Surveillance Radar Research Articles

Cylindrical phased array with adaptive nulling using eigen‐correlation technique

In this research work, eigen-correlation matrix based technique is developed for cylindrical antenna array to generate main beam and nulls simultaneously. The array complex weights (amplitude and phase) computed using the developed technique are used for single-beamforming, multi-beamforming, and beamforming with nulls steering simultaneously. The limitations of null steering range are investigated for different surface deformations of the cylindrical antenna array. The effects of surface deformations for different cylindrical radii on peak gain of main beam, half-power beamwidth, first-null beamwidth, and sidelobe level is also investigated. It is concluded that the developed eigen-correlation matrix based technique for cylindrical antenna array can be used for desired main beam generation and nulls steering simultaneously. The MATLAB, CST, and measurement validation of eight elements microstrip cylindrical phased array for single/multi-beams steering and adaptive nulling capability is demonstrated. This in turn makes the cylindrical phased array with adaptive nulling, a potential candidate suitable for use on fuselage portion of aircraft, airport surveillance radars, and mobile communication applications.

Unsupervised Clustering Method to Discriminate Dense Deception Jamming for Surveillance Radar

With the development of digital radiofrequency memory devices, the deception jamming has become a major jamming type in radar electronic counter countermeasures, especially the dense deception jamming. Recent years, some methods using signal features are proposed for specific deception jamming excision scene. It verifies the feasibility that uses signal features to discriminate deception jamming. However, discriminator training and simulation are indeed hard to achievable since no jamming samples can be obtained in advance. In this letter, we focus on the online dense deception jamming discrimination problem without the offline data training. Since deception jamming signals generated by jammers are definitely different from physical backscattering target echoes on signal features and dense jamming signals generated by one jammer has similar signal fingerprint features, an unsupervised clustering method with heuristic feature extraction is proposed. All discrimination processes are data driven and can be executed online without <italic xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">a priori</i> information. To evaluate its effectiveness, the proposed method is applied to a group of experimental data collected from a trial <italic xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">C</i> -band radar. Results corroborate the proposed method and indicate the direction of future research.

The Effect of Strategic Surveillance Radar in Reducing Strategic Drift Analytical Research of the Opinions of a Sample of Workers in Private Universities in the Holy Karbala Governorate

This research seeks to determine the effect of Strategic Surveillance Radar based on (Khalil, 2019) in reducing Strategic drift based on (Hussein &amp; Abdul Hassan, 2020). Private universities in Karbala governorate-Iraq chosen as a field for research through a questionnaire that included (75) members of the research community, represented by deans, their assistants, and department heads. Some descriptive statistics, correlation analysis and regression analysis used. A set of recommendations submitted to guide them in limiting Strategic drift through adopting Strategic Surveillance Radar.

Range prediction issues for doppler related range error elimination, experiment results

Doppler related range measurement error (velocity error) can make a major contribution to the systematic error in radars with linear-frequency modulation of a probing pulse. The velocity error can be eliminated by range prediction. It was difficult to apply this approach to radars with analogue signal processing due to lack of advanced computer aids. In radars with digital signal processing, the velocity error in range measurements is often eliminated by estimating Doppler frequency. This paper covers issues related to the elimination of the velocity error by range prediction without Doppler frequency estimation and presents the experiment results at surveillance radar.

Tornado Formation and Intensity Prediction Using Polarimetric Radar Estimates of Updraft Area

AbstractA sample of 198 supercells are investigated to determine if a radar proxy for the area of the storm midlevel updraft may be a skillful predictor of imminent tornado formation and/or peak tornado intensity. A novel algorithm, a modified version of the Thunderstorm Risk Estimation from Nowcasting Development via Size Sorting (TRENDSS) algorithm is used to estimate the area of the enhanced differential radar reflectivity factor (ZDR) column in Weather Surveillance Radar – 1988 Doppler data; the ZDR column area is used as a proxy for the area of the midlevel updraft. The areas of ZDR columns are compared for 154 tornadic supercells and 44 non-tornadic supercells, including 30+ supercells with tornadoes rated EF1, EF2, and EF3; nine supercells with EF4+ tornadoes also are analyzed. It is found that (i) at the time of their peak 0-1 km azimuthal shear, non-tornadic supercells have consistently small (&lt; 20 km2) ZDR column areas while tornadic cases exhibit much greater variability in areas, and (ii) at the time of tornadogenesis, EF3+ tornadic cases have larger ZDR column areas than tornadic cases rated EF1/2. In addition, all nine violent tornadoes sampled have ZDR column areas &gt; 30 km2 at the time of tornadogenesis. However, only weak positive correlation is found between ZDR column area and both radar-estimated peak tornado intensity and maximum tornado path width. Planned future work focused on mechanisms linking updraft size and tornado formation and intensity is summarized and the use of the modified TRENDSS algorithm, which is immune to ZDR bias and thus ideal for real-time operational use, is emphasized.

