Time clocks and Latency

Does anyone have information on the latency between the GPS timestamp in the message and the time
a) the message is sent out
b) Ideas on how to look at the the time lag until it is received.
c) is the Edison’s clock set via GPS time?

I’m working on a project to provide both GPS and IMU data out of the reach. My approach is to have the Reach send the GPS data to itself over I use a python script to monitor the port and capture the message when it comes it. Then I a custom string that contains IMU data (via same script, running the IMU sampling at 100 Hz) and then combine both GPS+IMU sentences and send back out. What I don’t have a good feel for, is how closely correlated are the GPS and IMU data when I do it this way?

The IMU is running at 100 Hz and I can capture, create and send the new sentences in 1-2ms. I’m expecting the communication in and out will create measurable delay, but not sure how to test.

Also, I did a small routine where I captured the Edison’s time clock (python script using time.time()) and compared to the timestamp when the GPS RMC/GGA message is received. This is showing there is approx 100 ms delay, but I don’t know how accurate the Edison’s clock is vs GPS time.

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