Target Range Profile Research Articles

자율주행 무인차량용 레이더 신호처리부 개발 및 성능 분석

In this paper, we present signal processing procedure and carry out performance analysis of FMCW(Frequency Modulation Continuous Wave) radar for Autonomous Unmanned Vehicle(AUV). In order to detect range profile and velocity of the unknown target, we must implement two step FFT(Fast Fourier Transform) procedure. And the DBF(Digital Beam Forming) algorithm has to be performed to obtain the angle information of the unknown target. To verify the performance of manufactured autonomous unmanned ground vehicle FMCW radar, we use the data of the real corner reflecter target.

A Fast HRRP Synthesis Algorithm with Sensing Dictionary in GTD Model

In the paper, a fast high-resolution range profile synthetic algorithm called orthogonal matching pursuit with sensing dictionary (OMP-SD) is proposed. It formulates the traditional HRRP synthetic to be a sparse approximation problem over redundant dictionary. As it employs a priori that the synthetic range profile (SRP) of targets are sparse, SRP can be accomplished even in presence of data lost. Besides, the computation complexity decreases from O(MNDK) flops for OMP to O(M(N + D)K) flops for OMP-SD by introducing sensing dictionary (SD). Simulation experiments illustrate its advantages both in additive white Gaussian noise (AWGN) and noiseless situation, respectively. Keywords—GTD-based model, HRRP, orthogonal matching pursuit, sensing dictionary,.

Automatic recognition of targets in formation using range profiles

Range profile (RP) is an effective one-dimensional radar signature used to recognize a target, and many research results have been published regarding the classification of RPs of targets engaged in solo flight. However, because targets fly in formation with complicated motion parameters, further study is required to identify multiple targets simultaneously. This paper presents a method of recognizing multiple targets that are flying closely spaced in a formation using separate RPs of each target. However, it is very difficult to extract RPs from each target which uses reflected signals from several aircraft in a formation at several aspect angles. In this paper, RPs of each target are separated by using the segmentation method based on the range-Doppler algorithm. Classification results from using five targets that are composed of point scatterers prove the effectiveness of the proposed method.

Robust radar automatic target recognition algorithm based on HRRP signature

Automatic target recognition (ATR) is an important function for modern radar. High resolution range profile (HRRP) of target contains target structure signatures, such as target size, scatterer distribution, etc., which is a promising signature for ATR. Statistical modeling of target HRRPs is the key stage for HRRP statistical recognition, including model selection and parameter estimation. For statistical recognition algorithms, it is generally assumed that the test samples follow the same distribution model as that of the training data. Since the signal-to-noise ratio (SNR) of the received HRRP is a function of target distance, the assumption may be not met in practice. In this paper, we present a robust method for HRRP statistical recognition when SNR of test HRRP is lower than that of training samples. The noise is assumed independent Gaussian distributed, while HRRP is modeled by probabilistic principal component analysis (PPCA) model. Simulated experiments based on measured data show the effectiveness of the proposed method.

Aperture Effect Influence and Analysis of Wideband Phased Array Radar

Wideband phased array becomes a research focus with the development of modern radar technology.Wideband phased array radar is one of the advanced radar technology. However, the aperture fill time results in the beam pointing offset, limits the instantaneous bandwidth and effects of the 1-D target range profile. This paper analyses the scheme of sub-array compensation for aperture fill time. For LFM signals system, we analyze the compensation using filters for aperture fill time, and for stepping frequency signal system, we analyze the scheme of interveinal phase matching, then simulate by Matlab. The simulation results show that the sub array division technology can compensate the aperture effect and increase the instantaneous bandwidth effectively. Both the filter and the interveinal phase matching methods can solve the main lobe expansion and targets range migration; lastly get the high resolution range profile.

Range profile target recognition based on second-order fuzzy clustering

Concerning that fuzzy C-means(FCM) algorithm was sensitive to the initial value of cluster centers,a fuzzy clustering method based on Second-Order Fuzzy Clustering(SOFC) was proposed,which took advantage of Transitive Closure(TC) algorithm's non-initialization,the samples were classified according to certain classification level firstly,and then the number of class was selected.The sample means of these classes was used to initialize the FCM algorithm's cluster centers.On one hand,it can obtain good initial value of cluster centers;on the other hand,the level of value through the categories can optimize the number of cluster centers and cluster centers,avoiding local optimum and overcoming the consistency of clustering.The algorithm was used to recognize three types of aircraft targets based on one-dimensional image data.The experimental results show that the recognition of SOFC algorithm gets obvious improvement than FCM algorithm.

