Aerospace Corporation Team Wins Award for

Inventing New GPS Signal Structure

EL SEGUNDO, Calif. (12/7/98) -- Martin Bottjer, Dr. Jack Holmes, Steven Lazar and Dr. Srini Raghavan of The Aerospace Corporation have won a corporate award for inventing a new Global Positioning System (GPS) signal structure that may represent the most significant change in the system since its inception. The new signal structure allows the addition of a new military signal in the same frequency band as the existing signals, while protecting performance for civil users.

For their work they received a President's Achievement Award at an annual convocation which recognizes technical achievements. Presenting the award on Sept. 24 was Aerospace President Edward C. "Pete" Aldridge, Jr.

For years before their invention the GPS community had been unable to find a solution for the next GPS upgrade that would satisfy the growth requirements of civil and military users while retaining a national military advantage during times of war.

According to the award citation, the team invented, analyzed and demonstrated a new modulation scheme based on Manchester coding (Tricode Hexaphase Modulation) that fully satisfies these requirements without the use of additional radio-frequency (RF) spectrum and maintains compatibility with existing GPS receivers.

The team's innovative work relieved the government and industry of the search for a new frequency band and focused attention on the efficient use of existing frequency allocations, the citation stated.

The team members are all recognized innovators in the field of communications electronics and RF circuits.

Bottjer is a senior member of the technical staff in the Microwave/Millimeter-Wave Electronics office, Engineering and Technology Group (ETG). He joined The Aerospace Corporation in 1962. He attended

Hofstra College and the U.S. Air Force Electronics School.

Holmes and Raghavan are senior engineering specialists in ETG's Communication Systems Subdivision.

Holmes joined The Aerospace Corporation in 1991. He earned B.S., M.S., and Ph.D. degrees in electrical engineering from UCLA.

Raghavan came to The Aerospace Corporation in 1986. He attended Osmania University in India, earning bachelor's and master's degrees in electrical engineering, and the University of Missouri-Rolla, earning M.S. and Ph.D. degrees in electrical engineering.

Lazar, a senior project engineer in the GPS System Development and Engineering Directorate, Space Systems Group, joined The Aerospace Corporation in 1979. He received bachelor's and master's degrees in electrical engineering from UCLA.