Field
Report
April
11, 2003
Salar Grande, Atacama Desert, Chile
Agenda
- Initial checkout and calibration
- Set up operations tent and communication
- Autonomous navigation and power measurement experiments begin
Status and Progress
- Logged complete day of weather. The weather station has been online since yesterday logging temperature, relative
humidity, wind speed and direction (maximum and average), and insolation. We will log weather data continuously until
we leave. We've already observed a few interesting phenomena: the wind is from the east in the morning, south in
afternoon and north in the evening, the temperature decreases (down 15C) and humidity increases (up 30%) within an
hour of sunset, and fog/dew follow warm nights.
- Solar experiment operational. Logging of voltage, current and temperature from the test panels (Si and GaAs) is
working as is control of the variable load and pan/tilt mechanism so that we can automatically log panel performance
with varying pointing direction and load over the course of the day. Problems with the pan/tilt were compensated in
software although blown fuse remains a puzzle. The spectrophotometer, which measures power across the entire spectrum
(200 - 1200nm) must still be operated manually. This graph shows the short wavelengths of spectra taken of the Sun on
April 10, 2003 at times noted in the legend. This spectrophotometer also covers the visible blue and ultraviolet
portions of the spectrum up to about 1200 nm, but is not all shown here. For these measurements the spectrophotometer
was manually aligned to the Sun, so the pointing accuracy should be considered to be +/-10°.
- Set up remote software development environment. With the project just underway all software is in preliminary
development so we set up our software repository (CVS) on a single laptop which acts as a server. Hyperion and
development computers (all laptops) remain synchronized and completely portable. It took a bit of network
reconfiguration to get it all working smoothly but it now should serve well.
- Set up short range communication. We put together a wireless ethernet for initial rover checkout. This provided good
coverage for a few hundred meters around base camp (and probably much farther). For the next stage of testing we will
bring the long-range radio ethernet and VHF communication systems online.
- Drove Hyperion. Electronic and sensor checkout of Hyperion were completed. We installed the solar panels and began
charging batteries. (The maximum power point trackers are making an interesting noise but seem to be functioning well
and quickly brought batteries from transport voltage up to full charge. We added an additional strap to further secure
the panels and experienced wind peak of 40kph with no difficulty. The panel failure mode will likely be the epoxy that
bonds the panels to mounting brackets but so far there are not signs of damage. After a few short moves, Hyperion went
on its first excursion traveling from base camp to first operational test region and back again. The total distance
was about 360m. Hyperion was driven mostly by supervised teleoperation where it is given steering commands to execute
but about 100m was by autonomous navigation. These first tests revealed problems in camera calibration which were then
resolved.
- Calibrated navigation cameras. Initial calibration of the cameras did not provide sufficient accuracy for terrain
modeling so a second round of calibration images were collected and processed to provide new calibration that looks
promising for tomorrow.
Upcoming
- Full-day solar experiment
- Autonomous navigation and power measurement experiments
Weather
11-Apr-03.humidity.pdf
11-Apr-03.insolation.pdf
11-Apr-03.temperature.pdf
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"Sunday monkeys don't play piano some ... duuuh"