to create the edited file:

999999 was replaced with 9999 → control point near camp
the last 3 reading as listed on station 2250, were actually from 2300


Now the bigger issues is that the lat long was not set properly at the start of the day.
It was corrected on station 2100

The proof of concept.xls shows that ETC can be generated very close to the originals based off of the given lat long and UTC time
Then FWD-20190625_CG-6_ETC_corrected.csv was made that has the proper ETC