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One of the important obstacles in MIMO (Multiple Input Multiple Output) radars is the issue of designing proper transmit signals. Indeed, the capability of signal design is a significant advantage in MIMO radars, through which, the system can achieve much better performance. Many different aspects of this performance improvement have been considered yet, and the transmit signals have been designed to attain such goal, e.g., getting higher SNR or better detector's performance at the receiver. However, an important tool for evaluating the radar's performance is its ambiguity function. In this paper, we consider the problem of transmit signal design, in order to optimize the ambiguity function of a distributed MIMO radar system via maximizing its peak. HighlightsTransmit signals are designed to maximize the ambiguity function's peak of a WS-MIMO radar.Signal design is done for three cases of single target, multi-target, and prioritized ambiguity function.It is shown that in spite of increasing the number of antennas of MIMO radar, signal design does not provide diversity gain.Through simulations, it is shown that better performance can be achieved by the proposed signal design to maximize the AF's peak.

It is presumed that using multiple antennas at the transmit and receive sides can improve the radar's performance. One such improvement can be achieved in the detection of extended targets. However, in such multiple-input multiple-output systems, proper design of the transmit signals is an obstacle that can have significant influence on the performance. In this study, enforcing the peak-to-average-ratio (PAR) constraint, the authors consider the problem of transmit space-time code and receive space-time filter design of such a system detecting extended targets. In addition, the power allocation among the different antennas is another degree of freedom that should be optimised under a total power constraint. Here, the authors derive a constrained optimisation procedure for transmit code, receive filter and transmit powers, which sequentially improves the signal-to-interference plus noise ratio of the system.

Efficient combination of MIMO (multiple-input multiple-output) and PCL (passive coherent location) ideas is expected to improve performance of localization schemes. While, in general, adding the number of transmit and receive antennas provides spatial diversity, it is possible to obtain similar effects by using multiple transmitters that are already transmitting standard signals (such as digital TV (DTV) transmission) in the environment (also known as illuminators of opportunity). However, in the case of passive schemes, it is not always possible to ensure that signals of different transmitters are orthogonal to each other. In such cases in which nonorthogonal transmitter signals are to be used, resolving signals of multiple transmitters reflected from multiple objects is not a trivial problem. One such scenario arises when transmitters of a single frequency network (SFN) are used. Consequently, in order to obtain the desired diversity gain and maintain the correct localization, it is necessary to develop proper techniques to assign each echo that arrives at the receivers to a given transmitter and a specific object that is to be localized. We propose a scheme that addresses the association problem in an efficient way.

An important tool for assessing a radar's performance is the ambiguity function. On the other hand, many different schemes have been designed for the transmit waveforms of a MIMO radar. For each one, a criterion has been chosen to improve the performace, e.g. achieving better missed detection. In this paper, considering the ambiguity function as the benchmark, we propose a waveform design scheme, which optimizes the ambiguity function of the MIMO radar system.

In a MIMO (Multiple Input Multiple Output) radar system, proper design of transmit signal and receive filter is an advantageous tool to improve the detection performance. Thus, in this paper, we consider the problem of transmit code and receive filter design, in order to maximize the Signal to Noise Ratio (SNR) at the receiver while enforcing a similarity constraint between the transmit space-time code (STC) and a reference STC which has a desirable ambiguity function. We will show that by solving such constrained optimization problem through successive iterations, our proposed method leads to satisfactory results.

Based on the sparsity idea, the recently developed technique of compressive sensing (CS) is shown to be able to reduce significantly the need for huge amount of data and high sampling rates. On the other hand, moving target indication (MTI) processing has long been known in the traditional pulse radars to be able to detect weak signals of moving targets. The main drawback of the conventional approaches is the lack of accuracy in Doppler estimation; most of them suffer from low resolution to separate multiple targets from each other with low number of pulses. In this paper, we employ the CS technique to do the MTI processing in a radar system which employs measurements (echo pulses) efficiently to detect the target and estimate its Doppler. The two stages of the proposed algorithm, calculate the measurement matrix and perform the detection and estimation procedure. The simulations verify the proposed method, indicating the effectiveness of the CS technique in various applications.

In this paper, we devise a joint code-filter design method to optimize the signal-to-interference-plus-noise ratio (SINR) associated with the colocated MIMO radars. We consider constant-modulus wavefrom design for moving target detection and propose a cyclic algorithm to deal with the design problem.

Efficient combination of multiple input multiple output (MIMO) and passive coherent location (PCL) ideas is expected to improve performance of localisation schemes. While using multiple antennas at transmit and receive sides provides spatial diversity, it is possible to obtain similar performance by using multiple transmitters, already transmitting standard signals (such as digital TV) in the environment (also known as illuminators of opportunity). However, in this case, it is not always possible to ensure that signals of different transmitters are orthogonal to each other. In such cases, resolving signals of multiple transmitters reflected from multiple objects is not a trivial problem. One such scenario arises when transmitters of a single frequency network (SFN) are used. Consequently, in order to obtain the desired diversity gain, it is necessary to develop proper techniques to assign each echo arriving at the receiver to a given transmitter and a specific object to be localised. In this paper, we propose a scheme that addresses the association problem in an efficient way. Also, we consider the case of multiple antennas only at the transmit side while using a single receiver, which is the case of a multi-input single-output (MISO) system, a subset of MIMO systems, in general.