C4iSR: Joint & Common Equipment

GPS III brings new capabilities to space-based navigation

20 December 2018

The US Air Force (USAF) plans to soon launch the first satellite of its next-generation Global Positioning System III (GPS III) position, navigation, and timing (PNT) constellation.

The satellite was to be launched on 17 December from Florida's Cape Canaveral aboard a SpaceX Falcon 9, but that launch was scrubbed. A second attempt to launch the satellite on 18 December was also halted. According to SpaceX, the launches were delayed "to further evaluate an out of family reading on first stage sensors".

The first Lockheed Martin-built GPS III satellite packed for shipping to Cape Canaveral, Florida. (Lockheed Martin)The first Lockheed Martin-built GPS III satellite packed for shipping to Cape Canaveral, Florida. (Lockheed Martin)

A new launch date would be confirmed once the evaluation is complete, SpaceX said.

GPS III-1 is the first of a planned 32-satellite constellation to be placed into orbit over the next two decades. GPS III-1 represents the first of an entirely new design of GPS satellite meant to help the USAF modernise the legacy GPS constellation with new technology and advanced capabilities. GPS III is to have three-times better accuracy and up to eight-times improved anti-jamming capabilities, according to prime contractor Lockheed Martin.

GPS III also includes a new military code (M-Code) designed to enable military receivers to operate closer to jammers and under trees, enhancing their ability to track the GPS satellites, support a more secure and flexible cryptography architecture, detect and reject false signals, and provide higher power with comparable availability and accuracy improvements.

The GPS III programme also provides navigation and timing to a broad spectrum of civil users, which will include the three civil signals (L1C/A, L2C, and L5) flown on previous satellites. It will also transmit a new fourth civil signal, L1C, which is compatible with the European Galileo satellite navigation system signal. L1C is compatible with those signals planned for broadcast on Japan's Quazi-Zenith Satellite System (QZSS): a system meant to augment GPS services.

Once implemented, the common civil signal will be jointly broadcast by up to 60 satellites from GPS and Galileo constellations, further increasing the accuracy and availability of user PNT solutions.

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