MIMO Radar with Colocated Antennas

Abstract

Review of some recent work ]A multi-input multi-output (MIMO) radar system, unlike standard phased-array radar, can transmit, via its antennas, multiple probing signals that may be correlated or uncorrelated with each other. While the companion article by Blum et al., to appear in the November issue, exploited the diversity offered by widely separated transmit/receive antenna elements, we focus on the merits of the waveform diversity allowed by transmit and receive antenna arrays containing elements that are colocated. For the latter type of MIMO radar systems, we provide an overview of recent results showing that the waveform diversity enables the MIMO radar superiority in several fundamental aspects, including: 1) significantly improved parameter identifiability, 2) direct applicability of adaptive arrays for target detection and parameter estimation, and 3) much enhanced flexibility for transmit beampattern design. Specifically, we show that 1) the maximum number of targets that can be uniquely identified by the MIMO radar is up to M t times that of its phased-array counterpart, where M t is the number of transmit antennas, 2) the echoes due to targets at different locations can be linearly independent of each other, which allows the [ Jian Li and Petre Stoica ] MIMO Radar with Colocated AntennasDigital Object Identifier 10. 1109 /MSP.2007 direct application of many adaptive techniques to achieve high resolution and excellent interference rejection capability, and 3) the probing signals transmitted via its antennas can be optimized to obtain several transmit beampattern designs with superior performance. For example, the covariance matrix of the probing signal vector transmitted by the MIMO radar can be optimized to maximize the power around the locations of the targets of interest and also to minimize the cross-correlation of the signals reflected back to the radar by these targets, thereby significantly improving the performance of adaptive MIMO radar techniques. Additionally, we demonstrate the advantages of several MIMO transmit beampattern designs, including a beampattern matching design and a minimum sidelobe beampattern design, over their phased-array counterparts. In conclusion, the two articles in this issue show that MIMO radar is a fertile research ground that merits further investigation, including reaping the full benefits of both types of diversity covered in the two articles.

Joint optimization of MIMO radar waveform and biased estimator with prior information in the presence of clutter

“…Besides, by comparing Figure 2a with 2c or Figure 2b with 2d, it follows that the total CRB for MIMO radar (2.5, 0.5) is lower than that for MIMO radar (0.5, 0.5). This is because the virtual receiving array aperture for the former radar is much larger than that for the latter [3].…”

“…Multi-input multi-output (MIMO) radar has attracted more and more attention recently [1][2][3][4][5][6][7][8][9][10][11][12][13][14][15][16][17][18][19]. Unlike the traditional phased-array radar which can only transmit scaled versions of a single waveform, MIMO radar can use multiple transmitting elements to transmit arbitrary waveforms.…”

“…Unlike the traditional phased-array radar which can only transmit scaled versions of a single waveform, MIMO radar can use multiple transmitting elements to transmit arbitrary waveforms. Two categories of MIMO radar systems can be classified by the configuration of the transmitting and receiving antennas: (1) MIMO radar with widely separated antennas (see, e.g., [1,2]), and (2) MIMO radar with colocated antennas (see, e.g., [3]). For MIMO radar with widely separated antennas, the transmitting and receiving elements are widely spaced such that each views a different aspect of the target.…”

Low-Grazing Angle Target Detection and System Configuration of Mimo Radar

“…MIMO radar is categorized into two classes: statistical MIMO radar and colocated MIMO radar, depending on their antenna placement [1][2][3][4][5][6]. The advantages of MIMO radar with collocated antennas have been studied extensively, which include improved detection performance and higher resolution [7], higher sensitivity for detecting moving targets [8,9], and increased degrees of freedom for transmission beamforming [10].…”

Mimo Radar Systems Design Based on Maximum Channel Capacity

“…MIMO radar has gotten considerable attention in a novel class of radar system, where the term MIMO refers to the use of multipletransmit as well as multiple-receive antennas [1][2][3][4]. MIMO radar can transmit, via its antennas, multiple probing signals that may be correlated or uncorrelated with each other.…”