The coexistence between Bluetooth system and IEEE 802.11 frequency hoppingspread spectrum (FHSS) equipment is analyzed. Based on the capacity formulae and system simulation,the inter-affection between these networks i...The coexistence between Bluetooth system and IEEE 802.11 frequency hoppingspread spectrum (FHSS) equipment is analyzed. Based on the capacity formulae and system simulation,the inter-affection between these networks is compared. A fragment adaptive solution of packetpayload length is presented, which can be used to improve the capacity reduction of IEEE 802.11 FHSSnetwork. Analysis results show that the IEEE 802.11 WLAN standard with its inherent mechanismsupports this fragment length adaptive algorithm. With the increasing of Bluetooth interferingnetworks, this adaptive solution can effectively relieve capacity decreasing of IEEE 802.11 FHSSnetwork. The capacity analysis method and adaptive algorithm adopted in this paper can also begeneralized into other FHSS networks.展开更多
Coal mining monitoring system has been enforcing tests for the immunity of Electromagnetic Compatibility(EMC) since 2006.However,not all monitoring substations can pass the Electrical Fast Transient/Burst(EFT/B) immun...Coal mining monitoring system has been enforcing tests for the immunity of Electromagnetic Compatibility(EMC) since 2006.However,not all monitoring substations can pass the Electrical Fast Transient/Burst(EFT/B) immunity test and the explosion-proof test simultaneously.In order to enhance EMC,the EFT/B interfere transmission model was presented at the substation power port,after the EFT/B test method was used to analyze the monitoring substation power ports.Hence,a low-pass filter was designed by using the simulation software PIPICE and an anti-jamming method was proposed by way of a parallel connection of the discharge interfere circuit and the low-pass filter.The improved complex EMI filter was made up of an interference discharge device and a filter.The dynamic equivalent circuit was proposed for the EFT/B immunity test.As a result,the monitoring substation has passed the EFT/B immunity and explosion-proof tests with the complex filter.It is concluded that the complex EMI filter has significantly enhanced the immunity of the coal mining monitoring system.展开更多
A new Higher Order Statistics (HOS) and Genetic Algorithm (GA)-based interference rejection filter is introduced. Compared with the adaptive filters based on second-order statistics and gradient algorithm, the HOS and...A new Higher Order Statistics (HOS) and Genetic Algorithm (GA)-based interference rejection filter is introduced. Compared with the adaptive filters based on second-order statistics and gradient algorithm, the HOS and GA-based filter can reject the interference more efficiently, is independent of uncorrelated Gaussian noise, tends to converge to the optimum solution and is much less sensitive to the choice of the step size parameter. Computer simulations show that the method can reject narrowband interference efficiently.展开更多
In the Raymond mill grinding processes,high-accuracy control for the current of Raymond mill is vital to enhance the product quality and production efficiency as well as cut down the consumption of spare parts.However...In the Raymond mill grinding processes,high-accuracy control for the current of Raymond mill is vital to enhance the product quality and production efficiency as well as cut down the consumption of spare parts.However,strong external disturbances,such as variations of ore hardness and ore size,always exist.It is not easy to make the current of Raymond mill constant due to these strong disturbances.Several control strategies have been proposed to control the grinding processes.However,most of them(such as PID and MPC)reject disturbances merely through feedback regulation and do not deal with the disturbances directly,which may lead to poor control performance when strong disturbances occur.To improve disturbance rejection performance,a control scheme based on PI and disturbance observer is proposed in this work.The scheme combines a feedforward compensation part based on disturbance observer and a feedback regulation part using PI.The test results illustrate that the proposed method can obtain remarkable superiority in disturbance rejection compared with PI method in the Raymond mill grinding processes.展开更多
Betavoltaic radioisotope microbatteries have gradually become the research direction of micro-power sources because of their several advantages,including small scale,stable output performance,long service life,high en...Betavoltaic radioisotope microbatteries have gradually become the research direction of micro-power sources because of their several advantages,including small scale,stable output performance,long service life,high energy density,strong anti-jamming capability,and so on.Based on the theory of semiconductor physics,the current paper presented a design scheme of isotope microbattery with wide-gap semiconductor material GaN and isotope 147Pm.In consideration of the isotope's self-absorption effect,the current paper studied and analyzed the optimization thickness of semiconductor and isotope source,junction depth,depletion region thickness,doping concentration,and the generation and collection of electron hole pairs with simulation of transport process of beta particles in semiconductor material using Monte Carlo simulation program MCNP.In the proposed design scheme,for a single decay,an average energy of 28.2 keV was deposited in the GaN,and the short circuit current density,open circuit voltage,and efficiency of a single device were 1.636 μA/cm2,3.16 V,and 13.4%,respectively.展开更多
