Research On Two-step Phase Synchronization And Compressive Sensing Calibration Of Distributed Array

Distributed array is currently a research hotspot.The distributed cooperative beamforming technology is used for the directional transmission and reception of signals in the communication network.The same information is sent through multiple antennas,and multiple signals are combined to obtain the desired ideal data signal.Each transmission node transmits simultaneously as a separate sender.Due to the difference in frequency,time,and phase of the transmission node,the signal strength of the receiving end is lost.In addition,in the actual array system,affected by many factors such as the geometric uncertainty of the array and electromagnetic coupling,the array error is widespread and unavoidable.The array manifolds established by various algorithms based on idealization have deviations and disturbances.Discretely distributed sensor nodes are used to form an antenna array for collaborative work.As the receiver,when solving problems such as the direction of arrival estimation,it is necessary to complete the calibration of the array manifold matrix.As a communication sender,to enhance the transmission signal-to-noise ratio,it is necessary to complete the synchronization of frequency,time and phase.In this paper,a two-step 2-bit feedback phase synchronization method and a spatial small-sample array calibration method based on compressive sensing are designed.In the phase synchronization technology,too large a step length leads to poor synchronization effect,and a too small step length limits the convergence speed.This paper designs a two-step 2-bit feedback phase synchronization method.The first step is to traverse the discrete phase value of each node to find the local optimal solution,and find a good iterative starting point through discrete approximation.The second step is through 2-bit feedback iteration,using the direction score designed in this paper to adjust the disturbance,and the step size is reduced in high synchronization to achieve an excellent final synchronization effect.In this paper,through the manifold separation technology,the steering vector of an arbitrary geometric arrangement array is decomposed into the product of a sampling matrix and a vector with Vandermonde structure.Using the sparsity of the sampling matrix in the effective aperture distribution function,a model of compressive sensing is constructed,and an effective calibration method is designed.This method reduces the amount of test data for pilot calibration and reduces the restrictive conditions for each direction of the sampled signal.