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All sourcesNASA NTRSDOE OSTI
NASA NTRS2023

Backup Optical Navigation Attitude for Artemis-1 Backup Attitude Ground Tool

The Backup Optical Navigation Attitude (BONA) software was developed as a response to the Artemis1 Power Distribution Unit (PDU) hardware problems found early in 2021. The hardware problem, a capacitor installed incorrectly, removes the intended redundant path for which the PDU can relay its power and data to attached devices. Specific to the BONA context, the concern is that a failure of the single remaining path in this PDU would lead to an inability to communicate with one of the two-star trackers (STs) on Orion. By flight rule, being reduced to a single star tracker means an immediate turn around end-of-mission. The BONA software is not intended to extend the mission, but instead act as a single star tracker attitude confirmation tool. Insurance, if you will, for the Orion project that a ground tool is available to compare the single remaining ST results with optical navigation images retrieved during the mission. Engineers operating BONA in the Mission Control Center (MCC) Mission Evaluation Room (MER) will analyze the downlinked star field images and based on the stars identified and known time of image, derive vehicle attitude estimates, which can be compared with the ST results. Potentially, in extreme situations, and with expert recommendation, the derivations could lead to navigation state updates being commanded to Orion.

GNC↗
NASA NTRSDate not supplied

Optical Navigation Attitude Estimation and Calibration Performance Improvement using Outlier Rejection

Spacecraft optical navigation (OpNav) systems process a sequence of images of celestial bodies against a starfield background to estimate the position and velocity of the vehicle. While attitude is sometimes available from an onboard star tracker, it is often desirable to recognize the background stars in the OpNav images to better align the image. While many image processing algorithms exist for finding stars, efficiency and reliability remain key issues in the presence of extended bodies(e.g. the Moon, Earth), especially when attempting to solve the full lost-in-space problem. Some star outliers(stars identified with high residuals)could appear in the camera field of view, however using them in the attitude estimation or camera calibration would lead to less accurate results. Therefore, we require new and robust approaches to remove these outliers before any further processing. The emphasis of the work is on developing a simple and robust iterative technique to detect and reject the outliers which could be found in any frame during the lost in space attitude determination or during the camera calibration. These outliers are determined based on the residuals of the centroids of the detected stars and the corresponding location using the star catalog. If the residuals exceed a predetermined threshold value, the object will be detected as an outlier and will be removed before another attitude determination and calibration iteration is performed. The performance for both attitude determination and on-orbit camera calibration are improved by an almost two-fold increase in accuracy when applying this outlier rejection technique.

OpNav↗
NASA NTRS2024

Artemis I Optical Navigation System Performance

This paper summarizes the assessment of the Optical Navigation Flight Test Objective (FTO) during the flight of Artemis I. The Optical Navigation (OpNav) System was tested under a variety of range, target, and lighting conditions to evaluate the performance compared to the pre-flight predicted error models. In general, OpNav performed very well – successfully processing over a thousand images of starfields, Earth, and Moon. The performance of the algorithm when processing Moon images matched the pre-flight expected error models. The errors when processing Earth images were notably higher than the pre-flight models predicted, however this was found to be due to an over-estimation of the atmosphere bias used in the tuning of the algorithm. After the bias was re-tuned and the images reprocessed, performance significantly improved.

GNC↗
NASA NTRS1979

A model for testing centerfinding algorithms for automated optical navigation

An efficient software simulation of the imaging process for optical navigation is presented, illustrating results using simple examples. The problems of image definition and optical system modeling, including ideal image containing features and realistic models of optical filtering performed by the entire camera system, are examined. A digital signal processing technique is applied to the problem of developing methods of automated optical navigation and the subsequent mathematical formulation is presented. Specific objectives such as an analysis of the effects of camera defocusing on centerfinding of planar targets, addition of noise filtering to the algorithm, and implementation of multiple frame capability were investigated.