AltBOC(15,10) is the baseline of COMPASS B2 signal modulation.It is a BOC-like signal having different PN codes in the lower and the upper main split lobes,which allow one signal service per lobe.The two lobes can be ...AltBOC(15,10) is the baseline of COMPASS B2 signal modulation.It is a BOC-like signal having different PN codes in the lower and the upper main split lobes,which allow one signal service per lobe.The two lobes can be received and processed separately like two BPSK(10) signals,or coherently processed to achieve better performance.Interoperability among COMPASS B2,Galileo E5 and GPS L5 is also achievable using AltBOC modulation.However,Galileo's 4-code AltBOC has drawbacks such as low efficiency and great receiver complexity.This paper presents a new modulation type named TD-AltBOC (Time Division AltBOC).The signal generation scheme and receiving method are presented,and are compared with AltBOC in the areas of power spectrum,ranging accuracy,anti-multipath performance,anti-interference performance,processing flexibility and complexity.Analysis results show TD-AltBOC has similar spectrum characteristics,interoperability,flexibility and anti-interference performance with AltBOC.When the frontend bandwidth is more than 50 MHz,TD-AltBOC can achieve better ranging accuracy and anti-multipath performance.It also has such advantages as high efficiency and low receiver complexity.TD-AltBOC could be a good solution to COMPASS B2 navigation signal.展开更多
Cross-eye jamming is an electronic attack technique that induces an angular error in the monopulse radar by artificially creating a false target and deceiving the radar into detecting and tracking it.Presently,there i...Cross-eye jamming is an electronic attack technique that induces an angular error in the monopulse radar by artificially creating a false target and deceiving the radar into detecting and tracking it.Presently,there is no effective anti-jamming method to counteract cross-eye jamming.In our study,through detailed analysis of the jamming mechanism,a multi-target model for a cross-eye jamming scenario is established within a random finite set framework.A novel anti-jamming method based on multitarget tracking using probability hypothesis density filters is subsequently developed by combining the characteristic differences between target and jamming with the releasing process of jamming.The characteristic differences between target and jamming and the releasing process of jamming are used to optimize particle partitioning.Particle identity labels that represent the properties of target and jamming are introduced into the detection and tracking processes.The release of cross-eye jamming is detected by estimating the number of targets in the beam,and the distinction between true targets and false jamming is realized through correlation and transmission between labels and estimated states.Thus,accurate tracking of the true targets is achieved under severe jamming conditions.Simulation results showed that the proposed method achieves a minimum delay in detection of cross-eye jamming and an accurate estimation of the target state.展开更多
文摘The coexistence between Bluetooth system and IEEE 802.11 frequency hoppingspread spectrum (FHSS) equipment is analyzed. Based on the capacity formulae and system simulation,the inter-affection between these networks is compared. A fragment adaptive solution of packetpayload length is presented, which can be used to improve the capacity reduction of IEEE 802.11 FHSSnetwork. Analysis results show that the IEEE 802.11 WLAN standard with its inherent mechanismsupports this fragment length adaptive algorithm. With the increasing of Bluetooth interferingnetworks, this adaptive solution can effectively relieve capacity decreasing of IEEE 802.11 FHSSnetwork. The capacity analysis method and adaptive algorithm adopted in this paper can also begeneralized into other FHSS networks.
基金supported by the National Natural Science Foundation of China (No.50674093)the Pingdingshan Coal Co.Ltd. The EMI distribution measurements were obtained from several coal mines of the Pingdingshan Coal Co.
文摘Coal mining monitoring system has been enforcing tests for the immunity of Electromagnetic Compatibility(EMC) since 2006.However,not all monitoring substations can pass the Electrical Fast Transient/Burst(EFT/B) immunity test and the explosion-proof test simultaneously.In order to enhance EMC,the EFT/B interfere transmission model was presented at the substation power port,after the EFT/B test method was used to analyze the monitoring substation power ports.Hence,a low-pass filter was designed by using the simulation software PIPICE and an anti-jamming method was proposed by way of a parallel connection of the discharge interfere circuit and the low-pass filter.The improved complex EMI filter was made up of an interference discharge device and a filter.The dynamic equivalent circuit was proposed for the EFT/B immunity test.As a result,the monitoring substation has passed the EFT/B immunity and explosion-proof tests with the complex filter.It is concluded that the complex EMI filter has significantly enhanced the immunity of the coal mining monitoring system.
基金Supported by the National Key Lab Foundation No.99JS 63.3.1.JW0301
文摘A new Higher Order Statistics (HOS) and Genetic Algorithm (GA)-based interference rejection filter is introduced. Compared with the adaptive filters based on second-order statistics and gradient algorithm, the HOS and GA-based filter can reject the interference more efficiently, is independent of uncorrelated Gaussian noise, tends to converge to the optimum solution and is much less sensitive to the choice of the step size parameter. Computer simulations show that the method can reject narrowband interference efficiently.
