the positioning precision in the complex environment is improved, and the invention also adopts an iterative re-weighted least square algorithm and a forgetting factor mechanism, enhances the robustness to abnormal events and environmental changes, and realizes the long-term stable self-adaptive optimization.

Inventors

XIAO ZIYANG
WANG HUA
LI LUMING
ZHANG ZHIGUO
GU XUELIANG

Assignees

国网江西省电力有限公司信息通信分公司

Dates

Publication Date: 20260508
Application Date: 20260410

Claims (10)

1. The combined error dynamic correction method based on the optical fiber and wireless sensing co-judgment event is characterized by comprising the following steps of: Step S1, a DAS host outputs a vibration event list, wherein each DAS event in the vibration event list comprises an optical fiber position and a DAS local time stamp, a wireless sensor network synchronously outputs an acoustic event list, each wireless event in the acoustic event list comprises a preliminary positioning coordinate and a wireless network local time stamp, and a central processing unit uniformly converts the time stamps of two paths of data streams into an absolute time coordinate system by utilizing a time reference provided by a high-precision synchronous clock source; Step S2, for each DAS event, mapping the optical fiber position of each DAS event into estimated geographic coordinates through an optical fiber geographic information database, searching for a wireless event in a preset time window, calculating the spatial distance of each wireless event, and if the spatial distance is smaller than a preset spatial correlation threshold, judging that the DAS event and the wireless event are two observations of the same physical event, generating a co-judgment event instance and storing the co-judgment event instance into a co-judgment event pool; Step S3, defining error parameters to be estimated, wherein the error parameters comprise DAS error parameter vectors and wireless network error parameter vectors, establishing a combined observation model according to the error parameters, the observation data pairs and the optical fiber positions, and obtaining a residual equation by eliminating real geographic position parameters; S4, initializing an error function model, iteration times and initial weights by adopting an iterative re-weighting least square algorithm, performing first-order Taylor expansion on a residual equation to construct a linearization incremental equation, solving a weighted normal equation to finish parameter iterative updating, and repeatedly iterating until convergence conditions are met according to the iterative residual updating event weights, and outputting final error parameter estimation; S5, respectively carrying out real-time dynamic correction on the positioning output results of the DAS event and the wireless event according to the final error parameter estimation to obtain corrected coordinates, determining confidence coefficient according to the historical residual error of the corrected coordinates, and obtaining the final fusion positioning result of the co-judgment event through weighted average; And S6, maintaining a sliding window with a fixed size, retaining the latest co-judgment event data, and updating error parameter estimation by adopting a recursive least square algorithm combined with a forgetting factor when the latest co-judgment event enters the window, and adjusting the forgetting factor according to covariance traces or residual sequences of the error parameter estimation to realize the online self-adaptive optimization of the parameters.
2. The method for dynamically correcting joint errors based on co-judgment events of optical fibers and wireless sensing according to claim 1, wherein before executing the step S1, the method for dynamically correcting joint errors further comprises an initialization and optical cable identity calibration stage: applying a specifically encoded vibration signal to the target fiber optic cable at a known geographic coordinate point using a perturbation device; the DAS host detects and records the position and vibration characteristics of the optical fiber of each vibration event; The wireless sensor network synchronously detects and records the preliminary positioning coordinates of each acoustic event; And the central processing unit performs space-time correlation on DAS events and wireless events from the same physical excitation, confirms a co-judgment relationship, and establishes a reference mapping library of optical cable identity ID-optical fiber position-wireless sensor network actual measurement coordinates for optical cable identity identification during online monitoring.
3. The method for dynamically correcting the joint error based on the optical fiber and wireless sensing co-judgment event according to claim 1, wherein the DAS host in the step S1 is a distributed acoustic wave sensing host, and the DAS host obtains the optical fiber position and the DAS local timestamp of the vibration event list through phase demodulation and event detection by processing the backward rayleigh scattering signal in real time.
4. The method for dynamically correcting the joint error based on the co-judgment event of the optical fiber and the wireless sensor according to claim 1, wherein the preset time window in the step S2 is a front-back symmetric interval of the absolute time of the DAS event, the spatial distance is obtained by calculating the euclidean distance between the estimated geographic coordinates and the preliminary positioning coordinates of the wireless event, and the expression is as follows: , wherein, In order to be a spatial distance from each other, In order to estimate the geographic coordinates of the object, Is the preliminary location coordinates of the wireless event.
5. The method for dynamically correcting the joint error based on the optical fiber and wireless sensing co-judgment event according to claim 4, wherein the joint observation model in the step S3 satisfies: ; ; Wherein, the And As a function of the error of the parameterization, Representing the random observation noise of the image, For the DAS error parameter vector, As a vector of error parameters for the wireless network, Is the first in the co-judgment event pool The true geographic location of the individual events, For the position of the optical fiber, And Is a co-judgment event instance Is provided with a pair of observation data of the information, Is the first The DAS of each event observes noise, Is the first Wireless network observation noise for individual events; the expression of the residual equation is: ; Wherein, the The residual equations denoted as DAS error parameter vector and wireless network error parameter vector.
6. The method for dynamically correcting joint errors based on co-judgment events of optical fibers and wireless sensing according to claim 1, wherein the DAS error parameter vector in the step S3 is used for correcting mapping deviation from optical fiber position to geographic coordinates, and the wireless network error parameter vector is used for correcting positioning deviation caused by acoustic wave propagation speed deviation.
7. The method for dynamically correcting joint errors based on co-judgment events of optical fiber and wireless sensing according to claim 5, wherein the error function model in the step S4 comprises a linear drift model of the optical fiber sensing side and a regional translation model of the wireless sensing side; The expression of the linear drift model is as follows: , wherein, , Is a fixed offset vector in the DAS error, For the linear drift coefficient vector in the DAS error, Fiber positions for DAS events; the expression of the regional translation model is as follows: , wherein, , Is a regional translation vector in the wireless network error.
8. The method for dynamically correcting the joint error based on the optical fiber and wireless sensing co-judgment event according to claim 1, wherein the iterative weighted least square algorithm in the step S4 adopts a Huber weight function and a Tukey weight function to update the event weight, so that the influence of the abnormal co-judgment event on the error parameter estimation result is reduced.
9. The method for dynamically correcting the joint error based on the co-judgment event of optical fiber and wireless sensing according to claim 7, wherein the calculation formula of the corrected coordinates in the step S5 is as follows: For a newly arrived DAS event, its corrected coordinates are: ; For a newly arrived wireless event, its corrected coordinates are: ; Wherein, the The post-correction coordinates for the DAS event, The post-correction coordinates for the wireless event, For the final error parameter estimation of the DAS, And estimating final error parameters for the wireless network.
10. The method for dynamically correcting joint errors based on co-judgment events of optical fiber and wireless sensing according to claim 1, wherein the updating formula of the error parameter estimation in step S6 comprises: ; ; Wherein, the Is the regression vector corresponding to the new event, Is the observed difference value for the new event, For the updated error parameter estimate, In order to update the pre-update error parameter estimate, Is forgetting factor and meets , In order to update the covariance of the data in the data, In order for the pre-update covariance to be present, Is the number of iterations.

