针对发射波形正交性退化影响机载多输入多输出(multiple-input multiple-output,MIMO)雷达的杂波特性,基于信号空间和子阵空间的变换原理,建立了波形正交性退化下的机载MIMO雷达杂波通用模型和标准模型。基于带限信号的最优逼近特性,分...针对发射波形正交性退化影响机载多输入多输出(multiple-input multiple-output,MIMO)雷达的杂波特性,基于信号空间和子阵空间的变换原理,建立了波形正交性退化下的机载MIMO雷达杂波通用模型和标准模型。基于带限信号的最优逼近特性,分析了波形正交性退化下的空时等效阵列孔径变化规律,提出了杂波自由度(degree of freedom,DOF)的估计准则。最后,仿真验证了杂波模型及杂波自由度估计准则的有效性。展开更多
A new technology of offshore oil rod pumping production is developed for offshore heavy oil recovery. A new type of miniature hydraulic pumping unit with long-stroke, low pumping speed and compact structure is designe...A new technology of offshore oil rod pumping production is developed for offshore heavy oil recovery. A new type of miniature hydraulic pumping unit with long-stroke, low pumping speed and compact structure is designed based on the spatial characteristics of offshore platforms. By combining the strengths of sinusoidal velocity curve and trapezoidal velocity curve, a kinematical model of the acceleration, the velocity and displacement of the pumping unit＇s hanging point is established. The results show that the pumping unit has good kinematic characteristics of smooth motion and small dynamic load. The multi-degree-of-freedom dynamic model of the single-well pumping unit is established. The first and second order natural frequencies of the sucker rod string subsystem and the pumping unit subsystem are studied. The results show that the first and the second order natural frequencies among the pumping rod string, pumping unit-platform subsystem and the dynamic excitation have differences over 5 times from each other, indicating that resonance phenomenon will not appear during the operation and the dynamic requirements for field use are met in the system.展开更多
文摘针对发射波形正交性退化影响机载多输入多输出(multiple-input multiple-output,MIMO)雷达的杂波特性,基于信号空间和子阵空间的变换原理,建立了波形正交性退化下的机载MIMO雷达杂波通用模型和标准模型。基于带限信号的最优逼近特性,分析了波形正交性退化下的空时等效阵列孔径变化规律,提出了杂波自由度(degree of freedom,DOF)的估计准则。最后,仿真验证了杂波模型及杂波自由度估计准则的有效性。
基金financially supported by the National Natural Science Foundation of China(Grant No.51174224)the National Science and Technology Major Projects of Oil and Gas(Grant Nos.2016ZX05066 and 2016ZX05042)the Natural Science Foundation of Shandong Province(Grant No.ZR2014El015)
文摘A new technology of offshore oil rod pumping production is developed for offshore heavy oil recovery. A new type of miniature hydraulic pumping unit with long-stroke, low pumping speed and compact structure is designed based on the spatial characteristics of offshore platforms. By combining the strengths of sinusoidal velocity curve and trapezoidal velocity curve, a kinematical model of the acceleration, the velocity and displacement of the pumping unit＇s hanging point is established. The results show that the pumping unit has good kinematic characteristics of smooth motion and small dynamic load. The multi-degree-of-freedom dynamic model of the single-well pumping unit is established. The first and second order natural frequencies of the sucker rod string subsystem and the pumping unit subsystem are studied. The results show that the first and the second order natural frequencies among the pumping rod string, pumping unit-platform subsystem and the dynamic excitation have differences over 5 times from each other, indicating that resonance phenomenon will not appear during the operation and the dynamic requirements for field use are met in the system.