Griffin, M. D.↗
NASA NTRS2011

Optical Navigation for the EPOXI Mission

The Deep Impact spacecraft flew by comet Hartley 2 on November 4, 2010 as part of its extended mission called EPOXI. Successful navigation depended critically on the quality and timing of optical navigation data processing, since pictures of the comet provided the most precise comet-relative position of the spacecraft. This paper describes the planning, including the picture timing and pointing; the methods used to determine the center of the comet image in each picture; and the optical navigation results, which provided the necessary information to allow the cameras to accurately target the comet for science imaging at encounter.

small-body mission↗
NASA NTRS2011

Optical navigation planning process for the Cassini Solstice Mission

During the Cassini Equinox Mission, the Optical Navigation strategy has gradually evolved toward maintenance of an acceptable level of uncertainty on the positions of the bodies to be observed. By counteracting the runoff of the uncertainty over time, this strategy helps satisfy the spacecraft pointing requirements throughout the Solstice Mission, while considerably reducing the required imaging frequency. Requirements for planning observations were established, and the planning process itself was largely automated to facilitate re-planning if it becomes necessary. This paper summarizes the process leading to the optical navigation schedule for the seven years of the Solstice Mission.

Cassini↗
NASA NTRSDate not supplied

New Optical Navigation Results Using Historical MESSENGER Data

This paper describes new optical navigation (OpNav) results obtained by processing previously collected measurements from the MESSENGER mission to Mercury. This project also serves to mature the tools and capabilities of NASA Goddard Space Flight Center (GSFC) in OpNav, using the open source Goddard Image Analysis and Navigation Tool (GIANT). New navigation measurements are obtained during the Mercury flyby and orbital phases, using OpNav measurements generated by GIANT, and these measurements are compared to predictions. The results obtained provide a set of improvements to be made in navigation tools and will pave the way for future missions to navigate near terrestrial bodies using optical measurements.

Optical Navigation↗
NASA NTRS1980

Interplanetary optical navigation using Charge Coupled Devices

Charge Coupled Devices (CCD) will be used as optical navigation image detectors in space missions planned for the 1980's. This paper presents analyses directed at assessing the performance of an imaging system employing a CCD (i.e., a solid state imager (SSI)), for a Jovian satellite tour environment. CCD operating principles are summarized and methods of calculating theoretical dynamic range presented. Methods of analyzing the SSI's ability to perform the fundamental optical navigation function of imaging a target body and one or more stars, are presented. This capability is expressed as a function of SSI optical and electronic parameters and of astrophysical parameters. The influence of these factors and pointing control errors on navigation picture budgets is analyzed. The effect of the sun's glare is analyzed from the standpoint of its reduction of SSI dynamic range and increase of navigation picture budget. Radiation effects on SSI navigation imaging performance are discussed and a method of analyzing probabilities of distinguishing real from false stars presented.

Davis, R. P.↗
NASA NTRS2016

Parametric Covariance Model for Horizon-Based Optical Navigation

This Note presents an entirely parametric version of the covariance for horizon-based optical navigation measurements. The covariance can be written as a function of only the spacecraft position, two sensor design parameters, the illumination direction, the size of the observed planet, the size of the lit arc to be used, and the total number of observed horizon points. As a result, one may now more clearly understand the sensitivity of horizon-based optical navigation performance as a function of these key design parameters, which is insight that was obscured in previous (and nonparametric) versions of the covariance. Finally, the new parametric covariance is shown to agree with both the nonparametric analytic covariance and results from a Monte Carlo analysis.

Optical Navigatio↗
NASA NTRS1992

Optical navigation for the Galileo Gaspra encounter

The optical navigation process as practiced during the Gaspra encounter is presented. The characteristics of image formation for a single-frame mosaic picture required the development of a new image processing algorithm to extract the optical measurements. A detailed formulation of this algorithm is presented along with the results of applying it to the pictures returned from the spacecraft.

Vaughan, R. M.↗
NASA NTRS1975

Mariner-Venus-Mercury optical navigation demonstration - Results and implications for future missions

Optical navigation uses spacecraft television pictures of a target body against a known star background in a process which relates the spacecraft trajectory to the target body. This technology was used in the Mariner-Venus-Mercury mission, with the optical data processed in near-real-time, simulating a mission critical environment. Optical data error sources were identified, and a star location error analysis was carried out. Several methods for selecting limb crossing coordinates were used, and a limb smear compensation was introduced. Omission of planetary aberration corrections was the source of large optical residuals.

Acton, C. H., Jr.↗
NASA NTRS1972

On-board optical navigation data from Mariner '71.'

