The Air Force's first Global Positioning System Block IIF satellite is progressing on schedule through its on-orbit checkout phase, USAF space officials
announced Monday. The satellite was
launched into orbit in May and is about halfway through its 90-day checkout period, said GPS officials with the Space and Missile Systems Center at Los Angeles AFB, Calif. They said the satellite is currently broadcasting the same L1 and L2 navigation signals as previous GPS satellites as well as the new L5 safety-of-life signal. They are monitoring the quality and characteristics of the signals and the satellite's overall performance. Tests done by German researchers showed that, while the three signals are operating nominally, there are higher residual errors than expected. GPS officials are investigating the root cause. They think it may be due to the satellite's sensitivity to changes in its thermal environment.
