The Experts below are selected from a list of 360 Experts worldwide ranked by ideXlab platform
Steven W Squyres - One of the best experts on this subject based on the ideXlab platform.
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overview of the opportunity Mars Exploration rover mission to meridiani planum eagle crater to purgatory ripple
Journal of Geophysical Research, 2006Co-Authors: Steven W Squyres, Philip R Christensen, J F Bell, R E Arvidson, D Bollen, J Bruckner, Nathalie A Cabrol, Wendy M Calvin, Michael H Carr, B C ClarkAbstract:The Mars Exploration Rover Opportunity touched down at Meridiani Planum in January 2004 and since then has been conducting observations with the Athena science payload. The rover has traversed more than 5 km, carrying out the first outcrop-scale investigation of sedimentary rocks on Mars. The rocks of Meridiani Planum are sandstones formed by eolian and aqueous reworking of sand grains that are composed of mixed fine-grained siliciclastics and sulfates. The siliciclastic fraction was produced by chemical alteration of a precursor basalt. The sulfates are dominantly Mg-sulfates and also include Ca-sulfates and jarosite. The stratigraphic section observed to date is dominated by eolian bedforms, with subaqueous current ripples exposed near the top of the section. After deposition, interaction with groundwater produced a range of diagenetic features, notably the hematite-rich concretions known as "blueberries." The bedrock at Meridiani is highly friable and has undergone substantial erosion by wind-transported basaltic sand. This sand, along with concretions and concretion fragments eroded from the rock, makes up a soil cover that thinly and discontinuously buries the bedrock. The soil surface exhibits both ancient and active wind ripples that record past and present wind directions. Loose rocks on the soil surface are rare and include both impact ejecta and meteorites. While Opportunity's results show that liquid water was once present at Meridiani Planum below and occasionally at the surface, the environmental conditions recorded were dominantly arid, acidic, and oxidizing and would have posed some significant challenges to the origin of life. Copyright 2006 by the American Geophysical Union.
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Mars Exploration rover mission
Journal of Geophysical Research, 2003Co-Authors: J A Crisp, Steven W Squyres, R E Arvidson, Mark Adler, Jacob R Matijevic, David M KassAbstract:[1] In January 2004 the Mars Exploration Rover mission will land two rovers at two different landing sites that show possible evidence for past liquid-water activity. The spacecraft design is based on the Mars Pathfinder configuration for cruise and entry, descent, and landing. Each of the identical rovers is equipped with a science payload of two remote-sensing instruments that will view the surrounding terrain from the top of a mast, a robotic arm that can place three instruments and a rock abrasion tool on selected rock and soil samples, and several onboard magnets and calibration targets. Engineering sensors and components useful for science investigations include stereo navigation cameras, stereo hazard cameras in front and rear, wheel motors, wheel motor current and voltage, the wheels themselves for digging, gyros, accelerometers, and reference solar cell readings. Mission operations will allow commanding of the rover each Martian day, or sol, on the basis of the previous sol's data. Over a 90-sol mission lifetime, the rovers are expected to drive hundreds of meters while carrying out field geology investigations, Exploration, and atmospheric characterization. The data products will be delivered to the Planetary Data System as integrated batch archives.
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Mars Exploration rover engineering cameras
Journal of Geophysical Research, 2003Co-Authors: J N Maki, J F Bell, Kenneth E Herkenhoff, Steven W Squyres, A Kiely, M Klimesh, M Schwochert, T Litwin, Reg G Willson, Andrew JohnsonAbstract:[1] NASA's Mars Exploration Rover (MER) Mission will place a total of 20 cameras (10 per rover) onto the surface of Mars in early 2004. Fourteen of the 20 cameras are designated as engineering cameras and will support the operation of the vehicles on the Martian surface. Images returned from the engineering cameras will also be of significant importance to the scientific community for investigative studies of rock and soil morphology. The Navigation cameras (Navcams, two per rover) are a mast-mounted stereo pair each with a 45° square field of view (FOV) and an angular resolution of 0.82 milliradians per pixel (mrad/pixel). The Hazard Avoidance cameras (Hazcams, four per rover) are a body-mounted, front- and rear-facing set of stereo pairs, each with a 124° square FOV and an angular resolution of 2.1 mrad/pixel. The Descent camera (one per rover), mounted to the lander, has a 45° square FOV and will return images with spatial resolutions of ∼4 m/pixel. All of the engineering cameras utilize broadband visible filters and 1024 × 1024 pixel detectors.
