Autonomous Aerial Refueling for Unmanned Combat Air System

Northrop Grum­man, U.S. Navy Test Autonomous Aer­i­al Refu­el­ing for Unmanned Com­bat Air Sys­tem Demon­stra­tion
Sur­ro­gate Test­ing With Lear­jet Val­i­dates Flight Con­trol Algo­rithms, Vision Sys­tems That Will Enable Autonomous Refu­el­ing Oper­a­tions

ST. AUGUSTINE, Fla. — Northrop Grum­man Cor­po­ra­tion (NYSE:NOC) and the U.S. Navy have suc­cess­ful­ly com­plet­ed a series of flight tests to demon­strate tech­nol­o­gy that could help extend the oper­at­ing range and flight dura­tion of future car­ri­er-based unmanned sys­tems.

The flight tests, com­plet­ed Jan. 21 in St. Augus­tine, proved the func­tion­al­i­ty of the hard­ware and soft­ware that will enable the X-47B unmanned air­craft to demon­strate autonomous aer­i­al refu­el­ing (AAR) in 2014.

The AAR activ­i­ty is part of the Navy’s Unmanned Com­bat Air Sys­tem Car­ri­er Demon­stra­tion (UCAS-D) pro­gram. Northrop Grum­man is the Navy’s UCAS-D prime con­trac­tor.

“These tests are a crit­i­cal step toward prov­ing that the X-47B can per­form autonomous aer­i­al refu­el­ing using either the Navy’s probe-and-drogue refu­el­ing tech­nique or the U.S. Air Force’s boom/receptacle approach,” said Carl John­son, vice pres­i­dent and UCAS-D pro­gram man­ag­er for Northrop Grumman’s Aero­space Sys­tems sec­tor. “Future unmanned sys­tems will need to use both refu­el­ing tech­niques if they plan to con­duct longer range sur­veil­lance or strike mis­sions from the car­ri­er.”

The AAR tests were con­duct­ed by a Northrop Grumman/Navy team using Calspan Corporation’s (Nia­gara Falls, N.Y.) Vari­able Sta­bil­i­ty Lear­jet as the X-47B sur­ro­gate air­craft, and a K707 tanker pro­vid­ed by Omega Air Refu­el­ing (Alexan­dria, Va.). The tests includ­ed sim­u­lat­ed flight demon­stra­tions of both boom/receptacle and probe-and-drogue aer­i­al refu­el­ing tech­niques. No fuel was exchanged between the air­craft dur­ing the test events, how­ev­er.

The Lear­jet sur­ro­gate was equipped with real or func­tion­al equiv­a­lents of the nav­i­ga­tion sys­tems, flight con­trol proces­sor and vision sys­tem that the X-47B will use to con­duct refu­el­ing oper­a­tions. The air­craft con­tained no refu­el­ing recep­ta­cle or refu­el­ing probe. The K707, which is near­ly iden­ti­cal in size and shape to an Air Force KC-135, was equipped with a Navy style refu­el­ing drogue only.

For each sim­u­lat­ed refu­el­ing event, the Lear­jet/X-47B sur­ro­gate was pilot­ed to a ren­dezvous posi­tion approx­i­mate­ly one nau­ti­cal mile from the tanker. Then the pilot trans­ferred con­trol of the air­craft to the X-47B’s autonomous flight con­trol proces­sor, which con­trolled the Lear­jet dur­ing the test event.

Dur­ing a typ­i­cal refu­el­ing event, the tanker oper­a­tor or a mis­sion oper­a­tor on the ground com­mand­ed the Lear­jet to fly, in sequence, to each of the major posi­tions asso­ci­at­ed with aer­i­al refu­el­ing: (1) the pre-tank­ing obser­va­tion point off one wing of the tanker; (2) the refu­el­ing con­tact posi­tion behind the tanker; and (3) the post-tank­ing “reform” posi­tion off the oth­er wing of the tanker.

“These flights demon­strat­ed empir­i­cal­ly that an unmanned sys­tem can con­duct aer­i­al refu­el­ing oper­a­tions with accu­ra­cy and pre­ci­sion,” said Pablo Gon­za­lez, pro­gram man­ag­er for Northrop Grumman’s UCAS-D AAR pro­gram. “The air­craft nev­er gets tired, and it responds exact­ly the same way to oper­a­tor com­mands every time.”

“The X-47B will use a hybrid GPS/vi­sion-based rel­a­tive nav­i­ga­tion sys­tem in con­junc­tion with its autonomous flight con­trol sys­tem to estab­lish and main­tain a pre­cise dis­tance between tanker and the receiv­er air­craft,” he added.

The Northrop Grumman/Navy test team plans to con­duct addi­tion­al AAR sur­ro­gate test­ing using the same air­craft when flight-qual­i­fied ver­sions of the rel­e­vant X-47B hard­ware and soft­ware become avail­able.

The UCAS-D pro­gram plans to demon­strate in 2013 the abil­i­ty of the tail­less, autonomous, low-observ­able rel­e­vant X-47B demon­stra­tor to safe­ly oper­ate from a Navy air­craft car­ri­er, includ­ing launch, recov­ery, bolter and wave-off per­for­mance, fol­lowed by the autonomous aer­i­al refu­el­ing in 2014. The pro­gram also plans to mature tech­nolo­gies required for poten­tial future Navy unmanned air sys­tem pro­grams. For the lat­est X-47B news and infor­ma­tion, please vis­it

Northrop Grum­man is a lead­ing glob­al secu­ri­ty com­pa­ny pro­vid­ing inno­v­a­tive sys­tems, prod­ucts and solu­tions in aero­space, elec­tron­ics, infor­ma­tion sys­tems, and tech­ni­cal ser­vices to gov­ern­ment and com­mer­cial cus­tomers world­wide. Please vis­it for more infor­ma­tion.

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