Devlin Barrett reports at The Wall Street Journal:

The program cuts out phone companies as an intermediary in searching for suspects. Rather than asking a company for cell-tower information to help locate a suspect, which law enforcement has criticized as slow and inaccurate, the government can now get that information itself. People familiar with the program say they do get court orders to search for phones, but it isn’t clear if those orders describe the methods used because the orders are sealed.