Aviation Week & Space Technology - 30 March-12 April 2015

AviationWeek.com/awst AVIATION WEEK & SPACE TECHNOLOGY/MARCH 30-APRIL 12, 2015 61

Amy Butler and Guy Norris Edwards AFB, California

Seeing Eye to Eye

Software patch designed to fi x snag

in ship-to-ship F-35 data ‘fusion’

F

lights of two F-35 test jets have

begun here with a software patch

to explore the effectiveness of

upgrades designed to improve the

“fusion” of the threat picture within

multi-aircraft F-35 formations.

Fusion is a hallmark selling point

for the stealthy, single-engine F-35.

Prime contractor Lockheed Martin

and of cials from the Pentagon’s F-35

Joint Program Of ce (JPO) say data

collected through the aircraft’s elec-

tro-optical targeting system, radio-

frequency electronic warfare system

and advanced electronically scanned

array radar will be blended for the pilot

in a single display by onboard software

in an unprecedented manner.

The result is expected to be a re-

duced pilot workload and improved

awareness of the battlespace, includ-

ing threats as well as objects that

should not be targeted.

Additionally, the aircraft are de-

signed to work in a network, sharing

the same threat picture among pilots

in ship formations through use of the

new Multifunction Advanced Datalink

(MADL). This link is intended to trans-

mit data covertly to allow for opera-

tions in protected airspace; Link 16, the

current data-sharing standard, by con-

trast, broadcasts and does not function

stealthily. The result should be to allow

multiship formations to distribute the

workload more quickly and ef ectively

during missions and to more wisely

use the limited munitions onboard

the aircraft to attack targets. Though

often referenced, F-35 data fusion has

been rarely described in detail.

Data fusion would seem to be simple,

as the use of mobile telephones with

fused data applications is widespread.

However, for the F-35, the data must be

extremely precise—the system cannot

confuse a school bus for a mobile mis-

sile erector, for example. The threat

data relies on thousands of mission

fi les that cue the F-35’s software, in-

dicating what objects are (a surface-

to-air missile site, enemy radar, enemy

vehicle, etc.).

Doing this on a single jet is a chal-

lenge in and of itself, but creating a

single, fused picture based on data col-

lected by four jets in dif erent locations

with varying views of the battlespace

is another challenge altogether. This is

the latest of many unprecedented tasks

being tackled by the F-35 team.

Late last year, U.S. Air Force Lt.

Gen. Christopher Bogdan, the F-35

program executive officer, said the

latest software challenge was to cre-

ate an accurate “fused” picture across

multiship formations.

“Ideally with fusion working at the

100% level, each F-35 has its picture

from its own sensors and shares that

picture over the data links—all the

wingmen in that link also have their

own-ship sensor picture as well as the

shared info,” says one program of cial.

“Fusion should correlate what wing-

men are seeing to what each own-ship

sees so that there is one and only one

symbol on each airplane’s [display] for

each target out there.”

That is the ideal. Test pilots have re-

ported problems when targets on the

display have more than one symbol—

a sign the system has not “fused” the

inputs on that particular target. Or in

some cases, not all wingmen are see-

ing everything the other pilots in their

formation are viewing on the displays.

This latest patch—called the “en-

gineering test build” or ETB by tes-

ters —is not a full software release. It

is akin to an update one might imple-

ment on a mobile telephone and is

DEFENSE

F-35 AF-1 is conducting asymmetric load testing with

new 3F software that allows for external weapons loads.

In this confi guration—with one AIM 9 air-to-air missile

and two 500-lb. GBU-12 laser-guided bombs on

a single wing—the most asymmetry observed

is 30,000 ft.-lb. including fuel slosh. This is

the highest asymmetry expected for

testing in the F-35 development

program, but that will be increased

with use of the 1,000-lb. GBU-31

after the development

program concludes.

LOCKHEED MARTIN/JONATHAN CASE