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Traffic radar-based speed meter (TRSM) is an important measuring instrument for measuring the speed of target vehicle based on the radar Doppler effect, and has been legally used in road vehicle speeding enforcement for more than 30 years in China. TRSM with target position determination (TRSM-TPD) is a new generation of TRSM with the advantages of speeding enforcement by lane, high accuracy of speed measurement and target position determination, high efficiency, low cost, etc. This paper proposes a new verification method for TRSM-TPD in road vehicle speeding enforcement. The proposed verification method includes the simulated speed calibration method for initial verification in the laboratory, and the online speed and position calibration method for subsequent verification in the field. The range of simulated radial speed is up to (1∼400) km/h and the maximum permissible error is within ±0.03 km/h, which can satisfy the full-range and high-accuracy speed calibration requirements for TRSM-TPD. The uncertainty of the reference facility in actual traffic is 0.12% within the speed range of (60∼250) km/h, where coverage factor k = 3. The simulated and online calibration results validate the effectiveness of the proposed verification method and the feasibility of the realized target speed simulator and the established reference facility. [ABSTRACT FROM AUTHOR]

Research on the transfer and traceability of a dynamic angle has great value in the field of measurement. The fiber optic gyroscope (FOG), as a high-precision angular velocity sensor, has broad prospects in this application. The focus of this article is the evaluation of angle measurement uncertainty of the FOG based on the Monte Carlo method (MCM). The angle measurement uncertainty evaluation model is established based on the principle of the FOG, and the simulation is carried out in detail based on the model and MCM. Finally, the angle measurement experiments of the FOG are carried out in the National Institute of Metrology, China. The experimental results show that the angle measurement uncertainty within the range of 360° is about $0.96^{\prime \prime }$ in a relatively stable environment when the confidence probability is 95%. It is highly consistent with the simulation, which confirms the accuracy of the evaluation model and the effectiveness of MCM. [ABSTRACT FROM AUTHOR]

The Isochronous Mass Spectrometry (IMS) is a powerful tool for mass measurements of exotic nuclei with half-lives as short as several tens of micro-seconds in storage rings. In order to improve the mass resolving power while preserving the acceptance of the storage ring, the IMS with two Time-Of-Flight (TOF) detectors has been implemented at the storage ring CSRe in Lanzhou, China. Additional velocity information beside the revolution time in the ring can be obtained for each of the stored ions by using the double TOF detector system. In this paper, we introduced a new method of using a 658 nm laser range finder and a short-pulsed ultra-violet laser to directly measure the distance and time delay difference between the two TOF detectors which were installed inside the 1 0 − 11 mbar vacuum chambers. The results showed that the distance between the two ultra-thin carbon foils of the two TOF detectors was ranging from 18032.5 mm to 18035.0 mm over a measurable area of 20 × 20 mm 2. Given the measured distance, the time delay difference which comes with signal cable length difference between the two TOF detectors was measured to be Δ t d e l a y 1 − 2 = 99 (26) ps. The new method has enabled us to use the speed of light in vacuum to calibrate the velocity of stored ions in the ring. The velocity resolution of the current double TOF detector system at CSRe was deduced to be σ (v) ∕ v = 4. 4 × 1 0 − 4 for laser light, mainly limited by the time resolution of the TOF detectors. [ABSTRACT FROM AUTHOR]