Reconfigurable Intelligent Surfaces for N-LOS Radar Surveillance

This paper deals with the use of Reconfigurable Intelligent Surfaces (RISs) for radar surveillance in Non-Line Of Sight (N-LOS) scenarios. First of all, the geometry of the scene and the new system concept is described with emphasis on the required operative modes and the role played by the RIS. Then, the specific radar equation (including the RIS effect) is developed to manage the coverage requirements in the challenging region where the LOS is not present. Both noise and clutter interference cases (pulse length-limited and beamwidth-limited surface clutter as well as volume clutter) are considered. Hence, a digression on the use of the radar timeline for the new operative mode is presented together with the data acquisition procedure and the resolution issues for the range, azimuth, and Doppler domains. Finally, the interplay among the system parameters and, in particular, those involving the RIS is discussed and analyzed via numerical simulations.

Method for dealing with non-stationary natural and simulating interference in intellectual surveillance radars

The article discusses a method for dealing with non-stationary natural and simulating interference in intelligent surveillance radars. When creating simulating marks, the introduction of amplitude modulation into the relayed radar sounding signal is used. As a result of the analysis, it was possible to find out that in the imitating noise, in this case, the so-called "intelligent" fluctuations of the burst structure of false marks appear, which differ from the fluctuations of the packs of real marks and can be easily detected by a human operator. The method is based on the definition of semantic components at the stage of formation and analysis of a symbolic model of amplitude fluctuations of a burst of signals from non-stationary natural and simulating interference and from real moving objects. In this case, the semantic features of amplitude fluctuations are determined by solving predicate equations for transforming these fluctuations into symbolic images of noise marks and real mobile aircraft. As a result of semantic analysis of the amplitude fluctuations of the burst in the time domain, classification distinctive features of fluctuations in the burst of signals from natural imitating noise and air objects were obtained. The semantic components of the decision-making algorithm are investigated, which are similar to the decision-making algorithms by a human operator. Process knowledge of transforming radar signals into symbolic images of amplitude fluctuations of a burst in the time domain is formalized. The formalization of the processing of symbolic images includes a system of predicate equations, by solving which the types of amplitude fluctuations of the burst are identified. Based on the results of experimental data, the transformations of real radar signals into symbolic images of burst fluctuations were carried out on the basis of the algebra of finite predicates. The authors also managed to propose these transformations to be used as the basis of an effective toolkit for obtaining classification distinctive features of packet fluctuations from interference and from aircraft.

Increasing the Radar Equivalent Energy Potential by “Track Before Detect” Method

The problem of radar detection of small-sized targets using the traditional methods of selection of signals embedded in background noise is considered. It is shown that for a false alarm rate of 10–5, which provides for 1–2 false alarms within the entire coverage of the modern 3D radar, the probability of detection of a small-sized target is getting unacceptably low. Repeatedly decreasing the threshold can provide an acceptable level of the detection probability at ultra-low signal-tonoise ratio (SNR) values. At the same time, decreasing the threshold will result in an unacceptable increase of the false alarm rate. A new target detection procedure using the “track before detect” method (TBD) is proposed. In the TBD procedure, the target is considered detected when two conditions are met: the signal exceeds once a definite threshold; the target is detected within a strictly defined observation area (acquisition or tracking gate). For low SNR values in the range of 3–8 dB and equal false alarm rate, the detection probability increases by 20–50 % compared to the traditional detection method. The simulation results showed a strong dependence of efficacy of the TBD algorithm on the threshold value and the decision rule. The possibility is noted of adaptive control over the threshold due to the use the detection results in the preceding scanning cycles, as well as the introduction of matrix radar surveillance not only by the target coordinates and parameters, but also by the detection threshold, decision rules, etc. Examination of these issues is the subject of further research.