Absolute target range and target range profile in separate computational compartments: Synthetic aperture echolocation

Echolocating big brown bats emit wideband (20-100 kHz) FM sounds and perceive target range from echo delay with an accuracy determined by echo relative bandwidth (Q). They distinguish among target shapes by echo spectra, but they perceive shape in terms of distances to different parts (glints), or the target's range profile. Shape resolution based on glint delay differences extracted from target interference spectra is in fractions of millimeters. The bat's flight velocity is about 5 m/s, so that echo delay changes continuously during production of broadcasts and then again during reception of echoes, smearing and displacing delay estimates for target ranging by several hundred microseconds. Previous workers have identified a particular distance at which smearing is minimal, but it is not known whether this "distance of focus" has significance for the bat. However, perception of target shape is based on a spectral representation that is only slightly distorted by the bat's motion, and it is kept in separate computational path from absolute delay until after absolute delay is determined, whereupon it is attached to absolute delay to place the target's image in an approximate spatial position. The bat's system achieves synthetic aperture imaging of shape while avoiding motion-related blurring.

Nonuniform stretch processing for the range profile of a target with micro-motion

Abstract Complex motions such a micro-motions induce complex range-Doppler coupling effect in radar imaging. Hence it is a challenge to reconstruct a clear range profile of a target with micro-motion. Stretch processing with fine motion compensation cannot perform well while it tics to eliminate the distortion of range profile caused by Doppler effect, because it is difficult to accurately estimate each scattering center velocity during coherent processing interval. Based on nonuniform stretch processing (NSP), a new technology is proposed to decouple range, time and Doppler and then achieve range profile of target with micro-motion. The new technology uses a new synthetic wide-band waveform and has an innovative mathematic interpretation. Statistical properties of the new approach are primarily examined. Typical models of target with micro-motion for high resolution rader are presented. Monte Carlo simulations demonstrate the performance of the new technology and the simulation result confirm our expecta...

A New Approach for Synthesizing the Range Profile of Moving Targets via Stepped-Frequency Waveforms

In radar target imaging, motion induces a range-Doppler coupling effect, which results in distortion in synthesizing a range profile for a moving target. To eliminate or suppress the distortion of the synthetic range profile, conventional technology such as motion compensation requires velocity estimation. Unfortunately, for a high-speed moving target, it is difficult to achieve real-time accurate estimation of the velocity of the target. Based on phase cancellation, a new technology is proposed to achieve a motion target range profile via stepped-frequency waveform. The new technology does not need the estimation of the velocity. Hence, its computational cost can be minimized. It is also easier to use. The simulation result confirms the effect of the new technology

Effective CLEAN Algorithms for Performance-Enhanced Detection of Binary Coding Radar Signals

With binary coding waveform as radar pulse compression signal, the sidelobe of the matched processing result of the received signals is a serious interference to the effective detection of multiple targets. In this paper, the CLEAN algorithms are introduced to eliminate such sidelobes and significantly improve the target detection performance of binary coding radar signals. A novel modified CLEAN algorithm is proposed to remove the sidelobe interferences in formulating target range profile when wideband binary coding signals are used. The effectiveness of the CLEAN algorithms is demonstrated through the processing results.

Computer simulation of aerial target radar scattering recognition, detection, and tracking

Aerial Target Scattering Simulation in Decimeter and Centimeter Wave Bands - Possible Simulation Methods. Simplest Component Method. Consideration of Fast-Rotating Target Components. Consideration of Target Flight in Various Weather Conditions. Informativity of Recognition Features. Simulation of Recognition Features in the Cases of the Wide-Band and Narrow-Band Illumination. Signals - Target Range Profile Simulation by Various Wide-Band Probing Methods. Range-Polarization and Range-Frequency Target Profile Simulation. The 2-D Target Image Simulation. Simulation of Radar Cross-Sections and Polarization Parameters, Rotational Modulation Parameters and Correlation Factors of Fluctuations via Frequency Diversity in Narrow-Band Illumination. Simulation of the Aerial Target Recognition Algorithm Operation -Bayesian and Nonparametric Recognition Algorithm Variety. Direct Utilization and Wavelet Transform of Initial Data. Neural Recognition Algorithms Variety and their Use in Recognition. Simulation of the Aerial Target Detection and Tracking Algorithm Operation .- Comparison of Simulated and A Priori Fluctuation Models. Target Glint Models in Tracking. The Wideband Detection and Tracking. Peculiarity of Simulation in Ground Clutter and Ground Reflection of Narrowband and Wideband Signals.- General Principles of Simulation. Digital Terrain Maps and Peculiarities of their Use in Simulation. Recognition in the Ground Clutter and Ground Reflection. Augmented Physical Optics Utilization in Simulation. Scattering Effects for the Targets Uncovered, Partially and Completely Covered with Radar-Absorbing Materials in Bistatic and Monostatic Radar. References. Index.

