Design and Imaging of Ground-Based Multiple-Input Multiple-Output Synthetic Aperture Radar (MIMO SAR) with Non-Collinear Arrays

Abstract

Multiple-Input Multiple-Output (MIMO) radar provides much more flexibility than the traditional radar thanks to its ability to realize far more observation channels than the actual number of transmit and receive (T/R) elements. In designing the MIMO imaging radar arrays, the commonly used virtual array theory generally assumes that all elements are on the same line. However, due to the physical size of the antennas and coupling effect between T/R elements, a certain height difference between T/R arrays is essential, which will result in the defocusing of edge points of the scene. On the other hand, the virtual array theory implies far-field approximation. Therefore, with a MIMO array designed by this theory, there will exist inevitable high grating lobes in the imaging results of near-field edge points of the scene. To tackle these problems, this paper derives the relationship between target’s point spread function (PSF) and pattern of T/R arrays, by which the design criterion is presented for near-field imaging MIMO arrays. Firstly, the proper height between T/R arrays is designed to focus the near-field edge points well. Secondly, the far-field array is modified to suppress the grating lobes in the near-field area. Finally, the validity of the proposed methods is verified by two simulations and an experiment.

A Compensation Method for a Time–Space Variant Atmospheric Phase Applied to Time-Series GB-SAR Images

“…The radar system was independently implemented by the Beijing Institute of Technology. Generic GB-SAR systems have a large aperture based on the mechanical movement of antennas along a rail track, whereas the GB-MIMO system utilizes the waveform diversity technique to synthesize a large aperture with a multiple antenna structure [11,12]. Their largest difference is the way they synthesize a large aperture.…”

Compressive Sensing for Ground Based Synthetic Aperture Radar

“…In this article, the ϕ matrix is built using a the same reduced set of data for all the lines. This could reduce the incoherence of sampling (and so the quality of reconstruction), but it is a solution that could be easily implemented with a physical array or with a MIMO (multiple input multiple output), such as in [15][16][17].…”

Passive Bistatic Ground-Based Synthetic Aperture Radar: Concept, System, and Experiment Results

“…Based on Equations (8) and (9), the spectrum of the n-th TV channel with an integration time of T int can be expressed as…”

“…To reduce the influence of the amplitude-filtered spectrum, as mentioned previously, the flat spectrum can be extracted for range compression. For each TV channel, according to Equation (9), the extraction operation can be expressed as…”

“…Compared to spaceborne/air-borne SAR, it can continuously monitor the scene of interest with a much shorter revisiting period (from several seconds to tens of minutes). Besides, its data acquisition rate can be further increased by using one-dimensional (1D) or two-dimensional (2D) multiple input multiple output (MIMO) array, which has drawn attention in the last decade [9][10][11][12][13]. Moreover, GB-SAR can easily obtain higher system flexibility.…”