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selection of the Mars Exploration rover landing sites
Journal of Geophysical Research, 2003Co-Authors: M P Golombek, Steven W Squyres, J A Crisp, Mark Adler, David M Kass, A F C Haldemann, J A Grant, T J Parker, W J Lee, N T BridgesAbstract:[1] The selection of Meridiani Planum and Gusev crater as the Mars Exploration Rover landing sites took over 2 years, involved broad participation of the science community via four open workshops, and narrowed an initial ∼155 potential sites (80–300 × 30 km) to four finalists based on science and safety. Engineering constraints important to the selection included (1) latitude (10°N–15°S) for maximum solar power, (2) elevation (less than −1.3 km) for sufficient atmosphere to slow the lander, (3) low horizontal winds, shear, and turbulence in the last few kilometers to minimize horizontal velocity, (4) low 10-m-scale slopes to reduce airbag spin-up and bounce, (5) moderate rock abundance to reduce abrasion or strokeout of the airbags, and (6) a radar-reflective, load-bearing, and trafficable surface safe for landing and roving that is not dominated by fine-grained dust. The evaluation of sites utilized existing as well as targeted orbital information acquired from the Mars Global Surveyor and Mars Odyssey. Three of the final four landing sites show strong evidence for surface processes involving water and appear capable of addressing the science objectives of the missions, which are to determine the aqueous, climatic, and geologic history of sites on Mars where conditions may have been favorable to the preservation of evidence of possible prebiotic or biotic processes. The evaluation of science criteria placed Meridiani and Gusev as the highest-priority sites. The evaluation of the three most critical safety criteria (10-m-scale slopes, rocks, and winds) and landing simulation results indicated that Meridiani and Elysium Planitia are the safest sites, followed by Gusev and Isidis Planitia.
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Mars Exploration rover athena panoramic camera pancam investigation
Journal of Geophysical Research, 2003Co-Authors: J F Bell, H. M. Arneson, Kenneth E Herkenhoff, Steven W Squyres, J N Maki, Dennis Brown, S A Collins, A Dingizian, S T Elliot, E C HagerottAbstract:[1] The Panoramic Camera (Pancam) investigation is part of the Athena science payload launched to Mars in 2003 on NASA's twin Mars Exploration Rover (MER) missions. The scientific goals of the Pancam investigation are to assess the high-resolution morphology, topography, and geologic context of each MER landing site, to obtain color images to constrain the mineralogic, photometric, and physical properties of surface materials, and to determine dust and aerosol opacity and physical properties from direct imaging of the Sun and sky. Pancam also provides mission support measurements for the rovers, including Sun-finding for rover navigation, hazard identification and digital terrain modeling to help guide long-term rover traverse decisions, high-resolution imaging to help guide the selection of in situ sampling targets, and acquisition of education and public outreach products. The Pancam optical, mechanical, and electronics design were optimized to achieve these science and mission support goals. Pancam is a multispectral, stereoscopic, panoramic imaging system consisting of two digital cameras mounted on a mast 1.5 m above the Martian surface. The mast allows Pancam to image the full 360° in azimuth and ±90° in elevation. Each Pancam camera utilizes a 1024 × 1024 active imaging area frame transfer CCD detector array. The Pancam optics have an effective focal length of 43 mm and a focal ratio of f/20, yielding an instantaneous field of view of 0.27 mrad/pixel and a field of view of 16° × 16°. Each rover's two Pancam “eyes” are separated by 30 cm and have a 1° toe-in to provide adequate stereo parallax. Each eye also includes a small eight position filter wheel to allow surface mineralogic studies, multispectral sky imaging, and direct Sun imaging in the 400–1100 nm wavelength region. Pancam was designed and calibrated to operate within specifications on Mars at temperatures from −55° to +5°C. An onboard calibration target and fiducial marks provide the capability to validate the radiometric and geometric calibration on Mars.
J F Bell - One of the best experts on this subject based on the ideXlab platform.
