Notice ID:\u00a0<\/strong>1305M224Q0321<\/p>\n
The National Geodetic Survey (NGS) is a program office under the National Ocean Service (NOS).\u00a0 NGS provides the framework for all positioning activities in the Nation.\u00a0 The foundational elements – latitude, longitude, elevation, shoreline information and their changes over time – contribute to informed decision making and impact a wide range of important activities including mapping and charting, navigation, flood risk determination, transportation, land use and ecosystem management.\u00a0 NGS’ authoritative spatial data, models, and tools are vital for the protection and management of natural and manmade resources and support the economic prosperity and environmental health of the Nation.<\/p>\n
Description of Work.\u00a0 The expected outcome of this contract will result in a new C++ program to form and solve a linearized system of equations (Appendix C).\u00a0 Inputs to the program include a precise Standard Product 3 \u201csp3\u201d orbit file, to be used as the observations (O), and a \u201cT-file\u201d containing a set of a priori<\/em> estimates for satellite initial conditions, a model of computed satellite orbits (C), and partial derivatives (Aij<\/sub>). File format descriptions are provided in the appendices. The program will compute pre-fit residuals (observation minus computed, or O-Cs) and construct a system of equations (design matrix A) using the partial derivatives (A = [Aij<\/sub>]; see Appendix C) and a set of a priori<\/em> parameter constraints.\u00a0 The pre-fit residuals and design matrix will be used to form a normal equation system, which will be written out in a binary format to a file on disk.\u00a0 The system of equations will then be solved using a constrained least-squares algorithm. The computing requirement for solving the system of equations will be a fast, numerically stable method. The resulting solution vector shall contain adjustments to the initial conditions and estimates for non-gravitational force model parameters, so that the updated initial conditions and newly estimated force model parameters are consistent with the precise orbit file. The program shall output a G-file with the updated initial conditions and force model parameter estimates.<\/p>\n
To support the work, NGS will provide C++ object-oriented libraries.\u00a0 The contractor will use existing libraries, and also develop new C++ libraries and objects as needed to accomplish the goals of the program. New C++ libraries shall use the object-oriented approach demonstrated in the other NGS code. At minimum, a new C++ library (proposed name \u201cSatIC\u201d) shall be written, to read and write initial conditions in the G-file format.<\/p>\n
The new code shall be capable of being compiled and run on an HPC environment, such as Mississippi State High Performance Computing<\/a> systems. The M-PAGES code (C++ libraries) is already compiled and operational in this Linux environment. NOAA\/NGS will assist the awardee with securing system account(s), so that their development and testing can be conducted in this Linux environment.<\/p>\n
Read more here.<\/a><\/p>\n","protected":false},"excerpt":{"rendered":"