JJF(黔) 57-2021 网络时间（NTP）服务器校准规范

贵州省市场监督管理局发布贵州省地方计量技术规范JJF（黔）57—2021网络时间（NTP）服务器校准规范CalibrationSpecificationofNetworkTimeServersBasedonNetworkTimeProtocolXXXX-XX-XX发布XXXX-XX-XX实施JJF(黔)XX—XXXX网络时间（NTP）服务器校准规范CalibrationSpecificationofNetworkTimeServersBasedonNetworkTimeProtocol归口单位：贵州省市场监督管理局主要起草单位：贵州省计量测试院贵州装备制造职业学院参加起草单位：贵州航天计量测试技术研究所本规范委托贵州省计量测试院负责解释JJF(黔)57—2021JJF(黔)XX—XXXX本规范主要起草人：张宇（贵州省计量测试院）胡鹏飞（贵州装备制造职业学院）王菊凤（贵州省计量测试院）参加起草人：黄徐瑞晗（贵州省计量测试院）韩锋（贵州省计量测试院）李金阳（贵州航天计量测试技术研究所）王勇（贵州省计量测试院）JJF(黔)XX—XXXXI目录引言·························································································（II）1范围·····················································································（1）2引用文件···············································································（1）3概述·····················································································（1）4计量特性···············································································（2）4.1秒脉冲···············································································（2）4.2主振器性能·········································································（2）4.3时间保持偏差······································································（2）4.4NTP同步偏差·······································································（2）5校准条件···············································································（2）5.1环境条件············································································（2）5.2测量标准及其他设备·····························································（3）6校准项目和校准方法································································（4）6.1校准项目············································································（4）6.2校准方法············································································（4）7校准结果表达与处理································································（7）7.1校准记录············································································（7）7.2校准结果的处理···································································（7）8复校时间间隔·········································································（8）附录A网络时间服务器NTP同步偏差校准结果的不确定度评定示例·······（9）附录B校准记录格式···································································（14）附录C校准证书内页格式·····························································（15）JJF(黔)XX—XXXXII引言本规范依据JJF1071—2010《国家计量校准规范编写规则》、JJF1059.1—2012《测量不确定度评定与表示》、JJF1001—2011《通用计量术语及定义》的内容制定。JJF(黔)XX—XXXX1网络时间（NTP）服务器校准规范1范围本规范适用于采用网络时间协议（NetworkTimeProtocol,NTP）进行网络授时的网络时间服务器的校准。