Payload Derived Position Acquisition System (PDPAS) Algorithm Implementation with the Common Range Integrated Instrumentation System Rapid Prototype Initiative (CRIIS-RPI)

Abstract

The Payload Derived Position Acquisition System (PDPAS) was developed 1,2 to provide a Time-Space-Position Information (TSPI) solution for airdrop loads deployed from aircraft. The PDPAS provides a 6 degree of freedom (DOF) solution from aircraft exit to ground impact. The solution utilizes a unique Inertial Measuring Unit (IMU) initialization and processing algorithm that is designed for use in the airdrop environment. Current TSPI solutions for airdrop testing are threefold: Kineto Tracking Mount (KTM) derived, Differential Global Positioning System (GPS), and Radar. The KTM TSPI solution provides a 4DOF solution that is prohibitively expensive and limited to a single airdrop load at a time. Differential GPS provides a cost effective 3DOF solution, but does not provide the solution at aircraft exit due to limited antenna visibility of the sky upon rotation at exit and the high accelerations at canopy opening that saturate the GPS’s oscillators. Previously (ref 1), the use of the PDPAS was limited by the GPS and IMU hardware configurations because they were prohibitively expensive, comprised of low quality IMU sensors, and were not compatible with air droppable packaging. The Common Range Integrated Instrumentation System Rapid Prototype Initiative (CRIIS-RPI) program has provided a deployed GPS/IMU solution to the U.S. Army Yuma Proving Ground (YPG) that does not limit the implementation of the PDPAS algorithm for use in airdrop testing. The CRIIS-RPI program was developed to provide a common set of instrumentation U.S. Army wide for low dynamic vehicles in a real-time environment. The instrumentation in the CRIIS-RPI includes a medium quality IMU and differential GPS, which provides the necessary data types and quality for implementation of the PDPAS at YPG. The integration of the PDPAS with the CRIIS-RPI has completed initial implementation testing and validation through a series of ground testing, cargo airdrops, and personnel jumps. The conclusions from the testing is a set of instrumentation that provides a cost effective and improved stand-alone solution over other TSPI sources for airdrop applications but not for parachute opening performance. The PDPAS with the CRIIS-RPI is not a fully functional capability at YPG due to the CRIIS-RPI’s design and implementation method.