25 research outputs found
Airships: A New Horizon for Science
The "Airships: A New Horizon for Science" study at the Keck Institute for
Space Studies investigated the potential of a variety of airships currently
operable or under development to serve as observatories and science
instrumentation platforms for a range of space, atmospheric, and Earth science.
The participants represent a diverse cross-section of the aerospace sector,
NASA, and academia. Over the last two decades, there has been wide interest in
developing a high altitude, stratospheric lighter-than-air (LTA) airship that
could maneuver and remain in a desired geographic position (i.e.,
"station-keeping") for weeks, months or even years. Our study found
considerable scientific value in both low altitude (< 40 kft) and high altitude
(> 60 kft) airships across a wide spectrum of space, atmospheric, and Earth
science programs. Over the course of the study period, we identified
stratospheric tethered aerostats as a viable alternative to airships where
station-keeping was valued over maneuverability. By opening up the sky and
Earth's stratospheric horizon in affordable ways with long-term flexibility,
airships allow us to push technology and science forward in a project-rich
environment that complements existing space observatories as well as aircraft
and high-altitude balloon missions.Comment: This low resolution version of the report is 8.6 MB. For the high
resolution version see: http://kiss.caltech.edu/study/airship
Fully Self-Contained Vision-Aided Navigation and Landing of a Micro Air Vehicle Independent from External Sensor Inputs
Direct-lift micro air vehicles have important applications in reconnaissance. In order to conduct persistent surveillance in urban environments, it is essential that these systems can perform autonomous landing maneuvers on elevated surfaces that provide high vantage points without the help of any external sensor and with a fully contained on-board software solution. In this paper, we present a micro air vehicle that uses vision feedback from a single down looking camera to navigate autonomously and detect an elevated landing platform as a surrogate for a roof top. Our method requires no special preparation (labels or markers) of the landing location. Rather, leveraging the planar character of urban structure, the landing platform detection system uses a planar homography decomposition to detect landing targets and produce approach waypoints for autonomous landing. The vehicle control algorithm uses a Kalman filter based approach for pose estimation to fuse visual SLAM (PTAM) position estimates with IMU data to correct for high latency SLAM inputs and to increase the position estimate update rate in order to improve control stability. Scale recovery is achieved using inputs from a sonar altimeter. In experimental runs, we demonstrate a real-time implementation running on-board a micro aerial vehicle that is fully self-contained and independent from any external sensor information. With this method, the vehicle is able to search autonomously for a landing location and perform precision landing maneuvers on the detected targets