Presents the table of contents for this issue of this publication.

Provides a listing of current staff, committee members and society officers.

Kalman filter-based retrodiction plays an indispensable role in modern multitarget tracking and retrodiction (MTTR) algorithms. To this end, the Rauch–Tung–Striebel (RTS) smoother is a widely used Kalman filter-based target state smoother. With a large number of targets, MTTR algorithms, particularly with large window sizes, become very computationally intensive. If not addressed, these algorithms

This article addresses the problem of joint direction of departure (DOD) and direction of arrival (DOA) estimation with nested bistatic multiple input multiple output (MIMO) radar using tensor decomposition. We first employ the two-level nested transmit and receive arrays to develop the sum-difference coarray for constructing the Toeplitz and spatial smoothing matrices. We then generalize the three-way

Filters relying on the Gaussian approximation typically incorporate the measurement linearly, i.e., the value of the measurement is premultiplied by a matrix-valued gain in the state update. Nonlinear filters that relax the Gaussian assumption, on the other hand, typically approximate the distribution of the state with a finite sum of point masses or Gaussian distributions. In this work, the distribution

Understanding the decision-making process of deep learning networks is a key challenge that has rarely been investigated for synthetic aperture radar (SAR) images. In this article, a set of new analytical tools is proposed and applied to a convolutional neural network (CNN) handling automatic target recognition on two SAR datasets containing military targets. First, an analysis of the respective influence

How to utilize the limited antennas for tracking multiple targets plays a critical role in the collocated multiple-input multiple-output radar. A dynamic antenna selection strategy is proposed to address this problem. The basis of our strategy is to achieve the optimal antenna selection under the constraint of limited active antennas using the feedback information in the tracking recursion cycle, improving

The growing demand for radio frequency (RF) spectrum access poses new challenges for next-generation radar systems. To operate in a crowded electromagnetic environment, radars must coexist with other RF emitters while maintaining system performance. This work evaluates the performance of a spectrum sharing cognitive radar system, which predicts and avoids RF interference (RFI) in real time. The system

Presents the table of contents for this issue of the publication.

Presents a listing of the editorial board, board of governors, current staff, committee members, and/or society editors for this issue of the publication.

The ionosphere in low-latitude regions is a major challenge for a satellite-based augmentation system (SBAS). The intense dynamics of this layer of the atmosphere in this part of the globe is one of the main reasons why Brazil discarded years ago the idea of deploying its own SBAS. In this article, we re-examine the ionospheric error bounds for a high-density ground station network in Brazil by updating

For multiple unmanned aerial vehicles (UAVs) performing aerial search-attack tasks, there is a tradeoff between maximizing total benefit and minimizing consumption under the validity of constraints. This article proposes a dynamic discrete pigeon-inspired optimization algorithm to handle cooperative search-attack mission planning for UAVs, which integrates the centralized task assignment and distributed

This article deals with the problem of adaptive target detection in the presence of homogeneous Gaussian interference with frequency diverse array multiple-input multiple-output radar. Adaptive detectors are devised according to the generalized likelihood ratio test criterion, where the position of the target within each range cell is assumed unknown. To obtain the maximum likelihood estimate of the

This article proposes the design and implementation of an electrical power system (EPS) for 2U CubeSat using a single-ended primary-inductor converter (SEPIC) along with the perturbed and observe method for the maximum power point tracking (MPPT). SEPIC converters have the advantages of input current continuity, voltage boosting and bucking, short-circuit protection, low-side driver, and noninverted

To develop an adaptive beamformer against the signal of interest (SOI) steering vector mismatch, a robust Capon beamformer (RCB) like steering vector estimation method based on the interference matrix reduction is proposed. Different from the RCB and its modified versions that optimize the SOI steering vector with the Capon power estimator, this article designs an SOI power estimator to formulate the

Space robots have been proposed to perform several tasks in orbit, such as repairing, refueling, and assembly. All those activities require the robot to interact with external objects in a safe and compliant form to avoid high impact forces that may damage the robot's components or the object to manipulate. Impedance controllers have demonstrated to be a suitable approach to perform similar tasks in

In this article, a novel distributed attitude coordination control scheme is proposed for a group of rigid spacecraft with unknown disturbances. The communication topology is described by a general directed graph, and the leader's attitude is available to only a small fraction of followers. Different from existing attitude coordination control schemes, here an event-triggered communication strategy

