Radar marine maneuvering target detection via high resolution sparse fractional ambiguity function

To solve the problem of fast detection of high maneuvering targets in complex ocean background,a radar target detection algorithm via sparse fractional ambiguity function (SFRAF) was proposed.The sparse Fourier transform (SFT) was introduced after instantaneous autocorrelation function calculation,which combines the advantages of SFT and fractional ambiguity function (FRAF).Therefore,SFRAF has good processing performance on high maneuvering signals and can achieve lower computational complexity.The simulation experiments and the measured data processing results show that compared with classical detection method,the detection performance of maneuvering target can be significantly improved,and compared with FRAF,the proposed method can achieve higher detection efficiency.     

Radar target identification

The authors discuss the aspects of the radar target/identification problem which have made progress slow and difficult. They summarize their research program and discuss the mathematical foundations for solving the problem. To simplify the discussion, only aircraft-type targets are considered, and clutter is ignored. Target-library problems, are examined in some detail, including the proposed use of scattering-center models to mitigate problems and related electromagnetic-modeling considerations     

Radar signal design subject to simultaneous peak and average power constraints

Optimal amplitude modulations for a radar signal are derived and then used to calculate the efficiencies of various sub-optimal modulations. The choice of modulation is constrained by the total energy transmitted and the peak power (amplitude) of the transmitted signal. The peak power constraint is handled by the use of Pontryagin's Maximum Principle, an extension of the calculus of variations recently developed in the U.S.S.R. that is enjoying wide application in optimal control theory. The criterion of optimality is based on the error variances of estimates of the range motion parameters of a reflecting body, where the errors are caused by additive, white, zero mean, Gaussian noise. Explicit results are provided for bodies with constant velocity and bodies with constant acceleration. The analysis covers: 1) incoherent processing of a sequence of many range measurements; 2) coherent processing assuming the RF phase is known, 3) certain aspects of coherent processing assuming the RF phase is unknown. The optimal modulations turn out to be of the "on-off" type, requiring either no transmission or transmission at the maximum allowable power level.     

基于联合检测方法的雷达信号分选跟踪机设计

雷达信号分选是雷达对抗中一个重要的组成部分,只有从随即交迭的信号流中分选出各个雷达脉冲序列之后才能进行信号参数的测量、分析、识别。目前基于PRI参数提出很多分选方法,针对各种方法的优缺点,研究了一种基于SDIF算法和序列相关法联合检测的被动雷达信息处理系统信号分选跟踪机,经仿真证明,基于SDIF与序列相关法的联合检测增加了检测概率,具有较好的鲁棒性,可以较好地对空间多部不同雷达信号进行准确分选,正确给出跟踪波门。该信号分选跟踪机已在工程中应用。     

Radar resolution of moving targets

Conventional resolution theory is based on the assumption of constant range rate, and it neglects distortions of the modulation function as well as effects of the antenna pattern. Among the generalizations of the theory reported in the literature, some include the antenna pattern and others retain higher-order range derivatives in both carrier term and modulation function. The first part of this paper is tutorial and discusses the significance of the various generalizations of the ambiguity function. It is shown that an important class of problems can be accommodated when the conventional theory is extended by permitting higher-order range derivatives in the carrier term. Target resolvability on the basis of motion then depends only on the relative phase shifts introduced over the signal duration. In the second part, the ambiguity function is formally extended to arbitrary target motion. The modified theory retains the simplicity of the conventional approach and allows utilization of well-known results.     

Generalized likelihood signal resolution

This paper defines anM-ary generalized likelihood ratio test (MGLRT) that overcomes Root's early objection to the application of generalized likelihood ratio testing to the resolution of correlated signals. The proposed test extends the form of a conventional binary generalized likelihood ratio test (GLRT) in a manner that permits a generalization of the minimax properties of the binary test to theM- hypotheses case. When the estimated signals are orthogonal, the test reduces to a sequence of conventional binary tests duplicating the performance of a narrow-band matched filter envelope-detector receiver.     

DTTB的双基地雷达模糊函数及目标分辨力分析

通过双基地模糊函数分析比较了数字电视地面广播(DTTB)标准下单载波和多载波2种信号形式分别应用于双基地雷达的性能及目标分辨特性,研究了不同接收角度下,DTTB 系统2种信号应用模式的模糊函数图,得到了双基地模糊函数形式下副峰的相对位置、产生原因以及与单基地模糊函数副峰位置的关系。分析了双基地雷达应用中 DTTB 信号的速度分辨力和距离分辨力,指出 DTTB标准下单载波与多载波信号形式的双基地雷达分辨力大致相同,单载波形式的分辨力相对更优。     

Radar dynamic range centering for log-normal target statistics

The receiver dynamic range centering studies of Ward and Rappaport have been extended to the situation where the radar signal amplitude statistics have the log-normal form. Results analogous to those previously published for the Rayleigh and modified Rayleigh cases are presented graphically, and show that receiver dynamic ranges considerably larger than those for the Rayleigh distribution may be required for given minimum probabilities of signal exclusion.     

用于红外弱小点目标图像的超分辨增强技术

提出了一种适用于红外弱小点目标增强的超分辨重建技术.为实现这一目标,首先引入基于图像稠密描述的特征流场,然后将计算得到的高精度流场用于相邻帧配准,通过图像融合和不断迭代得到高分辨重建图像.实验表明,对图像进行超分辨处理后,弱小目标的分辨率可以得到有效增强,局部信噪比可以得到提升,复杂背景可以得到抑制.     

