无电离层组合模型和非差非组合模型是精密单点定位(precise point positioning,PPP)中最常用的两种函数模型。非差非组合模型中电离层误差常被描述为随机游走,随机游走过程中的功率谱密度成为决定PPP定位性能的主要因素,采用经验值功率...无电离层组合模型和非差非组合模型是精密单点定位(precise point positioning,PPP)中最常用的两种函数模型。非差非组合模型中电离层误差常被描述为随机游走,随机游走过程中的功率谱密度成为决定PPP定位性能的主要因素,采用经验值功率谱密度的方法没有考虑电离层小尺度变化。在非差非组合模型的基础上,分析电离层时间相关性信息,在电离层差分时间间隔较小时,观测噪声较大甚至淹没电离层的变化。因此,通过平滑去噪的方法削弱观测值噪声的影响,实时确定电离层功率谱密度,对非差非组合模型中的电离层延迟参数进行合理约束,从而改善定位性能。对12个测站10 d的北斗卫星导航系统(BeiDou satellite navigation system,BDS)数据进行不同电离层模型下的解算,结果表明:相对于传统无电离层组合PPP模型,所提方法在收敛时间上缩短约8.2%,水平方向精度相当,垂直方向定位精度提高约31%。相较于功率谱密度采用经验值方法,所提方法在收敛时间上缩短约9.7%,水平方向精度相当,垂直方向定位精度提高约31%。展开更多
Spatiotemporal information,positioning and navigation services have become important elements of new type infrastructure.The rapid development of global digital trade provides a large-scale application scenario for th...Spatiotemporal information,positioning and navigation services have become important elements of new type infrastructure.The rapid development of global digital trade provides a large-scale application scenario for the use of Beidou Navigation Satellite System(BDS)spatiotemporal information to support the certification of origin of agricultural products.The BDS spatiotemporal information agricultural product digital credit system uses such modules as BDS,spatiotemporal information collection,spatiotemporal coding,and spatiotemporal blockchain.It incorporates multi-level joint supervision mechanisms such as government,associations,and users.Starting from the initial production link of agricultural products,it realizes the correspondence and locking of online and offline products,effectively improves the integrity and credibility of information in the production process,finished product quality and circulation process of products,effectively manages the green production and anti-channel conflicts of producers,and provides credible information for consumers,thus realizing the digital credit certification of products.The successful practice of characteristic agricultural products in Yunnan Province has verified the application ability of the BDS spatiotemporal information agricultural product digital credit system.This system has played a significant role in promoting the online and offline locking,credible information,effective supervision and high quality and high price of characteristic agricultural products from the field.The BDS provides services for global digital trade and contributes to the further enhancement of the global application scale of GNSS.展开更多
基金Supported by Yunnan Provincial Science and Technology Plan Project(202102AE090051).
文摘Spatiotemporal information,positioning and navigation services have become important elements of new type infrastructure.The rapid development of global digital trade provides a large-scale application scenario for the use of Beidou Navigation Satellite System(BDS)spatiotemporal information to support the certification of origin of agricultural products.The BDS spatiotemporal information agricultural product digital credit system uses such modules as BDS,spatiotemporal information collection,spatiotemporal coding,and spatiotemporal blockchain.It incorporates multi-level joint supervision mechanisms such as government,associations,and users.Starting from the initial production link of agricultural products,it realizes the correspondence and locking of online and offline products,effectively improves the integrity and credibility of information in the production process,finished product quality and circulation process of products,effectively manages the green production and anti-channel conflicts of producers,and provides credible information for consumers,thus realizing the digital credit certification of products.The successful practice of characteristic agricultural products in Yunnan Province has verified the application ability of the BDS spatiotemporal information agricultural product digital credit system.This system has played a significant role in promoting the online and offline locking,credible information,effective supervision and high quality and high price of characteristic agricultural products from the field.The BDS provides services for global digital trade and contributes to the further enhancement of the global application scale of GNSS.
