NASA’s Next Generation Space Geodesy Network Typical Core Site Requirements and Layout

Abstract

NASA’s renewed commitment to the deployment of a new network of “core” space geodetic sites requires careful planning and consideration for location selection, instrument and facility layout, and required infrastructure. Following on National Research Council (NRC) recommendations [1] to upgrade U.S. stations with modern SLR, VLBI, and GNSS systems, and make a long-term commitment to maintaining the ITRF (among others), the Space Geodesy Project (SGP) at NASA Goddard has been defining the exact requirements and layout for a “typical” geodetic site, which includes Satellite Laser Ranging--SLR, Very Long Baseline Interferometry--VLBI, Global Navigation Satellite System--GNSS, and Doppler Orbitography and Radiopositioning Integrated by Satellite--DORIS stations (French system provided by CNES, France) tied together with a Vector Tie System (VTS), utilizing a Robotic Total Station (RTS). Within programmatic constraints, Core Site (CS) identification follows a systems engineering process where site characteristics are evaluated against identified requirements. Taking into consideration site stability, radiofrequency interference, infrastructure, and a host of other requirements this paper describes the process leading to identification, and it will illustrate the generic layout of an idealized CS with unencumbered terrain.