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For multiple-input multiple-output over-the-horizon radar( MIMO-OTHR),the minimum variance distortionless response( MVDR) is usually used to solve the impact of the ionospheric multimode clutter in the received echo on the detection of the target. The output signal-to-clutter-plus-noise ratio( SCNR) of traditional MVDR algorithm is low due to the omnidirectional emission of MIMO-OTHR,the inaccurate estimation of interference-noise covariance matrix,and a few training samples within a finite coherent accumulation time. Therefore,the MVDR algorithm is improved to enhance the multimode clutter suppression ability of MIMO-OTHR. A transmit beamspace preprocessing is realized by a second order cone programming( SOCP) to focus the energy on the principal mode angle,which is the transmit angle of the target path reflected by the ionosphere. The echo signal received by array is spatially smoothed to suppress the expected signal of principal mode and improve the estimation accuracy of interference-noise covariance matrix. A bi-iterative MVDR beamforming algorithm based on the beamspace preprocessing is proposed to reduce the computational load and the requirement of training samples. Simulated results show that the improved MVDR algorithm can be used to effectively suppress multi-mode clutter,and obtain higher output SCNR with fewer training samples and less computational load. [ABSTRACT FROM AUTHOR]

In the distributed resource management of shipborne phased array radar network,the inconsistent problem of resource management schemes is due to the estimated deviation of node states and the noise disturbance during information transmission between nodes. A consistency management algorithm for resource which is suitable for different topologies is proposed to solve the problem above. The topology of radar network is represented by using the graph theory,and the requirement analysis of consistency resource management is conducted for shipborne phased array radar network. A local optimization model for resource management is constructed from two aspects: radar load balancing and minimum resource consumption. A local resource management scheme of each radar is generated through this model. The consistency algorithm is used to obtain a global consistency resource management scheme through the information transmission between radar nodes of network. Simulated results show that the proposed algorithm is effective,and it can be applicated to conduct resource management for radar networks regardless of the topology and information transmission noise. [ABSTRACT FROM AUTHOR]

A specific emitter identification( SEI) method based on deep reinforcement learning is proposed on account of the deficiency of emitter individual feature extraction depending on artificial experience. Due to the differences of the transient information of signal envelope,which results from the change of the signal owing to a nonideal transmitter channel,an envelope rising edge is used as the input state of deep neural network,and the emitter classifications are used as the optional actions of the current input state. The envelope features are extracted automatically through the convolutional neural network( CNN),and Q values of the current state action pairs are fitted,thus completing the specific emitter identification task based on the reinforcement learning model. The applications of deep Q network( DQN),deep double Q network( DDQN) and Dueling network in the specific emitter identification are discussed. The measured results show that the recognition rate of traditional machine learning algorithm is less than 80%,but the deep reinforcement learning model can achieve the high recognition rate of98. 42%. [ABSTRACT FROM AUTHOR]

A new damage assessment method based on BN-Cloud model is put forward for the impact of complex and uncertain factors in modern battlefield environment. The characteristics of targets are analyzed,and a hierarchical evaluation index system is established,which is used to build a Bayesian network（ BN） structure. Monte Carlo method is introduced into parameter learning,a condition probability table（ CPT） of each network node is obtained through simulation,and the probability of each damage level is obtained by using the network inference. Finally,cloud model is used to transform target damage probability into real damage value so as to realize the transformation from uncertainty to certainty. The target physical damage degree is used as one of sub-nodes of functional damage degree in BN,in which CPT is used as a link. As a result,a new method to transform physical damage into function damage is realized. A radar target is taken as an example for simulation. The simulated result shows that the proposed method can be effectively used for target damage assessment,and achieves a significant improvement in accuracy and reliability compared with the existing algorithms. [ABSTRACT FROM AUTHOR]

