First, your cell phone sends out a radio-frequency signal to the towers within a radius of up to roughly twenty miles—or fewer, in urban areas—depending on the topography and atmospheric conditions.
A regional switching center detects the signal and determines whether to accept the call. There are hundreds of such regional centers across the country. The switching center determines the destination of your call and connects to the land lines that will take it to cell towers near the destination.
What does it mean?
The selection is determined by load-management software that incorporates dozens of factors, including signal strength, atmospheric conditions, and maintenance schedules. The system is so fluid that you could sit at your desk, make five successive cell calls and connect to five different towers. Designed for business and not tracking, call-detail records provide the kind of information that helps cell companies manage their networks, not track phones. Hypothetically, the system might send me to the next site, which might also be at capacity or down for maintenance, or to the next site, or the next.
The only thing that you can say with confidence is that I have connected to a cell site somewhere within a radius of roughly twenty miles. Aaron Romano, a Connecticut lawyer who says that he has seen many cases involving cell records, has done a series of calculations to show how imprecise these locations can be. Cell-tower coverage is divided into sectors. Most towers have three directional antennae, each of which covers one third of the circle.
Cell phone data plays growing role in police investigations
Including that factor gives you a sector of Some technologies can locate you precisely. You enable the G. They also use that technique when trying to find a kidnapping victim. When investigating a crime that occurred in the past, police tend to have two options: seize the G.
5 Ways Cell Phones Can Help Stop Crime
But the case law on getting cell-tower information is split. In most jurisdictions, police can obtain your call-detail records without a warrant. The disparity in requirements between the two could encourage police to rely increasingly on call-detail records, Hanni Fakhoury, a staff attorney for the Electronic Frontier Foundation, said.
Yet prosecutors often present those records as if they were DNA. A few years ago, the F. Cellular Analysis and Surveillance Team , with the mission of analyzing cell-location evidence. The Bureau declined requests for an interview, but C. The main difference between a search warrant and the court orders used in Carpenter is that a warrant requires a higher threshold of proof that a government search will result in evidence related to a crime.
To get a signal so it can make or receive a call, a cell phone establishes a radio connection with a nearby tower called a cell site. As the user moves, the device constantly scans for nearby towers for the strongest signal. Carriers also track the numbers involved, and the cell sites where a call began and ended.
As people continue to use their devices to send and store more sensitive data—about their finances and health records, for example—the courts must make sure law enforcement is held to the probable cause standard required to obtain a warrant, Wessler said. A recent Supreme Court case— United States v.
Jones —determined that law enforcement needed a search warrant to use a tracking device. In another related case— Riley v.
rarocpyapo.tk California —the court determined that officers needed a search warrant to examine the contents of a cell phone. Courts have interpreted the third-party doctrine to mean that, by sharing information or records with a company or some other organization, a person gives up any reasonable expectation that the information will remain private.
More likely, Cate adds, the court will limit its discussion and decision specifically to stored data, because that is what is most relevant to the Carpenter case. Larry Greenemeier is the associate editor of technology for Scientific American , covering a variety of tech-related topics, including biotech, computers, military tech, nanotech and robots. You have free article s left.
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