WASHINGTON (AP) - The Pentagon is close to awarding Boeing Co. or Lockheed Martin Corp. a contract worth roughly $1 billion to design and build a radio system connecting aircraft, ships and ground stations militarywide.

The deal, which is expected late Friday, could lead to the installation of tens of thousands of radios and ultimately be worth billions to the contract winner.

The award is a key piece of the Joint Tactical Radio System (JTRS), a major Defense Department program to replace much of the military's existing radio equipment with radios that will let Army, Navy, Air Force and Marine troops communicate. The new system will be able to transmit video and other data and as well as conversations.

Loren Thompson, a defense analyst and consultant based in Virginia, said he believes Lockheed has an edge over Boeing because of problems with an earlier Boeing contract for another key piece of the Joint Tactical Radio System.

"This is the digital backbone for all future military communications," said Thompson. "Eventually, it will enable any warfighter anywhere in the world to talk to any other warfighter in a split second."

Different branches of the military purchased so many different radio systems on a haphazard basis, many of the radio systems are not compatible - or "interoperable" - right now, Thompson explained. In some cases, he noted, military radios cannot even communicate with other radios inside the same service.

There are at least two dozen types of incompatible radio systems now in the field, Thompson estimated. That often forces troops to carry multiple radios with them, he said.

The new contract is for the "airborne, maritime and fixed site" piece of the JTRS program - much of which falls under the umbrella of the Air Force and Navy. It will upgrade radios on C-130 and C-5 transport aircraft, C-17 airlifters, Global Hawk and Predator unmanned aerial vehicles, Apache helicopters and Osprey tiltrotor vertical/short takeoff and landing aircraft.

It will also produce radios for surface ships and subsurface ships, including aircraft carriers, cruisers, destroyers and several amphibious vessels.

The goal is to connect "everything from the foxholes to high altitude," said Glenn Kurowski, who heads up the Lockheed team competing for the deal.

Boeing already holds the contract for another key piece of the JTRS program, supplying ground mobile radios, which are used primarily by the Army and Marines. Cost overruns, scheduling delays and technical hurdles forced the restructuring of that award several years ago, but a Boeing spokesman stressed that the program is now on track.

Thompson noted that the new radio system is critical to the success of Future Combat Systems, a massive Army modernization effort that will use futuristic communications technology to link manned and unmanned aircraft and vehicles in real time. Boeing is one of the lead contractors on that program.