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Brains behind the QF-16 spearhead AF aerial target drone program

  • Published
  • By Chrissy Cuttita
  • Team Eglin Public Affairs
EGLIN AIR FORCE BASE, FLA. --  (Editor's note: This is part one of two in a series of articles focused on the QF-16 software development and testing. In part one, we look at the "brains" behind the QF-16, how Eglin engineers develop cutting edge 4th gen aerial target drone software. In part two we look at the "brawn" behind the QF-16, how pilot experience arms cutting edge 4th gen target drone software development and testing.)

Although the Air Force QF-16 flies pilotless in the skies over the Emerald Coast, they are not void of human contact.

Eglin's Gulf Range Drone Control System is used to track and control aerial target drones, collect and display time space position information data for aircraft and surface vehicles, and display aircraft control instrumentation.

"The 96 RNCS has been directly involved with the QF-16 program since 2009, providing more than 34,000 hours towards the program's recent successful unmanned flight," said Rick Ulrich, the 96th Range Control Group director. "GRDCS is a critical component of the QF-16 capability, serving as the ground-based computer system that tracks and controls the full-scale aerial target from takeoff to landing."

An interdisciplinary team of 15 contract and civilian personnel at the 96th Range Control Squadron provide the systems and software engineering support for the development and testing of custom software for the automated control of full-scale and sub-scale aerial targets.

The difference between the QF-16 and reconnaissance drones is that the QF-16 control software is written to mimic a hostile target, said Jeff Gibson, Government Team Lead for GRDCS development.

"The GRDCS Team has responded superbly to every challenge," said Lt. Col. Joseph Kendall, 53rd Test Support Squadron commander at Tyndall AFB, Fla., where the warfighters are using the software for developmental test of the QF-16.

For example, engineers were challenged with adapting the landing algorithm from the QF-4 to the QF-16. The new aerial target drone flares, lands smoothly and uses the brakes to come to a stop whereas the current one requires a firm brake with cable engagement to stop.

"This has been a complete paradigm shift in drone recovery, and would not have been possible without the strong engagement of the GRDCS team," said Kendall.

The 96th RNCS was involved early in the program's risk reduction efforts in several ways: developing a portable GRDCS control trailer and the first-ever mobile towers for early contractor ground and flight testing at Boeing's facility in Cecil Field, Fla.; providing a GRDCS emulator to Boeing for software compatibility testing; and developing the GRDCS data link tester to ensure RF compatibility with the QF-16.

"Our ultimate goal is to have the aircraft represent a fourth or fifth generation threat," said Jeff Stebbins, GRDCS contractor and QF-16 Integration Team Lead. "During weapons test and evaluation is the time to learn how well the missiles operate. Combat is not the time to find out you did something wrong."

The use of the F-16 Fighting Falcon provides a relatively low-cost, high-performance weapon system for the United States and allied nations.

"It's fascinating to see what this team is doing," said Gibson who joined the team mid-way through their three-year development. "When I see the QF-16 in flight I think 'wow, that's being controlled by our software we designed in our building.'"

In the development's phases, a team of engineers took a basic existing F-16 flight control computer and aircraft simulation and installed it in the GRDCS system. Then they added Boeing's autopilot code that is in the real QF-16 hardware. This created a simulated full-scale, airborne advanced fighter jet.

Using that simulation, GRDCS engineers developed the guidance, navigation, and control systems to track, control, and maneuver the aircraft during operations. Takeoff and landing systems were also developed and tested.

"Each engineer develops their specialty component of the system and then everything is integrated to insure all the designs operate coherently with each other," said Gibson. "Systems incorporated into GRDCS include the GN&C code, realistic heads up display, health test displays, failure codes, recovery displays, navigation displays, push-button displays, and integrated maps of the local area to include its military assets."

Once they perfected their software release, they completed local integration testing before delivering it to the QF-16 Program Office. The software release went through a second round of tests at Boeing's System Integration Lab where it would interface with hardware-in-the-loop via an Ethernet connection. Once integration and system testing were completed, the software release was CCB approved before being loaded onto the system.

"There is a lot of satisfaction seeing the QF-16 fly," said Gibson about the recent first unmanned flight. "We took something that wasn't meant to fly unmanned and made it fly without a pilot in the cockpit."

Unique to GRDCS Development Team at Eglin is the integration of an Air Force aircraft that's still in use.

Modifications to the QF-16 airframe and installation of major systems to transform the
F-16 include installation of the primary and back-up automatic flight control system, command/telemetry system, vector scoring system, flight termination system, payloads control system and visual augmentation system.

GRDCS development for the QF-16 program will continue after the Air Force's newest aerial target drone is deemed at full operational capability to sustain the aircraft's operation in 2015.

"We'll move into a 'maintenance' sort of role," said Gibson. "As we receive system improvement requests, we'll integrate them and publish a new version of the software."

Every new software "drop" comes with developmental testing by pilots controlling simulated flights before integrating it into the aircraft.

The system also trains controllers in proper handling of emergency situations. GRDCS builds in the capability to "fail" parts of the aircraft system in the simulation, forcing the aircraft simulation to then operate as if the failure really occurred. The controllers can assess the situation and take corrective action as needed.

Currently, six prototypes of the QF-16, each of various blocks, continue to test capabilities at White Sands Missile Range, N.M. Eglin's GRDCS expects to see their product controlling aircraft off the Boeing production line in late 2015.