GPS World, April 2015

Policy and system news and developments GPS Galileo GLONASS BeiDou SYSTEM THE GPS IIF 9 Launch on March 25 A s this magazine went to press on March 19 the U S Air Forces ninth GPS Block IIF satellite GPS IIF 9 was being readied for a March 25 launch The satellite was encapsulated in the Delta IV rockets 4 meter diameter nose cone at a processing facility and moved to the launch pad at Space Launch Complex 37 for mating to its booster inside the mobile service tower Launch is scheduled for March 25 at 2 36 p m U S Eastern time from Space Launch Complex 37 at Cape Canaveral Air Force Station Fla GPS IIF 9 marks the 29th Delta IV launch and the 57th operational GPS satellite to launch on a ULA or heritage launch vehicle Celebrating 20 Years of GPS A pril marks the 20th anniversary of GPS FOC U S Air Force Space Command declared Full Operational Capability FOC for the GPS constellation April 27 1995 signifying the system met all requirements with 24 operational Block II IIA satellites in their assigned orbital slots and providing both the military Precise Positioning Service PPS performance standard and the civil Standard Positioning Service SPS performance standard FOC was formally announced on July 17 1995 CNAV Performance Compares Favorably to Legacy Signals A March 5 announcement concerning the new L2C and L5 GPS civil signals states CNAV Message Types 10 11 30 and 33 are currently transmitted on seven GPS IIR M L2C and eight GPS IIF satellites L2C and L5 A Modernized Navigation MODNAV Tool integrated with the GPS ground control software Architecture Evolution Plan or AEP is generating the CNAV data messages Daily CNAV uploads began December 31 2014 and the U S Air Force reports that signal performance of CNAV matches or slightly outperforms Legacy performance average user range error RMS URE from 25 February 3 March 2015 was 050 m for Legacy and 057 m for Modernized best week for Modernized signals since the broadcast initiated April 2014 was 042 m for 6 13 January 2015 Users are reminded that these CNAV signals are preoperational and should be used with discretion until they become fully operational the L5 message is currently set unhealthy concluded Rick Hamilton CGSIC Executive Secretariat USCG Navigation Center in a status email to the Civil Global Positioning System Service Interface Committee CGSIC More System News Online See www gpsworld com GPS World April 2015 www gpsworld com 8