Research On The Key Technology Of MIMO Imaging Of Millimeter Wave Radar

The millimeter wave radar system has the characteristics of narrow beam,wide band,short wavelength,low power consumption and strong penetrability.It is not affected by the weather and can work around the clock.Therefore,the millimeter wave radar imaging system can detect in various scenarios.In order to increase the amount of data acquired by a single snapshot,the MIMO concept is introduced into the millimeter wave radar system.This paper studies the key technologies of the millimeter wave radar MIMO imaging system.A millimeter wave radar MIMO imaging system with a working frequency of 77 GHz to 81 GHz is introduced and a MIMO signal model based on multiple orthogonal signals is establishes.Then this paper derives a MIMO echo signal based on a one-dimensional scanning geometric model of a one-dimensional MIMO array and it's imaging signal model.The MIMO imaging algorithm based on time domain for millimeter wave radar is studied.Firstly,the BP-based millimeter wave radar MIMO imaging algorithm flow is deduced,and the influence of the aperture length and the element spacing on the imaging performance is analyzed according to the algorithm.Aiming at the problem that BP algorithm is too slow,a RMA algorithm is based on frequency domain processing is presented.The RMA-based millimeter wave radar MIMO imaging algorithm flow is deduced.The two imaging algorithms are verified by point target simulation imaging experiment.Then based on the RMA algorithm,FEKO is used to simulate the radar echo of the 3D model of "N" and simulate the echo.And the two algorithms are compared and analyzed from two aspects of operation time and resolution.The paper introduces the concept of two equivalent arrays and illustrates the related principles based on two arrays.Based on the co-array,the method of array decomposition is deduced,and the related design example is given.Then the array performance is decomposed according to the spreading loss and array factor pattern.Finally,from the perspective of imaging simulation,the performance of the decomposed array and randomly distributed arrays has been compared.