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vnir multispectral observations of aqueous alteration materials by the pancams on the spirit and opportunity Mars Exploration rovers
American Mineralogist, 2016Co-Authors: W H Farrand, J R Johnson, M S Rice, Alian Wang, J F BellAbstract:Multispectral visible and near infrared (VNIR) observations from the Mars Exploration Rover Pancam multispectral stereo camera systems are consistent with materials having been subjected to various aqueous processes. Ferric oxides in the form of hematite in the Burns and Grasberg formations of Meridiani Planum have been well characterized by Opportunity on the basis of strong 535 and 864 nm absorptions and positive 754–1009 nm and 934–1009 nm slopes. On the rim of Noachian-aged Endeavour crater, Opportunity has observed light-toned veins with high Ca and S, as determined by the rover’s Alpha Particle X-ray Spectrometer (APXS), and a negative 934–1009 nm slope in VNIR spectra extracted from Pancam data, indicative of a 1000 nm H2O overtone absorption. Together these observations indicate that the veins are composed of gypsum. Rocks overturned by Opportunity on the Murray Ridge portion of the Endeavour crater rim display dark- and light-toned coatings. The dark-toned coatings have a red, featureless slope that is consistent with the slope observed in laboratory spectra of high-valence manganese oxide minerals. Potential Mn oxide coatings may also be associated with some exposures of the Grasberg formation. APXS results for high Mg and S in the light-toned coatings of the Murray Ridge overturned rocks and a negative 934–1009 nm slope are consistent with hydrated Mg-sulfates. Opportunity has also observed spectral features in rocks that are consistent with orbital observations of Fe-smectites, as well as Al-smectites and possible hydrated silica in light-toned fracture-fill materials. The Spirit rover observed sulfate-rich light-toned soils exposed by the rover’s wheels. Several of these soil observations contained spectral features, such as a broad absorption centered near 800 nm, consistent with ferric sulfate minerals, a finding confirmed by the rover’s Mossbauer spectrometer. Spirit also excavated light-toned Si-rich soils. These soils have a flat near-infrared spectrum with a drop in reflectance from 934–1009 nm that is consistent with free water contained in voids or adsorbed onto the surface of the silica.
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dust deposition on the decks of the Mars Exploration rovers 10 years of dust dynamics on the panoramic camera calibration targets
Earth and Space Science, 2015Co-Authors: K M Kinch, J. Joseph, J F Bell, M B Madsen, W Goetz, J R Johnson, Jascha SohldicksteinAbstract:The Panoramic Cameras on NASA's Mars Exploration Rovers have each returned more than 17,000 images of their calibration targets. In order to make optimal use of this data set for reflectance calibration, a correction must be made for the presence of air fall dust. Here we present an improved dust correction procedure based on a two-layer scattering model, and we present a dust reflectance spectrum derived from long-term trends in the data set. The dust on the calibration targets appears brighter than dusty areas of the Martian surface. We derive detailed histories of dust deposition and removal revealing two distinct environments: At the Spirit landing site, half the year is dominated by dust deposition, the other half by dust removal, usually in brief, sharp events. At the Opportunity landing site the Martian year has a semiannual dust cycle with dust removal happening gradually throughout two removal seasons each year. The highest observed optical depth of settled dust on the calibration target is 1.5 on Spirit and 1.1 on Opportunity (at 601 nm). We derive a general prediction for dust deposition rates of 0.004 ± 0.001 in units of surface optical depth deposited per sol (Martian solar day) per unit atmospheric optical depth. We expect this procedure to lead to improved reflectance-calibration of the Panoramic Camera data set. In addition, it is easily adapted to similar data sets from other missions in order to deliver improved reflectance calibration as well as data on dust reflectance properties and deposition and removal history.
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dust aerosol clouds and the atmospheric optical depth record over 5 Mars years of the Mars Exploration rover mission
Icarus, 2015Co-Authors: M T Lemmon, J F Bell, Michael J Wolff, Michael D Smith, B A Cantor, Peter H SmithAbstract:Abstract Dust aerosol plays a fundamental role in the behavior and evolution of the martian atmosphere. The first five Mars years of Mars Exploration Rover data provide an unprecedented record of the dust load at two sites. This record is useful for characterization of the atmosphere at the sites and as ground truth for orbital observations. Atmospheric extinction optical depths have been derived from solar images after calibration and correction for time-varying dust that has accumulated on the camera windows. The record includes local, regional, and globally extensive dust storms. Comparison with contemporaneous thermal infrared data suggests significant variation in the size of the dust aerosols, with a 1 μm effective radius during northern summer and a 2 μm effective radius at the onset of a dust lifting event. The solar longitude ( L S ) 20–136° period is also characterized by the presence of cirriform clouds at the Opportunity site, especially near L S = 50° and 115°. In addition to water ice clouds, a water ice haze may also be present, and carbon dioxide clouds may be present early in the season. Variations in dust opacity are important to the energy balance of each site, and work with seasonal variations in insolation to control dust devil frequency at the Spirit site.
