Technology that could someday "MapQuest" Mars and other bodies in
the solar system is under development at Rochester
Institute of Technology's Rochester Imaging Detector Laboratory (RIDL),
in collaboration with Massachusetts Institute of Technology's Lincoln Laboratory.
Three-Dimensional “super roadmaps” of other planets and moons would
provide robots, astronauts and engineers details about atmospheric composition,
biohazards, wind speed and temperature. Information like this could help land
future spacecraft and more effectively navigate roving cameras across a Martian
or lunar terrain.
RIT scientist Donald Figer and his team are developing a new type of detector
that uses LIDAR (LIght Detection and Ranging), a technique similar to radar,
but which uses light instead of radio waves to measure distances. The project
will deliver a new generation of optical/ultraviolet imaging LIDAR detectors
that will significantly extend NASA science capabilities for planetary applications
by providing 3-D location information for planetary surfaces and a wider range
of coverage than the single-pixel detectors currently combined with LIDAR.
The device will consist of a 2-D continuous array of light sensing elements
connected to high-speed circuits. The $547,000 NASA-funded program also includes
a potential $589,000 phase for fabrication and testing.
“The imaging LIDAR detector could become a workhorse for a wide range
of NASA missions,” says Figer, professor in RIT’s Chester F. Carlson
Center for Imaging Science and director of the RIDL. “It could support
NASA’s planetary missions like Europa Geophysical Orbiter or a Mars High-resolution
Spatial Mapper.”
LIDAR works by measuring the time it takes for light to travel from a laser
beam to an object and back into a light detector. The new detector can be used
to measure distance, speed and rotation. It will provide high-spatial resolution
topography as well as measurements of planetary atmospheric properties—pressure,
temperature, chemical composition and ground-layer properties. The device can
also be used to probe the environments of comets, asteroids and moons to determine
composition, physical processes and chemical variability.
Working with Figer are Zoran Ninkov and Stefi Baum from RIT and Brian Aull
and Robert Reich from Lincoln Laboratory. The team will apply LIDAR techniques
to design and fabricate a Geiger-Mode Avalanche Photodiode array detector. The
device will consist of an array of sensors hybridized to a high-speed readout
circuit to enable robust performance in space. The radiation-hard detector will
capture high-resolution images and consume low amounts of power.
The imaging component of the new detector will capture swaths of entire scenes
where the laser beam travels. In contrast, today’s LIDAR systems rely
upon a single pixel design, limiting how much and how fast information can be
captured.
“You would have to move your one pixel across a scene to build up an
image,” Figer says. “That’s the state of the art of LIDAR
right now. That’s what is flying on spacecraft now, looking down on Earth
to get topographical information and on instruments flying around other planets.”
The LIDAR imaging detector will be able to distinguish topographical details
that differ in height by as little as one centimeter. This is an improvement
in a technology that conflates objects less than one meter in relative height.
LIDAR used today could confuse a boulder for a pebble, an important detail when
landing a spacecraft.
“You can have your pixel correspond to a few feet by a few feet spatial
resolution instead of kilometer by kilometer,” Figer says. “And
now you can take LIDAR pictures at fine resolutions and build up a map in hours
instead of taking years at comparable resolution with a single image.”
The imaging LIDAR detector will be tested at RIDL in environments that mimic
aspects of operations in NASA space missions.
In addition to planetary mapping, imaging LIDAR detectors will have uses on
Earth. Other applications include remote sensing of the atmosphere for both
climate studies and weather forecasting, topographical mapping, biohazard detection,
autonomous vehicle navigation, battlefield friend/foe identification and missile
tracking, to name a few.
“There is an increasing demand for highly accurate three-dimensional
data to both map and monitor the changing natural and manmade environment,”
says Ninkov, professor of imaging science at RIT. “As well as spaceborne
applications there are terrestrial applications for LIDAR systems such as determining
bridge heights, the condition of highways and mapping coastal erosion as sea
heights rise.”