LOCALIZATION AND ‘CONTEXTUALIZATION’ OF CURIOSITY IN GALE CRATER, AND OTHERLANDED MARS MISSIONS. T. J. Parker1, M. C. Malin2, F. J. Calef1, R. G. Deen1, H. E. Gengl1, M. P.Golombek1, J. R. Hall1, O. Pariser1, M. Powell1, R. S. Sletten3, and the MSL Science Team. 1Jet Propulsion Labora-tory, California Inst of Technology (timothy.j.parker@jpl.nasa.gov), 2Malin Space Science Systems, San Diego, CA(malin@msss.com ), 3University of Washington, Seattle.

Introduction: Localization is a process by whichtactical updates are made to a mobile lander’s positionon a planetary surface, and is used to aid in traverseand science investigation planning and very high-resolution map compilation. “Contextualization” ishereby defined as placement of localization infor-mation into a local, regional, and global context, byaccurately localizing a landed vehicle, then placing thedata acquired by that lander into context with orbiterdata so that its geologic context can be better charac-terized and understood.

Curiosity Landing Site Localization: The Curi-osity landing was the first Mars mission to benefitfrom the selection of a science-driven descent camera(both MER rovers employed engineering descent im-agers). Initial data downlinked after the landing fo-cused on rover health and Entry-Descent-Landing(EDL) performance. Front and rear Hazcam imageswere also downloaded, along with a number ofMARDI thumbnail images. The Hazcam images wereused primarily to determine the rover’s orientation bytriangulation to the horizon. The landing site locationwas identified by the MARDI PI (Malin) based on theMARDI thumbnails on Sol 1. By Sol 3, the first 360°Navcam panorama had been downlinked, and the loca-tion of Bradbury Landing was determined to be at -4.589467° latitude, 137.441633° longitude (MOLA2000, E longitude), based on a controlled photomosaicof CTX and HiRISE images compiled prior to EDL[1].

MARDI EDL images are being compiled into twomosaics that will provide color coverage of the landingsite and science target regions imaged during EDL.These mosaics will be incorporated into the landingsite base map [1] in two ways. 1) All images prior to~#490 are lower in spatial resolution than HiRISE.This mosaic will be georeferenced to the HiRISE basemap and used to colorize the HiRISE data; 2) All im-ages after ~#490 are higher in spatial resolution thanthe HiRISE base map and will be georeferenced to andoverlain onto the HiRISE, with each successivelyhigher resolution MARDI image over the previousimage. The result will be georeferenced to the HiRISEbase mosaic.

Fig 1: Portion of mosaic of MARDI EDL images.MARDI imaged the landing site and science targetregions in color.

When is localization done?After each drive for which Navcam stereo da-

ta has been acquired post-drive and terrain mesheshave been processed and incorporated into MSLICE(Curiosity) or Maestro (Opportunity) as orthographic(overhead) projections. In most cases, these updatesare available in time for planning the next sol’s activi-ties.

The Localization Scientists (Parker and Calef)maintain a location map of the entire Curiosity traversefrom Bradbury Landing to the current location. Parkeralso maintains a similar map of Opportunity’s traverseacross Meridiani Planum.

“Contextualization” of Curiosity and otherlander observations: The traverse maps for Curiosi-ty, Opportunity, and Spirit, are the first step in placingeach vehicle in a local and regional geologic context.During the Viking and Pathfinder missions, the highestresolution images available to the science teams wereacquired by the Viking Orbiters during the late 70s andearly 80s. MOC and Themis VIS was available forlanding site selection for the MER rovers, and HiRISEimages became available for planning during the thirdyear of the MER mission. HiRISE images were alsoavailable for final site selection and localization ofPhoenix. HiRISE mosaics were acquired beginningwell in advance of the MSL landing, and have beenused for daily science planning since landing.

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The “resolution gap” between orbiter and ground-based images available during surface operations ismuch smaller for Curiosity, MER, and Phoenix than itwas for Pathfinder and Viking Landers 1 and 2. Yet, itis still desirable to “bridge” that gap by placing theground panoramas and DEMs into context with theorbiter images and DEMs now available. This workinvolves georeferencing orthorectified Navcam, Mast-cam, and Pancam panoramas and DEMs (MSL andMER), which can be produced at centimeter-scalepostings, to HiRISE orthorectified images and DEMs(1 meter-postings). A perspective view of a CuriosityNavcam panorama and DEM with 1cm-posting toHiRISE image and DEM with 1m-posting is shown inFig 2. Preliminary results suggest that Navcam-basedDEMs are reliable to a distance of about 50 meters forCuriosity and 20-30 meters for Opportunity and Spirit.It should be noted that the limit isn’t due to imageresolution, but to the typically-shallow viewing angle.When images are taken from a topographic vantagepoint, the viewing geometry will be more favorable forDEM generation using close range photogrammetry.

Fig 2: Perspective view of Curiosity Navcam panora-ma and DEM georeferenced to HiRISE image andDEM. Note individual rocks and small ledges are re-solved at 1cm-posting.

As of this writing, work is under way to generatesimilar DEMs from Mastcam stereo observations (bothfrom single-pointing L-R stereo and long baseline ste-reo).

Figure 3: Mastcam 100mm pan of Glenelg pro-jected onto HiRISE DEM, with additional georeferenc-ing in ArcMap.

Another method of “contextualizing” ground-basedobservations is to project monoscopic panoramas ontothe HiRISE 1 m post DEM (Navcam, Mastcam, andPancam) Fig 3 shows a portion of a Mastcam 100mmpan of the Glenelg region projected onto the DEM.

Additional georeferencing was required in Arcmapbecause projecting the high-frequency topographicdetails in the Mastcam pan onto the comparativelylow-frequency HiRISE DEM introduced distortionsinto the orthorectified mosaic (primarily range dispari-ties where the projected image intersected the DEM).As noted above, we find that the best results areachieved when projecting onto a slope facing the vehi-cle, or from an elevated viewpoint. Even at severalhundred meters distance, correlation between theground view and the HiRISE map is possible. Mastcam34mm images have a comparable IOF to HiRISE atabout 1 km distance. The 100mm camera is compara-ble to HiRISE at about 3 km. This suggests that fromthe right vantage point (e.g., climbing Mt. Sharp) Cu-riosity could, in effect, provide its own very high reso-lution orthographic image and topography maps.Contextualizing Opportunity observations: Oppor-tunity has amassed several hundred Navcam and Pan-cam stereo panoramas since it landed in Eagle Crater 9years ago. In several locations along its traverse, siteswhere these data were acquired are close enough to-gether to provide overlapping coverage, primarily fromNavcam. The most recent such example – MatijevicHill – was imaged deliberately in this manner, in partto allow compilation of a Navcam-scale orthorectifiedimage and DEM map that could be georeferenced tothe HiRISE image and DEM. Figure 4 is a samplefrom the Matijevic “Walkabout”. Incorporating theNavcam DEMs into this map gives the science teamthe ability to determine the extent of structures lateral-ly beyond the edges of a single rover location and helpunravel the stratigraphic record of the EndeavourCrater rim area.

Figure 4: Perspective view of a portion of MatijevicHill, looking north. Opportunity Navcam panoramasgeoreferenced to HiRISE image and DEM.Reference: [1] Parker et al. (2012) LPS 43, 2535.

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