IMAN is a Python tool that provides inertial sensor-based estimates of spacecraft trajectories within an atmospheric influence. It provides Kalman filterderived spacecraft state estimates based upon data collected onboard, and is shown to perform at a level comparable to the conventional methods of spacecraft navigation in terms of accuracy and at a higher level with regard to the availability of results immediately after completion of an atmospheric drag pass. A benefit of this architecture is that this technology is conducive to onboard data processing and estimation and thus can compute near realtime spacecraft state estimates making it suitable for autonomous operations and/or closed-loop guidance, navigation, and control strategies.
This tool can be used to reliably predict subsequent periapsis times and locations over all aerobraking regimes. It also yields accurate peak dynamic pressure and heating rates, which are critical for a successful corridor control strategy. These data are comparable to radiometric-based navigation team reconstructed values. IMAN also provides the first instance of the use of the Unscented Kalman Filter (UKF) for the purpose of estimating an actual spacecraft trajectory arc about another planet. A significant advantage to the implementation of this type of filter is that the UKF is a non-linear filter and thus accurate to at least second order. It provides more meaningful and realistic covariances and has been shown to be robust in the presence of sparse data sets.
Currently, IMAN is being used in an experiment to demonstrate Inertial Measurement Unit (IMU)-based aerobraking navigation for the Mars Reconnaissance Orbiter (MRO). It also can be used in other operational missions such as those using the atmosphere for entry-descent-landing or solar sail missions that experience significant solar radiation pressure for propulsion.
This program was written by Moriba Jah, Michael Lisano, and George Hockney of Caltech for NASA's Jet Propulsion Laboratory.
This software is available for commercial licensing. Please contact Karina Edmonds of the California Institute of Technology at (626) 395-2322. Refer to NPO-43677.
This Brief includes a Technical Support Package (TSP).
Inertial Measurements for Aero-Assisted Navigation (IMAN)
(reference NPO-43677) is currently available for download from the TSP library.
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Overview
The document discusses the Inertial Measurements for Aero-Assisted Navigation (IMAN) developed by NASA, specifically focusing on its application in aerobraking for planetary spacecraft. Aerobraking is a technique used to adjust the orbits of spacecraft, such as Magellan (Venus), Mars Global Surveyor, and Mars Odyssey, by utilizing atmospheric drag. Traditionally, spacecraft navigation during the aerobraking phase has relied heavily on radiometric tracking data collected before and after the atmospheric pass. While this method meets operational requirements, it is costly in terms of ground support and results in delayed data availability due to the need for post-drag pass analysis.
IMAN introduces a novel approach that integrates observations from an Inertial Measurement Unit (IMU) with models of the spacecraft and its environment to estimate the vehicle's state during the atmospheric pass. This method not only matches the accuracy of conventional navigation techniques but also offers immediate results upon completion of the aerobraking pass, significantly enhancing operational efficiency.
The IMAN software is capable of reliably predicting subsequent periapsis times and locations across various aerobraking scenarios. Additionally, it provides accurate measurements of peak dynamic pressure and heating rates, which are crucial for effective corridor control strategies during aerobraking maneuvers. The document highlights that IMAN employs the Unscented Kalman Filter, marking its first application for estimating actual spacecraft trajectory arcs around other planets.
Overall, the IMAN system represents a significant advancement in spacecraft navigation technology, offering improved accuracy, reduced costs, and faster data availability. The document serves as a technical support package under NASA's Commercial Technology Program, aiming to disseminate aerospace-related developments with potential broader technological, scientific, or commercial applications. For further inquiries or assistance, the document provides contact information for the Innovative Technology Assets Management at NASA's Jet Propulsion Laboratory.
In summary, the IMAN software enhances the efficiency and effectiveness of aerobraking maneuvers for planetary missions, showcasing NASA's commitment to advancing aerospace technology and its applications.
