AGAS is a low-glide trajectory control system for precision cargo airdrop. It is designed for use with existing parachutes and standard airdrop packages (e.g., A-22). Use of existing canopies and cargo delivery systems reduces the overall cost of deploying a payload fitted with the AGAS.

  The AGAS consists of the following elements:

• Guidance, Navigation and Control electronics and software (GN&C)
• A windsonde
• Mission Planner software
• Electromechanical parachute riser actuation system

The system control and GN&C equipment (components of the AGAS unit) are placed on top of the payload, and the electromechanical riser-actuation hardware is connected to the parachute risers. When a riser is actuated, the parachute deforms, causing it to glide in a direction relative to the actuation.

A windsonde (pictured at left) is first dropped from the airplane, and it transmits wind data to the mission-planner software on a laptop computer either on the ground or in the aircraft. The mission planner computes a trajectory and a release point for the payload, and these data are uploaded to the GN&C flight computer onboard the AGAS unit. Corrections to the glide path are made as necessary during the descent by actuating the parachute risers in order to achieve an accurate landing.

At right is pictured two AGAS units in flight. Note the deformation of the canopy as the units drive for the wind trajectory, which is the point in the sky at which the system should be at the current altitude in order to land on the target. There is a series of these trajectory points from release altitude all the way to the ground. The trajectory is computed from data retrieved from the windsonde, which provides up-to-the-minute wind information. AGAS accuracy and consistency are unmatched.

AGAS was designed to be simple and easy to use. It was also designed to be used with existing parachutes (e.g., the G-12) and cargo delivery systems (e.g. the A-22). All this results in low cost and an extremely shallow learning curve for new users. AGAS software was designed to be simple and easy to use. The user only needs to fill in a simple form and the software takes care of the rest.

At PATCAD 2003 (Precision Airdrop Technology Conference and Demonstration) AGAS demonstrated its incredible precision and reliability by putting all six of its payloads within a 26-meter CEP (circular error probable) of the target, after being dropped from 10,000 feet MSL. No other system came close to this level of accuracy or consistency. The following is the mission planner's graphical telemetry display of the first drop at PATCAD 2003 (click to enlarge). The payload was released at 10,000 feet MSL (above mean sea level) and telemetry transmission began at about 9,000 feet. Note in the Planned Trajectory Error window (with distance in feet from the planned trajectory on the vertical axis, altitude on the horizontal axis, and the yellow line indicating altitude at ground level) that the system was released about 1,100 feet from the ideal drop point (the CARP, or Computed Air Release Point). The AGAS then drove steadily for the appropriate point in the sky, based on the wind profile. In this graphic, the system is 70 feet from the trajectory at 6,000 feet MSL, having made up more than 1,000 feet of initial course error. In the System Proximity window note that riser #1 is actuated, or extended. This drives the canopy to the southwest, toward the target. This AGAS unit eventually landed about 50 feet from the target on the ground, after a descent of nearly two vertical miles!

A graph and table show the results of 11 AGAS drops. The last six (drops 6 through 11) were the PATCAD 2003 drops at the Army's Yuma Proving Ground in Arizona. The accuracy goal sought at PATCAD was a 100-meter CEP (circular error probable), which means that half the payloads must land within this radius of the target. AGAS smashed the Army's accuracy goal by almost a factor of four, with a 26-meter CEP. AGAS is not only accurate, but consistent.

The following graphic shows the profile of a typical AGAS mission. If the payload were released in exactly the right spot (the CARP, or computed air release point), and if the winds did not change at all, no correction would be necessary to stay on the calculated trajectory. In a real-life mission, however, numerous corrections must be made to fly the payload to its intended target.