Study On The Theory And Method For Electromagnetic Environmental Sensory Based MIMO Radar Signal Process

As the MIMO technology theory is getting mature and the advanced radartechnology improves continuously, multiple-input multiple-output (MIMO) radarcame into being and favored by more and more researchers. In the MIMO radarsystem, the transmitting array units can transmit many mutually orthogonal orindependent signals, which can cover the entire airspace; moreover, in the MIMOradar receiver, the received echo signal through the matched filter array unit can berestored to be the emission signal components. Thus it not only achieved digitalbeamforming, but also formed a virtual array element, expanding the array aperture.Compared with phased array radar systems, MIMO radar array can be sparse or dense,and array element spacing is not limited. So the system’s degrees of freedom increasesobviously, and the parameter estimation accuracy and spatial resolution are bothimproved. Therefore, the MIMO radar is another leap in the development of radartechnology.Interference problems still exist in the MIMO radar system, which is animportant problem. So in order to solve the problems, the article introduces TransformDomain Communication System (TDCS) technology into MIMO radar, and putsforward a kind of MIMO radar-electromagnetic environment sensory (EES) MIMOradar. This research consists of two important parts: the electromagnetic environmentsensing method of EES-MIMO radar and the orthogonal waveform design.In EES-MIMO radar, the most basic thing is effectively perceived interferenceand noise bands. Aimed at the noise power spectrum estimation of EES-MIMO radar,many common spectrum estimation algorithms are not suitable for theelectromagnetic environment perception. This paper discusses two kinds of commoninterference of power spectrum estimation problem: narrow aiming jamming is astationary process that can be described as an AR model, using the modern mutualSVD-TLS spectral estimation algorithm to estimate the parameters of its AR model.For point-frequency jamming, the SVD under colored background is proposed. This algorithm can improve the precision and stability of spectral estimation, and therobustness of the algorithm is also high.The transmitting signal waveforms of EES-MIMO radar are completelyorthogonal, in order to get stronger resolution, the autocorrelation function of theorthogonal waveforms should be close to alluvial function, which has low sidelobeenergy; At the receiving end, in order to get Mutually independent signals, the cross-correlation function values should be as low as possible.For the above requirements, this paper introduces two kinds of waveform designmethod: orthogonal discrete frequency coding (DFCW) and orthogonal frequencydivision multiplexing (OFDM) phase encoding, and the hybrid algorithm is applied tooptimize the waveform design. This hybrid algorithm is adding the annealingalgorithm to genetic algorithm.