The 50,000-square-foot, two-story headquarters building of PE Systems Inc. at 5520 Cherokee Ave. in Springfield is expected to be completed in January.

Funding for the project was provided through the Fairfax County industrial revenue bond program. The Mason Hirst Companies of Annandale is the developer.

The corporate offices of PE Systems, a high-tech research and development firm, will occupy 42,000 square feet of the building.

Terminal Data Corp., a California-based manufacturer and developer of high-tech imaging systems, will occupy 1,800 square feet of the PE building. The remaining square footage is available for lease.

The PE Systems Building is the first phase in the planned development of Mason Hirst's Cherokee Business Center. Construction on further phases is expected to begin in 1984.

Other recent developments in commercial realty in the Washington metropolitan area:

* Babcock and Wilcox Computer Services has leased 2,393 square feet of space at the Park Place Building at 7926 Jones Branch Drive in McLean.

* The D.C. Department of the Disabled has leased about 12,000 square feet of space at 1120 G. St. NW. The long-term lease has an aggregate rental value of about $1.1 million.

* The D.C. Department of Health and Human Services has leased about 71,000 square feet of space at 425 I St. NW. The long-term lease has an aggregate rental value of about $4 million.

* Robert Basil International, an international consulting firm, has leased about 6,500 square feet of space at 1275 K St. NW. The long-term lease has an aggregate rental value of about $1.5 million. The law firm of Hyatt & Rhodes has leased about 6,000 square feet at the same address. The long-term lease has an aggregate rental value of about $1.4 million.

* Safware Inc. has leased 10,000 square feet of warehouse space at the Kossow Warehouse Center at 3800 West St. in the Ardmore/Ardwick Industrial Park in Landover.

* Savin Corp. has leased about 25,000 square feet of space at 2098 Gaither Road in Rockville. The aggregate rental value of the long term lease is about $3.3 million.