We introduce a new bistatic synthetic-aperture imaging method for a radar system consisting of two receivers, which will be referred to as hitchhikers, and a source of opportunity. We assume the receivers y along arbitrary, but known, ight trajectories. We develop a correlation-based ltered-backprojection reconstruction method that preserves the visible edges of the target scene in the reconstructed image. We present an analysis of the computational complexity of the introduced method and demonstrate its applicability in numerical simulations. Potential applications of the proposed method include image formation using low earth orbiting and space-borne satellites as sources of opportunity.