Chaff jamming is one of the most commonly used passive jamming methods,and mainly depends on its electromagnetic scattering characteristics to jam radar receivers.In this paper,the radar cross section(RCS)of chaff scattering is studied,and the average RCS of a single chaff under different incident polarization conditions is derived by using incoherent model.The scattering ma-trix of chaff polarization is obtained,and the polarization scattering characteristics of single chaff are analyzed.An ideal placement model under coherent conditions is proposed,and the average RCS value of a single chaff is obtained,which is more close to the actual use,and lays a foundation for giving full play to the passive jamming efficiency of chaff.
Aiming at the requirement of accurate reconnaissance to dense targets,a sorting correla-tion method based on multi-dimensional feature fuzzy weighting is proposed.Firstly,the member-ship degree of each dimension parameter is measured by nonlinear Euclidean distance,then the membership degree of different parameter dimensions is fuzzily weighted by weight,and finally the sorting correlation is carried out according to the final weighted membership degree.The simula-tions of different scenes with medium and high repetition frequency show that the proposed method can carry out correct sorting correlation for dense targets with overlapping electromagnetic param-eters,also the algorithm is not sensitive to parameter setting and has good robustness.
In order to accurately estimate the influence of troposphere atmospheric environment on the absorption and attenuation of electromagnetic wave energy,and provide theoretical basis for the measurement equipment of electromagnetic wave emission to estimate the operating distance,measurement and control arrangement and radiation safety zone setting,the attenuation effect of troposphere atmospheric absorpting gas on electromagnetic wave energy propagation is studied.According to the suggestions of Rec.ITU-R P.676-9 of the International Telecommunication U-nion and the approximate estimation model of atmospheric attenuation rate,the equivalent altitude calculation model and the equivalent path refraction model for 1～54 GHz electromagnetic wave given by GJB/Z 87-97"Radar Wave Refraction and Attenuation Manual",the calculation model of electromagnetic wave inclined path attenuation across the equivalent height in the troposphere is revised and improved.The influence of different atmospheric pressure,temperature and water va-por density on the attenuation rate,and the influence of different propagation elevation,tempera-ture and relative humidity on the energy attenuation of electromagnetic wave at the same propaga-tion distance are studied by simulation.
This paper analyzes the strength,stiffness and vibration mode of busbar structure for high voltage electric slip ring for the single point mooring system.The simulation results show that the structure satisfies the usage conditions of strength and stiffness,but has a less first-order natu-ral frequency,which may result in structural resonances in transportation or engineering applica-tions,thereby there are certain security risks.Under the premise of ensuring the high voltage cur-rent-carrying performance of the bus structure,by increasing the structural size of the high-pres-sure casing,and adding a stainless steel sheet structure with a boss on the busbar,the structural stiffness is enhanced,vibration mode feature is changed,feature frequency intervals emerged possi-bly are avoided,which effectively improves the operational safety of the electric slip ring in vibra-tion environment.
According to the requirements of high flexibility of low side lobes for planar phased ar-ray,this paper proposes a weighting method for planar array based on asymmetric Taylor synthe-sis.Compared with the existing mainstream methods,this method can apply to planar arrays with random array arrangement,can perform asymmetric side-lobe control to the radiation pattern,and has the advantages of small antenna gain loss,simultaneous weighting of amplitude & phase and algorithm being non-iterative.This paper provides both symmetric and asymmetric Taylor weigh-ting formulas,as well as the side-lobe descending effect under different fronts arrangement.The simulation results show that the proposed method has fast speed,high flexibility and stable per-formance.
At present,many scholars have studied a lot to improve the signal-to-noise ratio of laser radar,and the main method is to use pulse compression technology to improve the signal-to-noise ratio and distance resolution of radar under the coherent detection system,which has significant effects,but the relative cost is high and the optical system is complex.It is proposed to improve the incoherent detection laser radar transmitting signal and the corresponding radar system,and the implementation cost of this system is low,meanwhile the signal-to-noise ratio can be effectively im-proved after the radar echo signal is compressed by digital pulse.Based on the radar system in-volved,this paper comprehensively considers the range equation of laser radar,atmospheric attenu-ation,background light interference noise and other factors,performs modeling and simulation to the echo signal,and performs digital pulse pressure processing and constant false alarm detection on the echo signal.The simulation results show that the performance of the designed system is sig-nificantly improved compared with that of the rectangular wave laser radar system.