Multiple-input multiple-output (MIMO) radar systems are popular for their ability to mitigate the target radar cross section fluctuations and null Doppler. However, MIMO radar fundamentally suffers from a notable signal-to-noise ratio (SNR) loss compared to an ideal phased-array (PA) radar. In order to overcome this drawback, a distributed MIMO radar scheme with joint optimal transmit and receive signal

Maximizing the coherent processing interval (CPI) is crucial when performing passive radar detection on weak signal reflections. In practice, however, the CPI is limited by the target movement. In this work, the extent of the range and Doppler migration effects occurring when using a long CPI to integrate the returns from an $L$ -band digital aeronautical communication system (LDACS) based passive

A nonlinear controllability analysis for fixed-wing aircraft has been performed in an earlier effort by the authors, which revealed a novel roll mechanism due to a nonlinear interaction between elevator and aileron control inputs. In this effort, we perform a detailed investigation of this novel roll mechanism, called Lie Bracket Roll Augmentation (LIBRA). First, we show the nonlinear flight physics

Infrared target detection is a challenging computer vision problem which involves detecting small targets in heavily cluttered conditions while maintaining a low false alarm rate. We propose a network that optimizes a “target to clutter ratio”(TCR) metric defined as the ratio of the output energies produced by the network in response to targets and clutter. A TCR-network (TCRNet) is presented in which

Formation reconfiguration of multiple unmanned aerial vehicles (UAVs) is a challenging problem. Mathematically, this problem is an optimal control problem subject to continuous state inequality constraints and terminal state equality constraints. The first challenge is that there are an infinite number of constraints to be satisfied for the continuous state inequality constraints, which makes the problem

The orbital pursuit-evasion game (OPE) is a topic of research that has been attracting increasing attention from scholars. However, most works based on the relative dynamics under a short-distance assumption is not applicable when the distance between two spacecrafts is too large. Accordingly, there should be two phases in the OPE, a long-distance OPE (LDOPE) as well as a short-distance one. This article

This article proposes a fault-tolerant finite-time controller for attitude tracking control of rigid spacecraft using intermediate quaternion in the presence of external disturbances, uncertain inertia parameter, and actuator faults. First, a novel nonsingular fast terminal sliding mode control law is derived using intermediate quaternion, free of singularity, ambiguity, and unwinding phenomenon. Second

Due to increasing demands for spectral resources in both communication and radar systems, the radio frequency electromagnetic spectrum is becoming more and more crowded with interfering nuisances. In order to tackle the scarcity of available spectral intervals, in recent years a multitude of sensing algorithms have been developed for improving spectrum sharing. Among these, two-dimensional (2-D) spectrum

In this article, we consider the problem of estimating the location and velocity of a moving source using a distributed passive radar sensor network. We first derive the maximum likelihood estimator (MLE) using direct sensor observations, when the source signal is unknown and modeled as a deterministic process. Since the MLE obtains the source location and velocity estimates through a search process

The utilization of extremely high-frequency (EHF) bands can achieve very high throughput in satellite networks (SatNets). Nevertheless, the severe rain attenuation at EHF bands imposes strict limitations on the system availability. Smart gateway diversity (SGD) is considered indispensable in order to guarantee the required availability with reasonable cost. In this context, we examine a load-sharing

To perform 3-D inverse synthetic aperture radar (ISAR) imaging through interferometric processing, all ISAR images should be correctly registered such that the same scatterer appears at the same position along both the range and Doppler directions. However, this condition generally does not hold in most situations because different radar view angles introduce additional angular motion errors that must

The capability of full-tensor gravity gradients for spacecraft orbit determination has been demonstrated in recent studies. The advantages lie in its independence from ground-based systems and its immunity against spoofing attacks. A common practice is to use Earth rotation parameters and star sensor measurements to isolate the orientation contributions to gravity gradients, which implies that the

Model-based approaches for target tracking and smoothing estimate the infinite number of possible target trajectories using a finite set of models. This article proposes a data-driven approach that represents the possible target trajectories using a distribution over an infinite number of functions. Recursive Gaussian process, and derivative-based Gaussian process approaches for target tracking, and

