By Ed Lopez November 22, 2016
PICATINNY ARSENAL, N.J. -- Engineers at Picatinny Arsenal are applying their expertise in software reliability to an advanced precision airdrop system designed to deliver vital supplies to the warfighter on time and in challenging terrain with minimum damage to cargo.
The joint precision airdrop system, or JPADS, is intended to provide increased tactical maneuverability and enable a sustainment capability to support total Army, multi-service, and multi-national ground forces.
Moreover, JPADS meets a sustaining combat power requirement to provide high-altitude, precision airdrop as a direct and theater delivery method into dynamic, dispersed and unsecured battle scenarios.
The JPADS air vehicles are a family of high altitude systems offering weight capabilities of 500, 2,400 and 10,000 pounds.
The JPADS systems provide a precision-guided capability for the accurate delivery of container delivery system (CDS) loads on to small drop zones from Air Force C-130 and C-17 aircraft flying at high altitudes and standoff distances.
JPADS is especially helpful to special forces, but it also has wider military applicability. The overall program has been a joint effort by the Army, Air Force and Marine Corps since 1997.
"We have worked with program partners to provide software engineering for challenging technologies used by the airdrop systems, resulting in an overall reduced cost and schedule for the program," said Judy Mazeski, Precision Control Unit Software Branch chief, Armament Software Engineering Center.
The software support at Picatinny is performed by the Armament Software Engineering Center, which is part of the larger Weapons and Software Engineering Center. Both organizations, in turn, belong to the Armament Research, Development and Engineering Center, or ARDEC.
ARDEC's software expertise supports the Product Manager Force Sustainment Systems (PM (O-5) FSS) program office, part of the Program Executive Office for Combat Support and Combat Service Support.
The office encompasses the management of airdrop equipment for personnel, supplies and equipment in support of mass airborne assaults, resupply, special operations, deep strike concepts, and humanitarian relief.
The software engineering center at Picatinny focuses its support on the PM (O-5) FSS goals for improved accuracy and reliability of parachutes, increased payloads, improved safety, and increased operational flexibility.
The JPADS leverages and reuses the software application code and, to meet future upgrades, all the JPADS variants employ a common software architecture.
"Software engineering requires [that] the right solution is [incorporated] early in the development process," said Devorah Burger, Team Lead, Armament Software Engineering Center. "It's not effective to 'bolt-on' engineering solutions at the end of system development."
JPADS provides guidance, navigation and control (GN&C) capabilities unattainable by simpler airdrop technologies. These modernization efforts improve the accuracy and performance of JPADS in numerous challenging weather and terrain conditions.
SOFTWARE CREATION CHALLENGES
Challenges that engineers faced in designing the software included:
-- Weather conditions: The software must be sophisticated enough to make significant real-time adjustments to its guidance strategy to compensate for high or changing winds.
-- Collision avoidance: The system must be able to prevent mid-air collisions, such as when multiple bundles are dropped in a single pass.
-- Combination drops: In the case where JPADS is dropped with jumpers in the same pass, the system must fly in a predictable manner, so the jumper can follow it to the point of impact.
-- Terrain avoidance: The software must account for variable terrain conditions. Dropping in a mountainous area is more difficult than dropping in a flat ground.
-- Hazard avoidance and airdrop estimation: The software must be able to determine the level of likelihood of a successful drop with hazardous conditions such as rivers and buildings. Also, the software must be able to adjust its flight path to avoid hitting any hazards within the drop zone.
-- GPS-denied environments: Delivering payloads in an area where there is no GPS data available.
THE JOINT PRECISION AIRDROP SYSTEM
JPADS increases aircraft and payload survivability and enables delivery of multiple loads to single or multiple drop zones in a single aircraft pass with an accuracy better than 150 meters for the JPADS 2K system and accuracy better than 250 meters for the JPADS 10K system.
The JPADS airdrop vehicles include an air parafoil, with a glide ratio of 3-to-1, coupled with a military GPS-based autonomous guidance unit (AGU).
The onboard guidance, navigation and control (GN&C) software in the AGU autonomously steers the parafoil to the designated impact point.
Onboard the aircraft, the JPADS 2K AGU is wirelessly integrated with the United States Air Force Mission Planner, which is used to monitor the health of the systems before flight and determine an appropriate launch acceptability region.
Just prior to landing, the AGU commands the parafoil to perform a flare maneuver and slow the system down for landing to increase load survivability.
The JPADS keeps warfighters and vehicles off the roads for resupply by utilizing military GPS-based, autonomously-guided navigation and control systems, steerable parachute decelerators, and autonomous operation and waypoint navigation.
WHAT THE SOFTWARE DOES
The JPADS autonomous guidance unit (AGU) houses the battery power pack; GPS receiver; guidance, navigation and control (GN&C) software package; and the hardware required to operate the steering lines.
Prior to deployment, the AGU is programmed with a point of impact, the gross rigged weight of the system, digital terrain elevation data (DTED), canopy type as well as the elevation of the point of impact. The system uses these inputs to calculate a projected trajectory.
The JPADS 2K AGU continues to calculate its position via the GPS throughout descent, landing near the point of impact with an accuracy better than 150 meters with an 80 percent confidence.
The steerable parafoil is called a "decelerator," and gives the JPADS system directional control throughout its descent by means of decelerator control lines attached to the MAGU.
The decelerator control lines create drag on either side of the decelerator, which turns the parachute, thus achieving directional control, and allow the JPADS to land near the point of impact, even though it is released at a high standoff distance.
The mission planner software gives the aircrew the ability to plan the mission, in flight if necessary, as well as provides a computed air release point (CARP), where the load is released.
JPADS software has been improved throughout the time that ARDEC has supported the program. In addition to accuracy improvements, the software has been updated to include user selectable flight software navigation strategies.
These strategies allow for normal operations, landing on an impact point in a mountainous area, as well as a predictable flight strategy for combination drops when jumpers are going to be following the bundle.
Additionally, the software helps reduce the chance of collision between bundles and increases payload survivability.
Future research may include camera-based navigation, which could be extended for use on an autonomous vehicle, manned aircraft, and unmanned aircraft. Vision-based software technologies compare what the camera sees with the latest satellite images of the ground target area to determine the drop zone.
That means a vision-based JPADS could provide a capability that autonomously steers the cargo delivery to the target without requiring outside signals or information, such as GPS.
ARDEC's Precision Control Unit Software Branch will ensure that every armament solution delivered to the warfighter is designed from the start with the most effective, adaptive and maintainable solutions.
ARDEC expects growth in the precision guided engineering competency due to emerging and evolving threats.
The U.S. Army Armament Research, Development and Engineering Center is part of the U.S. Army Research, Development and Engineering Command, whose mission is to provide innovative research, development and engineering to produce capabilities that provide decisive overmatch to the Army against the complexities of the current and future operating environments in support of the joint warfighter and the nation.