Asymptotically optimal signal detection against a background of non-gaussian interference with three-dimensional statistical coupling

Gorky Polytechnical Institute. Translated from Izvestiya Vysshykh Uchebnykh Zavedenii, Radiofizika, Vol. 33, No. 5, pp. 580–586, May, 1990.     

Energy detection of partially polarized radio signals against the background of Gaussian noise

We propose a structural diagram of the energy receiver of partially polarized radio signals. Analytical expressions for characteristics of the energy detection of partially polarized radio signals against the background of Gaussian noise are obtained. The behavior of these characteristics in various cases is analyzed.     

Energy detection of radio signals against the background of Nongaussian noise with unknown intensity

We find a distribution of the decision statistic of an adaptive energy detector with training. Expressions for the probabilities of false alarm and correct detection are obtained.     

Characteristics of the energy detection of unknown radio signals against the background of Likhter noise

We analyze operation of the energy detector in the case of a non-Gaussian noise background. Analytical expressions for the probabilities of correct detection and false alarm of the energy detector receiving unknown signals against the background of Likhter noise are obtained. Translated from Izvestiya Vysshikh Uchebnykh Zavedenii, Radiofizika, Vol. 51, No. 10, pp. 889–898, October 2008.     

Estimation of the background noise level with a horizontal array against spatially uncorrelated and structural interferences

A method of estimating the isotropic sea noise level with a horizontal array in the presence of uncorrelated interference and interference with a complex spatial structure is proposed and experimentally tested. The algorithm is based on the approximation of the Capon spatial spectrum of the received signal using a model Capon spectrum for the sum of isotropic noise and uncorrelated interference. A numerical simulation is carried out to study the dependence of the accuracy of the proposed method on the interference intensity, the distance from the array to the sources of structural interference, and the number of structural interference sources. It is shown that the use of the Capon spectrum provides a strong suppression of an intense structural interference source positioned near the array. The efficiency of the proposed method is confirmed experimentally.     

Detecting and filtering a flow of different pulsed signals against the noise background

We consider the problem of separate detection and filtration of a flow of pulsed signals. We assume that statistically independent pulsed signals of different shape and random amplitude appear randomly against the background of noise. An algorithm for estimation of the detection probability of each signal is obtained. Recurrent expressions for thea posteriori probability density of each signal are found. The results of numerical simulation of the proposed algorithms of signal processing are presented. Lobachevsky State University of Nizhny Novgorod Russia. Translated from Izvestiya Vysshikh Uchebnykh Zavedenii, Radiofizika, Vol. 42, No. 1, pp. 92–100, January, 1999.     

强杂波背景红外弱小目标检测算法

针对强杂波背景远距离红外弱小信号目标的特点,提出了一种基于自适应滤波的红外弱小信号检测方法。算法首先对图像进行消噪声处理,其次运用自适应滤波方式消除背景增强目标信号,最后进行基于点源目标（试验采集）成像信号特性的判决法则删除虚假目标,算法有效解决了光电探测设备高检测概率与低虚警率的矛盾。实验结果表明：该方法能够在单帧图像上有效提取出小区域信噪比为4的弱小信号目标,检测概率不低于0.75,虚警率不高于1次/100帧。     

强杂波背景红外弱小目标检测算法

针对强杂波背景远距离红外弱小信号目标的特点,提出了一种基于自适应滤波的红外弱小信号检测方法。算法首先对图像进行消噪声处理,其次运用自适应滤波方式消除背景增强目标信号,最后进行基于点源目标(试验采集)成像信号特性的判决法则删除虚假目标,算法有效解决了光电探测设备高检测概率与低虚警率的矛盾。实验结果表明:该方法能够在单帧图像上有效提取出小区域信噪比为4的弱小信号目标,检测概率不低于0.75,虚警率不高于1次/100帧。     

Exact theory of the (Einstein) gravitational field in an arbitrary background space-time

The Lagrangian based theory of the gravitational field and its sources at the arbitrary background space-time is developed. The equations of motion and the energy-momentum tensor of the gravitational field are derived by applying the variational principle. The gauge symmetries of the theory and the associated conservation laws are investigated. Some properties of the energymomentum tensor of the gravitational field are described in detail and the examples of its application are given. The desire to have the total energymomentum tensor as a source for the linear part of the gravitational field leads to the universal coupling of gravity with other fields (as well as to the self-interaction) and finally to the Einstein theory.     

