Optical Navigation (OpNav) measurements derived from spacecraft-based images are an enabling data type for small body proximity operations and are required to successfully navigate a spacecraft in the vicinity of asteroids, comets, and planetary satellites. Furthermore, onboard OpNav measurement processing and autonomous navigation have operational advantages compared to traditional ground-in-the-loop orbit determination, as proven by recent experiences on the OSIRIS-REx mission. Therefore, the NASA Goddard Space Flight Center (GSFC) has a strategic interest in developing in-house OpNav data processing for onboard autonomous navigation.
The Goddard Enhanced Onboard Navigation System (GEONS) is an in-house developed navigation system with flight heritage (MMS and GPM). SpaceCube is a cross-cutting, in-flight reconfigurable, Field Programmable Gate Array (FPGA) based, on-board, hybrid science data processing system developed at GSFC and is proposed to be used on many future planned and proposed missions. The purpose of this IRAD is to develop in-house OpNav tools and expertise to support the next generation of interplanetary and small body missions. This will be done by integrating and testing GEONS with the SpaceCube and leveraging work from multiple IRADs to perform an onboard Terrain Relative Navigation demonstration. This will benefit many future missions including but not limited to interplanetary missions.
The objective of this IRAD is to integrate in-house developed software and hardware to establish onboard OpNav measurement data processing. The target software includes GEONS and a TRN tool called Retina. GEONS is a high-heritage, flight-tested onboard navigation system developed in-house at GSFC. Retina is a Terrain Relative Navigation (TRN) software tool being developed at GSFC that processes images taken of the surface of an asteroid (or other small body,) correlates them to “predicted images,” and provides the OpNav measurements that would then be ingested into GEONS. The hardware platform would be the SpaceCube which is a cross-cutting, in-flight reconfigurable, FPGA-based, on-board hybrid science data processing system developed at GSFC and is proposed to be used on many future planned and proposed missions.
For proximity operations, image features including terrain-relative surface landmarks can be identified autonomously using Retina. Given the predicted location of a surface landmark and the spacecraft, Retina processes images and correlates these surface landmarks to previously generated “maplets” of the surface of the small body. This generates OpNav data consisting of sample and line pixel locations of identifiable features visible in each image. In FY 2016, a measurement model was added to GEONS that allows it to accurately predict the pixel and line locations of known celestial objects or landmarks given the current estimate of the spacecraft’s position and attitude, and process measurements generated by Retina. GEONS will minimize the difference between the predicted measurements and the measurements generated by Retina to produce an optimal updated navigation solution. This will allow Retina and GEONS to perform precision onboard navigation using images of the asteroid surface. These tools will be integrated onboard a SpaceCube processor and a demonstration will be performed using synthetically generated imagery. (The SpaceCube team has agreed to provide engineering models for this effort.)
To characterize system performance, results from the onboard orbit determination process will be compared and validated against independent software tools and truth measurements. Additional deliverables will include (but are not limited to) mathematical specifications, software design documents, and white papers.
More »This work will help to further capabilities in Optical and Autonomous Navigation near small bodies.
More »Organizations Performing Work | Role | Type | Location |
---|---|---|---|
Goddard Space Flight Center (GSFC) | Lead Organization | NASA Center | Greenbelt, Maryland |