MIMO radar capability on powerful jammers suppression (original) (raw)

Robust beamforming for jammers suppression in MIMO radar

2014 IEEE Radar Conference, 2014

Robust beamforming for multiple-input multipleoutput (MIMO) radar in the background of powerful jamming signals is investigated in this paper. We design two minimum variance distortionless response (MVDR) type beamformers with adaptiveness/robustness against the powerful jammers for colocated MIMO radar. Specifically, the MVDR beamformer is firstly designed for known jammers in the sector-of-interest, which maintains distortionless response towards the direction of the target while imposing nulls towards the directions of jammers. Then the adaptive/robust MVDR beamformer is designed for the general case of unknown in-sector jammers and/or out-of-sector interfering sources. Convex optimization techniques are used in both of the designs. Moreover, we derive a closed-form solution to the simplified second design. Based on this solution, we derive efficient power estimates of the desired and/or interfering sources in the context of powerful jammers and non-ideal factors such as array calibration errors and target steering vector mismatches. We demonstrate that the capability of efficient jammers suppression using these designs is unique in MIMO radar.

1 Efficient Transmit Beamspace Design for Search-free Based DOA Estimation in MIMO Radar

2016

In this paper, we address the problem of transmit beamspace design for multiple-input multiple-output (MIMO) radar with colocated antennas in application to direction-ofarrival (DOA) estimation. A new method for designing the transmit beamspace matrix that enables the use of searchfree DOA estimation techniques at the receiver is introduced. The essence of the proposed method is to design the transmit beamspace matrix based on minimizing the difference between a desired transmit beampattern and the actual one while enforcing the constraint of uniform power distribution across the transmit array elements. The desired transmit beampattern can be of arbitrary shape and is allowed to consist of one or more spatial sectors. The number of transmit waveforms is even but otherwise arbitrary. To allow for simple search-free DOA estimation algorithms at the receive array, the rotational invariance property is established at the transmit array by imposing a specific structure on the beamspace matrix. Semidefinite programming relaxation is used to approximate the proposed formulation by a convex problem that can be solved efficiently. We also propose a spatialdivision based design (SDD) by dividing the spatial domain into several subsectors and assigning a subset of the transmit beams to each subsector. The transmit beams associated with each subsector are designed separately. Simulation results demonstrate the improvement in the DOA estimation performance offered by using the proposed joint and SDD transmit beamspace design methods as compared to the traditional MIMO radar technique.

Efficient Transmit Beamspace Design for Search-free Based DOA Estimation in MIMO Radar

2013

In this paper, we address the problem of transmit beamspace design for multiple-input multiple-output (MIMO) radar with colocated antennas in application to direction-of-arrival (DOA) estimation. A new method for designing the transmit beamspace matrix that enables the use of search-free DOA estimation techniques at the receiver is introduced. The essence of the proposed method is to design the transmit beamspace matrix based on minimizing the difference between a desired transmit beampattern and the actual one under the constraint of uniform power distribution across the transmit array elements. The desired transmit beampattern can be of arbitrary shape and is allowed to consist of one or more spatial sectors. The number of transmit waveforms is even but otherwise arbitrary. To allow for simple search-free DOA estimation algorithms at the receive array, the rotational invariance property is established at the transmit array by imposing a specific structure on the beamspace matrix. ...

Transmit beamspace design for direction finding in colocated MIMO radar with arbitrary receive array

2011

Colocated multiple-input multiple-output (MIMO) radar is used for direction-of-arrival (DOA) estimation. The case of even but otherwise arbitrary number of transmit waveforms is considered. In order to obtain a virtual array with a large number of virtual antenna elements and at the same time obtain a significant signal-to-noise ratio (SNR) gain, a proper beamspace is designed. Moreover, to allow for simple DOA estimation algorithms at the receive array, the rotational invariance property (RIP) for the virtual array is guaranteed at the transmit array by a proper beamspace design. The main idea of such beamspace design is to obtain the RIP by imposing a specific structure on the beamspace matrix and then designing the beamspace matrix to obtain a desired beampattern and a uniform power distribution across antenna elements. Simulation results demonstrate the advantages of the proposed DOA estimation method based on colocated MIMO radar with beamspace design.

MIMO Radar Waveform Design with Practical Constraints: A Low-Complexity Approach

2018 IEEE 18th International Conference on Communication Technology (ICCT)

In this letter, we consider the multiple-input multiple-output (MIMO) radar waveform design in the presence of signal-dependent clutters and additive white Gaussian noise. By imposing the constant modulus constraint (CMC) and waveform similarity constraint (SC), the signal-to-interference-plus-noise (SINR) maximization problem is non-convex and NP-hard in general, which can be transformed into a sequence of convex quadratically constrained quadratic programming (QCQP) subproblems. Aiming at solving each subproblem efficiently, we propose a low-complexity method termed Accelerated Gradient Projection (AGP). In contrast to the conventional IPM based method, our proposed algorithm achieves the same performance in terms of the receive SINR and the beampattern, while notably reduces computational complexity.

