قُل لَّكُم مِّيعَادُ يَوْمٍ لَّا تَسْتَـْٔخِرُونَ عَنْهُ سَاعَةً وَلَا تَسْتَقْدِمُونَ ٣٠
Say, "For you is the appointment of a Day [when] you will not remain thereafter an hour, nor will you precede [it]."
Your location stays on this device and is only sent, rounded to about 1 km, to fetch the times.