Cape Canaveral, Sep 28 (IANS) The US Air Force has successfully launched a modernised Global Positioning System Block IIR (GPS IIR-M) satellite built by Lockheed Martin, the second in a series of eight such craft.

The spacecraft are the most technologically advanced GPS satellites ever developed and are designed to provide significantly improved navigation performance for the US military and civilian users worldwide, a company statement said.

The satellite will join the first modernised IIR satellite, GPS IIR-14(M), successfully launched and declared operational last year, and 12 other operational Block IIR satellites currently in-orbit in a 29-spacecraft constellation.

"We're proud of our partnership with the US Air Force in delivering unparalleled navigation capabilities to GPS users around the globe," said Don DeGryse, Lockheed Martin's vice president of Navigation Systems.

"We look forward to executing a successful in-orbit checkout so that this spacecraft can be quickly placed into operational service."

The GPS IIR-M spacecraft offer a variety of enhanced features for GPS users, such as a modernised antenna panel that provides increased signal power to receivers on the ground, two new military signals for improved accuracy, enhanced encryption and anti-jamming capabilities for the military, and a second civil signal that will provide users with an open access signal on a different frequency.

The US Air Force Space Command's 2nd Space Operations Squadron (2SOPS), based at Schriever Air Force Base in Colorado, manages and operates the GPS constellation for both civil and military users.

Lockheed Martin is also leading a team competing to build the next-generation Global Positioning System, known as GPS Block III. The new programme will address the challenging military transformational and civil needs across the globe, including advanced anti-jam capabilities and improved system security, accuracy and reliability.