A phased array radar seeker（PARS） must be able to effectively decouple body motion and accurately extract the line-of-sight（LOS） rate for target missile tracking.In this study,the realtime two-channel beam pointin...A phased array radar seeker（PARS） must be able to effectively decouple body motion and accurately extract the line-of-sight（LOS） rate for target missile tracking.In this study,the realtime two-channel beam pointing error（BPE） compensation method of PARS for LOS rate extraction is designed.The PARS discrete beam motion principium is analyzed,and the mathematical model of beam scanning control is finished.According to the principle of the antenna element shift phase,both the antenna element shift phase law and the causes of beam-pointing error under phantom-bit conditions are analyzed,and the effect of BPE caused by phantom-bit technology（PBT） on the extraction accuracy of the LOS rate is examined.A compensation method is given,which includes coordinate transforms,beam angle margin compensation,and detector dislocation angle calculation.When the method is used,the beam angle margin in the pitch and yaw directions is calculated to reduce the effect of the missile body disturbance and to improve LOS rate extraction precision by compensating for the detector dislocation angle.The simulation results validate the proposed method.展开更多
To meet the application requirements for a Ka-band space-based TT&C terminal for a launch vehicle,this paper proposes the implementation scheme of a space-based TT&C terminal,analyzes and solves the miniaturiz...To meet the application requirements for a Ka-band space-based TT&C terminal for a launch vehicle,this paper proposes the implementation scheme of a space-based TT&C terminal,analyzes and solves the miniaturized design of equipment and the key technology for high-efficiency heat dissipation.The phased array antenna test shows that without external heat dissipation measures,the phased array antenna can work for a long time to meet the working requirements of launch vehicle,which has been verified in the LM-8 mission,and has wide engineering application prospects.展开更多
The UWA channel is characterized as a time-dispersive rapidly fading channel, which in addition exhibits Doppler instabilities and limited bandwidth. To eliminate inter- symbol interference caused by multipath propaga...The UWA channel is characterized as a time-dispersive rapidly fading channel, which in addition exhibits Doppler instabilities and limited bandwidth. To eliminate inter- symbol interference caused by multipath propagation, spatial diversity equalization is the main technical means. The paper combines the passive phase conjugation and spatial processing to maximize the output array gain. It uses signal-to-noise-plus-interference to evaluate the quality of signals received at different channels. The amplitude of signal is weighted using Sigmoid function. Second order PLL can trace the phase variation caused by channel, so the signal can be accumulated in the same phase. The signals received at different channels need to be normal- ized. It adopts fractional-decision feedback diversity equalizer （FDFDE） and achieves diversity equalization by using different channel weighted coefficients. The simulation and lake trial data processing results show that, the optimized diversity receiving equalization algorithm can im- prove communication system＇s ability in tracking the change of underwater acoustic channel, offset the impact of multipath and noise and improve the performance of communication system. The performance of the communication receiving system is better than that of the equal gain combination. At the same time, the bit error rate （BER） reduces 1.8%.展开更多
In [1] and [2], the authors made a deep qualitative analysis of the equationwith the character of tangent detected phase and they mathematically provided atheoretical basis of why the phase looked loop has no look--lo...In [1] and [2], the authors made a deep qualitative analysis of the equationwith the character of tangent detected phase and they mathematically provided atheoretical basis of why the phase looked loop has no look--losing point. However,according to many practical experts, it is rather difficult to put such a phaselooked loop into practice, though it has fine properties. W. C. Lindsey [3] made a展开更多
For phase-controlled vacuum breakers,the acting time of Permanent Magnetic Actuator(PMA)should be precise.Variation of capacitor voltage,jamming,temperature,etc.(called disturbance factors)impact dispersion of closing...For phase-controlled vacuum breakers,the acting time of Permanent Magnetic Actuator(PMA)should be precise.Variation of capacitor voltage,jamming,temperature,etc.(called disturbance factors)impact dispersion of closing time seriously.Tracking control is used to suppress this dispersion.However,PMA is a nonlinear,high-order complex system.The control process is dynamic following control.Therefore,the dispersion suppression capability of conventional controllers faces challenges.In order to solve this problem,a new technology has been put forward in this paper.By using this technology,response speed and anti-interference ability of the control system are improved.Time scatter is better suppressed.A current-displacement double closed-loop controller(CDCC)based on inverse system method is proposed.During the motion stage,the dynamic characteristics of the controller can be optimized by using the inverse systems to correct output of the automatic displacement regulator(ADR)and the automatic current regulator(ACR).A simulation system is established and performance of different control methods commonly used in phase control is compared.Based on the aforementioned theory,many experiments have been performed when disturbance factors change,such as capacitor voltage,environment temperature,and so on.Results prove that current deviation and displacement deviation can be corrected under severe conditions and closing time can be stabilized within±0.5 ms.Therefore,anti-interference ability and dynamic performance of PMA are ensured when external factors change drastically,which will increase accuracy of the phase-controlled operation and prolong the lifespan of circuit breakers.展开更多
文摘A phased array radar seeker（PARS） must be able to effectively decouple body motion and accurately extract the line-of-sight（LOS） rate for target missile tracking.In this study,the realtime two-channel beam pointing error（BPE） compensation method of PARS for LOS rate extraction is designed.The PARS discrete beam motion principium is analyzed,and the mathematical model of beam scanning control is finished.According to the principle of the antenna element shift phase,both the antenna element shift phase law and the causes of beam-pointing error under phantom-bit conditions are analyzed,and the effect of BPE caused by phantom-bit technology（PBT） on the extraction accuracy of the LOS rate is examined.A compensation method is given,which includes coordinate transforms,beam angle margin compensation,and detector dislocation angle calculation.When the method is used,the beam angle margin in the pitch and yaw directions is calculated to reduce the effect of the missile body disturbance and to improve LOS rate extraction precision by compensating for the detector dislocation angle.The simulation results validate the proposed method.
