Research On Direct Positioning Method Based On Reflector Assistance

In modern war,electronic station is an important part.Passive location plays an important role in electronic warfare.Most of the traditional passive location technology systems are two-step estimation mode,that is,"parameter estimation + location solution".However,the two-step estimation method also has some shortcomings.The main problem of the two-step positioning method is that the position estimation error is large and the required observation value deviation is small,which leads to the problem of limited accuracy and resolution in the process of target positioning.Direct position determination(DPD)algorithm makes up for the shortcomings of two-step positioning algorithm.The basic theory is to obtain the position information of the target directly from the original target signal,and introduce the measurement parameter estimation and data association into a location model,without estimating other intermediate parameters,which has the advantages of high estimation accuracy and high resolution.In this paper,we study the corresponding DPD positioning algorithm in the reflector assisted positioning scenario,and construct the positioning model in different scenes with different angle and time delay measurements.The research work of this paper is carried out in two aspects: the two-step positioning model assisted by reflector and the direct positioning model assisted by reflector under the condition of array signal.Therefore,the specific research contents and achievements of this paper are as follows:1.A single station two-step location algorithm in the reflector assisted scene is studied.Aiming at the two situations that the reflector position is accurately known and unknown,the corresponding positioning model is established based on different observation.Under the condition that the reflector position is known accurately,three algorithms are proposed.One is the single station two-step positioning algorithm under the non direct propagation path,which uses the time difference information to locate the target;the other two are the single station two-step positioning algorithm under the direct and non direct propagation path,which uses the joint time difference and angle information,and only uses the time difference to locate the target.The simulation results show that the accuracy of position estimation is higher than that of the unknown reflector.Under the condition that the reflector position is unknown,a single station two-step positioning algorithm is proposed,which uses the time difference and angle information to establish the positioning model.The simulation results show that under the condition of unknown reflector position,twostep positioning can be used,but the positioning accuracy is low.2.The problem of reflector assisted direct positioning is studied.In this paper,two kinds of location scenarios are considered,one is that the reflector position is accurately known and the other is that there is a small reflector position deviation.Under the condition that the reflector position is known accurately,the signal model is established by using the joint delay and angle information,and the corresponding positioning model is constructed.In the first section of the direct positioning algorithm,the location is carried out under the condition that the reflector position is accurately known.In the second section,we propose a direct location algorithm under the condition of reflector position deviation,that is,there is a small deviation between the real reflector position and its nominal value,which is unknown.The signal model is approximated by the Taylor series expansion method,so that the position parameters of the target are separated from the position deviation of the reflector.