The Development of the Method of Radar Observation System Construction of the Airspace on the Basis of Genetic Algorithm

The methodological approaches to the use of genetic algorithm for the synthesis of the rational structure of the radar surveillance system are proposed in the paper. The structure of the radar surveillance system is presented in the form of an incidence matrix, which is used as a chromosome by the operators of the genetic algorithm. This matrix is used as a chromosome by the operators of the genetic algorithm. The elements of the incidence matrix that describe the relationships between the elements of the structure of the observation system are genes in the genetic algorithm. In each cycle of the genetic algorithm, a pair of chromosomes is paired, during which part of the genes are exchanged, which for the system under study means the appearance and disappearance of the corresponding connections between the elements. The calculation of the values of the efficiency of radar surveillance for each variant of the structure is proposed to be carried out using the ant colony optimization. The gain in the value of the conditional probability of correct detection with a fixed probability of false alarm is approximately 10% Keywords— genetic algorithm, artificial intelligence, optimization, route, radar surveillance system.

Research on Channel Optimization of Ads-B Aviation Target Surveillance Radar Based on Improved Filtering Algorithm

In order to improve the surveillance effect of the aviation target surveillance radar, this paper improves the traditional filtering algorithm and builds the channel optimization system of the ADS-B aviation target surveillance radar based on the improved filtering algorithm. Moreover, this paper uses algorithm improvement to ensure the positive definite or semipositive definiteness of the state covariance and uses the root mean square volume Kalman filter to avoid the filter divergence or tracking interruption caused by the nonpositive definiteness of the matrix; the filtering principle of the interactive multimodel is to use multiple filters for parallel processing and achieve the adaptive adjustment algorithm residual error by adjusting the one-step prediction covariance in the adjustment algorithm. In addition, this paper combines the actual needs to construct a system functional structure to optimize the channel of the ADS-B aviation target surveillance radar and uses software engineering methods to model and analyze the requirements. Finally, this paper designs experiments to verify system performance. The research results show that the performance of the system constructed in this paper meets actual needs.

ADS-B Crowd-Sensor Network and Two-Step Kalman Filter for GNSS and ADS-B Cyber-Attack Detection.

Automatic Dependent Surveillance-Broadcast is an Air Traffic Control system in which aircraft transmit their own information (identity, position, velocity, etc.) to ground sensors for surveillance purposes. This system has many advantages compared to the classical surveillance radars: easy and low-cost implementation, high accuracy of data, and low renewal time, but also limitations: dependency on the Global Navigation Satellite System, a simple unencrypted and unauthenticated protocol. For these reasons, the system is exposed to attacks like jamming/spoofing of the on-board GNSS receiver or false ADS-B messages’ injection. After a mathematical model derivation of different types of attacks, we propose the use of a crowd sensor network capable of estimating the Time Difference Of Arrival of the ADS-B messages together with a two-step Kalman filter to detect these attacks (on-board GNSS/ADS-B tampering, false ADS-B message injection, GNSS Spoofing/Jamming). Tests with real data and simulations showed that the algorithm can detect all these attacks with a very high probability of detection and low probability of false alarm.

Reversible Jump MCMC for Deghosting in MSPSR Systems.

This paper deals with bistatic track association and deghosting in the classical frequency modulation (FM)-based multi-static primary surveillance radar (MSPSR). The main contribution of this paper is a novel algorithm for bistatic track association and deghosting. The proposed algorithm is based on a hierarchical model which uses the Indian buffet process (IBP) as the prior probability distribution for the association matrix. The inference of the association matrix is then performed using the classical reversible jump Markov chain Monte Carlo (RJMCMC) algorithm with the usage of a custom set of the moves proposed by the sampler. A detailed description of the moves together with the underlying theory and the whole model is provided. Using the simulated data, the algorithm is compared with the two alternative ones and the results show the significantly better performance of the proposed algorithm in such a simulated setup. The simulated data are also used for the analysis of the properties of Markov chains produced by the sampler, such as the convergence or the posterior distribution. At the end of the paper, further research on the proposed method is outlined.

