Radar Cross Section Model Research Articles

Experimental Verification of Laser Radar Cross Section Model for Complex Targets with Gaussian Beam Irradiation

The reflection of a Gaussian laser beam from a flat Lambert disk is considered theoretically. It was found that the results of experimental measurements of the reflected beam power as a function of the disk radius at various distances from the photodetector to the target are in good agreement with the theoretical model. It was shown that when the radius of the laser beam is greater than the dimensions of the probed complex target this target can be replaced by an equivalent Lambert disk with the same laser radar cross section.

A Complementary Overview and Challenges in Radar Cross Section Modeling of Phased Array Antennas

The radar cross-section (RCS) is a critical factor in the design and performance of modern airborne weapon systems. These systems utilize phased array antennas due to their low profile, advanced beamforming, and angle measurement capabilities. The effect of phased array antennas on platform RCS can be crucial. Addressing the RCS of phased array antennas involves solving both structural and antenna mode scattering. Each component presents different challenges for computation and requires specific RCS reduction techniques. This short review delves into various existing methods for computing antenna and structural mode RCS and offers insights into their application. Simulating the RCS of large array antennas presents significant challenges due to the high demands on computing resources. Additionally, this review highlights existing solutions aimed at reducing the simulation times and memory usage in RCS modeling while maintaining accurate results. However, further advancements are necessary to simulate large scale array antennas more efficiently and accurately.

Analysis of bistatic multiphoton quantum radar cross section for the cylindrical surface.

A closed-form model of bistatic multiphoton quantum radar cross section (QRCS) for the cylindrical surface, the main structure of typical aircraft, especially missiles, is established to analyze the system and scattering characteristics. The influence of curvature of the three-dimensional target on QRCS is analyzed. By comparing and analyzing the bistatic multiphoton QRCS for a cylinder and a rectangular plate, we find that the QRCS for the convex surface target is the extension of the QRCS for the planar target with inhomogeneous atomic arrangement intervals and patterns. The characteristics of cylindrical QRCS are discussed by combining the transceiver system and the photon number of the transmitted signal, and the influences of the cylindrical radius, cylindrical length, and incident photon number on QRCS are analyzed. The bistatic results provide guidance on potential strong scattering directions for the target under various directions of photon incidence. Compared with the plane target, the cylindrical target amplifies scattering intensity near the target surface at the scattering angle side in the bistatic system. A bistatic multiphoton quantum radar system can achieve sharpening and amplification of the main lobe of the QRCS for a cylinder in an extensive scattering angle range. Bistatic multiphoton quantum radar has better visibility for the cylinder with a smaller length. These characteristics will provide prior information for research in many fields, such as photonic technology, radar technology, and precision metrology.

The influence of three-aircraft formation blinking jamming on the performance of ground monopulse radar

The purpose of this study is to evaluate the jamming effectiveness evaluation against monopulse radar when using a non-coherent blinking jamming model at regular intervals based on three aircraft flight trajectories. To begin, the formation trajectory is solved under various aircraft attitudes to provide the radar cross section model for three-aircraft formation flying. Following that, the jamming angle tracking error model for three-aircraft formation flying is built and coupled with the features of monopulse radar angle tracking. The effective decoy angle and other criteria are used to measure the variance in jamming performance and the efficacy of formation flying radar jamming under varying jamming power and jamming gain. Finally, using the jamming effectiveness assessment criterion, the jamming effectiveness of formation flight is calculated. The findings demonstrate that the three-aircraft formation based on time transformation jamming model can successfully induce the monopulse radar angular tracking error, enhance it to 1.54 times, and stabilize the jamming effectiveness at 0.84, and it also has a relatively good jamming effect under straight flight trajectory and circular flight trajectory. Our jamming strategy will contribute to the design of electronic countermeasures, of which the findings of this research have practical significance for the application of new jamming styles.

