The Philadelphia Water Department developed a unique, Web-based water quality forecasting system for the Schuylkill River called RiverCast. Based on real-time turbidity, flow, and rainfall data, it ...provides up-to-the-hour public service information on the estimated current fecal coliform concentrations in the river and the acceptable types of recreation based on those conditions. The system is designed to maximize accuracy while avoiding recommendations that suggest water quality is better than it is likely to be (avoidance of false positives). RiverCast can be reached on the Web at www.phillyrivercast.org.
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NASA/JPL's Mars exploration rovers acquire their attitude upon command and autonomously propagate their attitude and position. The rovers use accelerometers and images of the sun to acquire attitude, ...autonomously searching the sky for the sun with an articulated camera. To propagate the attitude and position the rovers use either accelerometer and gyro readings or gyro readings and wheel odometry, depending on the nature of the movement Earth-based operators have commanded. Where necessary, visual odometry is performed on images to fine tune the position updates, particularly in high slip environments. The capability also exists for visual odometry attitude updates. This paper describes the techniques used by the rovers to acquire and maintain attitude and position knowledge, the accuracy which is obtainable, and lessons learned after more than one year in operation.
In January, 2004, the Mars Exploration Rover (MER) mission landed two rovers, Spirit and Opportunity, on 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 visionbased 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 m 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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EMUNI, FIS, FZAB, GEOZS, GIS, IJS, IMTLJ, KILJ, KISLJ, MFDPS, NUK, OBVAL, OILJ, PNG, SAZU, SBCE, SBJE, SBMB, SBNM, UKNU, UL, UM, UPUK, VKSCE, ZAGLJ
Recent years have seen renewed attention to planetary exploration, and robotics is recognized as essential to many upcoming missions. In this article we describe the ongoing efforts of the Nomad ...project to develop robots for planetary and terrestrial exploration. The project is developing, demonstrating, and evaluating systems capable of long-distance, long-duration missions. In 1997 this work has resulted in the Atacama Desert Trek, in which a mobile robot named Nomad, explored the Atacama Desert of northern Chile. Nomad's 45-day objective was to travel 200 km across the rugged, barren landscape. We then will describe the technologies for Nomad's transforming chassis, high data-rate communication, safeguarded teleoperation and autonomy, panoramic imaging and visualization, and remote science. We then focus on issues of long-distance, long-duration exploration and describe the events and results of the Atacama Desert Trek.
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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.
Autonomous rover navigation is a critical technology for robotic exploration of Mars. Simulation allows more extensive testing of such technologies than would be possible with hardware test beds ...alone. A large number of simulations, running in parallel, can test an algorithm under many different operating conditions to quickly identify the operational envelope of the technology and identify failure modes that were not discovered in more limited testing. GESTALT is the autonomous navigation algorithm developed for NASA's Mars rovers. ROAMS is a rover simulator developed to support the Mars program. We have integrated GESTALT into ROAMS to test closed-loop, autonomous navigation in simulation. We have developed a prototype capability to run many copies of ROAMS in parallel on a supercomputer, varying input parameters to rapidly explore GESTALT's performance across a parameter space. Using these tools, we have demonstrated that large scale simulation can identify performance limits and unexpected behaviors in an algorithm. Such parallel simulation was able to test approximately 500 parameter combinations in the time required for a single test on a hardware test bed.
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Water is basic to all life on earth, and is vital for the functioning of society. Although water is vital to sustaining society, it is made increasingly impure as it is used. As populations expand, ...both in number and geographic area, the demand for fresh water supplies increases, the volume of pollutants available to contaminate water increases, and the competition between nature and society for use of the finite resource of fresh water intensifies. Whether to protect a relatively affluent way of life or to simply meet the basic needs of exploding populations, the need for water resource planning has never been greater. Unfortunately, water resource planning is often overlooked, and when done, plans are often incomplete or poorly constructed. There is a clear need for a more organized approach to water resource planning.
Increased attention has been focused in recent years on human-machine systems, how they are architected, and how they should operate. The purpose of this paper is to describe an actual instance of a ...practical human-robot system used on a NASA Mars rover mission that has been underway since January 2004 involving daily interaction between humans on Earth and mobile robots on Mars. The emphasis is on the human-robot collaborative arrangement and the performance enabled by mobility and robotic arm software functionality during the first 90 days of the mission. Mobile traverse distance, accuracy, and rate as well as robotic arm operational accuracy achieved by the system is presented.
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