Method for reducing MIMO imaging radar near-field grating lobes

Abstract

The invention discloses a method for reducing MIMO imaging radar near-field grating lobes. Grating lobe performance of an MIMO array when near-field imaging is performed can achieve an index requirement through usage of the method. Aiming at the fact that a near-field directional diagram has a characteristic of spatial variability, optimization is performed on the MIMO array obtained through design based on a virtual array theory, an emitting array is prolonged in an equal interval manner, windowing processing is performed on the emitting array, envelope sidelobes of the near-field directional diagram of the emitting array are overall lowered firstly, and then grating lobes of a receiving array all fall into an envelope sidelobe region of the emitting array, so the grating lobe performance of the MIMO array when the near-field imaging is performed can achieve the index requirement, low grating lobe near-field imaging is achieved through adoption of the optimized MIMO array, and a certain degree of universality is possessed. Compared with an existing technology, the method can overcome a high grating lobe problem, resulted from near-field directional diagram distortions of the emitting and receiving arrays, of a synthetic directional diagram of the MIMO array, and the method improves the imaging quality of an MIMO radar for a near-field target.

Description

technical field [0001] The invention relates to the technical field of MIMO radar, in particular to a method for reducing near-field grating lobes of MIMO imaging radar. Background technique [0002] MIMO radar is a new radar system introduced in the radar field in recent years. It adopts a multi-antenna structure at both the transmitting end and the receiving end. Each transmitting antenna radiates mutually orthogonal signal waveforms at the same time, and each antenna at the receiving end receives all transmitted signals. And signal sorting is performed at the back end, thus obtaining observation channels and degrees of freedom far more than the actual number of receiving and transmitting array elements. The multi-observation channels that coexist in space enable the radar to collect echo information with different amplitudes, time delays or phases of the target in real time. This ability to obtain information from multiple channels in parallel is the fundamental advantage...

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Problems solved by technology

Although this method can achieve the effect of suppressing grating lobes to a certain extent, the optimal grating lobe level that this method can achieve for the specified target is determined, and the optimal design cannot be carried out according to the requirements, and it may not be able to meet the index requirements of the actual array design. Therefore, this method cannot be used to guide the design of MIMO arrays with index requirements

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