激光打靶透镜的设计

本文介绍了激光打靶透镜的特点及用等光程原理求解非球面透镜的方法。     

S-K-H algorithm for signal design

An algorithm based on four ideas, two from Simon (hence S) and one each from Kronecker (K) and Hamming (H), has been developed to obtain ternary sequences of large lengths and high merit factors. Operationally, the Hamming scan and the Kronecker product are the two central ideas used     

Dense target signal processing

The problem of determining the density of targets at every range and velocity is addressed. These targets consist of a dense group of reflecting objects moving with different velocities and at different ranges. The problem of how to choose the outgoing signals and process the echoes of those signals from the targets to determine the density function is discussed. The problem is a classical inverse problem. The objective is to reconstruct a function of two variables (range and velocity) from limited information. Two schemes are given. The first of these methods modifies the method of J.R. Klauder et al. (1960) to the case of signals with a large range of frequency components (wideband signals). The second is an improvement on the first that uses a formula of I. Khalil (1974) from affine group theory. Numerical solutions support the conclusions. The method has applications in echocardiography, radar, sonar and fluid flow measurement     

Radar resolution properties of pulse trains

The concept of pulse compression has stimulated interest in the range and Doppler resolution properties of radar signals, but most of the theoretical investigations to date have been concerned with single pulse signals. The properties of coherent pulse trains, a practically important class of radar signals, have not received adequate treatment in the literature. Little information appears to be available on pulse trains using pulse-to-pulse waveform coding, frequency shifting, or repetition period staggering. The present paper attempts to fill a gap in the radar literature by analyzing the resolution potential of pulse trains. The treatment is limited to the practical class of pulse trains where all component pulses have identical envelopes and bandwidths, but the waveforms under these envelopes, frequency bands and repetition interval are left arbitrary. The results of the study convey an understanding of the effects of pulse train coding and thus give a clear indication of both the potential and the limitations of pulse trains in radar applications.     

雷达信号处理系统仿真

该文以海上作战指挥系统中的舰载雷达为背景,对战场环境下舰艇编队作战指挥系统中的舰载某脉冲压缩雷达信号处理系统进行建模与仿真,仿真结果表明这种方法能够较好的反映雷达信号处理系统的各部分性能,满足系统调试的要求。     

三频段准连续波雷达信号目标检测性能分析

准连续波雷达是一种低截获概率雷达,结合了脉冲雷达收发隔离和连续波雷达截获概率低的优点,但其检测性能的优劣很大程度依赖于信号形式,普通的编码信号和线性调频信号已经不能满足其对目标探测的要求。为解决这个问题,设计了一种三频段信号和与之相应的收发系统,对系统结构及三频段信号的参数选择原则、目标检测原理、模糊函数、抗近距离盲区性能做了详细分析,并指出了三频段信号相对于相位编码信号和分时发射信号的优势所在,最后通过仿真证明,将三频段信号应用于准连续波体制雷达中时能准确探测目标,得到目标的各个参数并且能有效消除近距离盲区。     

一种机载雷达信号处理系统的实现

介绍一种机载雷达信号处理系统的设计与实现,给出基于ADI公司TS101芯片的信号处理硬件整体结构和各个硬件模块间的接口设计,分析整个系统的软件架构,并对一些基本算法和处理方法作以描述.     

Millimeter Wave Radar for detecting the speech signal applications

MilliMeter Wave (MMW) Doppler Radar with grating structures for the applications of detecting speech signals has been discovered in our laboratory. The operating principle of detection the acoustic wave signals based on the Wave Propagation Theory and Wave Equations of The ElectroMagnetic Wave (EMW) and Acoustic Wave (AW) propagating, scattering, reflecting and interacting has been investigated. The experimental and observation results have been provided to verify that MMW CW 40GHz dielectric integrated radar can detect and identify out exactly the existential speech signals in free space from a person speaking. The received sound signal have been reproduced by the DSP and the reproducer.     

天气雷达产品VIL算法设计

VIL 被定义为云底上部单位体积内悬挂的可降水质量, 是通过对雷达体扫描资料进行加工处理后的一种新的产品资料, 利用雷达获得各个观测层的回波值的总体分布, 反演得到雷达探测范围内水成物的三维分布情况.文中首先介绍了VIL生成的理论原理,通过读出雷达数据,生成误差尽可能小的VIL,以及运用计算机图形处理功能实现对VIL的彩色显示,放大等功能.     

A high resolution frequency multiplier for clock signal generation

This paper presents a high resolution frequency multiplier (FMUL) with the ability to multiply frequency with a programmable high multiplication factor, in the order of 10²-10⁴ and of the form N/M. It was designed for chip-sets that use a real time clock (32768 Hz) for power-save operation, and an additional high-frequency oscillator, in the range of 40-60 MHz, for regular operation. Using the FMUL spares the need for the additional high-frequency oscillator. The FMUL's frequency resolution is 100 ppm, and its jitter is less than 200 ps. The circuit is designed to work with 25 V supply voltage. It is implemented in a standard 0.8 pm N-well CMOS process, and its area is 0.48 mm²     

可编程信号处理器的低功耗设计

可编程信号处理器已获得广泛应用，随着VLSI技术的发展，现在已可利用信号处理器实现SOC功能，实现SOC功能还必须降低处理器的功耗。本文首先叙述可编程信号处理器降低功耗的各种途径，然后介绍低功耗可编程处理器的结构设计，最后对最新的TMS320C55X的低功耗性能进行分析。