Mimo Leidafei Adaptive Processing Technology Research

As a new type radar system emerging in recent years, multiple-input multiple-output (MIMO) radar is indeed the developing product of traditional phased-array radar. MIMO radar employs multiple transmit antennas to emit multiple orthogonal signals, and uses multiple receive antennas to jointly process the returned signal. Therefore there are some new performance improvements in MIMO radar, such as better resolution between multiple targets, better anti-interception performance, and better velocity resolution, as well as advanced ability of slow-moving target detection under strong clutter environment. In the context of radar, non-adaptive processing technology is also called as conventional signal processing technique. Although adaptive processing technique has been developed rapidly, space-time adaptive processing (STAP) is not fully employed in MIMO radar. Consequently, non-adaptive processing technique is still widely used in engineering application.This dissertation focuses on the problem of the signal processing and target detecting in the MIMO radar, multi-beam angle measurement, sub-array dividing, and moving target detection in the airborne MIMO radar. The measured data processing obtained from the ground-based MIMO radar is also studied. The main contents are as follows:In terms of the similarity between MIMO and phased-array radar, various steps of MIMO radar signal processing (matched filtering, beam-forming, MTI, MTD, CFAR, etc.) are studied in detail. Differences between PA and MIMO radar are analyzed in view of transmitted signals and beam forming.Multi-beam forming technique of MIMO radar is applied to mono-pulse angle measurement, and two methods which enable mono-pulse angle measurement to be more precise are developed. One is∑-△mono-pulse angle measurement method and the other is amplitude-comparison angular estimation method.Aiming at the problem of grating lobes brought by sub-array division, this paper introduces an overlapped virtual transmit sub-array approach, which is a time-dividing process and able to effectively reduce the calculation of the matched filter caused by regular sub-array division. To maintain an equivalent search rate with a short CPI, the number of simultaneous beams can also be reduced.This paper applies non-adaptive processing technique to theoretical study in airborne MIMO radar system, in which analysis about how many parts of the processing affect the power of target, the power of clutter and the power of noise. Under the input consistency of both radar systems, SCNR performance comparison after MTD is analyzed, being considered as the standard of detection performance. Simulation results are shown by using airborne platform data. These theoretical and experimental results show that MIMO radar is superior than traditional phased-array radar in weak target detection.The measured data obtained from a ground-based MIMO radar system is processed and analyzed. Relevant information on the target can be obtained. These are helpful to build a MIMO radar experiment platform in the future.