benchmark, date, observer, organization, receiver, receiver_sn, receiver_type, antenna, antenna_sn, dome, height (m), slant height (m), interval, first_observation (s)
 x537 X_537_1989, 1993-08-16,  EYI ,  USGS-CVO ,  ASHTECH LM-XII3,  004,  7A26,  ASH700228D,  004,  NONE, 1.4541, 1.501, 15, 203645
 x537 X_537_1989, 1993-08-19,  EYI ,  USGS-CVO ,  ASHTECH LM-XII3,  004,  7A26,  ASH700228D,  004,  NONE, 1.4842, 1.5309, 15, 203245
 x537 X_537_1989, 1998-11-02,  GRD/NGS/NOAA ,  NGS/NOAA ,  TRIMBLE SSI,  3748A20591,  7.27,  TRM22020.00+GP,  0220108548,  NONE, 2, 0, 15, 2020
 x537 X_537_1989, 1998-11-03,  GRD/NGS/NOAA ,  NGS/NOAA ,  TRIMBLE SSI,  3748A20591,  7.27,  TRM22020.00+GP,  0220108548,  NONE, 2, 0, 15, 15550
 x537 X_537_1989, 2003-08-20,  CHS ,  USGS ,  ASHTECH,  LP019992804 ,  Z-XII3 CD00,  ASH701945E_M,  CR620022601,  NONE, 1.2976, 1.3459, 30, 1600
 x537 X_537_1989, 2003-08-21,  GDH ,  USGS ,  ASHTECH,  ZE120023208 ,  Z-X ZE00,  ASH701945B_M,  CR519993702,  NONE, 1.3289, 1.3769, 30, 16630