benchmark, date, observer, organization, receiver, receiver_sn, receiver_type, antenna, antenna_sn, dome, height (m), slant height (m), interval, first_observation (s)
 409a 4090_A_1981_NGS, 1996-08-06,  GDH ,  USGS ,  ASHTECH,  *LP00141 ,  Z-XII3 1F00,  ASH700718B,  11416,  NONE, 1.3802, 1.4277, 30, 15550
 409a 4090_A_1981_NGS, 1996-08-07,  KAS ,  USGS ,  ASHTECH,  O4597 ,  Z-XII3 1F00,  ASH700228A,  0598,  NONE, 1.5784, 1.6244, 30, 15310
 409a 4090_A_1981_NGS, 2002-08-15,  CHS ,  USGS ,  ASHTECH,  04600 ,  Z-XII3 CD00,  ASH701945B_M,  CR519993703,  NONE, 1.3864, 1.4339, 30, 15240
 409a 4090_A_1981_NGS, 2002-08-18,  CHS ,  USGS ,  ASHTECH,  LP00108.707 ,  Z-XII3 CD00,  ASH701945B_M,  CR519993703,  NONE, 1.4076, 1.4549, 30, 15290