This paper concentrates on super-resolution imaging of the ship target under the sparse aperture situation.Firstly,a multi-static configuration is utilized to solve the coherent processing interval(CPI)problem caused ...This paper concentrates on super-resolution imaging of the ship target under the sparse aperture situation.Firstly,a multi-static configuration is utilized to solve the coherent processing interval(CPI)problem caused by the slow-speed motion of ship targets.Then,we realize signal restoration and image reconstruction with the alternating direction method of multipliers(ADMM).Furthermore,we adopt the interferometric technique to produce the three-dimensional(3D)images of ship targets,namely interferometric inverse synthetic aperture radar(InISAR)imaging.Experiments based on the simulated data are utilized to verify the validity of the proposed method.展开更多
In this paper,a multi-static system working in an active way is made up of ionospheric oblique backscatter sounding system(IOBSS)and two separate receiving stations,which adopts discontinuous wave mechanism.We have ad...In this paper,a multi-static system working in an active way is made up of ionospheric oblique backscatter sounding system(IOBSS)and two separate receiving stations,which adopts discontinuous wave mechanism.We have advanced a new model that contains skywave condition to locate over-the-horizon targets.We use a single quasi-parabolic(QP)ionosphere model and an analytic ray-tracing program to obtain the coordinate registration(CR)index,which changes skywave group range to ground range.Also,IOBSS and other two receiving stations use this distance information to locate the target which is far away from the system.The analytic expression for the geometric dilution of precision(GDOP)under different station deployments are obtained,which shows GDOP is influenced by the system measurement precision,the stations'coordinates,and CR index.By computer simulation,we find that GDOP of isosceles right triangle deployment is smaller than that of line deployment and location precision will be improved with increasing base line length.The results indicate that this model is practicable with an acceptable range of error(less than 500 m under certain conditions in this paper).展开更多
Generally,to apply the MUltiple SIgnal Classification(MUSIC)algorithm for the rapid imaging of small objects,complete elements of the multi-static response(MSR)matrix must be collected.However,in some real-world appli...Generally,to apply the MUltiple SIgnal Classification(MUSIC)algorithm for the rapid imaging of small objects,complete elements of the multi-static response(MSR)matrix must be collected.However,in some real-world applications in microwave imaging,diagonal elements of theMSRmatrix are unknown.Nevertheless,it is possible to obtain imaging results using a traditional approach but theoretical reason of the applicability has not been investigated yet.In this paper,we consider the application of MUSIC for a fast identification of small objects from collected MSR matrix in both transverse magnetic(TM)and transverse electric(TE)polarizations.In order to examine the applicability,fundamental limitation,and various properties of MUSIC,we establish mathematical structure of the three imaging functions and explore that the main factors of the imaging functions are Bessel function of order zero,one,and two.The established structures demonstrate why the existence and location of small objects can be retrieved via MUSIC without the diagonal elements of the MSR matrix.Results of numerical simulations with noise-corrupted synthetic data are also provided to support the identified structures.展开更多
机床滑枕是机床的重要部件,滑枕的刚性对机床的加工精度影响很大。针对机床滑枕传统经验设计效率低、静动态特性难以平衡的问题,提出一种融合参数建模与多目标优化的混合设计方法。通过五因素三水平正交试验建立滑枕结构参数的岭回归模...机床滑枕是机床的重要部件,滑枕的刚性对机床的加工精度影响很大。针对机床滑枕传统经验设计效率低、静动态特性难以平衡的问题,提出一种融合参数建模与多目标优化的混合设计方法。通过五因素三水平正交试验建立滑枕结构参数的岭回归模型,结合非支配排序遗传算法(Non-dominated Sorting Genetic Algorithm-Ⅱ,NSGA-Ⅱ)生成Pareto解集,最后采用优劣解距离(Technique for Order Preference by Similarity to an Ideal Solution,TOPSIS)法决策最优参数组合。结果表明,优化后滑枕质量减少了29.3 kg,较优化前降低了4.7%,最大变形降低了5.8%,一阶固有频率保持稳定在553.3 Hz,表明该方法为机床零/部件多参数耦合优化提供了新的参考。展开更多
基金This work was supported by the National Natural Science Foundation of China(61871146).
文摘This paper concentrates on super-resolution imaging of the ship target under the sparse aperture situation.Firstly,a multi-static configuration is utilized to solve the coherent processing interval(CPI)problem caused by the slow-speed motion of ship targets.Then,we realize signal restoration and image reconstruction with the alternating direction method of multipliers(ADMM).Furthermore,we adopt the interferometric technique to produce the three-dimensional(3D)images of ship targets,namely interferometric inverse synthetic aperture radar(InISAR)imaging.Experiments based on the simulated data are utilized to verify the validity of the proposed method.
基金Supported by the National High Technology Research and Development Program of China (863 Program) (2009AAXXX1302)
文摘In this paper,a multi-static system working in an active way is made up of ionospheric oblique backscatter sounding system(IOBSS)and two separate receiving stations,which adopts discontinuous wave mechanism.We have advanced a new model that contains skywave condition to locate over-the-horizon targets.We use a single quasi-parabolic(QP)ionosphere model and an analytic ray-tracing program to obtain the coordinate registration(CR)index,which changes skywave group range to ground range.Also,IOBSS and other two receiving stations use this distance information to locate the target which is far away from the system.The analytic expression for the geometric dilution of precision(GDOP)under different station deployments are obtained,which shows GDOP is influenced by the system measurement precision,the stations'coordinates,and CR index.By computer simulation,we find that GDOP of isosceles right triangle deployment is smaller than that of line deployment and location precision will be improved with increasing base line length.The results indicate that this model is practicable with an acceptable range of error(less than 500 m under certain conditions in this paper).
基金supported by the National Research Foundation of Korea(NRF)grant funded by the Korea government(MSIT)(NRF-2020R1A2C1A01005221).
文摘Generally,to apply the MUltiple SIgnal Classification(MUSIC)algorithm for the rapid imaging of small objects,complete elements of the multi-static response(MSR)matrix must be collected.However,in some real-world applications in microwave imaging,diagonal elements of theMSRmatrix are unknown.Nevertheless,it is possible to obtain imaging results using a traditional approach but theoretical reason of the applicability has not been investigated yet.In this paper,we consider the application of MUSIC for a fast identification of small objects from collected MSR matrix in both transverse magnetic(TM)and transverse electric(TE)polarizations.In order to examine the applicability,fundamental limitation,and various properties of MUSIC,we establish mathematical structure of the three imaging functions and explore that the main factors of the imaging functions are Bessel function of order zero,one,and two.The established structures demonstrate why the existence and location of small objects can be retrieved via MUSIC without the diagonal elements of the MSR matrix.Results of numerical simulations with noise-corrupted synthetic data are also provided to support the identified structures.
文摘机床滑枕是机床的重要部件,滑枕的刚性对机床的加工精度影响很大。针对机床滑枕传统经验设计效率低、静动态特性难以平衡的问题,提出一种融合参数建模与多目标优化的混合设计方法。通过五因素三水平正交试验建立滑枕结构参数的岭回归模型,结合非支配排序遗传算法(Non-dominated Sorting Genetic Algorithm-Ⅱ,NSGA-Ⅱ)生成Pareto解集,最后采用优劣解距离(Technique for Order Preference by Similarity to an Ideal Solution,TOPSIS)法决策最优参数组合。结果表明,优化后滑枕质量减少了29.3 kg,较优化前降低了4.7%,最大变形降低了5.8%,一阶固有频率保持稳定在553.3 Hz,表明该方法为机床零/部件多参数耦合优化提供了新的参考。
