NOAA - NOS NGS-59 was developed by the National Geodetic Survey (NGS) for performing GPS surveys intended to achieve NAVD 88 Helmert orthometric elevation network accuracies of 5 cm and orthometric elevation local accuracies of 2 cm or 5 cm. Unlike tools such as OPUS and hybrid geoids, capable of obtaining these accuracies rarely or occasionally, the campaign-style guidelines in NGS-59 are intended to achieve these accuracies almost always.

Launch