Analysis of sun-moon gravitational acceleration and engineering realization of space target

Space target orbit determination is a core function of space target surveillance radar, which involves very complicated mathematical principles, and it is very difficult for professional radar system designers with no orbital mechanics to develop corresponding software modules. The difficulty in developing orbit determination software is the calculation of perturbation acceleration, which is the basis for realizing high-precision numerical orbit calculations. To this end, this paper takes the solar-moon gravitational perturbation that cannot be ignored in the precision orbit determination of high-orbit satellites as an example, introduces its mathematical principles, gives the program design ideas for acceleration calculation, implements the interface function and integrates it into the author’s early development radar orbit determination library (RadarOrbDet). The simulation results verify the effectiveness of the interface function and show that the orbit determination function library can assist scientific researchers in radar system design. The research results of this paper can be used as a reference for the spacecraft orbit analysis of interplanetary flight.

PENGASASAN DAN PERANAN AGENSI PENGUATKUASAAN MARITIM MALAYSIA, 2004-2014

This article examines the Malaysian Maritime Enforcement Agency (MMEA) in the context of its establishment and role to patrol and protect the Malaysian maritime zones. The discussion focuses on its establishment, its main roles, and the challenges faced. Qualitative analysis is used to study data obtained from both primary and secondary sources. Among the primary sources used include the acts related to national maritime zones, the MMEA Annual Reports, the Malaysian International Trade and Industry Reports, Malaysian Transportation Statistics, Parliamentary Hansards, and local periodicals. Based on the sources used, the study found that the lucrative importance of our national maritime zones compelled the government to create a new specific agency to patrol and protect our waters. The MMEA operations officially began on 30 November 2005. Although this agency is responsible for national security, its staff scheme is categorised as the public sector, in contrast to the schemes of service for the Marine Police and the Malaysian Royal Navy (TLDM). The largest role and challenge of the MMEA in patrolling national waters involve both supervision and coordination. Although equipped with radar surveillance system, our vast maritime zones naturally tempt activities of piracy, smuggling, encroachments by foreign fishermen, and movements by illegal immigrants. The vague legal provisions meant other enforcement agencies are seen as operating within the ambit of MMEA portfolio, causing problems of ineffectiveness and hindering the MMEA’s role of coordination.

Determination of the Spatial Resolution of Radar Images in Remote Sensing of the Earth

Introduction. The analysis of the current state and prospects of space-based radar surveillance tools is important for determining their functions in global aerospace information systems, which aim to monitor air and space, as well as the Earth's surface. Radar surveillance information is used for the purposes of economic analysis, environmental monitoring, mineral search, emergency monitoring, detection and recognition of specified object s at sea and on land, as well as for ensuring national security. In this regard, it is of relevance to develop methods for preliminary assessment of the resolution capacity of novel high-precision onboard radar systems installed on a spacecraft, considering their main technical characteristics, the parameters of the spacecraft movement and the influence of the atmosphere. A priori estimation of spatial resolution values requires a method for calculating the corresponding indicators meeting the required quality of the synthesized radio holograms.Aim. To derive mathematical dependencies and logical rules allowing a priori estimation of the spatial resolution of radar images obtained by the onboard equipment of a radar complex.Materials and methods. Analytical methods were used to determine the resolution error of onboard radar systems with a synthesized aperture in the lateral (azimuthal) direction and range, as well as the theory of radar signal processing.Results. A comparison of the experimental and analytical data on the resolution capacity of an actual radar system confirmed the validity on the proposed method. The developed methodology was used to determine the procedure of calculating the error when estimating the resolution capacity in terms of azimuth and range. Conclusion. The proposed method can be used for both designing novel radar systems and comparing existing radar complexes, depending on the resolution requirements.

Monopulse Secondary Surveillance Radar Coverage-Determinant Factors.

This paper presents a comprehensive study on monopulse secondary surveillance radar (MSSR) coverage. The design and radiation pattern of an improved MSSR antenna is presented herein, highlighting the horizontal and vertical factors of the SUM beam. Moreover, the impact of other determinant factors, such as signal reflection and atmospheric refraction, on the radar coverage were assessed in this work. Real positioning measurement data and coverage simulations were used to support and exemplify theoretical findings.

Foreign Object Debris Automatic Target Detection for Millimeter-Wave Surveillance Radar.

