Not confined to a certain point,such as waveform,this paper systematically studies the low-intercept radio frequency(RF)stealth design of synthetic aperture radar(SAR)from the system level.The study is carried out fro...Not confined to a certain point,such as waveform,this paper systematically studies the low-intercept radio frequency(RF)stealth design of synthetic aperture radar(SAR)from the system level.The study is carried out from two levels.In the first level,the maximum low-intercept range equation of the conventional SAR system is deduced firstly,and then the maximum low-intercept range equation of the multiple-input multiple-output SAR system is deduced.In the second level,the waveform design and imaging method of the low-intercept RF SAR system are given and verified by simulation.Finally,the main technical characteristics of the lowintercept RF stealth SAR system are given to guide the design of low-intercept RF stealth SAR system.展开更多
Synthetic aperture radar(SAR)is a high-resolution two-dimensional imaging radar.However,during the imaging process,SAR is susceptible to intentional and unintentional interference,with radio frequency inter⁃ference(RF...Synthetic aperture radar(SAR)is a high-resolution two-dimensional imaging radar.However,during the imaging process,SAR is susceptible to intentional and unintentional interference,with radio frequency inter⁃ference(RFI)being the most common type,leading to a severe degradation in image quality.To address the above problem,numerous algorithms have been proposed.Although inpainting networks have achieved excellent results,their generalization is unclear.Whether they still work effectively in cross-sensor experiments needs fur⁃ther verification.Through the time-frequency analysis to interference signals,this work finds that interference holds domain invariant features between different sensors.Therefore,this work reconstructs the loss function and extracts the domain invariant features to improve its generalization.Ultimately,this work proposes a SAR RFI suppression method based on domain invariant features,and embeds the RFI suppression into SAR imaging pro⁃cess.Compared to traditional notch filtering methods,the proposed approach not only removes interference but also effectively preserves strong scattering targets.Compared to PISNet,our method can extract domain invariant features and hold better generalization ability,and even in the cross-sensor experiments,our method can still achieve excellent results.In cross-sensor experiments,training data and testing data come from different radar platforms with different parameters,so cross-sensor experiments can provide evidence for the generalization.展开更多
在分析服装企业原材料仓库管理业务过程的基础上,指出仓库管理存在盘点工作量巨大、库存数量不准确等问题,结合RFID(radio frequency identification)技术的高速移动物体识别、多目标和非接触识别、环境适应性好等特点,提出在服装企业...在分析服装企业原材料仓库管理业务过程的基础上,指出仓库管理存在盘点工作量巨大、库存数量不准确等问题,结合RFID(radio frequency identification)技术的高速移动物体识别、多目标和非接触识别、环境适应性好等特点,提出在服装企业原材料仓库实施RFID的应用方案。该应用方案由3个部分组成,描述应用系统信息需求的信息方案,说明如何使用标签的方法与过程的标签方案和结合具体业务过程的应用方案。该方案可以给服装企业构建RFID应用系统提供较高的参考价值。展开更多
在分析现有基于(EPC Class 1Gen,2EPCGen2)标准的轻量级RFID相互认证协议的基础上,提出了一种符合EPCGen2标准的基于射频指纹的RFID认证协议。协议融合了RFID设备的物理层信息,实现了RFID标签的跨层融合认证,具有增强RFID系统安全强度...在分析现有基于(EPC Class 1Gen,2EPCGen2)标准的轻量级RFID相互认证协议的基础上,提出了一种符合EPCGen2标准的基于射频指纹的RFID认证协议。协议融合了RFID设备的物理层信息,实现了RFID标签的跨层融合认证,具有增强RFID系统安全强度的特点。分析显示,提出协议具有相互认证、私密性、防止重放攻击、防止去同步攻击等安全性能,尤其能有效对抗RFID标签的克隆攻击。展开更多
对月球水冰的研究关系到月球形成与演化的深入研究,关系到月球资源的利用以及人类能否借月球为踏板迈向宇宙更深处等问题的探索。在回顾了月球水冰探测进展、总结国内外研究现状基础上,依据极化合成孔径雷达的原理、特点以及水冰反射特...对月球水冰的研究关系到月球形成与演化的深入研究,关系到月球资源的利用以及人类能否借月球为踏板迈向宇宙更深处等问题的探索。在回顾了月球水冰探测进展、总结国内外研究现状基础上,依据极化合成孔径雷达的原理、特点以及水冰反射特性,采用小型化多模式双频率双极化合成孔径雷达(miniature radio frequency,Mini-RF)观测数据对月球北极部分撞击坑进行分析,讨论月球上是否存在水冰的问题。通过对Mini-RF的圆极化率数据分析认为,月球北极的部分撞击坑可能存在水冰,但对水冰储量及其存在形式等方面的问题还需要开展进一步的定量研究。展开更多
基金supported by the National Key R&D Program of China(2017YFC1405600)the Fundamental Research Funds for the Central Universities(JB180213)
文摘Not confined to a certain point,such as waveform,this paper systematically studies the low-intercept radio frequency(RF)stealth design of synthetic aperture radar(SAR)from the system level.The study is carried out from two levels.In the first level,the maximum low-intercept range equation of the conventional SAR system is deduced firstly,and then the maximum low-intercept range equation of the multiple-input multiple-output SAR system is deduced.In the second level,the waveform design and imaging method of the low-intercept RF SAR system are given and verified by simulation.Finally,the main technical characteristics of the lowintercept RF stealth SAR system are given to guide the design of low-intercept RF stealth SAR system.
