In the 2007 movie “The Bourne Ultimatum,” the CIA’s New York anti-terrorism office remotely tracks targets across Europe by monitoring radio-frequency signals emitted by cell phones. With a few taps of a computer keyboard, CIA agents identify calls made in real time, locate the phone and use it to track the caller to a specific hotel room.

That scenario is now technically feasible and could play out in the real world if companies succeed in marketing the technology for homeland security, national defense and law enforcement.

The concept can be traced to the mid- to late-1990s, when the U.S. Federal Communications Commission began requiring the American telecommunications industry to equip their networks with a capability to locate emergency 911 calls from wireless phones. Since then, a handful of mobile-location technology companies have emerged to help the carriers satisfy that public-safety mandate, known as Enhanced 911 (E911). Now, those companies are seeking to push the technology into new areas.

Within the past year, several information-technology companies have rolled out wireless location-intelligence systems that they say could help government agencies track terrorists, monitor borders and protect critical infrastructure such as power plants. These new systems combine the underlying E911 mobile-location technology with computer data-mining and data-analysis software capable of tracking the use and location of cell phones and other wireless devices in real time and over extended periods. They could be deployed by the government to create virtual electronic “geofences” along border territories or around buildings, alerting authorities if unauthorized cell phones penetrate into specified secure zones. In addition, they might offer the Pentagon a new tool, helping the military in Iraq and Afghanistan identify cell phones used to detonate improvised explosive devices.

The potential goes far beyond E911. “We can stretch that system by adding more processes and more applications so that not only can you locate people who need help, you can use it to locate the bad guys and potentially prevent crime,” said Bhavin Shah, director of marketing and business development for Polaris Wireless, a Silicon Valley technology firm.

Polaris’ system relies on software that analyzes the signature of incoming radio signals to pinpoint a caller’s location to within about 50 meters — currently an industry standard. Another company, Berwyn, Pa.-based TruePosition, mounts a small device on cell phone towers to measure the traveling distance of incoming radio signals and plots a caller’s latitude and longitude through a process of triangulation. Both systems must be connected to a carrier’s network. Cell phones also can be tracked by Global Positioning System chips installed in the handsets, but that method is less dependable because users can manually disable the locator chip and GPS signals can be unreliable indoors and in urban areas.

The new network-based technology also has limits. The mobile-location systems monitor a cell phone’s location by the radio signals it constantly emits to maintain connections to cell towers — even when it’s not being used. The phone must stay in contact with the towers so it is ready to make a call or send a text message. A terrorist who wanted to avoid detection could simply turn off the phone. A suspect also could throw off investigators by slipping a cell phone into the pocket of an innocent bystander.

“There is no silver bullet in the world of security,” said Dominic Li, TruePosition’s vice president of marketing and portfolio management. “We position our solution always as part of a layered defense.”

Because the systems are so new, there has been little public discussion about installing them for U.S. domestic security. A congressional staffer for a House committee that oversees homeland security issues such as border protection and critical infrastructure said the panel has not been briefed on the technology.

Since the systems could track large numbers of cell phone users, their use by the U.S. government could raise thorny legal issues involving personal privacy rights. Besides that potential obstacle, installation of the systems would require a high level of cooperation between government agencies and the private telecommunications industry. Currently, commercial carriers such as T-Mobile, AT&T, Verizon and Sprint operate their networks on different radio frequencies and use different systems to locate E911 callers. To be effective for national security purposes, the new mobile-location systems would need to connect to all of the wireless carriers, creating an interoperable system in which authorities could track phones regardless of which carrier provided the service. “It would take some real coordination, but sure it could be done,” said George Marble, a director of business development for Andrew LLC, the mobile-location division of CommScope of Hickory, N.C.

Faced with those logistics and potential privacy issues, Polaris and TruePosition initially are pursuing security markets in the Middle East and Asian Pacific. They declined to discuss potential customers, but Li said governments in those regions are interested in bolstering security around oil refineries, water-treatment plants and heavily traveled border areas. In many cases, those governments control their countries’ telecommunications networks, which makes negotiations less complicated. Also, privacy laws are either nonexistent or less strict than U.S. laws. “From a political stability standpoint and bombings, they’re more interested in these solutions,” Shah said.

Before the technology is deployed in the U.S., it should be field tested in a few high-value-target areas, such as New York City or Washington, D.C., said Mark Kagan, a research manager for Government Insights, a Falls Church, Va.-based information and telecommunications technology market research firm. Kagan, who has worked as a consultant to TruePosition, said a pilot project would demonstrate the technology and the costs to install, operate and maintain the system. More important, officials would be able to develop policies governing use by federal law enforcement and security agencies.

“As an analyst, my mantra is that technology is easy, people are hard,” Kagan said. “The technology may be completely proven and fine, but it’s how it’s used and the people who use it that have work things out first.”