Phase II Final Report - NASA's Institute for Advanced Concepts

Chapter 4.0 Entomopter Flight Operations
4.3 Entomopter-borne Active Emitters for Navigation and Communication
Altitudes are not expected to exceed 10 m, and distances to the refueling rover are assumed to be
within 200 m.
Side view
of entomopter body
Elevation plane, θ
ϕ = θ = 0
Azimuth plane, ϕ
Figure 4-6: Side View of Entomopter Illustrating Assumed Coordinate System
4.3.1.1 Obstacle Detection Assumptions
• Azimuthal coverage: ϕ = -90 o to 90 o for front and side coverage
• Elevation angle: θ = -90 o to 45 o for coverage below and in front of the Entomopter
• Minimum range: This minimum range will be determined by the maximum reaction
time of the Entomopter. A worst case five-second reaction time will be assumed. At
~14 m/s (cruising speed), this results in a minimum range of 70 m. At ~3 m/s (exploration/inspection
speed), this results in a minimum range of 15 m.
• Maximum range: ~ 200 m
• Range resolution: ~ 0.5 m
• Vertical resolution: ~ several meters at maximum range, ~ 25 m at minimum range
• Horizontal resolution: ~ several meters at maximum range, ~50 m at minimum range
The Entomopter will navigate autonomously. It will take off, explore the Mars terrain, and land
without human intervention. The multifunctional subsystem investigated here will be capable of
detecting objects in the Entomopter flight path, which will eventually be coupled with an
onboard auto-routing algorithm and navigational control for a complete collision-avoidance system.
It is unlikely that the Entomopter will fly into enclosed areas, so avoidance of obstacles from
above will not be a priority. Fine cross resolutions are not needed because the goal is to avoid
obstacles, not to achieve synthetic vision where detailed information is required to identify the
detected obstacles. Most obstacles will be terrain features, so the system resolution can be several
meters at maximum range. As obstacles get closer, they occupy a greater portion of the field
of view, so the ability to avoid smaller things will be enhanced as the Entomopter approaches
them. Vertical resolutions (elevation) can be larger than the horizontal (azimuth) resolutions
since it is unlikely that the Entomopter will be flying under things or through holes. Since most
natural obstacles will not afford a path beneath, obstacle avoidance responses will typically be to
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