# Synchronous Remote Calibration for Electricity Meters: Application and Optimization
## 2 Related Work  
### Remote Calibration Systems  
The advent of remote calibration facilitated by the Internet has significantly enhanced both the efficacy and accuracy of calibration processes, propelling it to the forefront of metrology research endeavors, as highlighted by [PERSON]'s work [4]. Numerous calibration laboratories around the world have developed specialized remote calibration systems, meticulously tailored to their respective calibration objectives. The National Institute of Standards and Technology (NIST) [6] has developed a remote calibration system for multifunctional electrical calibrators. This system uses a portable digital multimeter to interface with the device under calibration and a reference calibrator, utilizing internet connectivity to facilitate the dissemination of testing protocols, software, and data. The National Physical Laboratory Services (NPL) embarked on a remote calibration initiative for Vector Network Analyzers (VNAs) [7], initiating the UK's first calibration service in February 2001, capable of attributing measurement outcomes directly to national standards via the Internet. In Italy, a team led by [PERSON] [8] at the Polytechnic Universityof Turin developed a remote calibration system for data acquisition cards. This system is distinguished by its ability to process real-time data on the Internet, simultaneous measurements to determine precision, and the incorporation of temperature sensors to account for environmental impacts on measurement results. To improve data security, the system implements a dual backup strategy that replicates information on both the server and client platforms. Moreover, scholars have delved into remote calibration systems tailored to specific metering devices within their respective fields of study. [PERSON] et al. [9] introduced a remote calibration technique designed to explore the transmission of pressure standards via the calibration of pressure sensors. This technique facilitates the transportation of pressure standard devices to remote sites, the transmission and tracking of measurements through communication technologies, and the centralized processing and calibration of data in distant laboratories. [PERSON] et al. [20] engineered an automated system for remote resistance calibration using the LabVIEW platform, primarily intended for routine calibrations requiring modest precision. This system exemplifies advancements in leveraging digital platforms to enhance calibration efficiency and reach. Furthermore, researchers have integrated remote calibration systems into industrial applications and daily life, thereby enhancing productivity and product quality. [PERSON] et al. [21] investigated a remote calibration device incorporating edge intelligence for environmental monitoring. This device connects heterogeneous edge devices via network protocols to enhance the intelligence and efficiency of remote calibration, achieving identification accuracy over 90% for some instruments. [PERSON] et al. [22] improved remote environmental measurement systems and developed wireless environmental condition measuring devices for monitoring and recording, with their WEMMR device calibrated against national standards provided by the Indian National Physical Laboratory. In the energy sector, [PERSON] et al. [23] designed a remote measurement system to transmit battery parameters from remote areas to servers, enabling the monitoring of charging status and preventing overcharging and discharging. [PERSON] et al. [24] integrated a calibration board into smart electricity meters, incorporating an integrated calibration card into the power measurement chain to enable remote value transmission and traceability, ensuring stable AC voltage output despite fluctuations in input AC voltage. [PERSON] et al. [25] proposed a DC voltage source remote calibration system based on GPS common-view, installing standards in labs rather than calibration sites to avoid additional errors. [PERSON] et al.