Satellite-star optical navigation, a new spacecraft navigation technique has been successfully demonstrated during Mariner 9's approach to Mars in mid-November. As Mariner 9 approached Mars, 21 TV pictures of its satellites, Phobos and Deimos, were taken and transmitted to earth. On earth, these pictures were carefully processed in order to locate the positions of the bright satellites against the relatively faint star background. The objectives and performance of the preflight and real time activities leading to the successful demonstration of satellite-star navigation data are described.

Duxbury, T. C.↗
NASA NTRS1996

An Automomous Optical Navigation and Control System for Interplanetary Exploration Missions

The first fully autonomous deep-space navigation system ever implemented is planned to guide the New Millenium Deep Space-1 mission to an asteroid and comet beginning in mid-1998. This system is based to a large extent on Optical Navigation (OPNAV) technology developed for the NASA/JPL interplanetary exploration probes Voyager and Galileo. This paper describes the structure and algorithmic content of the Autonomous OPNAV system. The system has several major autonomous functions: picture planning, image analysis, orbit determination, manuever design and general interaction with other onboard autonomous systems.

optical navigation↗
NASA NTRS2017

Optical Navigation During Cassini's Solstice Mission

After nearly twenty years in flight, Cassini’s mission at Saturn will conclude as it purposely dives into Saturn’s atmosphere on September 15, 2017. Primarily to avoid moons potentially harboring conditions for life and with propellant very low, the intentional plunge into the atmosphere was set in motion years ago. We take this opportunity to give an overview of the optical navigation and its roles throughout the mission. The paper describes the navigation process and the evolution of optical navigation over the past thirteen years. The last equatorial phase of the Cassini mission was particularly challenging for the OD team as the Saturn system was not being estimated anymore, and it had been a few years since the last icy moon flybys. Science pictures of Enceladus one month prior to the Enceladus encounters confirmed the moon’s position to be in good agreement with the Saturn system dynamical modeling used. This reduced Enceladus’s absolute uncertainty by a factor of three, less than 1 km, and gave confidence the navigation team could achieve acceptable flybys and meet science objectives.

Tarzi, Zahi↗
NASA NTRS2011

Ground Optical Navigation for the Stardust-Next Mission to Comet 9P/TEMPEL1

Ground-based optical navigation (OpNav) using pictures taken by the Naviga-tion camera on the Stardust spacecraft provided the target-relative information needed to design maneuvers during its approach to comet Tempel 1. Hardware problems, limited downlink bandwidth, and changes in the flight profile affected the OpNav picture schedule, sometimes in near-real time. The Stardust naviga-tion camera and attitude control presented challenges. Picture-processing techniques were developed during approach that included background estimation, co-addition, and co-registration. These techniques, along with adaptive picture scheduling, successfully addressed the challenges.

9P/Temple 1↗
NASA NTRS1974

Mariner IX optical navigation using Mars lit limb

Optical spacecraft navigation data, i.e., the lit limb TV image of Mars, acquired during the approach phase of the Mariner IX spacecraft to Mars, has been successfully demonstrated to augment the radio spacecraft tracking data. Accurate in-flight calibration of the TV instrument and the scan platform was performed by referencing stars and planets. Simulated real-time processing and the detailed postflight analyses of the onboard optical data have shown that planet limb data is an important data source in a far-encounter period for which other types of onboard optical measurements, e.g., natural satellite(s) of the target planet with star background, may not be available.

Jerath, N.↗
NASA NTRS1978

Interplanetary approach optical navigation with applications

The use of optical data from onboard television cameras for the navigation of interplanetary spacecraft during the planet approach phase is investigated. Three optical data types were studied: the planet limb with auxiliary celestial references, the satellite-star, and the planet-star two-camera methods. Analysis and modelling issues related to the nature and information content of the optical methods were examined. Dynamic and measurement system modelling, data sequence design, measurement extraction, model estimation and orbit determination, as relating optical navigation, are discussed, and the various error sources were analyzed. The methodology developed was applied to the Mariner 9 and the Viking Mars missions. Navigation accuracies were evaluated at the control and knowledge points, with particular emphasis devoted to the combined use of radio and optical data. A parametric probability analysis technique was developed to evaluate navigation performance as a function of system reliabilities.

Jerath, N.↗