Geosat Geodetic Mission Sensor Data Records (SDR) for July, 1985 (NODC Accession 0002536)

This accession contains one month of sensor data records (SDRs) from the GEOSAT Geodetic Mission (GM) for the time period of July 01, 1985 to July 31, 1985. 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.

本次入藏数据集包含1985年7月1日至1985年7月31日期间，GEOSAT大地测量任务（Geodetic Mission, GM）的一个月传感器数据记录（Sensor Data Records, SDRs）。其包含的参数有：时间、轨道、经纬度以及海面高度。数据校正项涵盖：海平面数据、风浪数据、潮汐、干/湿对流层校正、电离层校正、高度偏差、高度计交叉轨迹差、高度计海面测量数据以及航天器姿态。本数据集由美国海军通过国家海洋局（National Oceanic Service）提交。

美国海军GEOSAT（大地测量卫星）雷达高度计任务持续近5年（1985年3月至1990年1月），在全球海洋范围内收集了约7.5亿条海平面、浪高及风速测量数据。在大地测量任务阶段（1985年3月至1986年9月），卫星全程未重复地面轨迹。1986年10月卫星轨道调整，启动精确重复任务（Exact Repeat Mission, ERM），该阶段自1986年11月8日起持续至1990年1月卫星失效。精确重复任务阶段中，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，与NOAA/NOS卫星高度计小组协作处理。数据产品移交至NOAA国家海洋数据中心（National Oceanographic Data Center, NODC）进行分发，所有数据产品均归档于该中心。