A sequential probability ratio test (SPRT) is introduced as a track management (TM) mechanism for the joint probabilistic data association (JPDA) multitarget tracking algorithm. The SPRT is based on an approximate target likelihood ratio that is derived from the JPDA event and association probabilities. SPRT-based TM functions are defined and compared to the joint integrated probabilistic data association

This work addresses code division multiple access (CDMA) implementation of automotive multiple-input multiple-output (MIMO) radars. The tansec frequency modulation (TSFM) is proposed as a single intracoding scheme for CDMA-MIMO radars. The properties of the TSFM coding family are analyzed and two novel codeword selection algorithms are proposed. The TSFM is compared to a variety of coding families

This article considers target separation detection (TSD) in the presence of homogeneous Gaussian interference. The problem is formulated as a hypothesis test for two typical situations: 1) the use of a low range-resolution radar or fast-track update rate; 2) the use of a high-resolution radar or low-track update rate. At the design stage, TSD tests are devised according to the generalized likelihood

This article extends previous work on location and intensity estimation for measurement extraction of targets in a focal plane array. Prior work has been done to extract single targets and two targets of equal intensity, whereas this work explores the case where two targets have unequal and unknown intensities. Here, we assume a Gaussian point spread function (PSF) with spread $\sigma _{\text{PSF}}$

Random frequency and pulse repetition interval (PRI) agile (RFPA) signals bring excellent performance of electronic counter-countermeasures to radar systems and have been received considerable attention in recent years. However, the research on their ambiguity function (AF) is not comprehensive. In this article, the analytical expressions of the AF expectation and variance are given. According to the

In a sensor network compensation of the correlated information caused by previous communication is of utmost interest for distributed estimation. In this article, we investigate an information decorrelation approach that can be applied when using interacting multiple model filters in the sensor nodes for a family of jump Markov linear systems. Implementation issues that might arise while applying the

The parametric CFAR detectors maintain a constant false alarm rate (CFAR) with an assumption of a known clutter distribution form. The representative ones of them are the cell-averaging (CA) CFAR, the greatest-of (GO) CFAR, and the ordered statistic (OS) CFAR, etc. In this work, we consider the rank sum (RS) nonparametric CFAR, which has an advantage that it can maintain CFAR even the distribution

Radar mounted on a moving vehicle returns time-varying detections corresponding to unstable scattering points, unlike optical sensors, which produce relatively stable detections. We present an efficient extended Kalman filter-based simultaneous localization and mapping (EKF-SLAM) algorithm for radar, utilizing new techniques of clustering and sifting the time-varying detections. Velocity bias and yaw

The article discusses dynamic requirements for designing ground manipulator platforms that can be utilized to verify the performance of controllers developed for space manipulators. Dimensional analysis is used to formalize the dynamic equivalence conditions and control scaling laws between a given space manipulator and the ground manipulator to be designed, such that the space manipulator and the

In this article, an energy optimal dynamic attitude for a solar-powered aircraft is determined and implemented using the finite-time sliding-mode approach. A nonlinear constrained optimization technique has been considered to determine the optimal attitude of the aircraft for given a geographical location, solar position, heading direction, and other flight conditions for clear sky conditions. The

In this article, an intelligent predictor–corrector entry guidance approach for lifting hypersonic vehicles is proposed to achieve real-time and safe control of entry flights by leveraging the deep neural network (DNN) and constraint management techniques. First, the entry trajectory planning problem is formulated as a univariate root-finding problem based on a compound bank angle corridor, and two

Linear least squares (LS) frequency estimators are popular because they are closed form and easy to implement. However, they are applicable to compressive frequency estimation only after reconstruction. This is because compressive sensing (CS) breaks up the temporal order of the original sinusoidal samples. This correspondence proposes an efficient sensing scheme to obtain CS samples. They are sums

In the field of indoor localization, ultra-wideband (UWB) technology is no longer dispensable. The market demands that the UWB hardware has to be cheap, precise, and accurate. These requirements lead to the popularity of the DecaWave UWB system. The great majority of the publications about this system deal with the correction of the signal power, hardware delay, or clock drift. It has traditionally

Presents the table of contents for this issue of the publication.

Presents a listing of the editorial board, board of governors, current staff, committee members, and/or society editors for this issue of the publication.

