The OS usually suspends apps in the background to save system resources like battery life, memory, CPU power etc. This is good - your phone/laptop battery would likely die a lot quicker without it.
The OS usually allows for some specific exceptions for specific purposes like GPS tracking, audio playback etc. but these are usually done in as limited a way as possible, e.g. only allowing a predefined audio track to play and trying not to actually wake the app as long as possible. So even in these cases, usually the app is still not actually running continually in the background. If you open the app and it has a log of things that happened while it was in the background, it might look like it was running in the background, but in reality it wasn't - it probably did something like obtain the log from the OS upon reopening the app.
This is a common question - people often ask how to make their apps run continually in the background, but the reality is modern apps don't do that, even if they look like they do.
Construct doesn't have a built-in feature to track GPS over time (it's an unusual feature for a game). Perhaps there's a third-party addon that can do it though. You may have to jump through various privacy/security hoops to get the app published though, as tracking people's location over time is a highly sensitive privacy issue.