To improve the long-distance measurement accuracy of the total station, an optimization method for the meteorological correction formula is proposed. Analysis revealed the potential for optimizing this formula. Adjusting the formula coefficients was approached as an optimization problem to minimize residual errors. Environmental parameter sensors recorded real-time data along a long baseline during continuous ranging. This data was then used to construct optimization functions. Various combinations of formula coefficients were optimized and validated. The mean ranging error was reduced by 99.8 %, and the standard deviation of the error decreased by 81.2 %. To verify the method, the optimized coefficients were applied to other measurement periods, resulting in a residual error reduction of over 37 %. The study demonstrates that optimizing the meteorological correction formula coefficients is a highly effective and promising method for significantly reducing field ranging errors.
For large-diameter irregular square pipes with a diameter exceeding 1 m,where the length of the curved section is short and there are no long straight pipes before and after,and the flow field inside the pipe is complex,there is a need for accurate measurement of the pipe flow.In this regard,a numerical simulation analysis is conducted,proposing a mean velocity evaluation method based on the coefficient of variation.This method selects multiple points that best represent the average flow velocity of the pipe,determining the insertion depth of the sensors and the weight coefficients of multiple measuring points.A calculation formula is then derived,with the cross-sectional average velocity as the function and the velocity values at multiple points in the flow field as the independent variable.Flow measurement experiments are conducted on a wind tunnel test bench,and the calculated values obtained from the formula derived through numerical analysis are compared.The relative error within the full range is less than 0.54％.
Limited by the discontinuity of atomic energy level, using Rydberg atoms we can only measure the discrete microwave electric field in the actual measurement, which greatly restricts their practical applications. In this paper, we adjust the energy level of the Rydberg atoms by adding LO(Local Oscillator) field. The added LO field can shift the energy level of the Rydberg atoms. The shift is controlled by the frequency and the power of the LO field. Using this method we achieved the measurement of the continuous-frequency field based on Rubidium( 87 Rb) Rydberg atoms.
In this paper,several typical four-parameter sine wave curve-fit methods are reviewed.A three- parameter sine wave curve-fit method is introduced.Based on this method a convergence algorithm of four- parameter sine wave curve-fit is proposed.With this algorithm,the optimization of four parameters(ampli- tude,frequency,phase and offset)is transformed into the searching and optimization of one parameter(only frequency).The convergence characteristic and rule of frequency parameter are discussed.The absolute convergent interval,the absolute convergence criterion and the implementation method are presented.Both the simulation and experiments prove the validity and feasibility of the algorithm,which can be applied to the four-parameter sine wave curve-fit and the digital demodulation of the modulated signal.
计量学是测量及其应用的科学，加强计量学学科建设是国家计量事业发展的重要技术人才支撑。学科交叉融合是推进计量学学科建设发展的有效途径，在国家建设现代先进测量体系背景下，聚焦高校推动计量学与相关学科交叉融合建设，借鉴高校开展学科交叉融合的典型模式，研究分析了学科目录指引下高校布局的模式与路径，探讨分析了“计量+学科”和“学科+计量”两种交叉融合模式和示例，介绍了中国计量大学推动实践探索过程中的一些建设经验，同时期望交叉融合模式的探索与实践，能为相关高校布局计量学相关学科交叉领域提供参考和支撑。