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spectrophotometric properties of materials observed by pancam on the Mars Exploration rovers 2 opportunity
Journal of Geophysical Research, 2006Co-Authors: J R Johnson, J F Bell, R E Arvidson, E A Guinness, W M Grundy, M T Lemmon, Miles J Johnson, R G Deen, W H Farrand, A G HayesAbstract:[1] The Panoramic Camera (Pancam) on the Mars Exploration Rover Opportunity acquired visible/near-infrared multispectral observations of soils and rocks under varying viewing and illumination geometries that were modeled using radiative transfer theory to improve interpretations of the microphysical and surface scattering nature of materials in Meridiani Planum. Nearly 25,000 individual measurements were collected of rock and soil units identified by their color and morphologic properties over a wide range of phase angles (0–150°) at Eagle crater, in the surrounding plains, in Endurance crater, and in the plains between Endurance and Erebus craters through Sol 492. Corrections for diffuse skylight incorporated sky models based on observations of atmospheric opacity throughout the mission. Disparity maps created from Pancam stereo images allowed inclusion of local facet orientation estimates. Outcrop rocks overall exhibited the highest single scattering albedos (≤0.9 at 753 nm), and most spherule-rich soils exhibited the lowest (≤0.6 at 753 nm). Macroscopic roughness among outcrop rocks varied but was typically larger than spherule-rich soils. Data sets with sufficient phase angle coverage (resulting in well-constrained Hapke parameters) suggested that models using single-term and two-term Henyey-Greenstein phase functions exhibit a dominantly broad backscattering trend for most undisturbed spherule-rich soils. Rover tracks and other compressed soils exhibited forward scattering, while outcrop rocks were intermediate in their scattering behaviors. Some phase functions exhibited wavelength-dependent trends that may result from variations in thin deposits of airfall dust that occurred during the mission.
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overview of the opportunity Mars Exploration rover mission to meridiani planum eagle crater to purgatory ripple
Journal of Geophysical Research, 2006Co-Authors: Steven W Squyres, Philip R Christensen, J F Bell, R E Arvidson, D Bollen, J Bruckner, Nathalie A Cabrol, Wendy M Calvin, Michael H Carr, B C ClarkAbstract:The Mars Exploration Rover Opportunity touched down at Meridiani Planum in January 2004 and since then has been conducting observations with the Athena science payload. The rover has traversed more than 5 km, carrying out the first outcrop-scale investigation of sedimentary rocks on Mars. The rocks of Meridiani Planum are sandstones formed by eolian and aqueous reworking of sand grains that are composed of mixed fine-grained siliciclastics and sulfates. The siliciclastic fraction was produced by chemical alteration of a precursor basalt. The sulfates are dominantly Mg-sulfates and also include Ca-sulfates and jarosite. The stratigraphic section observed to date is dominated by eolian bedforms, with subaqueous current ripples exposed near the top of the section. After deposition, interaction with groundwater produced a range of diagenetic features, notably the hematite-rich concretions known as "blueberries." The bedrock at Meridiani is highly friable and has undergone substantial erosion by wind-transported basaltic sand. This sand, along with concretions and concretion fragments eroded from the rock, makes up a soil cover that thinly and discontinuously buries the bedrock. The soil surface exhibits both ancient and active wind ripples that record past and present wind directions. Loose rocks on the soil surface are rare and include both impact ejecta and meteorites. While Opportunity's results show that liquid water was once present at Meridiani Planum below and occasionally at the surface, the environmental conditions recorded were dominantly arid, acidic, and oxidizing and would have posed some significant challenges to the origin of life. Copyright 2006 by the American Geophysical Union.
Mark Maimone - One of the best experts on this subject based on the ideXlab platform.
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two years of visual odometry on the Mars Exploration rovers field reports
Journal of Field Robotics, 2007Co-Authors: Mark Maimone, Yang Cheng, Larry MatthiesAbstract:NASA's two Mars Exploration Rovers (MER) have successfully demonstrated a robotic Visual Odometry capability on another world for the first time. This provides each rover with accurate knowledge of its position, allowing it to autonomously detect and compensate for any unforeseen slip encountered during a drive. It has enabled the rovers to drive safely and more effectively in highly sloped and sandy terrains and has resulted in increased mission science return by reducing the number of days required to drive into interesting areas. The MER Visual Odometry system comprises onboard software for comparing stereo pairs taken by the pointable mast-mounted 45 deg FOV Navigation cameras (NAVCAMs). The system computes an update to the 6 degree of freedom rover pose (x, y, z, roll, pitch, yaw) by tracking the motion of autonomously selected terrain features between two pairs of 256×256 stereo images. It has demonstrated good performance with high rates of successful convergence (97p on Spirit, 95p on Opportunity), successfully detected slip ratios as high as 125p, and measured changes as small as 2 mm, even while driving on slopes as high as 31 deg. Visual Odometry was used over 14p of the first 10.7 km driven by both rovers. During the first 2 years of operations, Visual Odometry evolved from an “extra credit” capability into a critical vehicle safety system. In this paper we describe our Visual Odometry algorithm, discuss several driving strategies that rely on it (including Slip Checks, Keep-out Zones, and Wheel Dragging), and summarize its results from the first 2 years of operations on Mars. © 2006 Wiley Periodicals, Inc.