文摘To meet the application requirements for a Ka-band space-based TT&C terminal for a launch vehicle,this paper proposes the implementation scheme of a space-based TT&C terminal,analyzes and solves the miniaturized design of equipment and the key technology for high-efficiency heat dissipation.The phased array antenna test shows that without external heat dissipation measures,the phased array antenna can work for a long time to meet the working requirements of launch vehicle,which has been verified in the LM-8 mission,and has wide engineering application prospects.
基金supported by National Natural Science Foundation of China(61531018)
文摘The UWA channel is characterized as a time-dispersive rapidly fading channel, which in addition exhibits Doppler instabilities and limited bandwidth. To eliminate inter- symbol interference caused by multipath propagation, spatial diversity equalization is the main technical means. The paper combines the passive phase conjugation and spatial processing to maximize the output array gain. It uses signal-to-noise-plus-interference to evaluate the quality of signals received at different channels. The amplitude of signal is weighted using Sigmoid function. Second order PLL can trace the phase variation caused by channel, so the signal can be accumulated in the same phase. The signals received at different channels need to be normal- ized. It adopts fractional-decision feedback diversity equalizer （FDFDE） and achieves diversity equalization by using different channel weighted coefficients. The simulation and lake trial data processing results show that, the optimized diversity receiving equalization algorithm can im- prove communication system＇s ability in tracking the change of underwater acoustic channel, offset the impact of multipath and noise and improve the performance of communication system. The performance of the communication receiving system is better than that of the equal gain combination. At the same time, the bit error rate （BER） reduces 1.8%.
文摘In [1] and [2], the authors made a deep qualitative analysis of the equationwith the character of tangent detected phase and they mathematically provided atheoretical basis of why the phase looked loop has no look--losing point. However,according to many practical experts, it is rather difficult to put such a phaselooked loop into practice, though it has fine properties. W. C. Lindsey [3] made a
基金supported by the National Natural Science Foundation of China(51877026).
文摘For phase-controlled vacuum breakers,the acting time of Permanent Magnetic Actuator(PMA)should be precise.Variation of capacitor voltage,jamming,temperature,etc.(called disturbance factors)impact dispersion of closing time seriously.Tracking control is used to suppress this dispersion.However,PMA is a nonlinear,high-order complex system.The control process is dynamic following control.Therefore,the dispersion suppression capability of conventional controllers faces challenges.In order to solve this problem,a new technology has been put forward in this paper.By using this technology,response speed and anti-interference ability of the control system are improved.Time scatter is better suppressed.A current-displacement double closed-loop controller(CDCC)based on inverse system method is proposed.During the motion stage,the dynamic characteristics of the controller can be optimized by using the inverse systems to correct output of the automatic displacement regulator(ADR)and the automatic current regulator(ACR).A simulation system is established and performance of different control methods commonly used in phase control is compared.Based on the aforementioned theory,many experiments have been performed when disturbance factors change,such as capacitor voltage,environment temperature,and so on.Results prove that current deviation and displacement deviation can be corrected under severe conditions and closing time can be stabilized within±0.5 ms.Therefore,anti-interference ability and dynamic performance of PMA are ensured when external factors change drastically,which will increase accuracy of the phase-controlled operation and prolong the lifespan of circuit breakers.
