Abstract
The National Geodetic Survey (NGS) and the Defense Mapping Agency, Hydrographic and Topographic Center (DMA/HTC) began joint absolute gravity measurements in the spring of 1987. The program’s two major objectives were to establish a more precise national gravity reference network and to monitor/study temporal gravity variations, particularly those related to vertical crustal motion. The NGS absolute gravity instrument, Jilag No. 4, used for this program was one of six such devices developed and built by the Joint Institute for Laboratory Astrophysics (Jila), established by the University of Colorado and the National Institute of Standards and Technology (Figure 1). DMA/HTC obtained one of the other gravity instruments; the remaining four were purchased by scientific institutions in Canada, Germany, Finland, and Austria.
Sign-in/Register to access full text options 
Talk to us
Join us for a 30 min session where you can share your feedback and ask us any queries you have
Schedule a callDisclaimer: All third-party content on this website/platform is and will remain the property of their respective owners and is provided on "as is" basis without any warranties, express or implied. Use of third-party content does not indicate any affiliation, sponsorship with or endorsement by them. Any references to third-party content is to identify the corresponding services and shall be considered fair use under The CopyrightLaw.
