ARKit: What is ARFrame.timestamp?

Question

In ARKit, ARFrame.timestamp is TimeIntervalwith values ​​such as

185726.884258291
185726.91759425
185726.950930291
...

I want to get the unix timestamp from these values, but they do not look familiar. What do these numbers represent?

Answer 1

These numbers represent uptime at the time of frame capture; see it yourself, causing

NSTimeInterval systemUptime = [[NSProcessInfo processInfo] systemUptime]; 

Ways and thoughts on converting it to a Unix timestamp .