RCS Modeling and Validation of Full Scale Launch Vehicle for its Real Time Dynamic Trajectory

Radar Cross Section (RCS) plays a significant role in detecting and tracking the space-based objects such as launch vehicles, missiles, aircrafts etc. In space applications, Radar systems are used to track and provide real-time trajectory information of the satellite launch vehicles after the lift off from the launch pad for range safety purpose. RCS is a critical key parameter that determines tracking performance of the Radar and it is highly dependent on both Radar operating parameters and the target characteristics. For space-based applications, a good quantity of RCS is required for quick detection by the Radar for continuous tracking. In order to choose the best Radar tracking configuration for real time tracking of the launch vehicle, it is required to model and simulate the launch vehicle’s RCS fluctuations prior to launch in order to predict the real time Signal to Noise Ratio (SNR) for its complete dynamic trajectory. This modeling and simulation methodology will help to choose the optimum Radar configuration for obtaining a good quantity SNR in the real-time launch. This study also provides good guidance to Radar operators for the effective Radar operation during real time space object tracking. This paper demonstrates, the real-time RCS fluctuations of a typical ISRO launch vehicle through simulation for its dynamic trajectory using physical optics based EM software prior to launch. Furthermore, the simulation results are validated with real time monostatic Radar tracking data, which showed good agreement.

Dynamic sequential radar cross section properties of airborne corner reflector in array

AbstractWith the spread of airborne corner reflector (ACR) in the field of shipborne equipment, radar guided anti‐ship missile is facing new challenges. In order to achieve the mastery of the jamming principle of this apparatus, the paper studied its motion properties and sequential Radar Cross Section (RCS) properties. Firstly, the motion model of the ACR was obtained under certain constraints, by deriving the centroid dynamics equation and rotation dynamics equation according to the theoretical mechanics. Then, the dynamic sequential RCS model of ACR array was established by combining the motion model with the modified geometric optics method and coherent synthesis method. Through the simulation and analysis of the motion model, it was found that the flight process of the ACR can be divided into two stages: fast falling and steady falling. In the fast falling stage, the variables of the ACR system change rapidly, while the ACR rotates slowly and falls smoothly in the steady falling stage. From simulation of dynamic sequential RCS model, the results showed that the obvious depolarisation effect is occur in the fast falling stage. Further statistical analysis showed that, the omnidirectivity of single ACR is well from the dynamic perspective, meanwhile array placement can effectively enhance RCS amplitude and improve the probability density distribution.

Sensitivity of Single-Pulse Radar Detection to Aircraft Pose Uncertainties

Mission planners for aircraft that operate in radar detection environments are often concerned with the probability of detection. The probability of detection is a nonlinear function of the aircraft pose and radar position. Current path planning techniques for this application assume that the aircraft pose is deterministic. In practice, however, the aircraft pose is estimated using a navigation filter and therefore contains uncertainty. The uncertainty in the aircraft pose induces uncertainty in the probability of detection, but this phenomenon is generally not considered when path planning. This paper provides a method for combining aircraft pose uncertainty with single-pulse radar detection models to aid mission planning efforts. The method linearizes the expression for the probability of detection and two radar cross section models. The linearized models are then used to determine the variability of the probability of detection induced by uncertainty in the aircraft pose. The results of this paper verifies the linearization using Monte Carlo analysis and explores the sensitivity of the probability of detection to aircraft pose uncertainty.

Distributed Communication and Sensing System Co-Design for Improved UAV Network Resilience

The progress in wireless technology over the past decade led to the rapid adoption of unmanned aerial vehicles (UAVs) for various applications. As the interest in UAVs is accelerating, increased attention is paid to the reliability and resilience of UAV-based systems with respect to the collision avoidance. One of the ways to improve this aspect is to utilize the RADAR functionality. In this work, we consider a cellular network employed for communication jointly with RADAR operation. The critical parameter that affects the RADAR algorithm is the radar cross-section (RCS). Since the task of obtaining the RCS of a complex-shaped object is extremely challenging, we first propose a novel, accurate, and fast method of scattered field assessment. We further perform radio network planning for the cellular deployment, as well as link budget estimations for the RADAR system that co-exists with it. Under this system model, we carry out detailed Monte-Carlo simulations of the RADAR detection process to obtain reliable statistical results and answer the question of how the actual bistatic RCS model affects the detection algorithm. We then apply mathematical modeling based on stochastic geometry to estimate the collision probability without the need to simulate an extensive number of flight-hours. Our numerical results confirm the robustness to RCS pattern nulls, which is crucial for safety-centric applications such as collision avoidance.

