| |
Project Overview
In September 2002, NASAÕs solar-powered Pathfinder-Plus UAV was used to conduct a proof-of-concept mission in U.S. national airspace above a 3500 acre commercial coffee plantation in Hawaii. The aircraft was equipped with a transponder for routine supervision by regional air traffic controllers. High resolution color and multispectral digital imaging payloads were housed in exterior-mounted environmental pressure pods. A local-area-network was used for camera control and image data downlink at rates exceeding 5 Mbit/sec, while a wide-area-network enabled U.S. mainland-based investigators to uplink payload control commands during part of the mission. Images were available enhancing, printing, and interpretation within minutes of collection. The color images were useful for mapping invasive weed outbreaks and for revealing irrigation and fertilization irregularities. Multispectral quantification of canopy color was related to mature fruit harvest from certain fields with significant fruit display on the tree canopy exterior.
During four hours of "loitering" above the plantation, ground-based pilots were able to precisely navigate the UAV along pre-planned flightlines, and also perform spontaneous maneuvers under the direction of the project scientist for image collection in cloud-free zones. Despite the presence of ground-obscuring cumulus cloudcover of ca. 70% during the image collection period, the UAV's maneuvering capability ultimately enabled collection of cloud-free imagery throughout most of the plantation. The mission demonstrated the capability of a slow-flying UAV, equipped with downsized imaging systems and line-of-sight telemetry, to monitor an agricultural region for an extended time period. Evolving long-duration (weeks to months) UAVs stand to make a future contribution to agricultural resource monitoring.
|
 |
|