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the Mars Exploration rover surface mobility flight software driving ambition
IEEE Aerospace Conference, 2006Co-Authors: Jeffrey J. Biesiadecki, Mark MaimoneAbstract:NASA's Mars Exploration rovers' (MER) onboard mobility flight software was designed to provide robust and flexible operation. The MER vehicles can be commanded directly, or given autonomous control over multiple aspects of mobility: which motions to drive, measurement of actual motion, terrain interpretation, even the selection of targets of interest (although this mode remains largely underused). Vehicle motion can be commanded using multiple layers of control: motor control, direct drive operations (arc, turn in place), and goal-based driving (goto waypoint). Multiple layers of safety checks ensure vehicle performance: command limits (command timeout, time of day limit, software enable, activity constraints), reactive checks (e.g., motor current limit, vehicle tilt limit), and predictive checks (e.g., step, tilt, roughness hazards). From January 2004 through October 2005, Spirit accumulated over 5000 meters and Opportunity 6000 meters of odometry, often covering more than 100 meters in a single day. In this paper we describe the software that has driven these rovers more than a combined 11,000 meters over the Martian surface, including its design and implementation, and summarize current mobility performance results from Mars.
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Autonomous navigation results from the Mars Exploration rover (MER) mission
Springer Tracts in Advanced Robotics, 2006Co-Authors: Mark Maimone, Richard Willson, Yang Cheng, Andrew Johnson, Larry H. MatthiesAbstract:In January, 2004, the Mars Exploration Rover (MER) mission landed two rovers, Spirit and Opportunity, oil the surface of Mars. Several autonomous navigation capabilities were employed in space for the first time in this mission. In the Entry, Descent, and Landing (EDL) phase, both landers used a vision system called the Descent Image Motion Estimation System (DIMES) to estimate horizontal velocity during the last 2000 meters (m) of descent, by tracking features on the ground with a downlooking camera, in order to control retro-rocket firing to reduce horizontal velocity before impact. During surface operations, the rovers navigate autonomously using stereo vision for local terrain mapping and a local, reactive planning algorithm called Grid-based Estimation of Surface Traversability Applied to Local Terrain (GESTALT) for obstacle avoidance. In areas of high slip, stereo vision-based visual odometry has been used to estimate rover motion. As of mid-June, Spirit had traversed 3405 m, of which 1253 m were done autonomously; Opportunity had traversed 1264 m, of which 224 in were autonomous. These results have contributed substantially to the success of the mission and paved the way for increased levels of autonomy in future missions.
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Mars Exploration rover surface operations driving spirit at gusev crater
Systems Man and Cybernetics, 2005Co-Authors: P C Leger, Jeffrey J. Biesiadecki, Eric T Baumgartner, R G Bonitz, A Trebiollennu, John R Wright, S Maxwell, Frank Hartman, Brian Cooper, Mark MaimoneAbstract:Spirit is one of two rovers that landed on Mars in January 2004 as part of NASA's Mars Exploration Rover mission. As of July 2005, Spirit has traveled over 4.5 kilometers across the Martian surface while investigating rocks and soils, digging trenches to examine subsurface materials, and climbing hills to reach outcrops of bedrock. Originally designed to last 90 sols (Martian days), Spirit has survived over 500 sols of operation and continues to explore. During the mission, we achieved increases in efficiency, accuracy, and traverse capability through increasingly complex command sequences, growing experience, and updates to the on-board and ground-based software. Safe and precise mobility on slopes and in the presence of obstacles has been a primary factor in development of new software and techniques.