2引用文件本规范引用了下列文件：JJG180电子测量仪器内石英晶体振荡器JJG181石英晶体频率标准JJG292铷原子频率标准JJF1180—2007时间频率计量名词术语及定义JJF1403—2013全球导航卫星系统（GNSS）接收机（时间测量型）校准规范JJF1724—2018时码发生器校准规范凡是注日期的引用文件，仅注日期的版本适用于本规范；凡是不注日期的引用文件，其最新版本（包括所有的修改单）适用于本规范。3概述基于NTP的网络时间服务器（以下简称NTP服务器）是用于在网络中提供NTP时间同步服务的授时设备，由参考信号输入单元、本地时间保持单元、信号输出单元组成。参考信号输入单元获取外部时间信息；本地时间保持单元接收参考信号输入单元的时间信号对本地时钟进行同步，并利用主振器进行时间保持；信号输出单元根据本地的时间频率信号，对外提供秒脉冲信号（1PulsePerSecond,1PPS）输出、频率信号输出、NTP服务等。NTP服务器工作原理框图如图1所示。参考信号输入单元可通过三种方式获取时间信息：接收全球导航卫星系统（GlobalNavigationSatelliteSystem,GNSS）信号进行解调解码；或外部1PPS、频率信号和时间信息；或通过网络中处于上一层的NTP服务器。JJF(黔)XX—XXXX2参考信号输入单元GNSS接收机1PPS+TODNTP服务器本地时间保持单元频率信号本地时钟主振器（晶振/原子钟）时间信号频率信号信号输出单元NTP服务时间信号频率信号1PPS输出频率输出图1NTP服务器工作原理框图4计量特性4.1秒脉冲4.1.1定时准确度≤20μs。4.1.2定时稳定度≤2μs。4.2主振器性能4.2.1主振器为石英晶体振荡器4.2.1.1相对频率偏差：±（1×10-5～1×10-10）。4.2.1.2频率稳定度：1×10-8～1×10-12（取样时间1s）。4.2.2主振器为石英晶体频率标准4.2.2.1相对频率偏差：±（1×10-8～1×10-10）。4.2.2.2频率稳定度：1×10-10～5×10-13（取样时间1s）。4.2.3主振器为铷原子频率标准4.2.3.1相对频率偏差：±（2×10-10～2×10-11）。4.2.3.2频率稳定度：5×10-11～2×10-12（取样时间1s）。4.3时间保持偏差±（5μs～1s）（保持时间24h）。4.4NTP同步偏差±10ms。注：以上技术指标不用于合格性判定，仅供参考。5校准条件5.1环境条件JJF(黔)XX—XXXX35.1.1环境温度、相对湿度、电源电压及频率要求见表1。表1环境温度、相对湿度、电源电压及频率要求一览表主振器类型环境温度相对湿度电源电压及频率石英晶体振荡器（15～30）℃环境温度波动在±2℃内不大于80%220（1±10%）V50（1±2%）Hz石英晶体频率标准（15～30）℃环境温度波动在±2℃内不大于80%220（1±2%）V50（1±2%）Hz铷原子频率标准（18～25）℃环境温度波动在±1℃内不大于80%220（1±10%）V50（1±2%）Hz5.1.2其他周围无影响仪器正常工作的电磁干扰和机械震动。5.2测量标准及其他设备5.2.1参考频标5.2.1.1输出频率为5MHz、10MHz。5.2.1.2频率稳定度小于被校NTP服务器相同取样时间频率稳定度的1/3。5.2.1.3相对频率偏差优于被校NTP服务器一个数量级。5.2.2参考时标5.2.2.1时间偏差的绝对值小于被校NTP服务器定时准确度的1/3。5.2.2.2具有1PPS信号输出功能。5.2.3频标比对器5.2.3.1输入频率为5MHz、10MHz。5.2.3.2比对不确定度（用阿伦标准偏差表示）应小于被校NTP服务器相同取样时间频率稳定度的1/3。5.2.4通用计数器5.2.4.1测量范围为10Hz～100MHz。5.2.4.2相对频率偏差优于被校NTP服务器一个数量级，或可外接参考频标。5.2.5时间间隔测量仪5.2.5.1测量范围为1ns～1s。5.2.5.2相对频率偏差优于被校NTP服务器一个数量级，或可外接参考频标。JJF(黔)XX—XXXX45.2.6时间综合测试仪5.2.6.1具有NTP服务器测量功能。5.2.6.2时间偏差的绝对值小于被校NTP服务器定时准确度的1/3，或可外接参考时标。5.2.7参考NTP服务器NTP同步偏差优于被校NTP服务器一个数量级，或可外接参考频标和参考时标。5.2.8其他辅助设备计算机、交换机。6校准项目和校准方法6.1校准项目校准项目见表2。表2NTP服务器校准项目一览表序号校准项目名称校准方法的条款1定时准确度6.2.22定时稳定度6.2.33主振器性能相对频率偏差6.2.44频率稳定度5时间保持偏差6.2.56NTP同步偏差6.2.66.2校准方法6.2.1校准前准备目测被校NTP服务器外观，仪器名称、型号、制造单位、出厂编号及输入输出接口标识清晰。通电后，仪器应正常工作。6.2.2定时准确度按图2连接仪器，被校NTP服务器正常锁定GNSS信号并达到仪器说明书规定的驯服和预热时间，设置时间间隔测量仪通道1、2的触发电平为信号幅度的50%，由时间间隔测量仪测量得到被校NTP服务器与参考时标1PPS24h的时间偏差数据（取样时间1s），按式（1）计算定时准确度。JJF(黔)XX—XXXX5参考时标1PPS输出被校NTP服务器1PPS输出天线输入时间间隔测量仪通道1通道2参考频率输入参考频标图2定时准确度校准示意图A11NiiTTN==（1）式中：AT——定时准确度，ns；iT——时间间隔测量仪第i秒测得的时间偏差测量值，ns；N——取样个数。6.2.3定时稳定度按图2连接仪器，被校NTP服务器正常锁定GNSS信号并达到仪器说明书规定的驯服和预热时间，设置时间间隔测量仪通道1、2的触发电平为信号幅度的50%，由时间间隔测量仪测量得到被校NTP服务器与参考时标1PPS24h的时间偏差数据（取样时间1s），按式（2）计算定时稳