Police chasing suspects on the ground normally use their radios to listen for instructions from helicopter pilots watching from above.

Now, some officers will be able to view exactly what the pilot sees — by tapping their smart phones or personal digital assistants into helicopters’ video feeds. Several local law-enforcement agencies, along with the Department of Homeland Security, have purchased the system, called HT 4Sight, which was developed by the California-based company Helinet.

The product can be used with BlackBerries and Windows mobile devices. The company is also working with Apple to make its software compatible with the iPhone.

“We wanted to get imagery to the officer on the street in an easy way that wouldn’t mean new equipment for everybody,” says Ron Magosci, the company’s chief technology officer. “We’re giving more tools to officers to protect themselves and catch bad guys.”

HT 4Sight also uses the device’s Global Positioning System to allow those at command-and-control centers to track officers, Magosci says. The video feeds are encrypted to prevent outsiders from accessing the streams.

Licensing the product for 200 devices could cost anywhere from $50,000 to $150,000, depending on several factors, including whether agencies will be renting space on Helinet’s server or using their own, Magosci says.