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This study discusses the integrated system of full‐duplex (FD) multiple‐input‐multiple‐output (MIMO) communication and MIMO radar, which has been rarely considered in published studies. Such an integrated system is composed of a base station and several uplink (UL) and downlink (DL) users, and is supposed to simultaneously implement three functionalities, that is, target detection, UL and DL communications. The degrees of freedom of system design involve the precoding and combining schemes for UL and DL communications, as well as the receiving filter for radar echo. An optimization problem is developed to maximise a compound communication sum‐rate metric subject to the SINR constraint imposed on target detection performance. The resulted non‐convex and NP‐hard problem is first divided into two sub‐problems. Then, for one of the sub‐problems that is still intractable, its solution is iteratively obtained based on the fractional programing technique and the consensus alternating direction method of multipliers algorithm. In the simulation part, the convergence performance and computational efficiency of the proposed algorithm are illustrated. In addition, the target detection performance, DL and UL communication performance of the integrated system are also evaluated. [ABSTRACT FROM AUTHOR]

In this study, a communication‐awareness adaptive resource scheduling (CARS) strategy for multiple target tracking in a multiple radar system (MRS) is proposed. The CARS strategy aims to maximise the tracking performance of MRS, whilst minimising the interference from MRS to communication systems (CSs), whose mechanism is to simultaneously control the revisit frame interval of each target and determine the activation of radar nodes, the radar‐target assignment and the allocation of transmitted power. Mathematically, the CARS strategy is formulated as an optimization problem, which contains both the continuous variable and the discrete (integer) variable. To tackle the resultant mixed‐integer, non‐convex, and non‐linear problem efficiently, incorporating with the proposed hybrid particle swarm optimization algorithm based on the Kullback–Leibler divergence, a two‐stage solution technique is developed to obtain the near‐optimal solution. Numerical simulation results are provided to validate the proposed CARS strategy and demonstrate its superiority over the traditional scheduling strategies. [ABSTRACT FROM AUTHOR]

For tracking of multiple extended targets with unknown and varying target number, the measurements partitioning is indispensable and plays an important role in achieving good performance. However, the number of possible partitions grows very fast with the increasing of total number of measurements, which causes heavy computational burden. Thus this Letter proposes a fast measurement partitioning algorithm, in which the target predictive information is explicitly considered and used to determine the clustering centres for measurement partitioning. To guarantee its robustness, the target predictions are further modified when the target number is overestimated. This flexible strategy reduces the dependence on original predictive information and significantly improves the accuracy of partitioning results. Besides, the proposed algorithm greatly reduces the partition number by fully considering possible changes of the number of newborn targets and spawned targets. It not only eliminates unreasonable and redundant measurement partitions for tracking performance improvement, but also fits well with the tracking of newborn targets and spawned targets. Simulation results verify the benefit of what the authors proposed. [ABSTRACT FROM AUTHOR]

High-frequency radar is easily affected by radio frequency interference (RFI) since it shares the band with many radio services. To mitigate the RFIs, this study designs receiver for radar's fast-time processing. Two optimisation problems are, respectively, proposed, both involving an objective function accounting for maximising the signal-to-interference plus noise ratio, but are distinguished with different constrains for sidelobes control. Furthermore, the authors show that the two proposed problems both can be reformulated as the second-order cone programming, hence some well-established interior point methods can be introduced to resolve them. Simulation results show that the designed filters can precisely control the sidelobe level from different perspectives, with the RFIs suppressed to achievable greatest extent. [ABSTRACT FROM AUTHOR]

This article designs waveform in fast-time domain to optimise high-frequency radar performances embedded in the co-channel interference and coloured noise. Considering the whitening filter is applied for fast-time processing, a novel objective function accounting for both signal to interference plus noise ratio (SINR) and integrated range sidelobe level (IRSL) is introduced and the constant modulus constraint is forced on the probing waveform. An iterative algorithm based on the alternating direction method of multipliers is presented, resolving such non-convex quartic optimisation problem with a polynomial-time computational complexity. In each iteration, two quadratic problems are presented, with the closed-form solutions given. Finally, the authors evaluate the effectiveness of the designed waveform in terms of the range-Doppler processing result, SINR, IRSL and power spectrum. [ABSTRACT FROM AUTHOR]