A non-offset slot antenna based on slot-line gap waveguide(GWG)technology is de-signed.The antenna realizes the GWG transmission line by means of the stop-band formed by the periodic structure of metal nail,and perturbs the electric field in GWG through the metal nail to re-alize the non-offset slot antenna.Different nail structures are used to compensate for the capacitor value and inductance value.The antenna is composed of upper and lower layers of metal structural parts,and the coaxial connector is fed from the center,and they are realized through the simulation that the voltage standing wave ratio(VSWR)of the slot antenna is less than 2 and the cross-polar-ization is less than-40 dB in the 34.04～37.68 GHz band.The antenna has the characteristics of high gain,low cross-polarization,large power capacity,and being easily processed and assembled.
As the core component of target detection and tracking,the ship radar system plays an important role.When traditional single radar detects moving targets and multiple targets at sea,the accuracy will decrease and targets will be lost.The working efficiency of radars can be improved by using the target detection and tracking technology based on generalized S-D assignment algorithm.By analyzing the working principle of ship radar,this paper proposes a multi-target track initiation algorithm in clutter environment,further studies the application of the algorithm to target tracking by using the generalized multidimensional allocation scheme,and verifies the effectiveness of the al-gorithm through simulation experiments.
Now different function electronic systems use different architectures,but with the devel-opment of micro-electronics and other technologies,system architectures have gradually con-verged.Along with the development of entire digital array technology,the realization of multifunc-tion and integration based on single platform is possible,but some technical problems exist.Based on this,this paper analyzes current architectures of different functional realizations,and proposes an all-digital array timesharing multifunctional integrated platform architecture,briefly introduces the system architecture and composition,and emphatically analyzes the technical bottlenecks in the realization process,puts forward the corresponding solutions.The architecture has been implemen-ted on the corresponding platform.
In view of the electronic countermeasure effectiveness evaluation in different application scenarios,this paper proposes the design method of evaluation system based on open architecture,introduces the design idea,gives the software and hardware structure and functions of the system,and briefly discusses the key technical points.The system can meet the functional requirements of fine evaluation for classification and grading,real-time online rapid evaluation and data application of analysis and mining,etc.,and has good application,scalability and reconfigurability,which pro-vides technical support and methods for the effectiveness evaluation of electronic countermeasure.
In view of the difficulty obtaining the image data of synthetic aperture radar(SAR)active jamming and the complexity developing the jamming countermeasure test,this paper discusses the basic principle and modeling simulation flow of SAR active jamming countermeasure,designs and completes the simulation software of SAR active jamming countermeasure based on Matlab Appde-signer.The software can realize SAR countermeasure simulation at functional level,generate vari-ous types of SAR jamming images,and perform jamming effectiveness evaluation &jamming de-tection,etc.to the imaging results,which lays an experimental foundation for the subsequent re-searches of SAR active jamming,such as scheme demonstration,system design,jamming technolo-gy development,image processing,etc.
In response to the problem that the search strategy is single in planar sparse array forma-tion optimization algorithm,this paper proposes an improved pigeon inspired optimization algo-rithm to optimize the rectangular planar sparse array formation that has a half wavelength space a-mong array elements and the maximum number of array elements is 400.The simulation results demonstrate that compared with particle swarm algorithm and traditional pigeon inspired algo-rithm,the improved pigeon inspired optimization has better effect in planar sparse array formation optimization.
With the evolution of war concepts and the development of space technology,it is a new electronic countermeasure method to jam shipborne radars in anti-ship missions by using low earth orbit(LEO)satellite groups.The anti-ship attack process is divided into several time profiles from a microscopic perspective,then the dynamic jamming efficiency is obtained according to the spatio-temporal configuration of each time profile,and the whole jamming efficiency is reconstructed from a macroscopic perspective.A jamming scenario is constructed,and the jamming effectiveness simu-lation is carried out based on spatio-temporal configuration and radar jamming parameters,which verifies the jamming effectiveness of LEO satellite group in anti-ship mission.
