Generates a GPS L1 C/A baseband I/Q file from a RINEX broadcast ephemeris and a chosen static or moving position, for transmission by an SDR (HackRF / bladeRF / USRP). Because civilian C/A is unauthenticated, a replayed/synthesised signal at higher power can pull a receiver's position and clock to attacker-chosen values — the canonical GPS spoofing tool. AUTHORIZED, RF-CONTAINED testing only: transmitting GPS over the air is illegal in most jurisdictions — use a shielded enclosure or a cabled (conducted) setup. Repo is archived but remains the de-facto reference.