Foreign Object Debris (FOD) refers to any foreign material on the airfield that may injure and threaten the aircraft and airport system. Due to the complex background on the airfield pavement and weak target echoes in long-distance monitoring, it is not easy to detect objects of various types and sizes. The existing FOD radar system’s detection method has a short effective range, and the detectable objects’ radar cross-section intensity is no less than −20 dBsm. In this paper, we propose an integrated FOD automatic target detection algorithm for millimeter-wave (MMW) surveillance radar to improve small target detection under long-range conditions of over 660 m. The signal form of FOD and a clutter model of ground clutter received by millimeter-wave radar are primarily utilized and established theoretically. The runway edge detection means that it is employed based on the in-continuity features as the runway region of interest during the automatic extraction step. Following the clutter map constant false alarm detection algorithm, we utilize a time-domain algorithm that functions as the vital detection processor. Moreover, an explicit definition of the FOD detection performance is developed in a characteristic quantitative way. This criterion involves an absolute reference value for all FOD radar systems. The well-designed FOD frequency-modulated continuous-wave MMW surveillance radar is utilized, and actual experiments are carried out in a real airport in Beijing, China. The results validate the proposed method’s effectiveness and the superior performance of FOD target detection in long-range situations.

Observed Bulk Hook Echo Drop Size Distribution Evolution in Supercell Tornadogenesis and Tornadogenesis Failure

AbstractThe time preceding supercell tornadogenesis and tornadogenesis “failure” has been studied extensively to identify differing attributes related to tornado production or lack thereof. Studies from the Verification of the Origins of Rotation in Tornadoes Experiment (VORTEX) found that air in the rear-flank downdraft (RFD) regions of non- and weakly tornadic supercells had different near-surface thermodynamic characteristics than that in strongly tornadic supercells. Subsequently, it was proposed that microphysical processes are likely to have an impact on the resulting thermodynamics of the near-surface RFD region. One way to view proxies to microphysical features, namely drop size distributions (DSDs), is through use of polarimetric radar data. Studies from the second VORTEX used data from dual-polarization radars to provide evidence of different DSDs in the hook echoes of tornadic and non-tornadic supercells. However, radar-based studies during these projects were limited to a small number of cases preventing result generalizations. This study compiles 68 tornadic and 62 non-tornadic supercells using Weather Surveillance Radar–1988 Doppler (WSR-88D) data to analyze changes in polarimetric radar variables leading up to, and at, tornadogenesis and tornadogenesis failure. Case types generally did not show notable hook echo differences in variables between sets, but did show spatial hook echo quadrant DSD differences. Consistent with past studies, differential radar reflectivity factor (ZDR) generally decreased leading up to tornadogenesis and tornadogenesis failure; in both sets, estimated total number concentration increased during the same times. Relationships between DSDs and the near-storm environment, and implications of results for nowcasting tornadogenesis, also are discussed.

New Numerical and Measurements Flow Analyses Near Radars

An experimental and numerical investigation of the flow near a blunt body has been conducted in this study. Most experimental methods of flow studies use flow visualization and probes introduction into the flow field. The main goal of this research was the development of a new methodology to analyze flows, and to measure flow characteristics without taking into account the distorting effects of measuring probes. A series of experiments were performed on a ground surveillance radar in the Price-Païdoussis subsonic wind tunnel. Forces and moments were measured as functions of wind speeds and angular positions by the use of a six-component aerodynamic scale. A Computational Fluid Dynamics three-dimensional model was employed to analyze the wake region of the ground surveillance radar. A turbulence reduction system was proposed and analyzed in this research. The use of the proposed turbulence reduction system was found to be an effective way to reduce turbulent flow intensity by 50%, drag coefficients by 9.6%, and delay the flow transition point by 7.6 times.

A Gaussian Mixture Model to Separate Birds and Insects in Single-Polarization Weather Radar Data

Recent and archived data from weather radar networks are extensively used for the quantification of continent-wide bird migration patterns. While the process of discriminating birds from weather signals is well established, insect contamination is still a problem. We present a simple method combining two Doppler radar products within a Gaussian mixture model to estimate the proportions of birds and insects within a single measurement volume, as well as the density and speed of birds and insects. This method can be applied to any existing archives of vertical bird profiles, such as the European Network for the Radar surveillance of Animal Movement repository, with no need to recalculate the huge amount of original polar volume data, which often are not available.