As you said, in all that mess it's not likely someone had a pager at arm's reach, and from the very few appearances of Captain Marvel in the movie, we know she's zooming around in space to saves various planets.
That requires a way to detect these planets being threatened to begin with. We see at the beginning that "mere" human tech was able to detect the power surge of the Stones being destroyed some millions of kilometers away. In her solo movie, Kree tech was already far more advanced than our own, if you add to that 25 years of progress, and perhaps some Skrull scientists friends, she likely has such a sensor miniaturised and embedded in her suit.
Furthermore, she's part of the gang now and bossed by Black Widow. It's possible, before the Time Heist, that Natasha left instructions to her in case not everyone came back. Or Carol could have just been back for some kind of regular report, or was wondering no one was answering her calls.
Note that her sense of timing was already shown at the beginning of the movie, when she saves Tony and Nebula, without a clear-cut explanation of how she knew where they were.