针对海上遇险报警终端定位精度和实时性不足等问题,设计一种兼具北斗短报文和紧急无线示位标(emergency position indicating radio beacon,EPIRB)功能的海上搜救终端.结合指挥中心和相关软件系统,实现遇险快速上报和精确定位.北斗短报...针对海上遇险报警终端定位精度和实时性不足等问题,设计一种兼具北斗短报文和紧急无线示位标(emergency position indicating radio beacon,EPIRB)功能的海上搜救终端.结合指挥中心和相关软件系统,实现遇险快速上报和精确定位.北斗短报文可以实现终端和卫星之间的通讯.全球卫星搜救系统(COSPAS-SARSAT)是由国际海事卫星组织推行的海上遇险搜救系统的重要组成部分,通过EPIRB发送的信号,来定位事故地点和事故信息.将北斗短报文和EPIRB结合,并联合定位模块和温度、心率等传感器.当持有者遇险时,海上搜救终端会立刻不断向指挥中心发送遇险信息,通过指挥中心解析可对救援任务展开提供支持.经测试,其动态、静态定位精度达到10 m级;具有北斗短报文,紧急无线示位标通讯功能.展开更多
水文负载对中国大陆构造环境监测网络(crustal movement observation network of China,CMONOC)测站坐标时间序列具有重要的影响,而降雨量直接影响了水文负载的量级大小。利用ITRF2014(international terrestrial reference frame 2014...水文负载对中国大陆构造环境监测网络(crustal movement observation network of China,CMONOC)测站坐标时间序列具有重要的影响,而降雨量直接影响了水文负载的量级大小。利用ITRF2014(international terrestrial reference frame 2014)参考框架下CMONOC坐标时间序列、MERRA2(modern-era retrospective analysis for research and applications, version 2)水文负载模型以及中国区域降雨量数据来分析三者之间的关系。结果表明,水文负载对CMONOC测站的影响主要体现在垂直方向上,尤其在珠江流域、长江流域以南、西南以及东南诸河流域,水文负载对测站位移的影响尤为显著,水文负载序列的均方根最大可达5.47 mm。水文负载和降雨量都呈现出较为明显的纬度相关性,纬度越高,其量级越小,二者与纬度的线性拟合优度分别为0.63和0.55;同时,降雨量与水文负载也呈现明显的线性关系,拟合优度为0.49,且随着年均降雨量的增加,水文负载的量级会随之增大。对于周期性信号,降雨量、水文负载以及CMONOC坐标时间序列具有一致性,水文负载的周年振幅和CMONOC坐标时间序列的周年振幅与年均降雨量的拟合优度分别为0.64和0.37。在研究水文负载对GNSS坐标时间序列的影响时,除了土壤湿度、积雪以及冠层水,降雨量也是不可忽略的因素。展开更多
Analyzing up to ten years of pulsar timing data observed by the 25-m Nanshan telescope at Urumqi, China, we studied power spectra of timing residuals for four pulsars based on orthogonal polynomials. Our work reveals ...Analyzing up to ten years of pulsar timing data observed by the 25-m Nanshan telescope at Urumqi, China, we studied power spectra of timing residuals for four pulsars based on orthogonal polynomials. Our work reveals that an index of -4 is consistent with a power law model and reveals random walk noise in the rotating frequency. Stability with A8 is investigated and found to be consistent with previous results. A new method called the morphology filter is applied to denoise the pulsar timing residuals and to perform further spectrum analysis. The spectra obtained with this method are improved in accuracy compared with those from timing residuals of pulsars directly.展开更多
文摘针对海上遇险报警终端定位精度和实时性不足等问题,设计一种兼具北斗短报文和紧急无线示位标(emergency position indicating radio beacon,EPIRB)功能的海上搜救终端.结合指挥中心和相关软件系统,实现遇险快速上报和精确定位.北斗短报文可以实现终端和卫星之间的通讯.全球卫星搜救系统(COSPAS-SARSAT)是由国际海事卫星组织推行的海上遇险搜救系统的重要组成部分,通过EPIRB发送的信号,来定位事故地点和事故信息.将北斗短报文和EPIRB结合,并联合定位模块和温度、心率等传感器.当持有者遇险时,海上搜救终端会立刻不断向指挥中心发送遇险信息,通过指挥中心解析可对救援任务展开提供支持.经测试,其动态、静态定位精度达到10 m级;具有北斗短报文,紧急无线示位标通讯功能.
文摘水文负载对中国大陆构造环境监测网络(crustal movement observation network of China,CMONOC)测站坐标时间序列具有重要的影响,而降雨量直接影响了水文负载的量级大小。利用ITRF2014(international terrestrial reference frame 2014)参考框架下CMONOC坐标时间序列、MERRA2(modern-era retrospective analysis for research and applications, version 2)水文负载模型以及中国区域降雨量数据来分析三者之间的关系。结果表明,水文负载对CMONOC测站的影响主要体现在垂直方向上,尤其在珠江流域、长江流域以南、西南以及东南诸河流域,水文负载对测站位移的影响尤为显著,水文负载序列的均方根最大可达5.47 mm。水文负载和降雨量都呈现出较为明显的纬度相关性,纬度越高,其量级越小,二者与纬度的线性拟合优度分别为0.63和0.55;同时,降雨量与水文负载也呈现明显的线性关系,拟合优度为0.49,且随着年均降雨量的增加,水文负载的量级会随之增大。对于周期性信号,降雨量、水文负载以及CMONOC坐标时间序列具有一致性,水文负载的周年振幅和CMONOC坐标时间序列的周年振幅与年均降雨量的拟合优度分别为0.64和0.37。在研究水文负载对GNSS坐标时间序列的影响时,除了土壤湿度、积雪以及冠层水,降雨量也是不可忽略的因素。
基金supported by the Fundamental Research Funds for the Central Universitiesthe National Natural Science Foundation of China (Grant Nos.41074023 and 10903019)+2 种基金the Knowledge Innovation Program of CAS project (Grant No.KJCX2-YW-T09)the National Basic Research Program of China (Grant No.2009CB824800)the Key Laboratory of Radio Astronomy of CAS and the program of the West Light Foundation of the Chinese Academy of Sciences (Grant No.XBBS201021)
文摘Analyzing up to ten years of pulsar timing data observed by the 25-m Nanshan telescope at Urumqi, China, we studied power spectra of timing residuals for four pulsars based on orthogonal polynomials. Our work reveals that an index of -4 is consistent with a power law model and reveals random walk noise in the rotating frequency. Stability with A8 is investigated and found to be consistent with previous results. A new method called the morphology filter is applied to denoise the pulsar timing residuals and to perform further spectrum analysis. The spectra obtained with this method are improved in accuracy compared with those from timing residuals of pulsars directly.
