A new synergy tracking method of infrared and radar is presented. To improve tracking accuracy, the unscented Kalman filter （UKF）, which has better nonlinear approximation ability, is adopted. In addition, to reduce...A new synergy tracking method of infrared and radar is presented. To improve tracking accuracy, the unscented Kalman filter （UKF）, which has better nonlinear approximation ability, is adopted. In addition, to reduce the possibility of radar being locked-on by adverse electronic support measure （ESM）, radar is under the intermittent-working state. After radar is turned off, the possible target position is estimated by a set of time polynomials, which is constructed based on the sufficient observations done before radar is turned off, the estimated values from time polynomials are compared with the current observation values from infrared to determine the time when radar is turned on. Simulation results show the method has a good tracking accuracy and effectively reduces the possibility of radar being locked-on by adverse ESM.展开更多
In this paper, the use of a signal to noise ratio (SNR) is proposed for the quantification of the goodness of some selected processing techniques of thermographic images, such as differentiated absolute contrast, skew...In this paper, the use of a signal to noise ratio (SNR) is proposed for the quantification of the goodness of some selected processing techniques of thermographic images, such as differentiated absolute contrast, skewness and kurtosis based algorithms, pulsed phase transform, principal component analysis and thermographic signal reconstruction. A new hybrid technique is also applied (PhAC—Phase absolute contrast), it combines three different processing techniques: phase absolute contrast, pulsed phase thermography and thermographic signal reconstruction. The quality of the results is established on the basis of the values of the parameter SNR, assessed for the present defects in the analyzed specimen, which enabled to quantify and compare their identification and the quality of the results of the employed technique.展开更多
The reconfigurable metasurfaces which can regulate the microwave absorption performance at the sub wavelength scale provide a possibility to construct intelligent stealth system.However,the existing reconfigurable-met...The reconfigurable metasurfaces which can regulate the microwave absorption performance at the sub wavelength scale provide a possibility to construct intelligent stealth system.However,the existing reconfigurable-metasurface-based absorbers seriously limit the medium and long-distance regulation in practical application due to the complex circuit path and regulation mode.Here,an infrared-coded dual-polarized metasurface absorber(IDMA)with remote-control mode was proposed,which realized the realtime dynamic regulation of the intensity and frequency range of absorption peaks by combining the infrared-coding remotecontrol technology with the active metasurface absorber.The proposed remote-control system can switch the 8-bit binary coding sequences stored in the microcontroller unit(MCU)by an infrared transceiver,so as to regulate the state of active devices under X-and Y-polarizations,respectively.The experimental results showed that the reflection/absorption responses can be regulated by switching different binary codes,and the reflection loss(RL)can be tuned below−7.5 dB(absorptivity over 82%)in wide range of 6.20–18 GHz.Furthermore,the corresponding equivalent circuit model was established and the distributions of surface current and electric field were analyzed to elucidate the dynamic reconfigurable mechanism of the metasurface absorber.The proposed IDMA,which combines intelligent electronic technology with active metasurface absorber,creatively realizes the remote control of active metasurface absorber and opens up a new way for the stealth technology of smart absorber in the future.展开更多
基金This project was jointly supported by the National Natural Science Foundation of China (60375008) ,the China Ph.D.Discipline Special Foundation (20020248029) and the China Aviation Science Foundation (02D57003)
文摘A new synergy tracking method of infrared and radar is presented. To improve tracking accuracy, the unscented Kalman filter （UKF）, which has better nonlinear approximation ability, is adopted. In addition, to reduce the possibility of radar being locked-on by adverse electronic support measure （ESM）, radar is under the intermittent-working state. After radar is turned off, the possible target position is estimated by a set of time polynomials, which is constructed based on the sufficient observations done before radar is turned off, the estimated values from time polynomials are compared with the current observation values from infrared to determine the time when radar is turned on. Simulation results show the method has a good tracking accuracy and effectively reduces the possibility of radar being locked-on by adverse ESM.
文摘In this paper, the use of a signal to noise ratio (SNR) is proposed for the quantification of the goodness of some selected processing techniques of thermographic images, such as differentiated absolute contrast, skewness and kurtosis based algorithms, pulsed phase transform, principal component analysis and thermographic signal reconstruction. A new hybrid technique is also applied (PhAC—Phase absolute contrast), it combines three different processing techniques: phase absolute contrast, pulsed phase thermography and thermographic signal reconstruction. The quality of the results is established on the basis of the values of the parameter SNR, assessed for the present defects in the analyzed specimen, which enabled to quantify and compare their identification and the quality of the results of the employed technique.
基金the National Natural Science Foundation of China(Nos.52103334,52071053,and U1704253)China Postdoctoral Science Foundation(Nos.2020M680946 and 2020M670748)the Fundamental Research Funds for the Central Universities(No.DUT20GF111).
文摘The reconfigurable metasurfaces which can regulate the microwave absorption performance at the sub wavelength scale provide a possibility to construct intelligent stealth system.However,the existing reconfigurable-metasurface-based absorbers seriously limit the medium and long-distance regulation in practical application due to the complex circuit path and regulation mode.Here,an infrared-coded dual-polarized metasurface absorber(IDMA)with remote-control mode was proposed,which realized the realtime dynamic regulation of the intensity and frequency range of absorption peaks by combining the infrared-coding remotecontrol technology with the active metasurface absorber.The proposed remote-control system can switch the 8-bit binary coding sequences stored in the microcontroller unit(MCU)by an infrared transceiver,so as to regulate the state of active devices under X-and Y-polarizations,respectively.The experimental results showed that the reflection/absorption responses can be regulated by switching different binary codes,and the reflection loss(RL)can be tuned below−7.5 dB(absorptivity over 82%)in wide range of 6.20–18 GHz.Furthermore,the corresponding equivalent circuit model was established and the distributions of surface current and electric field were analyzed to elucidate the dynamic reconfigurable mechanism of the metasurface absorber.The proposed IDMA,which combines intelligent electronic technology with active metasurface absorber,creatively realizes the remote control of active metasurface absorber and opens up a new way for the stealth technology of smart absorber in the future.
