benchmark, date, observer, organization, receiver, receiver_sn, receiver_type, antenna, antenna_sn, dome, height (m), slant height (m), interval, first_observation (s)
 z558, 1998-07-01,  unknown ,  CALIF DEPT TRANSPORT,  TRIMBLE 4000SSE,  7286,  NP,  TRM14532.00,  115365,  NONE, 2, 0, 15, 185745
 z558, 1998-07-02,  unknown ,  CALIF DEPT TRANSPORT,  TRIMBLE 4000SSE,  7286,  NP,  TRM14532.00,  115365,  NONE, 2, 0, 15, 143945
 z558, 1998-07-06,  unknown ,  CALIF DEPT TRANSPORT,  TRIMBLE 4000SSE,  7286,  NP,  TRM14532.00,  115365,  NONE, 2, 0, 15, 202515
 z558, 1998-07-07,  unknown ,  CALIF DEPT TRANSPORT,  TRIMBLE 4000SSE,  7286,  NP,  TRM14532.00,  115365,  NONE, 2, 0, 15, 153115
 z558, 2004-09-27,  P. A. Gonzales ,  CALIF DEPT TRANSPORT,  TRIMBLE 5700,  220309531,  NP,  TRM41249.00,  12354012,  NONE, 1.8, 1.8521, 15, 17160
 z558, 2004-09-30,  T. Beitler ,  CALIF DEPT TRANSPORT,  TRIMBLE 5700,  0220298188,  NP,  TRM41249.00,  12425996,  NONE, 2, 2.0514, 15, 16410
 z558 Z558_1957_USCGS, 2010-03-30,  JLS ,  USGS ,  ASHTECH,  ZE1200331006 ,  Z-X ZE210,  ASH700936D_M,  CR14333,  NONE, 1.3723, 1.4199, 15, 152715
 z558 Z558_1957_USCGS, 2010-04-29,  CHS ,  USGS ,  ASHTECH,  ZE1200526028 ,  Z-X ZE210,  ASH701945E_M,  CR520031615,  NONE, 1.3975, 1.4449, 15, 153815
 z558 Z558_1957_USCGS, 2012-05-11,  CHS ,  USGS ,  ASHTECH,  ZE120023208 ,  Z-X ZE210,  ASH701945E_M,  CR620022605,  NONE, 1.3622, 1.4099, 15, 154315
 z558 Z558_1957_USCGS, 2012-05-14,  CHS ,  USGS ,  ASHTECH,  ZE120023208 ,  Z-X ZE210,  ASH701945E_M,  CR620022605,  NONE, 1.3501, 1.3979, 15, 152215
 z558 Z558_1957_USCGS, 2015-05-31,  ELP ,  USGS ,  JAVAD,  00598 ,  TRE_G3TH SIGMA3.3.1,  ASH701945E_M,  CR520031615,  NONE, 1.3904, 1.4379, 15, 16745
 z558 Z558_1957_USCGS, 2015-06-01,  ELP ,  USGS ,  JAVAD,  00621 ,  TRE_G3TH SIGMA3.3.1,  ASH701945E_M,  CR520031615,  NONE, 1.3622, 1.4099, 15, 155615