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

Image

Detection

Airborne sensor identifi es small targets at sea

V

iDAR, or visual radar, is the term coined by Australian

computer vision specialist Sentient for a newly devel-

oped sensor that combines a high-defi nition electro-optic

(EO) camera with automatic target detection algorithms to de-

tect small maritime targets. Already in service with an undis-

closed customer, the Kestrel Maritime ViDAR sensor has been

evaluated by the Australian navy and the U.S. Coast Guard.

Standard EO and infrared (IR)

sensors have high resolution but

very narrow fields of view, which

limits their usefulness for wide-area

search. The Kestrel Maritime ViDAR

is based on a 9-megapixel visible light

sensor with 20-deg. field of view. (A

night-vision version with a 4-mega-

pixel IR sensor is also available.)

The camera system is designed to

“step-stare” around a 180-deg. arc

to perform an area search along the

platform’s flightpath.

The automated target detection

software is based on the Kestrel

Maritime program that is in service

FRONT LINE

Set, Fire and Forget

Airburst round has high kill probability

C

TA International, the Nexter/BAE

Systems joint venture responsible

for the CTA40 gun and its cased,

telescoped ammunition, is developing an

anti-air airburst round for use against

airborne targets. Similar in principle to

Rheinmetall’s 35-mm Ahead , the 40-mm

airburst round detonates at a calculated

range and releases tungsten pellets that

form a lethal cone along the fl ightpath.

The round is expected to have “100%

kill probability” at a range of 2 km

(1.25 mi.) and will be ef ective to 4 km

with a normal eight-round burst, accord-

ing to a Nexter executive. The company

sees a renewed need for air-defense guns

as protection against small unmanned

aerial vehicles, which are likely to be so

cheap and numerous that engaging them

with guided missiles is unaf ordable (see

related story on page DTI 6).

After a long development, the CTA40

is expected to enter service next year

with the British Army’s upgraded War-

rior infantry fi ghting vehicle, to be fol-

lowed by the General Dynamics Scout

Specialist Vehicle.

CTA40 rounds comprise a cylindri-

cal case with the projectile embedded

in the propellant. On fi ring, an initiator

charge propels the projectile out of the

case, leaving the main charge more room

to expand. As a result, the round can

use more propellant without excessive

chamber pressure, giving the weapon

a muzzle velocity of 5,000 fps. Also, be-

cause the round is short, and the gun has

a rotating breech, the weapon is com-

pact and does not protrude as far into

the turret as a conventional gun. The

cylindrical rounds are, moreover, easier

to store and handle due to their size—at-

tributes that are useful when placing a

40-mm gun in a vehicle class that usually

is armed with smaller weapons.

Development by what were then Giat

and Royal Ordnance factories started

in the mid-1990s, and Nexter of cials

point out that two-nation backing is

almost essential to the arduous task of

qualifying a new family of rounds.

Nexter and Thales have developed a

two-crew turret compatible with Nex-

ter’s VBCI 8 X 8 armored vehicle, report-

edly for a Middle Eastern customer. c

CTA International’s 40-mm anti-air airburst round is small and lethal over a long range. —Bill Sweetman

A ViDAR imaging sensor can be

carried by a small UAV such as the

Insitu Integrator.

with conventional EO/IR sensors. The

software scans an image for moving

objects and characteristic shapes and

edges in order to pull targets out of

sea clutter. The use of a high-resolu-

tion, wide-angle sensor increases the

coverage area 20-80 times, accord-

ing to Sentient, which says targets as

small as submarine periscopes and

survivors in lifejackets can be reli-

ably detected at ranges of up to 18.5

nm. The target image is automatically

presented to the operator as a snap-

shot, and a long-focus sensor can be

cued on to it.

Detecting such small targets usual-

ly requires large maritime radar, Sen-

tient says. The ViDAR system, howev-

er, draws only 20 watts of power and

is compact enough to be carried on a

small unmanned aerial vehicle such

as the Insitu Integrator. c

—Bill Sweetman

INSITU

BILL SWEETMAN/AW&ST

DTI4 MARCH 30 -APRIL 12, 2015 AVIATION WEEK & SPACE TECHNOLOGY DEFENSE TECHNOLOGY INTERNATIONAL AviationWeek.com/dti