Frequency agility mode is widely used in modern radar. Traditional algorithms often result in the increasing batch in signal sorting. This algorithm estimates the frequency of received signals with high precision firstly. The results can be got by dividing the frequency differences of two adjacent signals. Within a certain range, the signals from different radars are sorted by comparing the fractional part of the results. According to the signals from the same radar, frequency dividing coefficients are estimated by the same way. Finally, reference frequency can be gained. Simulation results show that this algorithm can sort the signals from frequency agility radar effectively. And, it can restrain the increasing batch in the signal sorting and recognize the specific emitters accurately. [ABSTRACT FROM AUTHOR]

The amplitude and phase characteristics of complex radar cross section (RCS) of a metallic sphere are analyzed based on the precise solution of its back scattering. The high resolution range profile of a sphere takes on one or two peaks at different bands, while its 2D image can be typified by an arc or a point at different bands and rotation angles. A sphere should be characterized by a dispersive, migratory or point-like scattering center model under different conditions. These conclusions may provide an important reference for RCS calibration and scattering source diagnosis. [ABSTRACT FROM AUTHOR]

A novel phase-comparison sum-difference monopulse radar angular glint modeling algorithm based on deterministic model is proposed by analyzing the shortage of conditional angular glint deviation models based on energy flow tilt theory and wave front distortion theory. The number of scattering dots and the parameters of radar can be set in this model, and the echo signals of summing channel and differential channel needed by angle measurement verification can be obtained. Theoretical analysis and simulation results show that the novel model is more accurate for the large deviation angle of each scattering point. This model is more conducive to the simulation of angular glint suppression algorithm. [ABSTRACT FROM AUTHOR]

A method which discriminates the coherent dual-source angle deception interference by using the relative difference between the co-polarization and cross-polarization components of target and interference is proposed. A model of mono-pulse polarization radar echo is established, and the co-polarization and cross-polarization echoes of the sum and difference beams are obtained. A statistic to distinguish the existence of coherent dual-source interference is constructed by using the difference between the interference and the radar target response function in the different polarization channels. A certain confidence level threshold is given according to the measured data of typical warhead and aircraft target and the simulation of coherent dual-source interference. The measured data obtained in darkroom and the computer simulation show that the algorithm is feasible and valid. [ABSTRACT FROM AUTHOR]

The radar data of multi-period is regarded as binary image by the gaining enlightenment from the man-made track initiation method. A track initiation algorithm is proposed based on the Hough transform and dilation on morphology to improve the efficiency of track initiation methods under heavy- clutter environment. Firstly a pre-processing method is proposed to filter the image and to delete the false alarm point based on the association gate formed by the maximum velocity and the radar scan period. An approximate method is proposed to describe the distribution of the target position by analyzing the effect of measurement error on target position. And then the structural element is formed to dilate the binary image so as to emphasize the linear characteristic of the true tracks. Hough transform is used to detect the lines on the binary image. The simulation experiment presents the output of each step, and the results show the efficiency of the proposed pre-processing method and the initiation algorithm. [ABSTRACT FROM AUTHOR]

The application of ultra wide band (UWB) technology in the minefield has good prospects and great significance. The existent path loss models of UWB can not satisfy the requirements in minefield environment. In order to make it practicable, a minefield model was established and the UWB signal's propagation features and laws were analyzed. Based on the theoretical analysis, a feasible UWB path loss model was put forward and the numerical simulations and experiments were also carried out. The results show that the new model can exactly reflect the UWB signal's propagation characteristic in the minefield and it is flexible and can be used in different conditions. The results can provide a basis for the application of the UWB technology in the mine weapons and equipment [ABSTRACT FROM AUTHOR]

In order to solve the problem of anti-reverberation in shallow water, a modified method of space-time adaptive processing (STAP) for sonar was proposed. Firstly, the principle of STAP was analyzed according to the echo model of radar. Secondly, comparing the echo model of sonar with radar, the space-time coupling guiding vector was used in space-time processing. Finally, the proposed method was applied in optimization processing and object detection. The simulation results illustrate that the modified method is beneficial to underwater object detection, and the application of space-time coupling guiding vector can increase the accuracy of the direction estimation of targets. [ABSTRACT FROM AUTHOR]

