Flight-Testing of a Low-Cost Precision Aerial Delivery System

Abstract

The Affordable Guided Airdrop System is essentially an enhancement for a Container Delivery System (CDS) payload that allows the payload to be deployed over a drop zone from high altitude (10,000'+ MSL), while maintaining or even dramatically improving upon the accuracy achievable with low-altitude deployments. The ability of an aircraft to deliver payloads from these high altitudes greatly enhances the survivability of the aircraft when re- supplying units in hostile areas of operation. To achieve accurate payload delivery with the round parachutes used with CDS payloads, we have developed an autonomously guided actuator system that uses knowledge of the wind intensity and direction over the drop zone to guide these low-performance round parachutes to an accurate landing. The effectiveness of this method of aerial re-supply was demonstrated at the Precision Airdrop Technology Conference and Demonstration (PATCAD) 2003 using early prototype Airborne Guidance Units (AGUs). After demonstrating with proof-of-concept prototype AGAS units that riser slips can be used to effectively control the descent of a round parachute system, we set out to design an actuator system that would provide effective control while reducing the weight and complexity of the control unit. We also needed to answer questions about the best method of parachute rigging, what actuation stroke length would provide the best drive performance, expected system response times, what the upper and lower practical payload limits for the system would be, and what factors would have the greatest impact on system accuracy. Instrumented drop tests of the AGAS prototype systems provided data about loads in the parachute risers during actuations, the performance of the parachutes using various actuation stroke lengths, and electrical current-draw requirements of the actuators during operation. The data were analyzed and used to identify the ideal operating characteristics of an AGAS-equipped payload. In a joint effort between Capewell Components and Vertigo Inc., these characteristics were used to refine the design of the guidance system and to develop the design into a mature product. The result of this effort was a lighter, more compact, and more reliable actuator system, and better integration of the subsystems that support AGAS deployments. Five redesigned Airborne Guidance Units (AGUs), two windpacks, and a mission computer were then fabricated. Six separate test missions have been conducted with the new systems, with multiple payloads being deployed on each mission. The payloads were all of similar weight and configuration, were programmed for the same target coordinates, and were deployed on the same pass. This near simultaneous deployment of multiple systems with the same rate of descent and the same target resulted in close formation flying of the systems, and frequent collisions between the systems, but the overall accuracy results were excellent. System development and testing is ongoing, with the