Amphion/NAV: deductive synthesis of state estimation software

Previous work on domain-specific deductive program synthesis described the Amphion/NAIF system for generating Fortran code from high-level graphical specifications describing problems in space system geometry. Amphion/NAIF specifications describe input-output functions that compute geometric quantities (e.g., the distance between two planets at a point in time, or the time when a radio communication path between a spacecraft and earth is occluded) by composing together Fortran subroutines from the NAIF subroutine library developed at the Jet Propulsion Laboratory. In essence, Amphion/NAIF synthesizes code for glueing together the NAIF components in a way such that the generated code implements the specification, with a concurrently generated proof that this implementation is correct. Amphion/NAIF demonstrated the success of domain-specific deductive program synthesis and is still in use today within the space science community. However, a number of questions remained open that we will attempt to answer in this paper.