The Impacts of Terrestrial Wind Turbine’s Operation on Telecommunication Services

This paper presents a compendious review for the evaluation and description of the mathematical modelling of the affected components in wind turbines which cause the scattering of communication signals. The impact of an adjacent wind farm operation on telecommunication signals is that it induces electromagnetic interference (EMI) in radar, television and radio signals, resulting from the complex rotating blade’s geometry of the wind turbines. Thus, altering the quality of the reflected signal, especially the capability of the radar detection. In all the modelling studies, the radar cross section (RCS) model of a wind turbine’s blade is found to be the most complex, due to its huge computational burden. However, clutter filtering is another interesting technique, which employs the Doppler signal processing to obviate the huge computational task in RCS. In this case, the rotating blades of the wind turbine produce Doppler echoes, which in turn are used to estimate the model of the blade by modelling the echo of the scattering points. Therefore, this review succinctly compiles the basic steps of theoretical analysis and simulations of the impact of wind turbines on communication signals, and the remedies to minimize the impact.

FDA-MIMO radar detection for independent and nonidentically distributed fluctuating targets

Due to its range-dependent target response, frequency diverse array multiple-input multiple-output (FDA-MIMO) radar systems enable superior detection capabilities as compared with conventional phased-array radars. This paper proposes an incoherent detector for airborne FDA-MIMO radar to detect independent but possibly non-identically distributed fluctuating targets. For FDA-MIMO, variations in the target's flight attitude result in different distributions of the target radar cross section (RCS) for different pulses. In order to allow the FDA-MIMO RCS to vary due to the large frequency increments across the array antennas, we formulate a statistical FDA-MIMO RCS model for the reflected signal. We further derive the analytical detection probability for an FDA-MIMO radar measuring independent and non-identically distributed fluctuating targets. The resulting expression takes the form of an infinite sum; to enable evaluation in practice, an upper bound of the truncation error is also derived. The proposed method and all theoretical analysis are verified by numerical results, which provides theoretical basis and guidance for FDA-MIMO system implementation and design in independent and non-identically distributed fluctuating targets detection.

Insect-Equivalent Radar Cross-Section Model Based on Field Experimental Results of Body Length and Orientation Extraction

Migratory insects constitute a valuable component of atmospheric and terrestrial biomass, and their migratory behavior provides abundant information for insect management and ecological effect assessment. Effective monitoring of migratory insects contributes to the evaluation and forecasting of catastrophic migration events, such as pest outbreaks. With a large-scale monitoring technique using S-band weather radar, the insect density is estimated based on the linear relationship between radar reflectivity and the average radar cross-section (RCS) of the insects. However, the average RCS model neglects the morphological and observation parameters of the insects, which reduces the estimation accuracy. In this paper, we established an insect-equivalent RCS model based on the joint probability distribution of “body length–incident angle”. Then, we observed and extracted the morphological and observational parameters of the migratory insects by conducting a 69-day field experiment, using a Ku-band fully polarimetric entomological radar, in Dongying, Shandong Province, China. Finally, combined with the experimental results and the simulated scattering characteristics of individual insects with different body lengths, the typical insect-equivalent RCS model was established. The RCS of the model fluctuates between 0.233 mm2 and 0.514 mm2, with different incident angles. Our results lay a data foundation for the quantitative analysis of insects by weather radar.

Radar Cross Section Modelling and Analysis of Static and Dynamic Targets using MATLAB

Radar Cross Section (RCS) is an important characteristic of the electromagnetic system for target detection. This study presents detailed modelling of Radar Cross Section (RCS) of static simple objects like sphere, cylinder, triangular plate, circular flat plate, truncated cone and complex objects using MATLAB Radar toolbox. The RCS modelling of simple objects is also done with MATLAB POFACET GUI 4.3 and the results are compared with MATLAB Radar tool box. The RCS of complex objects are vectorially added in MATLAB and modelled in this work. Modelling includes 1. A cylinder with a circular flat plate on both ends 2. A circular cylinder with ellipsoid at front end 3. A truncated cone (frustum) with circular plates at both ends 4. The half ellipsoid with a frustum and the flat plate. The simulation and comparison of the RCS variations in dBsm with respect to aspect angle for parameters such as size and frequency of the simple and complex objects have been carried out in this work. RCS of a complex object with dynamic characteristics is also analysed using the Chi-square probability density function. ’The scope of this paper is limited to the objects with deterministic shapes and the combined objects using those shapes. The detailed experimental study on the sphere shows that RCS remains the constant in all directions for sphere. The study also highlights the RCS return is maximum at 180 degrees when the cylinder is aligned horizontally with the RADAR and minimum RCS is obtained at 90 degrees and 270 degrees. In the case of ellipsoid, the RCS is maximum at 90 degrees and 270 degree and minimum at 180 degrees. For the triangular flat plate, the RCS is maximum at 0 degree and 180 degrees and minimum at 90 degrees. For the truncated cone the RCS has maximum and minimum values at aspect angles of zero degrees and 80 degrees. The model of the frustrum with flat plate at both ends provides maximum RCS due to the frustrum and minimum due to flat plate and the normal incidence occurs at 73.3008 degrees. The Swerling models for the fluctuating RCS are also analysed in detail which will be used to measure RCS of high-speed debris revolving around the earth's surface by the radar in Low Earth Orbit (LEO).

