Joint estimation of vertical total electron content (VTEC) and satellite differential code biases (SDCBs) using low-cost receivers
Joint estimation of vertical total electron content (VTEC) and satellite differential code biases (SDCBs) using low-cost receivers
复制标题
使用低成本接收器联合估计垂直总电子含量 (VTEC) 和卫星差分码偏差 (SDCB)
DOI：
10.1007/s00190-017-1071-5
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发表时间：
2018-04-01
影响因子：
4.4
通讯作者：
Li, Min
中科院分区：
文献类型：
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作者：
Zhang, Baocheng;Teunissen, Peter J. G.;Li, Min
利用全球导航卫星系统（GNSS）数据估算垂直总电子含量（VTEC）参数对于电离层探测具有重要意义。卫星差分码偏差（SDCB）是一种误差源，如果不加以校正，则会使定位、定时和其他应用的性能恶化。从双频GNSS数据估计VTEC沿着SDCB的常规方法（下文称为DF方法）由两个连续步骤组成。第一步是通过载波-码调平技术获取电离层观测数据。该观测值与沿卫星接收器视线沿着的倾斜总电子含量（STEC）有关，也受到SDCB和接收器差分码偏置（RDCB）的偏置。第二步，利用电离层薄层模型，将VTEC、SDCB和RDCB从电离层观测量中分离出来。在这项工作中，我们提出了一个单频（SF）的方法，使联合估计的VTEC和SDCB使用低成本的接收机;该方法也基于两个步骤，并且其与DF方法的不同之处仅在于第一步骤，在第一步骤中，我们转向精确点定位技术以从单频GNSS数据中检索电离层可观测量，解释为STEC的组合，SDCB和枢轴时期的偏置接收器时钟。我们的数值分析澄清SF的方法时，被应用到一个单一的接收机在平静和扰动电离层条件下收集的GPS L1数据执行。天顶VTEC估计的每日时间序列具有从TEC单位（TECU）的十分之几到大约2 TECU的范围的准确度。对于观测到的73-96%的GPS卫星，SDCB的每日估计值与欧洲轨道确定中心公布的地面实况值的绝对值偏差不超过1 ns。
Vertical total electron content (VTEC) parameters estimated using global navigation satellite system (GNSS) data are of great interest for ionosphere sensing. Satellite differential code biases (SDCBs) account for one source of error which, if left uncorrected, can deteriorate performance of positioning, timing and other applications. The customary approach to estimate VTEC along with SDCBs from dual-frequency GNSS data, hereinafter referred to as DF approach, consists of two sequential steps. The first step seeks to retrieve ionospheric observables through the carrier-to-code leveling technique. This observable, related to the slant total electron content (STEC) along the satellite–receiver line-of-sight, is biased also by the SDCBs and the receiver differential code biases (RDCBs). By means of thin-layer ionospheric model, in the second step one is able to isolate the VTEC, the SDCBs and the RDCBs from the ionospheric observables. In this work, we present a single-frequency (SF) approach, enabling the joint estimation of VTEC and SDCBs using low-cost receivers; this approach is also based on two steps and it differs from the DF approach only in the first step, where we turn to the precise point positioning technique to retrieve from the single-frequency GNSS data the ionospheric observables, interpreted as the combination of the STEC, the SDCBs and the biased receiver clocks at the pivot epoch. Our numerical analyses clarify how SF approach performs when being applied to GPS L1 data collected by a single receiver under both calm and disturbed ionospheric conditions. The daily time series of zenith VTEC estimates has an accuracy ranging from a few tenths of a TEC unit (TECU) to approximately 2 TECU. For 73–96% of GPS satellites in view, the daily estimates of SDCBs do not deviate, in absolute value, more than 1 ns from their ground truth values published by the Centre for Orbit Determination in Europe.