Ionosphere
============================= ionodef.txt ===================================
This file defines the columns of data in the iono.log files produced by the
GRID software receiver. Each iono.log file contains time-stamped ionospheric
measurements. See channeldef.txt for a definition of ORT. ORT time stamps
indicate approximately the time at which the measurements apply.
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Column Quantity
1 ----------- ORT week number.
2 ----------- ORT whole seconds of week.
3 ----------- ORT fractional second.
4 ----------- Pseudorange-derived slant total electron content (STEC) along
the path from the receiver to the transmitter, in TEC units
(TECU).
5 ----------- Change in phase-derived STEC since the previous measurement, in
TEC units (TECU).
6 ----------- Transmitter identification number (TXID).
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