Time information

Dear all,

I'm running INS app with u-blox zed f9P (NMEA protocol) and openimu 300ZI eval kit (also connecting 1PPS).
The output from IMU in .csv format has the first two columns that regard time information, namely TimeCntr and Time. Can anyone explain what these times are referred to?
This is useful if one want to fuse data in postprocessing with another KF (some time reference or time stamp to sinchronize GPS data and IMU sensors readings is needed).

Hope someone can help me.

Thanks

Matteo

UPDATE:
I was able to understand what those columns mean: specifically they are the time from which the board was powered on.
Thus, there Isn't a way ti sinchronize in post Mission the IMU output and GPS positions.
How can I add a columns to the CSV file in order to have a time reference to fuse data?
TOW( time of week) should be a good
way and, diggin into the code It seems that is already computed by the INS app so I should Just take It and print It into the CSV. How can I do It?

UPDATE 2:
I understood data in some packets like a1 ITOW is already written in the csv.
In order to make the app write it also in packet e2 (the packet in the INS app) I've just to modify the json file or something else?