Two companies with private satellites are eyeing each other for acquisition.

Longmont-based DigitalGlobe says it has rejected an unsolicited acquisition proposal from GeoEye Inc. but disclosed that it has previously offered to buy its rival.

GeoEye, which is based in Herndon, Va., announced Friday it had made a $792 million offer for DigitalGlobe.

A combined company would create the world’s largest fleet of high-resolution earth-imagery satellites.