Direction finding for MIMO radar with colocated antennas using transmit beamspace preprocessing

2009 3rd IEEE International Workshop on Computational Advances in Multi-Sensor Adaptive Processing (CAMSAP), 2009

The problem of direction finding for multiple targets in mono-static multiple-input multiple-output (MIMO) radar systems is considered. Assuming that the targets are located within a certain spatial sector, we focus the energy of multiple (two or more) transmitted orthogonal waveforms within that spatial sector using appropriately designed transmit beamforming. The transmit beamformers are designed so that matchfiltering the received data to the waveforms yields multiple (two or more) data sets with rotational invariance property that allows applying search-free direction finding techniques such as ESPRIT. Unlike previously reported MIMO radar ESPRITbased direction finding techniques, our method is applicable to arbitrary arrays and achieves better estimation performance at lower computational cost.

Hybrid Sparse Array Beamforming Design for General Rank Signal Models

IEEE Transactions on Signal Processing

The paper considers sparse array design for receive beamforming achieving maximum signal-to-interference plus noise ratio (MaxSINR) for both single point source and multiple point sources, operating in an interference active environment. Unlike existing sparse design methods which either deal with structured environment-independent or non-structured environment-dependent arrays, our method is a hybrid approach and seeks a full augumentable array that optimizes beamformer performance. This approach proves important for limited aperture that constrains the number of possible uniform grid points for sensor placements. The problem is formulated as quadratically constraint quadratic program (QCQP), with the cost function penalized with weighted l1-norm squared of the beamformer weight vector. Simulation results are presented to show the effectiveness of the proposed algorithms for array configurability in the case of both single and general rank signal correlation matrices. Performance comparisons among the proposed sparse array, the commonly used uniform arrays, arrays obtained by other design methods, and arrays designed without the augmentability constraint are provided.

Hybrid Phased-MIMO Radar: A Novel Approach With Optimal Performance Under Electronic Countermeasures

IEEE Communications Letters, 2018

This letter presents a novel technique for optimizing the performance of a phased-MIMO radar in presence of strong jamming effects. The proposed technique not only overcomes the noise jamming but also counters the effects of deception jamming. Two orthogonal waveforms beam-formed by coherent operation of two sub-arrays are used to leverage the advantages of both MIMO and phased-radar simultaneously. The heart of the idea lies with its coherent receive operation where matched filtering and Karhunen-Loève Transform is applied for separating the signals. We make use of MUSIC algorithm for angle estimation; thereafter signal to noise plus jamming ratio is maximized by solving a convex optimization problem. The output shows remarkable results with an excellent peak to side-lobe ratio of more than 40 dB.

Robust constrained waveform design for MIMO radar with uncertain steering vectors

EURASIP Journal on Advances in Signal Processing, 2017

This paper considers the robust waveform design of multiple-input multiple-output (MIMO) radar to enhance targets detection in the presence of signal-dependent interferences assuming the knowledge of steering vectors is imprecise. Specifically, resorting to semidefinite programming (SDP)-related technique, we first maximize the worst-case signal-to-interference-plus-noise ratio (SINR) over uncertain region to optimize waveform covariance matrix forcing a uniform elemental power requirement. Then, based on least square (LS) approach, we devise the waveform accounting for constant modulus and similarity constraints by the obtained waveform covariance matrix using cyclic algorithm (CA). Finally, we assess the effectiveness of the proposed technique through numerical simulations in terms of non-uniform point-like clutter and uniform clutter.

Suppression of Mainbeam Deceptive Jammer With FDA-MIMO Radar

IEEE Transactions on Vehicular Technology, 2020

Suppression of radar-to-radar jammers, especially the mainbeam jammers, has been an urgent demand in vehicular sensing systems with the expected increased number of vehicles equipped with radar systems. This paper deals with the suppression of mainbeam deceptive jammers with frequency diverse array (FDA)-multiple-input multiple-output (MIMO) radar, utilizing its extra degrees-of-freedom (DOFS) in the range domain. At the modelling stage, false targets, which lag several pulses behind the true target, are considered as a typical form of mainbeam jammers. To this end the data-independent beamforming is performed to suppress false targets by nulling at the equivalent transmit beampattern with an appropriate frequency increment. However, the suppression performance degrades in the presence of transmit spatial frequency mismatch, which could be induced by quantization errors, angle estimation errors and frequency increment errors. To solve this problem, a preset broadened nulling beamformer (PBN-BF) is proposed by placing artificial interferences with appropriate powers around the nulls of the equivalent transmit beampattern. In such a way, effective suppression of deceptive jammer can be guaranteed owing to the broadened notches. At the analysis stage, numerical results in a scenario with multiple unmanned aerial vehicles (UAVs) are provided to illustrate the effectiveness of the devised data-independent BF, and the signal-to-interference-plus-noise ratio is improved compared with the conventional data-independent BF.