We developed a measuring instrument that had wide range, high precision, small measuring touch force. The instrument for three-dimensional (3D) surface topography measurement was composed of a high precision displacem...We developed a measuring instrument that had wide range, high precision, small measuring touch force. The instrument for three-dimensional (3D) surface topography measurement was composed of a high precision displacement sensor based on the Michelson interference principle, a 3D platform based on vertical scanning, a measuring and control circuit, and an industrial control computer. It was a closed loop control system, which changed the traditional moving stylus scanning style into a moving platform scanning style. When the workpiece was measured, the lever of the displacement sensor returned to the balanced position in every sample interval according to the zero offset of the displacement sensor. The non-linear error caused by the rotation of the lever was, therefore, very small even if the measuring range was wide. The instrument can measure the roughness and the profile size of a curved surface.展开更多
A new method of increasing the range measure preci- sion by Chirp- Z transform in the level Radar has been put up in this paper. The main assignment of this research is to accom- plish the FFT and Chirp- Z transform. ...A new method of increasing the range measure preci- sion by Chirp- Z transform in the level Radar has been put up in this paper. The main assignment of this research is to accom- plish the FFT and Chirp- Z transform. At the same time, the af- fection of the two range measure methods has been analyzed in this paper. This method can increase both the calculation effi- ciency and range measure precision remarkably by theory calcu- lating and digital emulation.展开更多
A dual transponder carrier ranging method can be used to measure inter-satellite distance with high precision by combining the reference and the to-and-fro measurements. Based on the differential techniques, the oscil...A dual transponder carrier ranging method can be used to measure inter-satellite distance with high precision by combining the reference and the to-and-fro measurements. Based on the differential techniques, the oscillator phase noise, which is the main error source for microwave ranging systems, can be significantly attenuated. Further, since the range measurements are derived on the same satellite, the dual transponder ranging system does not need a time tagging system to synchronize the two satellites. In view of the lack of oscillator noise analysis on the dual transponder ranging model, a comprehensive analysis of oscillator noise effects on ranging accuracy is provided. First, the dual transponder ranging system is described with emphasis on the detailed analysis of oscillator noise on measurement precision. Then, a high-fidelity numerical simulation approach based on the power spectrum density of an actual ultra-stable oscillator is carried out in both frequency domain and time domain to support the presented theoretical analysis. The simulation results under different conditions are consistent with the proposed concepts, which makes the results reliable. Besides, the results demonstrate that a high level of accuracy can be achieved by using this oscillator noise cancelation-oriented ranging method.展开更多
针对现有基于测距的集群UAV协同导航方法普遍忽略了空间构型对定位定能的影响,难以获得精确的导航定位结果,提出一种基于空间构型优选的5G集群UAV协同导航方法。构建了复杂环境下基于5G信号的UAV相对测距误差模型,基于最小几何精度因子(...针对现有基于测距的集群UAV协同导航方法普遍忽略了空间构型对定位定能的影响,难以获得精确的导航定位结果,提出一种基于空间构型优选的5G集群UAV协同导航方法。构建了复杂环境下基于5G信号的UAV相对测距误差模型,基于最小几何精度因子(geometric dilution of precision,GDOP)准则建立了协同导航节点寻优策略,实现了协同导航空间构型的实时优选;设计了基于5G测距网络的协同导航滤波器,对UAV导航信息进行在线估计和实时补偿,提高集群UAV的协同定位精度。仿真结果表明:该方法从机定位精度平均提升了约42.05%,为集群UAV实现在卫星不可用条件下的自主导航提供了一种有效的新方法。展开更多
基金the National Science Foundation of China (No.50745020).
文摘We developed a measuring instrument that had wide range, high precision, small measuring touch force. The instrument for three-dimensional (3D) surface topography measurement was composed of a high precision displacement sensor based on the Michelson interference principle, a 3D platform based on vertical scanning, a measuring and control circuit, and an industrial control computer. It was a closed loop control system, which changed the traditional moving stylus scanning style into a moving platform scanning style. When the workpiece was measured, the lever of the displacement sensor returned to the balanced position in every sample interval according to the zero offset of the displacement sensor. The non-linear error caused by the rotation of the lever was, therefore, very small even if the measuring range was wide. The instrument can measure the roughness and the profile size of a curved surface.
文摘A new method of increasing the range measure preci- sion by Chirp- Z transform in the level Radar has been put up in this paper. The main assignment of this research is to accom- plish the FFT and Chirp- Z transform. At the same time, the af- fection of the two range measure methods has been analyzed in this paper. This method can increase both the calculation effi- ciency and range measure precision remarkably by theory calcu- lating and digital emulation.
基金Project(61106113)supported by the National Natural Science Foundation of China
文摘A dual transponder carrier ranging method can be used to measure inter-satellite distance with high precision by combining the reference and the to-and-fro measurements. Based on the differential techniques, the oscillator phase noise, which is the main error source for microwave ranging systems, can be significantly attenuated. Further, since the range measurements are derived on the same satellite, the dual transponder ranging system does not need a time tagging system to synchronize the two satellites. In view of the lack of oscillator noise analysis on the dual transponder ranging model, a comprehensive analysis of oscillator noise effects on ranging accuracy is provided. First, the dual transponder ranging system is described with emphasis on the detailed analysis of oscillator noise on measurement precision. Then, a high-fidelity numerical simulation approach based on the power spectrum density of an actual ultra-stable oscillator is carried out in both frequency domain and time domain to support the presented theoretical analysis. The simulation results under different conditions are consistent with the proposed concepts, which makes the results reliable. Besides, the results demonstrate that a high level of accuracy can be achieved by using this oscillator noise cancelation-oriented ranging method.
文摘针对现有基于测距的集群UAV协同导航方法普遍忽略了空间构型对定位定能的影响,难以获得精确的导航定位结果,提出一种基于空间构型优选的5G集群UAV协同导航方法。构建了复杂环境下基于5G信号的UAV相对测距误差模型,基于最小几何精度因子(geometric dilution of precision,GDOP)准则建立了协同导航节点寻优策略,实现了协同导航空间构型的实时优选;设计了基于5G测距网络的协同导航滤波器,对UAV导航信息进行在线估计和实时补偿,提高集群UAV的协同定位精度。仿真结果表明:该方法从机定位精度平均提升了约42.05%,为集群UAV实现在卫星不可用条件下的自主导航提供了一种有效的新方法。