基金Supported by the National Natural Science Foundation of China(62001489)。
文摘Synthetic aperture radar(SAR)is a high-resolution two-dimensional imaging radar.However,during the imaging process,SAR is susceptible to intentional and unintentional interference,with radio frequency inter⁃ference(RFI)being the most common type,leading to a severe degradation in image quality.To address the above problem,numerous algorithms have been proposed.Although inpainting networks have achieved excellent results,their generalization is unclear.Whether they still work effectively in cross-sensor experiments needs fur⁃ther verification.Through the time-frequency analysis to interference signals,this work finds that interference holds domain invariant features between different sensors.Therefore,this work reconstructs the loss function and extracts the domain invariant features to improve its generalization.Ultimately,this work proposes a SAR RFI suppression method based on domain invariant features,and embeds the RFI suppression into SAR imaging pro⁃cess.Compared to traditional notch filtering methods,the proposed approach not only removes interference but also effectively preserves strong scattering targets.Compared to PISNet,our method can extract domain invariant features and hold better generalization ability,and even in the cross-sensor experiments,our method can still achieve excellent results.In cross-sensor experiments,training data and testing data come from different radar platforms with different parameters,so cross-sensor experiments can provide evidence for the generalization.
文摘在分析服装企业原材料仓库管理业务过程的基础上,指出仓库管理存在盘点工作量巨大、库存数量不准确等问题,结合RFID(radio frequency identification)技术的高速移动物体识别、多目标和非接触识别、环境适应性好等特点,提出在服装企业原材料仓库实施RFID的应用方案。该应用方案由3个部分组成,描述应用系统信息需求的信息方案,说明如何使用标签的方法与过程的标签方案和结合具体业务过程的应用方案。该方案可以给服装企业构建RFID应用系统提供较高的参考价值。
文摘在分析现有基于(EPC Class 1Gen,2EPCGen2)标准的轻量级RFID相互认证协议的基础上,提出了一种符合EPCGen2标准的基于射频指纹的RFID认证协议。协议融合了RFID设备的物理层信息,实现了RFID标签的跨层融合认证,具有增强RFID系统安全强度的特点。分析显示,提出协议具有相互认证、私密性、防止重放攻击、防止去同步攻击等安全性能,尤其能有效对抗RFID标签的克隆攻击。
文摘对月球水冰的研究关系到月球形成与演化的深入研究,关系到月球资源的利用以及人类能否借月球为踏板迈向宇宙更深处等问题的探索。在回顾了月球水冰探测进展、总结国内外研究现状基础上,依据极化合成孔径雷达的原理、特点以及水冰反射特性,采用小型化多模式双频率双极化合成孔径雷达(miniature radio frequency,Mini-RF)观测数据对月球北极部分撞击坑进行分析,讨论月球上是否存在水冰的问题。通过对Mini-RF的圆极化率数据分析认为,月球北极的部分撞击坑可能存在水冰,但对水冰储量及其存在形式等方面的问题还需要开展进一步的定量研究。