Binary Golay pairs are examined with an interest in finding examples, in which members of the pair can be replaced with other codes sharing the same autocorrelation, but not due to negation and reversal. These are referred to as shared-autocorrelation (or shared- $\rm ACS$ ) Golay pairs. Golay pairs can always formed from other Golay pairs by reversing and/or negating codes in those pairs; the discovery

Fault detection algorithms (such as advanced RAIM) developed for aviation can be applied in situations where the probabilities of fault are arbitrarily high. However, with large probabilities, the user receiver needs to protect against a large number of fault modes (which results from the combination of simultaneous independent faults). In baseline ARAIM algorithms, the user receiver must compute a

Recent works have shown that the optimal state feedback for deterministic, nonlinear autonomous systems can be approximated by deep neural networks. In this article, we consider the stability of nonlinear systems controlled by such a network representation of the optimal feedback. First, we show that principal methods from stability theory readily applies. We then propose a novel method based on differential

This article proposes a new recursive linearly constrained minimum variance (LCMV) beamformer based on the extended instrumental variable (EIV) method for planar radial coprime arrays (PRCAs) under spatially colored noise. The proposed recursive LCMV beamformer is able to deal with multiple constraints with high precision and low complexity and can be applicable to various array geometrical configurations

Nowadays, mutual interference among automotive radars has become a problem of wide concern. In this article, a decentralized spectrum allocation approach is presented to avoid mutual interference among automotive radars. Although decentralized spectrum allocation has been extensively studied in cognitive radio sensor networks, two challenges are observed for automotive sensors using radar. First, the

This article studies the robust fuzzy attitude control strategy for the networked spacecraft consisting of physically independent modules that interact through network communication. The effects of inertia uncertainties, delayed feedback, actuator saturation, and external disturbances are simultaneously taken into account when designing the attitude control law. Based on aperiodic sampling, an adaptive

This article provides a comparative performance analysis of different acquisition and tracking methods of GPS L1 C/A and GPS L5 signals testing their robustness to the presence of scintillations in the propagation environment. This article compares the different acquisition methods in terms of probabilities of detection/false alarm, peak-to-noise floor ratios for the acquired signal and execution time

Land vehicle navigation based on the inertial navigation system (INS) and odometers (ODs) is a classical autonomous navigation application and has been extensively studied over the past several decades. In this article, we seriously analyze the error characteristics of the OD pulses and investigate three types of OD measurement models in the INS/OD integrated system. Specifically, in the pulse velocity

Sea-surface small target detection is always a difficult problem in high-resolution maritime ubiquitous radars for complex characteristics of sea clutter, weak target returns, and diversity of targets. Multiple features extracted from radar returns in different domains have ability but not enough to solely distinguish radar returns with target from sea clutter. Joint exploitation of multiple features

An analytic model for calculating the instantaneous and average orbital power available to a satellite in a circular low Earth orbit is presented. By accounting for the effects of angle of solar incidence and eclipsing, for both stabilized and tumbling satellites, this model allows for fast, simple, accurate calculations of available power without the use of complex, often expensive, numerical simulation

This article investigates a distributed game strategy for formation control of multispacecraft subjected to nonlinear dynamics and $J_2$ perturbations. In the proposed problem, each spacecraft is devoted to minimize its own performance cost using only local information, whereas the overall formation system attempts to seek an optimized decision based on communication topology. Therefore, in our scheme

Reusable liquid-propellant rocket engines (LPREs) imply more demanding robustness requirements than expendable ones due to their extended capabilities. Therefore, the goal of this article was to develop a control loop adapted to all the operating phases of LPRE, including transients, and robust to internal parametric variations. First, thermo-fluid-dynamic simulators representative of the gas-generator-cycle

Global navigation satellite systems (GNSS) provide ubiquitous, continuous, and reliable positioning, navigation, and timing information around the world. However, GNSS space segment design decisions have been based on the precursor Global Positioning System, which was designed in the 1970s. This article revisits those early design decisions in view of major technological advancements and new GNSS environmental

All-source navigation has become increasingly relevant over the past decade with the development of viable alternative sensor technologies. However, as the number and type of sensors informing a system increases, so does the probability of corrupting the system with sensor modeling errors, signal interference, and undetected faults. Though the latter of these has been extensively researched, the majority