Accuracy analysis of the GPS instrumental bias estimated from observations in middle and low latitudes

Abstract

Abstract. With one bias estimation method, the latituderelated error distribution of instrumental biases estimated from the GPS observations in Chinese middle and low latitude region in 2004 is analyzed statistically. It is found that the error of GPS instrumental biases estimated under the assumption of a quiet ionosphere has an increasing tendency with the latitude decreasing. Besides the asymmetrical distribution of the plasmaspheric electron content, the obvious spatial gradient of the ionospheric total electron content (TEC) along the meridional line that related to the Equatorial Ionospheric Anomaly (EIA) is also considered to be responsible for this error increasing. The RMS of satellite instrumental biases estimated from mid-latitude GPS observations in 2004 is around 1 TECU (1 TECU = 10 16 /m 2 ), and the RMS of the receiver's is around 2 TECU. Nevertheless, the RMS of satellite instrumental biases estimated from GPS observations near the EIA region is around 2 TECU, and the RMS of the receiver's is around 3-4 TECU. The results demonstrate that the accuracy of the instrumental bias estimated using ionospheric condition is related to the receiver's latitude with which ionosphere behaves a little differently. For the study of ionospheric morphology using the TEC derived from GPS data, in particular for the study of the weak ionospheric disturbance during some special geo-related natural hazards, such as the earthquake and severe meteorological disasters, the difference in the TEC accuracy over different latitude regions should be paid much attention.

The nature of GPS differential receiver bias variability: An examination in the polar cap region

“…While several techniques exist for determining these biases, one must take care in their application in regions outside their initial design [Lanyi and Roth, 1988;Ma and Maruyama, 2003;Ma et al, 2005;Rideout and Coster, 2006;Arikan et al, 2008]. Recent studies have attempted to characterize variabilities in these biases estimated through single-station approaches using real data and simulations [Ciraolo et al, 2007;Mazzella, 2009;Zhang et al, 2009;Brunini and Azpilicueta, 2010;Zhang et al, 2010;Conte et al, 2011;Coster et al, 2013]. These studies highlight the need to understand not only the nature of true bias variability but also the impact of the fundamental assumptions made in standard bias estimation techniques on bias estimation.…”

A new short-term forecasting model for the total electron content storm time disturbances

“…In this case, the model's error in terms of both MAE and RMSE is comparable to 3 TECu that in turn, is comparable to the TEC measurement error at middle latitudes (e.g. Zhang et al, 2010 and references therein). Significant improvement (>10%) over climatology is recorded in both cases.…”

Global propagation features of large-scale traveling ionospheric disturbances during the magnetic storm of 7~10 November 2004

“…We used the data with satellite elevation larger than 30 • to minimize the errors caused by converting slant TEC into vertical TEC and the multipath effects. B s r was the main error source of the ionospheric TEC deriving from GPS observation and could reach up to several TECU (1 TECU = 10 16 electrons m −2 ) or even larger than the real slant TEC (Sardón and Zarraoa, 1997;Zhang et al, 2010), and the effect of this biases must be removed to get the absolute measurements of TEC. Here, we eliminated the B s r by combining the vertical TEC time series (VTEC) with the JPL GIM data which was interpolated in both space and time.…”