At present,the research in the radar field is becoming more and more in-depth,a large number of new radar concepts have been proposed,and the radar resolution has also been improved with the development.In response to these new radars,electronic countermeasure experts have pro-posed a variety of new jamming technologies.Among them,coherent repeater jamming technology based on digital radio frequency memory is widely used because it is easy to implement and can ob-tain the gain of radar system.While both jamming and radar are evolving to newer systems,the re-ality that low-resolution radars are still deployed in large scale all over the world is ignored.The in-fluence of newer coherent repeater jamming patterns on low-resolution radar has not been analyzed in detail.In this paper,aiming at the low-resolution radar still widely used at present,the influence of coherent repeater jamming on echo characteristics is analyzed by means of signal-level simula-tion,and the influence of three representative coherent repeater jamming patterns,namely smart noise jamming,interrupted sampling repeater jamming and Doppler fine-tuning jamming on the echo characteristics of low-resolution radar is focused on.
In the future battlefield dominated by small intelligent unmanned carriers,deceptive jam-ming technology of satellite navigation has attracted widespread attention because of its conceal-ment and threat.Firstly,the implementation mode of unmanned aerial vehicle(UAV)satellite navigation deceptive jamming technology is introduced.Then,the research status of UAV satellite navigation deception jamming technology is elaborated from three aspects:UAV satellite naviga-tion deception induction technology,UAV combined navigation deception technology and UAV sat-ellite navigation deception concealment technology.Finally,the shortcomings of UAV navigation deception jamming technology are analyzed,and the future development trend of this technology is prospected.
The conventional printed log-periodical antenna(PLPDA)is fed by coaxial cable,and the welding point of the cable is at the top side of the antenna.At higher working band(6 GHz or higher),the antenna performance is seriously affected by the cable and the welding point,which limits the application of the PLPDA.In this paper,a PLPDA with bottom feed based on the strip-line structure is analyzed.The simulation result shows that,in the frequency band of 6～18 GHz,the antenna standing wave≤2 and the direction & width of wave beam are stable.
The threat environment that the future sea battlefield faces with is characterized by"sin-gle/multi-directional continuous target saturation attack","low altitude concealed penetration"and"target attack under complex electromagnetic interference".Relying on a single surface ship lay-ered defense combat system can no longer meet the battlefield environment that is rapidly develo-ping.It is an important development direction to build an integrated air defense operation system based on formation coordination for adapting to the future sea defense operation.The formation co-ordinated air defense integrated combat system should be studied from the aspects of early warning detection system,command and control system,combat planning and rehearsal system and fire strike system,etc..The key technology lies in the realization of unified situation map,high-speed data link,sea air space integration command and control,multi-weapon coordinated defense and other technical difficulties.
In order to reach the goal of"family of capability"of penetrating counter air(PCA),a new equipment form concept of family of systems(FoS)is put forward.This paper analyzes the PCA FoS from the aspects of battlefield air control,information superiority,dynamic superiority,all domain attack,space-time superiority,battlefield survival,science and technology superiority,etc.The development and perfection of PCA FoS of U.S.military will bring more systematic threat to the integrated air defence system of various countries,and is also an important means for the U-nited States to contain the strategic opponents and maitain world hegemony.
Prognostics and health management(PHM)system plays an important role in the assess-ment of equipment health status and maintenance according to the situation.The sensor collects the health information of equipment system,so it also plays an important role in PHM system.Based on the characteristics of radar receiver system,this paper analyzes the types and characteristics of the sensor,establishes a configuration model,optimizes the objective function by using the condi-tional function,and obtains the sensor configuration scheme,which will provide a useful reference for the sensor configuration of various types of radar receivers.
This paper studies the method of false target jamming to phase code radar,analyzes the signal characteristics of phase code radar,taking 13 bit barker code phase code radar as an example,simulates and analyzes the false targets generated by front edge replication jamming,interrupted sampling jamming and code element interception jamming.The simulation results show that front edge replication jamming,interrupted sampling jamming and code element interception jamming can generate the expected false targets with good jamming effects.
