The Affordable Guided Airdrop System (AGAS) is being evaluated as a low-cos
t alternative for meeting the military's requirements for precision airdrop
. Designed to bridge the gap between relatively expensive high-glide ratio
parafoil systems and uncontrolled ballistic parachutes, the AGAS concept of
fers the benefits of high-altitude parachute releases as well as the potent
ial for highly accurate point-of-use delivery of material. The design goal
of the AGAS development is to provide a guidance, navigation, and control s
ystem that can be placed in line with cargo parachute systems, for example
the G-12 flat-circular parachute, and standard delivery containers (A-22) w
ithout modifying these fielded systems. The AGAS is required to provide an
accuracy of 328 ft (100 m), circular error probable (CEP), with a desired g
oal of 164 ft (50 m) CEP. The feasibility of this concept was investigated
through modeling and simulation. A three-degree-of-freedom (3DOF) point mas
s flight dynamics model, sensor models of a commercial global positioning s
ystem (GPS) receiver and magnetic compass, and a model of the control and a
ctuator system were incorporated into a Monte Carlo simulation tool. A bang
-bang controller was implemented with trajectory tracking algorithms using
position and heading information. Flight testing, using a radio-controlled
scaled prototype, provided parachute dynamic and control response data to s
upport the modeling efforts. The study demonstrated that this concept has t
he potential to provide control of previously unguided round parachutes to
accuracies of approximately 210 ft (64 m) CEP. The program is now continuin
g into the next phase to include the development of a full-scale prototype
system for payloads up to 2200 lb (1000 kg).