The Analytic Sciences Corp., a high-tech strategic planning and analysis company that provides consulting services to the federal government, broke ground last month for their new office at the Reston Executive Center.

The company, which has headquarters in Reading, Mass., has offices in McLean and Rosslyn. When the new building is completed in June 1988, employes from the McLean office will relocate there. About 600 people will be employed at the Reston site, a company spokesman said.

The six-story building, to be located at 12100 Sunset Hills Rd., is the first phase of construction at the Reston Executive Center. When completed, the office park will span 13.8 acres and will include more than 420,000 square feet of space divided among three buildings. The office park is being developed as the gateway to the planned Reston Town Center.

Centennial Development Corp. is the developer. Weihe Partnership, a Virginia architectural firm, designed the buildings. Centennial Contractors is the general contractor.

Annual lease rates for the remaining two buildings, which will be leased for single-tenant use, are expected to be about $22 per square foot. Construction on those buildings is slated to begin in October. Centennial expects to complete the Reston Executive Center in late 1989, a company spokesman said. The project's cost was not disclosed.

In other developments in commercial realty:

Arbitron Ratings Corp., a national audience-measurement firm, leased 62,380 square feet at the Ammendale Commerce Center in Beltsville.

MetPath Inc., a clinical laboratory testing company, leased 44,500 square feet at 1550 East Gude Dr., Rockville, from B.F. Saul Co.