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Mars Exploration rover surface operations driving opportunity at meridiani planum
Systems Man and Cybernetics, 2005Co-Authors: Jeffrey J. Biesiadecki, Mark Maimone, Eric T Baumgartner, R G Bonitz, P C Leger, S Maxwell, Frank Hartman, Brian Cooper, A Trebiollenu, Edward TunstelAbstract:On January 24, 2004, the Mars Exploration Rover named Opportunity successfully landed in the region of Mars known as Meridiani Planum, a vast plain dotted with craters where orbiting spacecraft had detected the signatures of minerals believed to have formed in liquid water. The first pictures back from Opportunity revealed that the rover had landed in a crater roughly 20 meters in diameter - the only sizeable crater within hundreds of meters - which became known as Eagle Crater. And in the walls of this crater just meters away was the bedrock MER scientists had been hoping to find, which would ultimately prove that this region of Mars did indeed have a watery past. Opportunity explored Eagle Crater for almost two months, then drove more than 700 meters in one month to its next destination, the much larger Endurance Crater. After surveying the outside of Endurance Crater, Opportunity drove into the crater and meticulously studied it for six months. Then it went to examine the heat shield that had protected Opportunity during its descent through the Martian atmosphere. More than a year since landing, Opportunity is still going strong and is currently en route to Victoria Crater - more than six kilometers from Endurance Crater. Opportunity has driven more than four kilometers, examined more than eighty patches of rock and soil with instruments on the robotic arm, excavated four trenches for subsurface sampling, and sent back well over thirty thousand images of Mars - ranging from grand panoramas to up close microscopic views. This paper details the experience of driving Opportunity through this alien landscape from the point of view of the Rover Planners, the people who tell the rover where to drive and how to use its robotic arm.
Larry H. Matthies - One of the best experts on this subject based on the ideXlab platform.
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Two years of Visual Odometry on the Mars Exploration Rovers
Journal of Field Robotics, 2007Co-Authors: M.W. Maimone, Yang Cheng, Larry H. MatthiesAbstract:NASA's two Mars Exploration Rovers (MER) have successfully demonstrated a robotic Visual Odometry capability on another world for the first time. This provides each rover with accurate knowledge of its position, allowing it to autonomously detect and compensate for any unforeseen slip encountered during a drive. It has enabled the rovers to drive safely and more effectively in highly sloped and sandy terrains and has resulted in increased mission science return by reducing the number of days required to drive into interesting areas. The MER Visual Odometry system comprises onboard software for comparing stereo pairs taken by the pointable mast-mounted 45 deg FOV Navigation cameras (NAVCAMs). The system computes an update to the 6 degree of freedom rover pose (x, y, z, roll, pitch, yaw) by tracking the motion of autonomously selected terrain features between two pairs of 256×256 stereo images. It has demonstrated good performance with high rates of successful convergence (97% on Spirit, 95% on Opportunity), successfully detected slip ratios as high as 125%, and measured changes as small as 2 mm, even while driving on slopes as high as 31 deg. Visual Odometry was used over 14% of the first 10.7 km driven by both rovers. During the first 2 years of operations, Visual Odometry evolved from an “extra credit” capability into a critical vehicle safety system. In this paper we describe our Visual Odometry algorithm, discuss several driving strategies that rely on it (including Slip Checks, Keep-out Zones, and Wheel Dragging), and summarize its results from the first 2 years of operations on Mars. © 2006 Wiley Periodicals, Inc.
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Autonomous navigation results from the Mars Exploration rover (MER) mission
Springer Tracts in Advanced Robotics, 2006Co-Authors: Mark Maimone, Richard Willson, Yang Cheng, Andrew Johnson, Larry H. MatthiesAbstract:In January, 2004, the Mars Exploration Rover (MER) mission landed two rovers, Spirit and Opportunity, oil the surface of Mars. Several autonomous navigation capabilities were employed in space for the first time in this mission. In the Entry, Descent, and Landing (EDL) phase, both landers used a vision system called the Descent Image Motion Estimation System (DIMES) to estimate horizontal velocity during the last 2000 meters (m) of descent, by tracking features on the ground with a downlooking camera, in order to control retro-rocket firing to reduce horizontal velocity before impact. During surface operations, the rovers navigate autonomously using stereo vision for local terrain mapping and a local, reactive planning algorithm called Grid-based Estimation of Surface Traversability Applied to Local Terrain (GESTALT) for obstacle avoidance. In areas of high slip, stereo vision-based visual odometry has been used to estimate rover motion. As of mid-June, Spirit had traversed 3405 m, of which 1253 m were done autonomously; Opportunity had traversed 1264 m, of which 224 in were autonomous. These results have contributed substantially to the success of the mission and paved the way for increased levels of autonomy in future missions.