基金Projects(61504027,61573099)supported by the National Natural Science Foundation of ChinaProject(BK20140647)supported by the Natural Science Foundation of Jiangsu Province,ChinaProject supported by the Priority Academic Program Development of Jiangsu Higher Education Institutions,China
文摘In the Raymond mill grinding processes,high-accuracy control for the current of Raymond mill is vital to enhance the product quality and production efficiency as well as cut down the consumption of spare parts.However,strong external disturbances,such as variations of ore hardness and ore size,always exist.It is not easy to make the current of Raymond mill constant due to these strong disturbances.Several control strategies have been proposed to control the grinding processes.However,most of them(such as PID and MPC)reject disturbances merely through feedback regulation and do not deal with the disturbances directly,which may lead to poor control performance when strong disturbances occur.To improve disturbance rejection performance,a control scheme based on PI and disturbance observer is proposed in this work.The scheme combines a feedforward compensation part based on disturbance observer and a feedback regulation part using PI.The test results illustrate that the proposed method can obtain remarkable superiority in disturbance rejection compared with PI method in the Raymond mill grinding processes.
基金supported by the China Postdoctoral Science Foundation Funded Project (Grant No. 20100481140)the Nanjing University of Aeronautics and Astronautics Basic Research Funded Project (Grant No. Y1065-063)
文摘Betavoltaic radioisotope microbatteries have gradually become the research direction of micro-power sources because of their several advantages,including small scale,stable output performance,long service life,high energy density,strong anti-jamming capability,and so on.Based on the theory of semiconductor physics,the current paper presented a design scheme of isotope microbattery with wide-gap semiconductor material GaN and isotope 147Pm.In consideration of the isotope's self-absorption effect,the current paper studied and analyzed the optimization thickness of semiconductor and isotope source,junction depth,depletion region thickness,doping concentration,and the generation and collection of electron hole pairs with simulation of transport process of beta particles in semiconductor material using Monte Carlo simulation program MCNP.In the proposed design scheme,for a single decay,an average energy of 28.2 keV was deposited in the GaN,and the short circuit current density,open circuit voltage,and efficiency of a single device were 1.636 μA/cm2,3.16 V,and 13.4%,respectively.
文摘AltBOC(15,10) is the baseline of COMPASS B2 signal modulation.It is a BOC-like signal having different PN codes in the lower and the upper main split lobes,which allow one signal service per lobe.The two lobes can be received and processed separately like two BPSK(10) signals,or coherently processed to achieve better performance.Interoperability among COMPASS B2,Galileo E5 and GPS L5 is also achievable using AltBOC modulation.However,Galileo's 4-code AltBOC has drawbacks such as low efficiency and great receiver complexity.This paper presents a new modulation type named TD-AltBOC (Time Division AltBOC).The signal generation scheme and receiving method are presented,and are compared with AltBOC in the areas of power spectrum,ranging accuracy,anti-multipath performance,anti-interference performance,processing flexibility and complexity.Analysis results show TD-AltBOC has similar spectrum characteristics,interoperability,flexibility and anti-interference performance with AltBOC.When the frontend bandwidth is more than 50 MHz,TD-AltBOC can achieve better ranging accuracy and anti-multipath performance.It also has such advantages as high efficiency and low receiver complexity.TD-AltBOC could be a good solution to COMPASS B2 navigation signal.
基金Project supported by the National Natural Science Foundation of China(No.61401475)
文摘Cross-eye jamming is an electronic attack technique that induces an angular error in the monopulse radar by artificially creating a false target and deceiving the radar into detecting and tracking it.Presently,there is no effective anti-jamming method to counteract cross-eye jamming.In our study,through detailed analysis of the jamming mechanism,a multi-target model for a cross-eye jamming scenario is established within a random finite set framework.A novel anti-jamming method based on multitarget tracking using probability hypothesis density filters is subsequently developed by combining the characteristic differences between target and jamming with the releasing process of jamming.The characteristic differences between target and jamming and the releasing process of jamming are used to optimize particle partitioning.Particle identity labels that represent the properties of target and jamming are introduced into the detection and tracking processes.The release of cross-eye jamming is detected by estimating the number of targets in the beam,and the distinction between true targets and false jamming is realized through correlation and transmission between labels and estimated states.Thus,accurate tracking of the true targets is achieved under severe jamming conditions.Simulation results showed that the proposed method achieves a minimum delay in detection of cross-eye jamming and an accurate estimation of the target state.