Radar system simulation and non-Gaussian mathematical model under virtual reality technology

Abstract The characteristics of non-Gaussian clutter in radar systems are different from standard waveforms. To fully filter to achieve the accuracy of radar detection, the paper developed a radar simulation system based on virtual reality technology. The article uses a non-Gaussian mathematical model to simulate and collect the clutter generated by the system and realise the generation of data sequence according to the power spectrum. The research results show that the radar cross-section modelling, target recognition, anti-recognition and data fusion technology of visible targets can all be well applied in this system.

Reinforcement learning-based radar-evasive path planning: a comparative analysis

AbstractThis paper discusses the utilisation of deep reinforcement learning algorithms to obtain optimal paths for an aircraft to avoid or minimise radar detection and tracking. A modular approach is adopted to formulate the problem, including the aircraft kinematics model, aircraft radar cross-section model and radar tracking model. A virtual environment is designed for single and multiple radar cases to obtain optimal paths. The optimal trajectories are generated through deep reinforcement learning in this study. Specifically, three algorithms, namely deep deterministic policy gradient, trust region policy optimisation and proximal policy optimisation, are used to find optimal paths for five test cases. The comparison is carried out based on six performance indicators. The investigation proves the importance of these reinforcement learning algorithms in optimal path planning. The results indicate that the proximal policy optimisation approach performed better for optimal paths in general.

Detection performance of airborne FDA-MIMO radar under non-IID RCS scenario

ABSTRACT This paper studies the incoherent square-law detector in the Neyman–Pearson sense for airborne frequency diverse array multiple-input multiple-output (FDA-MIMO) radar system under a non-independent and identically distributed radar cross section model. The presented incoherent square-law detector is suitable for airborne FDA-MIMO radar with arbitrary frequency increments and correlation coefficients and achieves the optimal detection performance. The superiority of FDA-MIMO radar over traditional phased array and MIMO radars in target detection is validated by both theoretical analysis and numerical results.

High-Frequency Radar Cross Section of Ocean Surface for an FMICW Source

The frequency-modulated interrupted continuous waveform (FMICW) has been widely used in remotely sensing sea surface states by high-frequency ground wave radar (HFGWR). However, the radar cross section model of the sea surface for this waveform has not yet been presented. Therefore, the first- and second-order cross section models of the sea surface about this waveform are derived in this study. The derivation begins with the general electric field equations. Subsequently, the FMICW source is introduced as the radar transmitted signal to obtain the FMICW-incorporated backscattered electric field equations. These equations are used to calculate range spectra by Fourier transforming. Therefore, Fourier transformation of the range spectra calculated from successive sweep intervals gives the Doppler spectra or the power spectral densities. The radar cross section model is obtained by directly comparing the Doppler spectra with the standard radar range equation. Moreover, the derived first- and second-order radar cross section models for an FMICW source are simulated and compared with those for a frequency-modulated continuous waveform (FMCW) source. Results show that the cross section models for the FMICW and FMCW cases have different analytical expressions but almost the same numerical results.

Dynamic RCS Modelling of Launch Vehicle Prior to Launch for Estimation of Real-time SNR

The Radar Tracking System plays a crucial role in tracking launch vehicles by providing continuous trajectory information in order to assess their performance in real-time for range safety purpose. The target Radar Cross Section (RCS) determines radar tracking efficiency and highly depends on both the target characteristics and the radar parameters. A good amount of RCS is warranted for space-based applications for easy detection and continuous tracking by the radar. It is essential to model and simulate the RCS fluctuations of the launch vehicle prior to launch for estimating the real-time received Signal to Noise Ratio (SNR) variations for its dynamic trajectory. This modelling will aid in selecting the best radar configuration to obtain a good amount of SNR in real-time and it also provides guidance for the radar operation in tracking the target. This paper analysed the RCS fluctuations of the launch vehicle for its dynamic trajectory prior to launch by software simulation and also compute the expected real time launch vehicle SNR variations.

