You'd need unique signature of cell phone signal to separate it from other cell signals In terms of timestamp, when multiple satellites measure different times

You'd need unique signature of cell phone signal to separate it from other cell signals In terms of timestamp, when multiple satellites measure different times of receipt from same cell signal they could reverse compute the location Could probably incorporate differences in received signal strength as well At least thats my guess I don't think you'd wanna use timestamp info from the sender, since you have no control over the accuracy of that, even if it was available