Lockheed Martin GPS Block III (Vespucci)
Lockheed Martin · Navigation Satellite Constellation / Global Navigation Satellite System (GNSS) · USA · Digital Age (2010–present)
The GPS Block III (nicknamed Vespucci) is the third-generation US GPS satellite constellation — Lockheed Martin's principal next-generation positioning + navigation + timing satellite. Lockheed Martin developed GPS Block III in 2008-2018 to replace the aging Block IIA + IIR satellites with much-improved positioning accuracy + anti-jamming + L1C civil channel. First launch: GPS III SV01 (Vespucci) on 23 December 2018 aboard a SpaceX Falcon 9. About 10 Block III satellites have been launched as of 2026; the planned full constellation is 32 satellites by 2030.
The GPS Block III satellite (built at Lockheed Martin Waterton facility) carries multiple PNT (positioning + navigation + timing) payloads. Mass: 3,800 kg in orbit, 4,400 kg at launch. Orbit: medium Earth orbit (MEO) at 20,200 km altitude, 55° inclination, 12-hour period. Performance: 3× better positioning accuracy than Block IIR-M (~30 cm vs 1 m horizontal CEP), 8× better anti-jamming + spoofing resistance, + new L1C civil channel interoperable with Galileo + GLONASS + BeiDou. Design life: 15 years (vs Block IIR's 10 years). Payload: 6 atomic clocks (4 rubidium + 2 hydrogen maser), L1 + L2 + L5 navigation transmitters, L1C civilian broadcast, secure military M-code transmitter.
GPS Block III service began in 2018 + has progressively replaced older satellites as they fail or retire. Block III satellites broadcast the new L1C public broadcast (compatible with Galileo + BeiDou + GLONASS — the first interoperable worldwide public PNT signal) + the M-code military channel (high-power, anti-jamming + spoofing-resistant). The 2022-onwards Russian + Chinese GPS-jamming + spoofing in Ukraine + the Black Sea region demonstrates the wartime importance of the Block III's improved anti-jamming. Lockheed Martin is also developing the Block IIIF follow-on (with even-higher-power M-code + commercial-position services). The full Block III + IIIF constellation will operate through ~2045.
Variants
- Block III (2018-present)
- Current variant. 32-satellite constellation goal.
- Block IIIF (2026+ planned)
- Follow-on with higher-power M-code + LADGNSS.
Notable Operators
- US Space Force (2018-present)
- Sole operator. Schriever AFB control segment.
Frequently Asked Questions
What is the L1C signal + why does interoperability matter?
The L1C is a new public GPS channel introduced with GPS Block III, broadcast at the L1 frequency (1575.42 MHz) using a structure interoperable with Europe's Galileo, China's BeiDou, + (when added) Russia's GLONASS K-2 satellites. Public + commercial receivers (including smartphones from 2025+) can use broadcasts from any of the constellations simultaneously — providing 3-4× more visible satellites + dramatically-improved positioning in urban + canyoned environments + better integrity monitoring. Interoperability matters because (1) it improves public + commercial PNT performance + safety (e.g. self-driving cars + drones), + (2) it provides automatic redundancy if any one network is jammed or fails. Aerospace + automotive industries have advocated for + designed-around L1C compatibility since the 2010s.