Description

Combined error dynamic correction method based on optical fiber and wireless sensing co-judgment event Technical Field The invention relates to the technical field of distributed optical fiber sensing, in particular to a combined error dynamic correction method based on an optical fiber and wireless sensing co-judgment event. Background The optical fiber distributed acoustic wave sensing (DAS) technology can continuously locate and identify vibration events along sensing optical fibers, and the wireless acoustic wave sensing network can realize regional monitoring on sound sources. In order to improve the monitoring performance, the prior art proposes a fusion monitoring scheme for combining the two. In the prior art, a high-precision time synchronization technology is generally relied on to perform space-time correlation matching on a vibration event detected by a distributed acoustic wave sensing system and an acoustic event detected by a wireless acoustic wave sensing network, and when the same disturbance event is determined, geographic coordinates obtained by distributed acoustic wave sensing through a static mapping relation are typically fused with coordinates estimated by the wireless acoustic wave sensing network through an acoustic positioning algorithm, such as direct comparison or weighted average. However, the technical scheme has the obvious defect that the scheme fusion process essentially belongs to shallow fusion of the post-correlation and the data layer, and cannot fundamentally treat the inherent and environment-changing systematic errors of two independent sensing systems. Specifically, the positioning error of the distributed acoustic wave sensing mainly comes from the expansion and contraction of the physical length of the optical fiber caused by temperature and stress changes, and the preset static optical fiber-geographic coordinate mapping table is difficult to accurately reflect complex laying routes, and the positioning error of the wireless acoustic wave sensing network mainly comes from the changes of the propagation speed of the acoustic wave in the air caused by the influence of temperature, humidity and wind speed, and the environmental interference such as multipath effect, non-line-of-sight propagation and the like. Because the system errors are not effectively modeled, estimated and compensated on line, the fusion positioning accuracy is limited when the problems of complex signal propagation attenuation, time delay change and the like in the actual environment are solved by the prior art, and the long-term stability and environmental adaptability of the system are insufficient, so that stable and reliable high-accuracy positioning is difficult to realize. Based on the method, a combined error dynamic correction method based on the optical fiber and wireless sensing co-judgment event is provided, so that the defects existing in the prior art scheme can be overcome. Disclosure of Invention The invention aims to provide a combined error dynamic correction method based on an optical fiber and wireless sensing co-judgment event, so as to solve the problems that in the prior art, when the problems of complex signal propagation attenuation, time delay change and the like in an actual environment are solved, the fusion positioning precision is limited, the long-term stability and the environmental adaptability are insufficient, and the stable and reliable high-precision positioning is difficult to realize. In order to achieve the above purpose, the present invention provides the following technical solutions: The method for dynamically correcting the joint error based on the optical fiber and wireless sensing co-judgment event specifically comprises the following steps: Step S1, a DAS host outputs a vibration event list, wherein each DAS event in the vibration event list comprises an optical fiber position and a DAS local time stamp, a wireless sensor network synchronously outputs an acoustic event list, each wireless event in the acoustic event list comprises a preliminary positioning coordinate and a wireless network local time stamp, and a central processing unit uniformly converts the time stamps of two paths of data streams into an absolute time coordinate system by utilizing a time reference provided by a high-precision synchronous clock source; Step S2, for each DAS event, mapping the optical fiber position of each DAS event into estimated geographic coordinates through an optical fiber geographic information database, searching for a wireless event in a preset time window, calculating the spatial distance of each wireless event, and if the spatial distance is smaller than a preset spatial correlation threshold, judging that the DAS event and the wireless event are two observations of the same physical event, generating a co-judgment event instance and storing the co-judgment event instance into a co-judgment event pool; Step S3, defining error parameters to be estimated,