Research On Beamforming And Angle Measurement In Subarray Of Large Planar MIMO Radar

Multiple input multiple output (MIMO) radar employs multiple transmittingchannels and multiple receiving channels to detect the characteristics of targets. Itspotential has attracted extensive attention of experts and scholars both at home andabroad. Compared with the traditional phased array radar, MIMO radar transmitsorthogonal signals to better performance in anti-interception and improve the efficiencyin the use of time resource and energy resource. Moreover, transmitting waveforms areseparated by using matched filter group at the receiving end, thus a virtual array isformed equivalently. Virtual array extends the array aperture and is conducive toimprove the estimation accuracy of parameters.This thesis mainly focuses on the beam-forming, virtual array forming and anglemeasurement technology research of MIMO radar based on2D planar array. The mainwork includes the following:1. The beam-forming technology is studied when MIMO radar transmittingarray is divided into different sub-arrays. The modeling of steering matrix isespecially researched when the phase center of transmitting sub-array is irregularlyarranged. Then the equivalent forming of virtual array of2D MIMO radar isanalyzed.2. The theoretical accuracy of sum and difference amplitude comparisonmono-pulse angle measurement technology applied to MIMO radar and phasedarray radar is analyzed. The application of the angle measurement technology inMIMO radar and phased array radar in cosinusoidal spatial coordinate is verified bysimulation, including the influence of different sub-array division, the fitting width,the deviation angle between the direction of target and predict beam direction andsignal-to-noise ratio on angle measurement. What’s more, the influence of somenon-ideal factors, including the target echo’s doppler frequency shift, MIMO radartransmitting signals’ non-strictly orthogonal characteristics and side-lobe resultingfrom multiple targets are studied.3. The phase comparison angle measurement based on the actual array of MIMO radar and phased array radar makes use of the same information, so theirmeasuring accuracy should be the same. This thesis validates it from two aspects oftheoretical deduction and simulation validation. But the information used by thephase comparison angle measurement based on the virtual array is different from theabove two, so this dissertation studies it in measuring sensitivity and accuracy bysimulation. The influence of doppler frequency shift and MIMO radar transmittingsignals’ non-strictly orthogonal characteristics are also studied.4. The super resolution angle measuring technology of2D MIMO radar isstudied. SSMUSIC algorithm, modified spatial smoothing technology and themethod of reusing matched filtering output data are adopted to improve DOAestimation performance. Simulation results show that the algorithm effectivelyimproves the performance of angle estimation...