ESRL Global Systems Division

PADS and LAPS Increase Accuracy of Military Airdrops

NOAA's Forecast Systems Laboratory (FSL) has been collaborating with the US Army Natick Soldier Systems Center (NSSC) and the USAF Air Mobility Command (AMC) to develop and field the latest technologies applied to precision airdrops. Air operations in Bosnia, Kosovo, and Afghanistan underscored the need for a precision aerial delivery capability operating from high altitude to avoid ground threats. Responding to a request for assistance, FSL has helped to create the Precision Airdrop System (PADS). Numerous operational tests, in the hands of operational aircrews, have demonstrated that PADS significantly improves the accuracy of airdrops from altitudes up to 25,000 feet MSL.

Historically, re-supply and humanitarian airdrop relief operations have been conducted at low altitudes, placing the aircraft at risk in hostile environments. To correct this, high-resolution forecast fields from weather models, in-situ atmospheric measurements, and a customized version of FSL's Local Analysis and Prediction System (LAPS) are used on-scene to provide short-range forecasts to support high-altitude precision airdrop operations. Improved precision is achieved through LAPS assimilation of high-resolution four-dimensional forecast data produced by supercomputers at the Air Force Weather Agency, in-situ weather data from GPS-based dropsondes deployed near the drop zone, and high-resolution topographic data. With the LAPS-generated, three-dimensional forecast wind and density fields modified by the underlying topography, the system next determines the computed airdrop release point for parachuted ballistic cargo by the application of a fully-dynamic, payload-release, parachute-opening, and descent-trajectory model. These components are all integrated in PADS, running on an altitude-resistant laptop computer operated aboard the airdrop aircraft. PADS also includes utilities for pre-flight planning, in-flight updates, and mission execution decisions.

The pairing of PADS with LAPS has yielded big improvements in airdrop accuracy. The Army's goal was to bring cargo airdrops to within 400 meters of the desired impact point (versus over 1000 meters in the past). This integrated technology has resulted in demonstrated accuracies consistently in the range of 200-400 meters from altitudes between 18,000 and 25,000 feet AGL from C-130 and C-17 airdrop aircraft. PADS and selected guided parachute systems are earmarked for fielding to Army operations this coming summer.

The significant advances in precision airdrop to date are the result of a strong team from government, university laboratories, and industry, headed by NSSC. In addition to NSSC and FSL, the team includes staff from AMC who contributed requirements and test deployments, the MIT Charles Stark Draper Laboratory who developed the parachute release and trajectory models, and Planning Systems, Inc. (PSI) who integrated the complete system on the laptop and developed the mission-specific dropsondes. For more information, contact Richard Benny at NSSC (, 508-233-5835); for specific information on PADS contact Bob Wright at PSI (, 703-788-7746).

Contact information
Name: John A McGinley
Tel: 303 497 6161