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Visual odometry on the Mars Exploration Rovers
2005 IEEE International Conference on Systems, Man and Cybernetics, 2005Co-Authors: Yang Cheng, M.W. Maimone, Larry H. MatthiesAbstract:NASA's Mars Exploration Rovers (MER) was designed to traverse in Viking Lander-I style terrains: mostly flat, with many small non-obstacle rocks and occasional obstacles. During actual operations in such terrains, onboard position estimates derived solely from the onboard inertial measurement unit and wheel encoder-based odometry achieved well within the design goal of at most 10% error. However, MER vehicles were also driven along slippery slopes tilted as high as 31 degrees. In such conditions an additional capability was employed to maintain a sufficiently accurate onboard position estimate: visual odometry. The MER visual odometry system comprises onboard software for comparing stereo pairs taken by the pointable mast-mounted 45 degree FOV navigation cameras (NAV-CAMs). The system computes an update to the 6-DOF rover pose (x, y, z, roll, pitch, yaw) by tracking the motion of autonomously-selected "interesting" terrain features between two pairs of stereo images, in both 2D pixel and 3D world coordinates. A maximum likelihood estimator is applied to the computed 3D offsets to produce a final, corrected estimate of vehicle motion between the two pairs. In this paper we describe the visual odometry algorithm used on the Mars Exploration Rovers, and summarize its results from the first year of operations on Mars.
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Visual terrain mapping for Mars Exploration
2004 IEEE Aerospace Conference Proceedings (IEEE Cat. No.04TH8720), 2004Co-Authors: Clark F Olson, Larry H. Matthies, Rongxing Li, J.r. Wright, Kaichang DiAbstract:One goal for future Mars missions is to navigate a rover to science targets not visible to the rover, but seen in orbital or descent images. In order to support and improve long-range navigation capabilities, we generate 3D terrain maps using all available images, including surface images from the lander and/or rover, descent images from the lander, and orbital images from current and future Mars orbiters. The techniques used include wide-baseline stereo mapping for terrain distant from the rover, bundle adjustment for high-accuracy mapping of surface images, and structure-from-motion techniques for mapping using descent and orbital images. The terrain maps are compiled using a system for unifying multi-resolution models and integrating three-dimensional terrains.
Yang Cheng - One of the best experts on this subject based on the ideXlab platform.
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two years of visual odometry on the Mars Exploration rovers field reports
Journal of Field Robotics, 2007Co-Authors: Mark Maimone, Yang Cheng, Larry MatthiesAbstract:NASA's two Mars Exploration Rovers (MER) have successfully demonstrated a robotic Visual Odometry capability on another world for the first time. This provides each rover with accurate knowledge of its position, allowing it to autonomously detect and compensate for any unforeseen slip encountered during a drive. It has enabled the rovers to drive safely and more effectively in highly sloped and sandy terrains and has resulted in increased mission science return by reducing the number of days required to drive into interesting areas. The MER Visual Odometry system comprises onboard software for comparing stereo pairs taken by the pointable mast-mounted 45 deg FOV Navigation cameras (NAVCAMs). The system computes an update to the 6 degree of freedom rover pose (x, y, z, roll, pitch, yaw) by tracking the motion of autonomously selected terrain features between two pairs of 256×256 stereo images. It has demonstrated good performance with high rates of successful convergence (97p on Spirit, 95p on Opportunity), successfully detected slip ratios as high as 125p, and measured changes as small as 2 mm, even while driving on slopes as high as 31 deg. Visual Odometry was used over 14p of the first 10.7 km driven by both rovers. During the first 2 years of operations, Visual Odometry evolved from an “extra credit” capability into a critical vehicle safety system. In this paper we describe our Visual Odometry algorithm, discuss several driving strategies that rely on it (including Slip Checks, Keep-out Zones, and Wheel Dragging), and summarize its results from the first 2 years of operations on Mars. © 2006 Wiley Periodicals, Inc.