Enhancing the Resolution of the Radar Target Range Profiles Using a Class of Subspace Eigenanalysis-Based Techniques

Quinquis, A., Demeter, S., and Radoi, E., Enhancing the Resolution of the Radar Target Range Profiles Using a Class of Subspace Eigenanalysis-Based Techniques, Digital Signal Processing11 (2001) 288–303The problem of estimating with better accuracy the time delays corresponding to the scattering centers of a radar target is considered in this paper. The analyzed signature is the range profile, which represents the scattering center projection on the line of sight. The inverse Fourier transform of the frequency spectra, which is often used to obtain range profiles, is limited in resolution by the available frequency band. The maximum likelihood method or the genetic techniques give better results, but they converge very slowly because of the global nature of the used algorithms. A class of subspace, eigenanalysis-based superresolution methods is considered in this paper in order to overcome the limitations of the Fourier method and to give a real-time estimate of the scattering center positions with much better accuracy. Some theoretical remarks, a statistical study, and experimental results are aimed to give a deeper insight concerning their application to enhancing the resolution of the range profiles.

Echo-delay resolution in sonar images of the big brown bat, Eptesicus fuscus.

Echolocating big brown bats (Eptesicus fuscus) broadcast ultrasonic frequency-modulated (FM) biosonar sounds (20-100 kHz frequencies; 10-50 microseconds periods) and perceive target range from echo delay. Knowing the acuity for delay resolution is essential to understand how bats process echoes because they perceive target shape and texture from the delay separation of multiple reflections. Bats can separately perceive the delays of two concurrent electronically generated echoes arriving as little as 2 microseconds apart, thus resolving reflecting points as close together as 0.3 mm in range (two-point threshold). This two-point resolution is roughly five times smaller than the shortest periods in the bat's sounds. Because the bat's broadcasts are 2,000-4,500 microseconds long, the echoes themselves overlap and interfere with each other, to merge together into a single sound whose spectrum is shaped by their mutual interference depending on the size of the time separation. To separately perceive the delays of overlapping echoes, the bat has to recover information about their very small delay separation that was transferred into the spectrum when the two echoes interfered with each other, thus explicitly reconstructing the range profile of targets from the echo spectrum. However, the bat's 2-microseconds resolution limit is so short that the available spectral cues are extremely limited. Resolution of delay seems overly sharp just for interception of flying insects, which suggests that the bat's biosonar images are of higher quality to suit a wider variety of orientation tasks, and that biosonar echo processing is correspondingly more sophisticated than has been suspected.

A detection method of high resolution radar targets based on position correlation

This paper studies a detection method of targets of high resolution radar operating at the band of millimeter-wave(32∼38GHz) under the background of the clutters, and proposes a new nonparametric detection method, which not only does less computation, but also is able to detect multiple extended targets radially distributed along distance “corridor”, based on the position (range) correlation information of one-dimensional range images(or called range profiles) of high resolution radar targets. The experimental results, on the real echo data of tank illuminated by the millimeter-wave stepped frequency high resolution radar, have certified that such a method presented in this paper is a very effective detection method for multiple extended targets.

Matching score properties between range profiles of high-resolution radar targets

In this paper, how the statistical properties of the matching scores are affected by the carrier frequency, the aspect variation, the range resolution, and the target complexity are studied. The statistical parameters (mean and standard deviation) of the matching scores among range profiles of independent objects are derived, and their values are used as references to determine the threshold values for target identification. It is found that the range profile obtained at a certain carrier frequency can also be used as the feature vector for radars operated at shifted frequencies if the range resolution is fine enough or the target is simple. It is also found that a radar with higher range resolution can tolerate more aspect variation, yielding a significant advantage in saving memory space for establishing the data base. The results obtained can have several applications such as target identification, data association in multiple target tracking, and target direction determination when widely-spaced high-resolution radars are employed.

Using range profiles for data association in multiple-target tracking

A parameter, the matching score, is used to discuss the correlation property between range profiles of the same target or different targets. The property that the matching score between range profiles of two consecutive aspects from the same target is greater than that from different targets is utilized to correlate tracks in the multiple-target tracking problem. A data association algorithm based on comparing matching scores is proposed. How the aspect variation size and signal to noise ratio affect the success of data association is discussed.