The GPS Block IIR and IIR-M Broadcast L-band Antenna Panel: Its Pattern and Performance

The Global Positioning System (GPS) Block II Replenishment (IIR) space vehicle (SV) has made up at least one-half of the GPS constellation since 2006. This consists of the 12 original 'classic' IIR SVs and the eight 'modernized' IIR-M SVs. As a stepping-stone toward the IIR-M modernization, Lockheed Martin developed and deployed an updated version of the satellite antenna panel for the L-band broadcast signal. This is the signal used by the worldwide GPS user population. This paper describes both antenna panel versions, their broadcast signal patterns, the performance observed in factory testing, and their on-orbit performance. This is the initial publication of these antenna panel patterns. Ground and on-orbit measurements of both versions of the antenna show that all specification requirements are exceeded. They also reflect the increased antenna gain for the new IIR antenna. The L1 signal shows an increase of 1 dB in received power at edge of Earth, and L2 shows an increase of 2 dB in received power. All users, both terrestrial and on-orbit, benefit from this enhanced power profile. Copyright (C) 2015 The Authors NAVIGATION (C) 2015 Institute of Navigation