Eleven major defense contractors whose products increasingly depend on sophisticated computer software plan to form a joint research group to study new ways to produce computer programs and explore advanced artificial-intelligence software techniques.

The companies, most of them in the aerospace business, have hired BTG Inc. of Vienna to develop a plan for their venture, which would be similiar to a computer industry research consortium headed by retired admiral Bobby Inman, former head of the National Security Agency.

Participants in the proposed Software Productivity Consortium include TRW Inc., Boeing Co., E-Systems, General Dynamics Corp., Ford Aerospace & Communications Corp., GTE Government Systems Corp., Lockheed Missiles & Space Co., McDonnell Douglas Astronautics Co., Rockwell International Co, United Technologies Corp. and Science Applications International Corp.

"We want to increase software productivity in these companies by orders of magnitude," said V. Edward Jones, a TRW executive based in San Diego who heads the consortium effort.

"If you look at these companies, you see that software's not our major line -- it's not our bread and butter," he said. But most high-technology defense contractors have computers in their products and need sophsticated software to make them work.

Edward H. Bersoff, president of BTG, said particpants in the project he is planing "typically have not had the appropriate resources to spend on software research because they've focused on applications."

Pooling their research resources is a way for these companies to get the economies of scale necessary to make breakthroughs in software technology, he said.

In many respects, the Software Productivity Consortium is similar to Microelectronics & Computer Technology Corp., which is based in Austin, Texas. This 19-corporation computer research and development effort, headed by Inman, went into operation last year after the Justice Department decided not to raise antitrust objections.

TRW's Jones said that the Justice Department has approved the new consortium's effort to create a formal business plan and that many aspects of the software consortium are patterned after the computer initiative. "The final structure will be governed by tax and financial issues," he said.

The SPC is being initially budgeted at close to $1 million and will be in the planning stage through the end of the year. A site for the consortium's headquarters has not yet been selected.

According to Bersoff, the research efforts will focus on hardware and software interface standards, software metrics, knowledge engineering, prototyping and reusable software.

Reusable software refers to computer programs and techniques that can be used on a wide variety of different machines, Bersoff explained. He said that the consortium plans to develop "conversion mechanisms" so that useful software developed on one company's computer system can be transported to another company that uses a different system.

Similarly, the group will do research in the measurement of software productivity -- called software metrics -- and plans to design "knowledge systems" that use sophisticated artificial-intelligence techniques to write computer software.