A new technique for mapping of total electron content using GPS network in Japan

By Yuichi Otsuka, T. Ogawa, A. Saito, Takuya Tsugawa, S. Fukao, S. Miyazaki. 2002

307 citations recorded by the source corpus.

The dual frequency radio signals of the Global Positioning System (GPS) allow measurements of the total number of electrons, called total electron content (TEC), along a ray path from GPS satellite to receiver. We have developed a new technique to construct two-dimensional maps of absolute TEC over Japan by using GPS data from more than 1000 GPS receivers. A least squares fitting procedure is used to remove instrumental biases inherent in the GPS satellite and receiver. Two-dimensional maps of absolute vertical TEC are derived with time resolution of 30 seconds and spatial resolution of 0.15° × 0.15° in latitude and longitude. Our method is validated in two ways. First, TECs along ray paths from the GPS satellites are simulated using a model for electron contents based on the IRI-95 model. It is found that TEC from our method is underestimated by less than 3 TECU. Then, estimated vertical GPS TEC is compared with ionospheric TEC that is calculated from simultaneous electron density profile obtained with the MU radar. Diurnal and day-to-day variation of the GPS TEC follows the TEC behavior derived from MU radar observation but the GPS TEC is 2 TECU larger than the MU radar TEC on average. This difference can be attributed to the plasmaspheric electron content along the GPS ray path. This method is also applied to GPS data during a magnetic storm of September 25, 1998. An intense TEC enhancement, probably caused by a northward expansion of the equatorial anomaly, was observed in the southern part of Japan in the evening during the main phase of the storm.

Subfields: Aerospace Engineering, Astronomy and Astrophysics, Geophysics

View Paper: https://www.semanticscholar.org/paper/e4e183de5da1727f78fc71b5e0568b69791f5be9

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Citations in the corpus

Ionospheric disturbances detected by GPS total electron content observation after the 2011 off the Pacific coast of Tohoku Earthquake (2011, methodology): “The absolute TEC values were derived applying a technique in which a weighted-least-square fitting is used to determine unknown instrumental biases, assuming that the hourly TEC average 875 is uniform within the area covered by a given GPS receiver (Otsuka et al., 2002).”
Derivation of TEC and estimation of instrumental biases from GEONET in Japan (2002, methodology): “Our method is different from that of Otsuka et al. (2002) in that along with the TEC, both the satellite and the receiver biases can be obtained.”
Calibration errors on experimental slant total electron content (TEC) determined with GPS (2007, methodology): “…IFB, the spatial and temporal variability of sTEC is represented by means of a variety of approaches (e.g., Ma et al. 2005, Brunini et al. 2003, Otsuka et al. 2002, Jakowsky et al. 1996), while IFB are assumed to be constant for a given period of time, usually 1–3 days (Bishop et al. 1994,…”