基于最优滤波器的强混沌背景中谐波信号检测方法研究

强混沌背景中的微弱谐波信号检测有重要的工程研究意义. 目前的检测方法主要是基于Takens理论的混沌相空间重构方法, 然而这些方法往往对信干噪比要求高, 且对高斯白噪声敏感等. 本文注意到混沌信号的二阶统计特性是不变的, 根据这个特点提出了一种基于最优滤波器的强混沌背景中的微弱谐波信号检测方法. 该方法首先构建一个数据矩阵, 在频域上对每个频率通道分别检测谐波信号, 从而将信号检测问题转化为最优化问题, 然后利用最优化理论设计滤波器, 使待检测频率通道的信号增益保持不变, 而尽量抑制其他频率通道的信号, 最后通过判断每一频率通道的输出信干噪比来检测谐波信号. 与传统方法相比, 本文方法有如下优点: 1)可以检测更低信干噪比下的微弱谐波信号; 2)可检测的信号幅度范围更大; 3)抗白噪声性能更强. 仿真结果证明了本文方法的有效性.     

强背景下模糊闪烁成像目标探测与跟踪

强背景下空中运动目标主要表现为边缘残缺、模糊,甚至出现闪烁、间断等复杂成像特性,这成为制约目标探测和成像跟踪的瓶颈问题。结合跟踪过程反馈信息来确定目标点扩展函数,利用一种新的Ben-Ezra图像复原模型,解决了目标运动模糊的图像复原问题;采用基于特征伴随值的相似性判断方法,构造联结机制的联想网络模型,来解决目标闪烁和残缺特征的联想问题。对提出的方法进行了图像序列的仿真,取得了较好的实验结果。     

Chiral perturbation theory in a nuclear background

We propose a novel way to formulate chiral perturbation theory (ChPT) in a nuclear background, characterized by a static, non-uniform distribution of the baryon number that describes the finite nucleus. In the limiting case of a uniform distribution, the theory reduces to the well-known zero-temperature in-medium ChPT. The proposed approach is used to calculate the self-energy of the charged pion in the background of the heavy nucleus at O(p⁵) in the chiral expansion, and to derive the leading terms of the pion-nucleus optical potential.     

The theory of microwave detection by a discharge

The presented paper tries to establish a compact theory of the hitherto only slightly explored effect of modulated electro-magnetic microwave field detection in a glow discharge. Apart from theoretical analyses aimed at maximum possible generality and applicability also for other types of discharges, the paper presents the most important results of experimental verifications. The whole theory is divided into two parts: the macroscopic part where the discharge is studied as a disrupted macroscopic system, and the microscopic one dealing with the change in the discharge structure caused by a microwave field. Apart from discovering the mechanism of the detection effect, the theory also provides possibilities of application for plasma diagnostics.The field of plasma physics is so developed now that all other considerations would depart from the aim and scope of this paper. Finally, the author thanks Dr. A. Tálský for support and interest in this work and Mr. F. Frainic for his devoted assistance in constructing the discharge tubes and the vacuum apparatus.     

Generalization of the problem of optimal detection of signals in the presence of non-Gaussian passive clutter

We have synthesized asymptotically optimal detectors of weak and strong signals with random noninformative parameters against a background of non-Gaussian passive clutter. A possibility of using an adaptive approach to synthesis has been considered and an appropriate structure of an optimal detector of signals with an unknown initial phase has been found.VZRKU, Nizhny Novgorod. Translated from Izvestiya Vysshikh Uchebnykh Zavedenii. Radiofizika, Vol. 38, No. 8, pp. 870–885, August, 1995.