For the isolation problem of transmitting-receiving antenna in continuous wave radar, the phase offset in ripple wave-guild with capacitive clapboard was analyzed, the ripple structure was used to improve the isolation of antenna, and a new method was proposed to improve the isolation of transmitting-receiving antenna based on structure counteraction. CST simulation and experimental results show that this method is able to make the isolation reach - 80 dB in 400 MHz band. So it has a very huge application value because of its simple structure and low cost. [ABSTRACT FROM AUTHOR]

The optimum scheduling for radar radiation occasions with emission time constraint is concerned, the model of the radar radiation occasions optimum scheduling is established with optimizing objective function the trace of target statement estimation error covariance, the rule of optimum scheduling for radar radiation is drawn. Research results demonstrate, given the emission time constraint, the closer the radar radiation occasions to the end of the time segment is, the less the target statement estimation error is. A method of real-time radar radiation controlling is put forward based on the rule, using the prediction covariance threshold and the estimation covariance threshold to control the radar radiation on real time. The simulation results show that, the proposed method can control radar's radiation to track targets smoothly, the radar radiation times is related to the prediction covariance threshold and the estimation covariance threshold, and radar radiation can be controlled by setting different parameter based on different tracking demand. These conclusions can be used for optimum scheduling for radar radiation to obtain high estimation accuracy. [ABSTRACT FROM AUTHOR]

In order to simplify the separation of radar echo and deception and to get the Jones vector of deception, a simple and convenient method to extract radar deception is proposed. By transmitting a group of relative polarization agile signals, the scattered wave and deception can be separated during the calculation of the signal output by the receiver, while utilizing the polarization effect of the target and the constant polarization state of deception. Compared with existing interference feature extraction algorithms, resources can be saved when this algorithm is implemented in single chip. The simulation results show that the relative errors of the calculation are less than 10% , when INR is more than 11.8 dB. [ABSTRACT FROM AUTHOR]

Particle filter has the defects of low precision and weak robustness, it is not able to meet the requirement of radar target tracking . To solve these problems, a new particle filter algorithm based on Hybrid algorithm is proposed. It looked for satisfactory solution space with artificial fish swarm algorithm and made the particles move to the high likelihood region under the action of particle swarm optimization algorithm. By doing simulation under glint noise environment, the results show that this algorithm can jump local optimum to search the best value of particle, it improves the precision of radar target tracking under glint noise environment. [ABSTRACT FROM AUTHOR]

The Multiple-Input Multiple-Output (MIMO) radar was proposed in recent years. Using MIMO radar to detect the location of multi-target, a lot of algorithms are failure when the multi-target echo signals are coherent. Concerning this problem, a localization algorithm of coherent multi-target is presented in bistatic MIMO radar. The algorithm constructs virtual array for both the transmit and receiver array to de-correlate the coherent multi-target echo signals, and then the location of multi-target can be obtained. The estimated parameters are automatically paired without additional paring computation. The proposed method avoids the array aperture loss and the performance of angle estimation is improved. Theoretical analysis and simulation results verify the effectiveness of this method. [ABSTRACT FROM AUTHOR]

Referring to the problems of parameters selection, sidelobe suppression and Doppler tolerance expansion, the relationships among mainlobe to sidelobe ratio and the pulse compression length, Doppler frequency, signal to noise ratio of the echo and other parameters after the pulse compression in noise continuous wave radar are studied. The mathematical expressions of statistical mainlobe to mean square sidelobe ratio (SMMSSR) and statistical mainlobe to peak sidelobe ratio (SMPSR) are deduced by researching the statistical properties of the sidelobes which constitute a random fluctuant noise floor, respectively. The parameters influencing SMMSSR and SMPSR are analyzed. The correctness of the conclusion is verified by the computer simulation. [ABSTRACT FROM AUTHOR]