Research On Passive Location Technology And Node Selection Method Based On TDOA

With the continuous development of technology in recent years,especially the development of 5G technology,passive positioning technology has penetrated into every aspect of life,bringing a wider range of application scenarios to target positioning technology,especially in signal processing and vehicle positioning.In the fields of navigation,target detection,wireless communication,and wireless sensor networks,target positioning technology has an irreplaceable position.Research on passive target positioning technology has great application value.In-depth research on the application of passive positioning technology in different environments and positioning scenarios can not only promote people's quality of life and meet the needs of positioning scenarios in daily life,but also improve electronic countermeasures and regional protection.The military strength of a country is of great military significance.This article focused on the application of TDOA passive positioning technology,and expanded on the basis of previous research,and researched the key points and difficult problems in TDOA passive positioning technology.The modeling and solving process of the actual problem was deduced in detail,and the method of node selection based on sensor network was researched,and the solution to the problem of sensor node selection was proposed.The main research results of this article were following:1.A target location method based on improved constrained total least squares method was in the study.In order to solve the problem of poor target positioning performance of traditional analytical algorithms in the case of poor noise environmental conditions,that was,when the TDOA measurement error was large or the geometric relationship between the target and the sensor network was not ideal,a target location method based on improved constrained total least squares(CTLS)was proposed.First,the hyperbolic positioning equations were transformed and simplified into a set of pseudo-linear matrix equations.Based on the constraint total least squares method,an intermediate variable was introduced to improve the objective function in the CTLS method to transform a single-variable optimization problem into a multi-variable optimization problem.Then this study used the ADMM method to iteratively solve it to get a rough estimate of the target position,used the rough estimated position to calculate a coefficient matrix with higher accuracy,and iterated again to get an accurate estimate of the target position.Finally,the influence of the TDOA measurement errors,the number of sensors and the geometric distribution of the sensor network on the performance of the algorithm were given through simulation,and the comparative analysis result of the algorithm complexity was given.It was verified that the proposed algorithm could still have a high positioning performance when the noise environment was poor.2.A TDOA-based over-the-horizon target positioning method was in the study.When the target radiation signal propagates along the surface of the earth,owing to the key technical problem of achieving passive positioning of the target under the condition of TDOA as the measurement quantity,passive positioning method for beyond-horizon target based on TDOA was proposed.First,the conversion relationship of some parameters under the WGS84 earth model was given,and the nonlinear mathematical model of the target positioning in the spherical triangle was established,and the corresponding target position solution method suitable for the above nonlinear model was given,and the detailed algorithm was given.Then the mathematical expression of CRLB for target positioning was derived,and the main factors affecting the positioning accuracy were given theoretically,that was,the TDOA measurement errors and the geometric position relationship between the target and each receiving station.Then,by deriving the calculation formula of the geometric positioning accuracy factor GDOP,under the given parameters,the influence of each variable on the positioning performance of the passive positioning system was analyzed.Finally,the effectiveness of the proposed method was verified by computer simulation experiments.3.The method of selecting sensor nodes based on TDOA positioning was in the study.Due to the system energy consumption of the sensor network,each node in the sensor network could not always be in working condition.In order to comprehensively consider the positioning performance of the sensor network and the relationship between the service life of the sensor network and the system loss,a tabu-based search,TDOA passive positioning system sensor node optimization method was proposed.Firstly considering the TDOA passive positioning method under the double errors condition of the position errors of the sensor and the TDOA measurement errors,this study derived the approximate restricted least squares closed-form solution under the double errors condition,and then derived the positioning errors agreement under this condition.The expression of the variance matrix transformed the sensor node optimization problem into a Boolean vector solving problem by introducing a Boolean vector,and then used the tabu search method to solve the optimization problem.Finally,in the simulation experiment,the TDOA measurement errors,the position errors of the sensor itself,the scale of the sensor network,the geometric position relationship between the target position and the sensor node were given on the performance of the algorithm.Compared with existing algorithms,the proposed algorithm has had advantages in performance and computational efficiency.