The frequency‐modulated continuous wave (FMCW) radar will play a more important role in future intelligent traffic systems due to low cost and high adaptability to complex environments. Generally, a 2D array is utilised to measure range, speed and azimuth and elevation angles (4D) for multiple vehicles simultaneously. However, a traffic radar utilising a 2D array will enhance its system complexity; therefore, the increased cost would make it less superior to LiDAR. In this Letter, an azimuth and elevation angles estimation method of FMCW radar utilising only 1D array is proposed. Thus, it can provide 4D parameters to multiple vehicles simultaneously. The feasibility of the proposed approach is verified by on‐road measurement data. [ABSTRACT FROM AUTHOR]

In this Letter, the problem of waveform design for MIMO radar with good transmit beampattern performance is investigated. The binary transmit waveforms are designed via minimising the beampattern integrated sidelobe to mainlobe ratio. Since the resulting binary combination optimisation problem is NP‐hard, a generalised likelihood ascent search algorithm is proposed to deal with it. Besides, the effectiveness of the proposed algorithm is demonstrated via simulation results. [ABSTRACT FROM AUTHOR]

In this Letter, the authors propose an approach to evaluate the average signal‐to‐clutter ratio loss (ASCRL) of an adaptive radar filter with a parametrically constrained clutter covariance matrix (CCM). The approach is a two‐step strategy, the constrained Cramér–Rao bound of the CCM estimate is first derived, and then it is used to derive the ASCRL. More specifically, the ASCRL of an adaptive filter with a trace constrained CCM is derived. Simulation results show that our approach performs well in evaluating the trace constrained ASCRL for both complex Gaussian clutter and compound‐Gaussian clutter. [ABSTRACT FROM AUTHOR]

This study considers the design of optimal receive filter under similarity constraint in coloured noise and compares it with signal design methods and conventional schemes. Similarity constraint restricts the sought-after filter to be close to the transmit waveform to control the output sequence envelope, avoiding potential risks of poor range solution and high sidelobes of whitening filter (WF) in severe coloured noise. The detailed solution to this constrained optimisation problem is provided. Then, the authors compare the filter design (FD) with the schemes of conventional or designing signal based on the matched/whitening filter. Five schemes are analysed on their performances of output signal-to-noise ratio, sequence control and requirements for practical applications. The merits of five schemes are concluded. In simulations, comparison between the designed filter and whitening filter illustrates the necessity of similarity constraint. FD under similarity constraint is regarded as a robust scheme for output sequence envelope control, easy to implement for coloured noise suppression. [ABSTRACT FROM AUTHOR]

A robust transmit beampattern matching synthesis approach is described for a multiple‐input and multiple‐output radar with manifold vectors perturbation. This synthesis technique minimises the worst‐case matching performance between the transmit beampattern and the desired beampattern (in a least absolute deviations sense), through designing the waveform covariance matrix. Also, the resulting minimax problem can be translated into a convex problem is showed. Finally, simulation results verify good performance of the proposed robust transmit beampattern synthesis approach. [ABSTRACT FROM AUTHOR]

Transient interference cancellation is necessary for high‐frequency sky‐wave radar and usually requires accurate interference detection and localisation which is complicated due to the non‐uniform noise level caused by sea‐clutter mitigation in Doppler domain. A novel approach is proposed by converting the detection of interference into a problem of straight line extraction in the constructed fast‐ and slow‐time images. The line edges are detected by an edge detector, such as Canny method, followed by Hough transform. Then, each edge is classified as a rising, falling or false‐alarm edge based on multi‐threshold segmentation of image sub‐blocks. Experimental results demonstrate the effectiveness of the proposed approach. [ABSTRACT FROM AUTHOR]

Here a novel mainlobe interference suppression technique based on eigenprojection algorithm and beam pattern similarity constraints is proposed. This method can effectively suppress the multiple mainlobe interferences and sidelobe interferences. The output of adaptive beamforming is calculated via adaptive weight vector obtained by the convex objective function and processed echo data based on the eigenprojection matrix. The simulations have been presented to evaluate the theoretical analysis. [ABSTRACT FROM AUTHOR]