My earliest memory of reading about a person being so tracked was the murder of well-known cocaine hci trafficker Paublo Escabar. As that was about 15 years ago, that phone likely lacked a gps device, but the police were not only able to determine the location of his cell, but also his location within that cell, by triangulating the strength of the signal. By making a call from his cell phone, Escabar unwittingly sent an electronic signal telling the police where he was, leading to his ambush and death.
Advances in gps technologies, and in related software make the use of cell phones as tracking devices technologically routine as a police officer calling in a drivers license.
Some companies offer this service as a means to track employees and children. As such participation is voluntary as a condition of employment, or for parents to track their children.
Such technologies have other legitimate uses, such as locating people who are lost in undeveloped areas, such as mountain climbers and the family that was snowbound in an automobile which they burned its tires for heat before the father went off to look for help only to die from the cold. However, this would require far greater cell phone coverage – additional towers – either temporary or permanent to locate the cell phone “pings”.