Antenna of Z12 Ashtech GPS receiver

Its phase centre defines the location of the HERS IGS site and has been surveyed very accurately relative to the fiducial reference point of the SLR system and to the phase centre of the Z18 joint GPS/GLONASS receiver. GPS data is recorded continuously and submitted to IGS both hourly and daily in standard 30-second sampled RINEX files.

Following a period of inferior data quality that was eventually traced to an antenna fault, the system is currently producing very high quality observations. The plot shows a recent timeseries of derived station coordinates computed by the Scripps Orbit and Permanent Array Center, at the Cecil H. and Ida M. Green Institute of Geophysics and Planetary Physics (IGPP), Scripps Institution of Oceanography (SIO), University of California, San Diego (UCSD) in La Jolla, California.