Tdoa Estimation And Localization In Over-The-Horizon Environments Using Ground-wave

With the development of time difference estimation technology and the better support of GPS for synchronization technology,TDOA Localization technology has attracted more and more people's attention.Many algorithms for TDOA Localization have been proposed,which prove the method has the civil or military value.For this reason,this article continues to explore the potential value of time difference extraction and time difference location.In this paper,the pulse signal time difference extraction is first ly studied.The pulse signal time difference extraction is generally divided into signal sorting and pulse pairing in single pulse signal.Thereinto,the signal sorting process uses PRI transform method for main sorting.Then,the jitter PRI pulse signal is studied.The PRI information of the jitter PRI pulse signal is successfully extracted by the combination of the SDIF method and the PRI transform.Pulse pairing uses an angle-space search method based on azimuth prior information.This method recalculates the time difference window in the background of over-the-horizon,and the azimuth prior information can reduce the computational complexity.Secondly,this paper discusses the time difference extraction of aperiodic continuous signals.At the beginning of this section,the idea of matching graph is used to mesh the target region to obtain a standard TDOA measurement matrix.Then,the CS method is used to perform the sparse recovery,and the time difference value related closely to the target is selected from the standard matching map.Finally,the method is modified to accommodate multi-source continuous signals.Whereafter,we propose a new over-the-horizon TDOA localization model based on the ground-wave and simultaneously put forward a modified Semi-Definite Programming algorithm,which is called G-SDP.If both the target and the base stations are on the surface of the earth and far away from each other,the propagation path of the signal is a curve along the surface instead of a straight line,thus making the traditional positioning model inefficient.To overcome the problem,we develop a novel localization model and explore a priori information to achieve improvements on SDP algorithms.Here we mainly use an iterative trick to get better performance.Finally,this paper discusses the constraints of the targets on the surface of Earth.In the past,the constraints on the targets on the surface of Earth were all equality constraints,which obviously deviated from the facts.In this regard,this paper scales the equality constraint,and finally makes the G-SDP2 algorithm achieve the satisfying result under the condition of inequality constraints.