Geodetic data records (GDRs) from the GEOSAT Exact Repeat Mission (ERM) from 15 January 1987 to 17 February 1987 (NODC Accession 8700124)

This accession contains one month of geodetic data records (GDRs) from the GEOSAT Exact Repeat Mission (ERM) for the time period of January 15, 1987 to February 17, 1987. Parameters include: time, orbit, latitude/longitude, and sea surface height. Corrections to the data include: sea level, wind and wave data, tides, dry and wet troposphere, ionosphere, height bias, altimeter crossover differences, altimeter sea surface measurement, and spacecraft orientation. These data were submitted by the U.S. Navy via National Oceanic Service. The US Navy Geosat (Geodetic Satellite) radar altimeter mission lasted for nearly 5 years (March 1985 to January 1990) and collected approximately 750 million measurements of sea level, wave height, and wind speed over the global oceans. During the Geodetic Mission (March 1985 to September 1986), the satellite did not repeat its ground track for the duration of the mission. The orbit of the satellite was changed in October 1986 to begin the Exact Repeat Mission (ERM) which lasted from November 8, 1986 until the satellite quit functioning in January 1990. During the ERM, the satellite repeated its ground track every 17 days. Data were initially processed by the Johns Hopkins University Applied Physics Laboratory in Laurel, MD in coordination with the NOAA/NOS Satellite Altimeter Group. Data products were transferred to the NOAA National Oceanographic Data Center (NODC) for distribution. Data products are archived at the NODC.本次入藏的数据集包含1987年1月15日至1987年2月17日期间，大地卫星（GEOSAT）精确重复任务（Exact Repeat Mission，简称ERM）产出的为期一个月的大地测量数据记录（Geodetic Data Records，简称GDRs）。数据集参数涵盖时间、轨道、经纬度与海面高度。数据修正项包含海平面数据、风浪数据、潮汐、干/湿对流层、电离层、高度偏差、高度计交叉轨迹差、高度计海面测量值以及航天器姿态。该数据集由美国海军通过国家海洋服务局提交。 美国海军大地卫星（GEOSAT，全称Geodetic Satellite）雷达高度计任务总时长近5年（1985年3月至1990年1月），在全球海洋范围内采集了约7.5亿条海平面、浪高与风速观测数据。在大地测量任务阶段（1985年3月至1986年9月），卫星在轨期间未重复地面轨迹。1986年10月卫星轨道完成调整，自此开启精确重复任务（ERM），该任务自1986年11月8日持续至1990年1月卫星停止运行。在ERM任务阶段，卫星每17天重复一次地面轨迹。数据最初由马里兰州劳雷尔市的约翰·霍普金斯大学应用物理实验室（Johns Hopkins University Applied Physics Laboratory）与美国国家海洋和大气管理局/国家海洋服务局（NOAA/NOS）卫星高度计团队协作处理。后续数据产品移交至美国国家海洋和大气管理局国家海洋数据中心（NOAA National Oceanographic Data Center，简称NODC）进行分发，所有数据产品均归档于该中心。