benchmark, date, observer, organization, receiver, receiver_sn, receiver_type, antenna, antenna_sn, dome, height (m), slant height (m), interval, first_observation (s)
 h231 H2_1931_USGS, 2005-10-31,  GDH ,  USGS ,  ASHTECH,  ZE1200331018 ,  Z-X ZE21,  ASH701945E_M,  CR520031626,  NONE, 1.2177, 1.2669, 30, 171030
 h231 H2_1931_USGS, 2005-12-04,  CHS ,  USGS ,  ASHTECH,  ZE1200331018 ,  Z-X ZE21,  ASH701945B_M,  CR619992805,  NONE, 1.2278, 1.2769, 30, 15580
 h231 H2_1931_USGS, 2006-08-09,  CHS ,  USGS ,  ASHTECH,  LP03360 ,  Z-XII3 CC00,  ASH701945E_M,  CR520031615,  NONE, 1.2794, 1.3279, 30, 14590
 h231 H2_1931_USGS, 2006-08-15,  GDH ,  USGS ,  ASHTECH,  LP019992809 ,  Z-XII3 CD00,  ASH701945E_M,  CR520031622,  NONE, 0.4898, 0.5579, 30, 161630
 h231 H2_1931_USGS, 2008-07-30,  CHS ,  USGS ,  ASHTECH,  ZE120023208 ,  Z-X ZE21,  ASH701945E_M,  CR620022602,  NONE, 1.3107, 1.3589, 30, 15270
 h231 H2_1931_USGS, 2008-07-31,  CHS ,  USGS ,  ASHTECH,  ZE120023208 ,  Z-X ZE21,  ASH701945E_M,  CR620022602,  NONE, 1.2723, 1.3209, 30, 1530
 h231 H2_1931_USGS, 2010-06-17,  CHS ,  USGS ,  ASHTECH,  ZE1200331018 ,  Z-X ZE210,  ASH701945B_M,  CR619992805,  NONE, 1.2854, 1.3339, 15, 153315
 h231 H2_1931_USGS, 2010-06-23,  JMS ,  USGS ,  ASHTECH,  ZE1200526043 ,  Z-X ZE210,  ASH701945E_M,  CR620022601,  NONE, 1.3349, 1.3829, 15, 153815
 h231 H2_1931_USGS, 2018-12-18,  ELP ,  USGS ,  JAVAD,  01337 ,  TRE_G3TH SIGMA3.5.1,  JAVRINGANT_DM,  00585,  NONE, 1.2561, 1.3049, 15, 161245
 h231 H2_1931_USGS, 2018-12-21,  ELP ,  USGS ,  JAVAD,  00621 ,  TRE_G3TH SIGMA3.6.9,  JAVRINGANT_DM,  00585,  NONE, 1.2834, 1.3319, 15, 133830