On the Nonlinear Mapping of an Ocean Wave Spectrum into a New Polarimetric SAR Image Spectrum

AbstractA new nonlinear transformation relation is derived to describe the mapping of a two-dimensional ocean wave spectrum into a new polarimetric synthetic aperture radar (SAR) image spectrum. It is a further expansion and improvement of Hasselmann’s work. First, the nonlinear mapping relation proposed is derived on the basis of a new polarimetric SAR image instead of the conventional single-polarization SAR image. Second, the nonlinear mapping relation no longer includes the complex hydrodynamic modulation transfer function (MTF). Third, the traditional tilt MTF, which is not accurate enough for the retrieval of sea wave spectrum, is replaced by an empirical tilt MTF derived on the basis of the C-band geophysical model function [i.e., C-band synthetic aperture radar (CSAR) normalized radar cross section (NRCS) model]. A sea wave spectrum retrieval algorithm is then proposed that is based on the new nonlinear mapping and the empirical tilt MTF. The retrieved spectra from C-band polarizedRADARSAT-2SAR images are compared with the results obtained by the ECMWF Ocean Wave Model (ECWAM) and buoy measurements.

Stochastic Geometry for Automotive Radar Interference With RCS Characteristics

With the widespread application of millimeter-wave (mmWave) radar technology in modern vehicles, vehicle-to-vehicle radar interference becomes a significant concern in exploiting the benefits of mmWave radar. This letter studies the radar mutual interference among vehicles on a practical bi-directional multi-lane road. Particularly, the fluctuation of the target radar cross-section (RCS) is modeled by Swerling I model and Chi-square model. Closed-form expression for successful ranging probability that works as the radar ranging performance metric is obtained by applying the stochastic geometry. Compared with constant RCS model in previous literature, the proposed performance metric based on random RCS models can provide more precise and intuitive results. The simulation results show that the increasing ranging distance and intensity of vehicles lead to a sharp decrease of the successful ranging probability.

Electrodynamic Model of the Signal Scattered by the Multilayer Structure with the Use of Physical Optics and Ray Tracing Technique

Introduction. Remote monitoring of layered underlying surfaces is an urgent task. To assess the performance of new algorithms for processing the radar signal reflected from the surfaces, full-scale tests are required. As their carrying out demands big expenses, simulation modeling is actual. There are many methods of estimating an electromagnetic field (EMF) scattered by the earth's surface. However, there are no proven methods and algorithms for engineering calculation of the reflected radio signal in the conditions of this problem.Aim. The aim is to develop and to verify a software model to simulate the reflected multilayer extended structure of the radio signal received on board the aircraft.Materials and methods. The core of the model was based on high-frequency electrodynamics' methods, which allowed rapid calculation for large areas of targets with any number of layers. Simulation was produced using the MATLAB software package. The developed simulation model represented the result in the form of the normalized radar cross-section (RCS) of the multilayer structure. Since the layered structure had rough boundaries, the model provided triangulation of the boundaries of the volume-distributed object. The resulting EMF was calculated using the superposition principle. Each partial EMF value on the facet was calculated taking into account the phase and the polarization of the locally incident EMF.Results. In the paper the comparison of simulation results with theoretical calculations for the normalized RCS of a two-layer structure (difference is less than 10 percent) was presented. Verification for the coefficient of variation of the envelope of the reflected radio signal from the depth of groundwater (critical error was 7 percent) was performed. RCS modeling of the absorbing layer with different degrees of roughness of the layer boundaries was carried out. The upper boundary roughness (for maximal height deviation 0.1 m) affected on specific EPR more than lower boundary. It manifested itself in decreasing of RCS down to 30 dB.Conclusion. The developed model is intended to reduce expenses for designing synthesis of subsurface imaging systems with comparison of scheme "model of device development – field tests – completion – etc". The model is designed to verify the new signal processing algorithms for subsurface radar.