Estimation of total electron content using GPS data: How stable are the differential satellite and receiver instrumental biases?
Estimation of total electron content using GPS data: How stable are the differential satellite and receiver instrumental biases?
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DOI：
10.1029/97rs01457
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发表时间：
1997-09
期刊：
影响因子：
1.6
通讯作者：
E. Sardón;N. Zarraoa
中科院分区：
文献类型：
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作者：
E. Sardón;N. Zarraoa
在从双全球定位系统（GPS）数据估计TEC（总电子含量）的误差的主要来源是差分卫星和接收器仪器延迟偏差的影响。这些偏差通常与TEC同时估计。然而，仪器偏差的附加估计在某些实际应用中可能构成难以克服的负担，例如TEC的真实的时间估计，或者估计可能是困难的或与电离层参数相关，特别是在TEC行为可能难以建模的情况下（赤道或极光区，电离层风暴等）。如果我们能够确定工具偏差在时间上的稳定性以及我们需要检查或重新估计其值的频率，那么在良好条件下或通过全球网络估计的工具偏差的先验值可以解决这些问题。在本文中，我们将提出我们的GPS卫星和接收机仪器偏差的估计，从19个月的数据和研究他们在这段时间内的变化。我们还将展示一些情况下的变化，在仪器的偏见和可能的影响，antispoofmg（AS）。本文的主要结论是：在19个月的时间里，GPS卫星差分偏差的变化在大多数情况下小于1 ns（1 ns = 2.86 × 1016 e/m2），平均RMS为0.15ns。对于所使用的全球定位系统接收器，这种变化大于卫星，较大的变化对应于接收器的物理变化。在连续两天之间估计的差分仪器偏差的差对于GPS卫星在几乎所有情况下都小于0.5ns，对于GPS接收器小于1 ns。关于AS的影响，我们已经检测到一些卫星和一些站的仪器偏差的一些显着的变化是否激活AS。我们的主要结论是，由于GPS仪器偏差的稳定性，只有估计或校准他们（在最佳条件下）不时需要。
The main source of error in the estimation of TEC (total electron content) from dual Global Positioning System (GPS) data is the effect of the differential satellite and receiver instrumental delay biases. These biases are normally estimated simultaneously with the TEC. However, the additional estimation of the instrumental biases may constitute an insurmountable burden in some practical applications like real‐time estimation of TEC, or the estimation may be difficult or correlated to the ionospheric parameters, particularly in situations where the TEC behavior may be harder to model (equatorial or auroral zone, ionospheric storms, etc.). A priori values of the instrumental biases, estimated under good conditions or with global networks, could solve those problems if we could determine how stable those instrumental biases are in time and how often we need to check or reestimate their values. In this paper we will present our estimation of the GPS satellite and receiver instrumental biases from 19 months of data and the study of their variation during that time. We will also show some situations of changes in the instrumental biases and the possible influence of antispoofmg (AS). The main conclusion of this work is that the variation of the estimated differential GPS satellite biases during the 19 months is smaller than 1 ns (1 ns = 2.86 × 1016 e/m2) in most of the cases, with a mean RMS of 0.15 ns. For the GPS receivers used, that variation is greater than for the satellites, with the larger variations corresponding to physical changes in the receivers. The difference of the estimated differential instrumental biases between two consecutive days is in practically all cases smaller than 0.5 ns for the GPS satellites and smaller than 1 ns for the GPS receivers. Regarding the influence of AS, we have detected some significant changes in the instrumental biases of some satellites and some stations whether AS is activated or not. Our main conclusion is that due to the stability of the GPS instrumental biases, only an estimation or calibration of them (under optimal conditions) from time to time is required.