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Two years of Visual Odometry on the Mars Exploration Rovers
Journal of Field Robotics, 2007Co-Authors: M.W. Maimone, Yang Cheng, Larry H. MatthiesAbstract:NASA's two Mars Exploration Rovers (MER) have successfully demonstrated a robotic Visual Odometry capability on another world for the first time. This provides each rover with accurate knowledge of its position, allowing it to autonomously detect and compensate for any unforeseen slip encountered during a drive. It has enabled the rovers to drive safely and more effectively in highly sloped and sandy terrains and has resulted in increased mission science return by reducing the number of days required to drive into interesting areas. The MER Visual Odometry system comprises onboard software for comparing stereo pairs taken by the pointable mast-mounted 45 deg FOV Navigation cameras (NAVCAMs). The system computes an update to the 6 degree of freedom rover pose (x, y, z, roll, pitch, yaw) by tracking the motion of autonomously selected terrain features between two pairs of 256×256 stereo images. It has demonstrated good performance with high rates of successful convergence (97% on Spirit, 95% on Opportunity), successfully detected slip ratios as high as 125%, and measured changes as small as 2 mm, even while driving on slopes as high as 31 deg. Visual Odometry was used over 14% of the first 10.7 km driven by both rovers. During the first 2 years of operations, Visual Odometry evolved from an “extra credit” capability into a critical vehicle safety system. In this paper we describe our Visual Odometry algorithm, discuss several driving strategies that rely on it (including Slip Checks, Keep-out Zones, and Wheel Dragging), and summarize its results from the first 2 years of operations on Mars. © 2006 Wiley Periodicals, Inc.
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Autonomous navigation results from the Mars Exploration rover (MER) mission
Springer Tracts in Advanced Robotics, 2006Co-Authors: Mark Maimone, Richard Willson, Yang Cheng, Andrew Johnson, Larry H. MatthiesAbstract:In January, 2004, the Mars Exploration Rover (MER) mission landed two rovers, Spirit and Opportunity, oil the surface of Mars. Several autonomous navigation capabilities were employed in space for the first time in this mission. In the Entry, Descent, and Landing (EDL) phase, both landers used a vision system called the Descent Image Motion Estimation System (DIMES) to estimate horizontal velocity during the last 2000 meters (m) of descent, by tracking features on the ground with a downlooking camera, in order to control retro-rocket firing to reduce horizontal velocity before impact. During surface operations, the rovers navigate autonomously using stereo vision for local terrain mapping and a local, reactive planning algorithm called Grid-based Estimation of Surface Traversability Applied to Local Terrain (GESTALT) for obstacle avoidance. In areas of high slip, stereo vision-based visual odometry has been used to estimate rover motion. As of mid-June, Spirit had traversed 3405 m, of which 1253 m were done autonomously; Opportunity had traversed 1264 m, of which 224 in were autonomous. These results have contributed substantially to the success of the mission and paved the way for increased levels of autonomy in future missions.
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Visual odometry on the Mars Exploration Rovers
2005 IEEE International Conference on Systems, Man and Cybernetics, 2005Co-Authors: Yang Cheng, M.W. Maimone, Larry H. MatthiesAbstract:NASA's Mars Exploration Rovers (MER) was designed to traverse in Viking Lander-I style terrains: mostly flat, with many small non-obstacle rocks and occasional obstacles. During actual operations in such terrains, onboard position estimates derived solely from the onboard inertial measurement unit and wheel encoder-based odometry achieved well within the design goal of at most 10% error. However, MER vehicles were also driven along slippery slopes tilted as high as 31 degrees. In such conditions an additional capability was employed to maintain a sufficiently accurate onboard position estimate: visual odometry. The MER visual odometry system comprises onboard software for comparing stereo pairs taken by the pointable mast-mounted 45 degree FOV navigation cameras (NAV-CAMs). The system computes an update to the 6-DOF rover pose (x, y, z, roll, pitch, yaw) by tracking the motion of autonomously-selected "interesting" terrain features between two pairs of stereo images, in both 2D pixel and 3D world coordinates. A maximum likelihood estimator is applied to the computed 3D offsets to produce a final, corrected estimate of vehicle motion between the two pairs. In this paper we describe the visual odometry algorithm used on the Mars Exploration Rovers, and summarize its results from the first year of operations on Mars.
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the Mars Exploration rovers descent image motion estimation system
IEEE Intelligent Systems, 2004Co-Authors: Yang Cheng, J Goguen, A Johnson, C Leger, Larry Matthies, M S Martin, Reg G WillsonAbstract:Descent image motion estimation system is the first machine-vision system for estimating lander velocity during planetary descent. Composed of sensors and software, DIMES features a descent imager, a radar altimeter, an inertial-measurement unit, and an algorithm for combining sensor measurements to estimate horizontal velocity - the speed across the planet's surface the lander travels as it descends. Although the sensors are not novel technology, the algorithm and flight software that combines them are new. This algorithm combines radar, image, and inertial data in a novel way to create a low-cost, robust, and computationally efficient solution to the horizontal-velocity-estimation problem. This article describes the DIMES algorithm, its testing, and its performance during both Mars Exploration rover landings.