September 5, 2004
Salar Grande, Atacama Desert, Chile

Agenda
• Resume testing of power management and distribution system
• Continue testing of orientation estimation
• Focus, balance, and calibrate stereo panoramic imager
• Test and tune autonomous navigation system

Status and Progress
Power system working. Zoë’s power monitoring computer is online and sensors throughout the rover are connected. Voltage is sensed on each power bus (computing/instruments and locomotion) and currents are sensed on each of two batteries, at the power management computer, and going into each of the four drive train amplifiers. This allows us to distinguish energy expended in locomotion from that going into computers and instruments. Eventually the power distribution computer will allow the rover onboard software to turn off and on components to save power. Monitoring voltage and current into the drive train will allow health monitoring software to detect faults as well as when wheels are stalled or slipping.

Orientation undetermined. We continue to work on sun-based orientation determination and are tracking down issues in the input parameters to the ephemeris calculation. Zoë is able to estimate its relative motion and changing in heading but because these measurements drift (particularly the heading gyro), periodic correction from absolute estimation of orientation will improve the overall result.

Confirmed stereo terrain mapping. We spend the day verifying the calibration of the navigation stereo pair and reviewing the quality of near-field terrain models. The cameras held their calibration from Pittsburgh and after a few minor configuration corrections on the video bus we appear to be getting good quality traversability estimates in the autonomous navigation system. Initial testing of autonomous navigation has been delayed somewhat as we work to tune steering performance at higher speeds.

Intermittent satellite communication. We’ve had our satellite link disappear occasionally, resulting in brief periods of isolation (unlike last field season when we were isolated for an entire month). Maybe it’s solar flares, maybe it’s the world cup tournament match, but the cause is unknown so communication may be sporadic for the time being

Upcoming
• Continue checkout of the position estimator
• Rebuild hard drive in the environmental station
• Grab images with the fluorescence imager
• Verify tuning of motion controller
• Navigate autonomously

Weather
Morning: Clear, calm, 15C, humidity 80%, heavy dew
Afternoon: Clear, light breeze 5-15kph from the south, 22, humidity 55%
Evening: Clear, light breeze, 10-20kph from the north, cool 10C,
humidity 65%

Quote of the Day
"You are the commandant of the wooly mammoth"