Distributed Passive Positioning Technology

In modern warfare,the concealment of reconnaissance equipment is critical.The advent of passive positioning technology has brought new ideas to traditional positioning methods,and the target position can be determined without actively transmitting electromagnetic waves.Distributed passive positioning means that multiple measurement stations work together to find the target position by silently receiving the electromagnetic waves of the radiation source to achieve the purpose of positioning.Distributed passive positioning technology has a wide range of applications and plays an important role in the field of electronic countermeasures.There are many positioning technologies that can be used in distributed passive positioning systems,such as angular positioning,time difference positioning,frequency difference,phase difference positioning,and hybrid positioning.In recent years,many scholars have studied single-site and multi-site passive positioning technology based on sparse airspace.Among these positioning technologies,time difference positioning has the advantages of flexible positioning,high accuracy,simple algorithm,and high robustness.Therefore,it is one of the most widely used and researched distributed passive positioning technologies.Time difference positioning is a positioning algorithm that uses the time of arrival difference to determine the position.It needs at least two TDOA estimates to locate the target.Each TDOA estimation value can form a hyperbola,and the target position is determined by solving the intersection of several hyperbola.Therefore,time difference positioning can also be called hyperbola positioning.This paper will systematically study the distributed passive positioning technology based on TDOA through two aspects,mainly including the following aspects:(1)time difference estimation technology;(2)target position solution technology based on TDOA estimation;(3)MATLAB simulation of time difference estimation;(4)Simulation analysis of factors affecting the accuracy of target position positioning.The following details:The first chapter elaborates the background,research significance and current status of domestic and foreign research on distributed passive location technology.Finally,it gives the structure of the paper.The second chapter first introduces the existing TDOA estimation technology,time synchronization and signal synchronization time difference measurement technology,and gives the traditional time interval measurement method and the specific phase difference measurement time difference method,and then proposes the compression transmissionbased TDOA estimation technology.Finally,two TDOA estimation technologies based on compressed transmission: ML and PDC non-reconstructed time difference estimation algorithms were simulated,which verified that this technology has accurate and stable performance for time difference estimation.The third chapter introduces the model and principle of time difference positioning,and then introduces two specific types of time difference positioning algorithms: nonlinear positioning algorithms and linear positioning algorithms.Nonlinear positioning algorithms include nonlinear least squares(NLS)and maximum likelihood.Algorithm(ML).Linear positioning algorithms include Linear Least Squares(LLS)and Weighted Linear Least Squares(WLLS).Finally,the four positioning algorithms are simulated separately,and the various factors that affect the positioning accuracy are simulated and analyzed,including the time difference measurement error,the station layout method,the baseline length of the station layout,the positioning algorithm,the number of measurement stations and the compression ratio in the compression transmission-based TDOA estimation technology.