针对未配备气象传感器的全球卫星导航系统(GNSS)站缺乏实测气象参数,通常利用再分析数据、经验模型替代反演大气可降水量(PWV)的问题,定量分析地面气压(P)和加权平均温度(Tm)在反演PWV中的适用性:利用欧洲中期天气预报中心(ECMWF)发布...针对未配备气象传感器的全球卫星导航系统(GNSS)站缺乏实测气象参数,通常利用再分析数据、经验模型替代反演大气可降水量(PWV)的问题,定量分析地面气压(P)和加权平均温度(Tm)在反演PWV中的适用性:利用欧洲中期天气预报中心(ECMWF)发布的第五代再分析数据集(ERA5)、美国国家环境预报中心(NCEP)/国家大气研究中心(NCAR)再分析数据、第二代和第三代全球气压和温度模型(GPT2和GPT3)、全球格网非线性加权平均温度模型(GGNTm)计算P和Tm;然后以探空站实测气象数据为参考,评估不同P和Tm的精度及其对PWV反演的影响。结果表明:1)ERA5、NCEP、GPT2、GPT3获取P的偏差(bias)绝对值小于1 h Pa,均方根误差(RMSE)小于5.5 h Pa;2)在获取Tm方面,ERA5、NCEP、GGNTm、GPT3的bias绝对值小于2.5 K,RMSE小于5.5 K;3)将ERA5、NCEP、GPT2+GGNTm、GPT3获取的气象参数应用到PWV反演中,PWV偏差绝对值小于0.5 mm,RMSE小于3 mm。分析得出应用非实测气象参数反演的GNSS大气可降水量也可获得较高精度的结论。展开更多
A lifetime prediction method for high-reliability tantalum （Ta） capacitors was proposed, based on multiple degradation measures and grey model （GM）. For analyzing performance degradation data, a two-parameter mode...A lifetime prediction method for high-reliability tantalum （Ta） capacitors was proposed, based on multiple degradation measures and grey model （GM）. For analyzing performance degradation data, a two-parameter model based on GM was developed. In order to improve the prediction accuracy of the two-parameter model, parameter selection based on particle swarm optimization （PSO） was used. Then, the new PSO-GM（1, 2, co） optimization model was constructed, which was validated experimentally by conducting an accelerated testing on the Ta capacitors. The experiments were conducted at three different stress levels of 85, 120, and 145℃. The results of two experiments were used in estimating the parameters. And the reliability of the Ta capacitors was estimated at the same stress conditions of the third experiment. The results indicate that the proposed method is valid and accurate.展开更多
文摘针对未配备气象传感器的全球卫星导航系统(GNSS)站缺乏实测气象参数,通常利用再分析数据、经验模型替代反演大气可降水量(PWV)的问题,定量分析地面气压(P)和加权平均温度(Tm)在反演PWV中的适用性:利用欧洲中期天气预报中心(ECMWF)发布的第五代再分析数据集(ERA5)、美国国家环境预报中心(NCEP)/国家大气研究中心(NCAR)再分析数据、第二代和第三代全球气压和温度模型(GPT2和GPT3)、全球格网非线性加权平均温度模型(GGNTm)计算P和Tm;然后以探空站实测气象数据为参考,评估不同P和Tm的精度及其对PWV反演的影响。结果表明:1)ERA5、NCEP、GPT2、GPT3获取P的偏差(bias)绝对值小于1 h Pa,均方根误差(RMSE)小于5.5 h Pa;2)在获取Tm方面,ERA5、NCEP、GGNTm、GPT3的bias绝对值小于2.5 K,RMSE小于5.5 K;3)将ERA5、NCEP、GPT2+GGNTm、GPT3获取的气象参数应用到PWV反演中,PWV偏差绝对值小于0.5 mm,RMSE小于3 mm。分析得出应用非实测气象参数反演的GNSS大气可降水量也可获得较高精度的结论。
基金Project(Z132012) supported by the Second Five Technology-based Fund in Science and Industry Bureau of ChinaProject(1004GK0032) supported by General Armament Department for the Common Issues of Military Electronic Components,China
文摘A lifetime prediction method for high-reliability tantalum （Ta） capacitors was proposed, based on multiple degradation measures and grey model （GM）. For analyzing performance degradation data, a two-parameter model based on GM was developed. In order to improve the prediction accuracy of the two-parameter model, parameter selection based on particle swarm optimization （PSO） was used. Then, the new PSO-GM（1, 2, co） optimization model was constructed, which was validated experimentally by conducting an accelerated testing on the Ta capacitors. The experiments were conducted at three different stress levels of 85, 120, and 145℃. The results of two experiments were used in estimating the parameters. And the reliability of the Ta capacitors was estimated at the same stress conditions of the third experiment. The results indicate that the proposed method is valid and accurate.
