PLA Guided Bombs

Kopp, Carlo; Andrew, Martin

Last Updated: Mon Jan 27 11:18:09 UTC 2014

PLA Guided Bombs

Technical Report APA-TR-2009-0808

Dr Carlo Kopp, AFAIAA, SMIEEE, PEng
Dr Martin Andrew, RAAF(Retd)
August 2009
Updated January, 2011
Updated April, 2012
Text © 2009-2012 Carlo Kopp
Text © 2011 Martin Andrew
Line Artwork © 2009 Carlo Kopp

Background
PLA-AF and PLA-N Electro-Optical Guided Bombs
PLA-AF and PLA-N Inertially Guided Bombs
Notes/References

Introduction

The PLA-AF and PLA-N now operate a diverse mix of indigenously manufactured and imported Russian guided bombs. To date the most widely deployed indigenous weapon is the very basic LT-2 laser guided bomb, similar in capabilities to the Paveway I/II series.

More recent weapon designs are considerably more sophisticated. The FT and LS series of satellite aided inertially guided weapons are analogues to the US JDAM series, including glide wing equipped variants. The LT-3 is a fusion of satellite aided inertial guidance technology and a gimballed P-nav laser seeker, this weapon being an analogue to the very recent US EGBU-24 and GBU-54/55/56(V)/B Laser JDAM.

PLA-AF and PLA-N Electro-Optical Guided Bombs

Luoyang/CASC LT-2/LS-500J Laser Guided Bomb

The LT-2 (Ler Ting 2) LGB is China's first volume production guided bomb. The basic bomb kit is sized for a 500 kg / 1,000 lb class general purpose bomb body. The seeker uses a Paveway I/II style annular airfoil seeker with a conventional quadrant detection assembly. The tailkit is similar in configuration to the Paveway I. The design will use a bang-bang guidance control law without roll stabilisation. Control is effected by trailing edge surfaces on the cruciform tail in an arrangement similar to the GNPP KAB-500L.

The LT-2 has been widely deployed on PLA-AF combat aircraft, including the JH-7 Flying Leopard / Flounder, A-5/Q-5 Fantan, FC-1, J-8B Finback, and J-10 Sinocanard.

Specifications
Length	3580mm
Diameter	380mm
Tail fin span	950mm
Weight	570kg
Ground designating mode accuracy	CEP≤5m
A/C designating mode accuracy	CEP≤6.5m
Launching speed	≥230m/s
Launching mode	level, dive, toss
Wind speed	≤10m/s
Damage Capability	Equivalent to 500kg low-drag aero bombs
Source: http://www.loec.cn/e32.html

Above: LT-2 LGBs on a precision strike variant of the A-5C Fantan. Note the nose mounted laser targeting device and conformal ventral fuel tank. Below: LT-2 on Q-5M Fantan (Chinese internet).

LT-2 on the JH-7A (Chinese internet).

Three images showing the loading of the LT-2 on the JH-7A (Chinese internet).

Luoyang/CASC GB1 P-Nav Laser Guided Bomb

A new weapon displayed at the Zhuhai 2008 Airshow was the GB1, a derivative of the LT-2 500 kg Laser Guided Bomb, with a proportional navigation seeker design. The seeker is closest in appearance to the Russian KBTochmash/Nudelman P-nav seeker developed for the latest weapons in the GNPP KAB-1500LG series, with a planar optical window in the seeker nose section.

The guidance kit otherwise appears identical to the existing LT-2 series design, employing what appears to be an identical tail control tailkit and fixed canard stabilisers.

Luoyang/CASC LT-3 Laser / Satellite Aided Inertially Guided Bomb

The “Lerting” (Thunderbolt) LT-3 is 3.58m long, has a diameter of 0.38 m and the unfolded wings have a [cited] span of 0.95m. It weighs 564 kg and has a range of up to 24km. It can penetrate up to 1.5 m of steel reinforced concrete¹.

The LT-3 is the most sophisticated guided bomb developed to date by Chinese industry. This weapon combines a satellite/inertial guidance package in a tailkit derived from the LS-6 250 kg glidebomb, and a gimballed proportional navigation semi-active laser homing seeker.

The weapon employs a strap-on strake kit similar to that used with the GBU-31/32 JDAM series. The gimballed detector platform is closest in concept to the TI Paveway III LLLGB design - the LT-3 occupies the same capability niche as the US enhanced EGBU-24 or GBU-54/55/56(V)/B Laser JDAM (LJDAM) weapons.

Boeing GBU-55(V)/B LJDAM on F-16C (Boeing).

LT-3 P-Nav SALH seeker (Chinese internet).

PLA-AF and PLA-N Inertially Guided Bombs

Luoyang/CASC FT-1/FT-2 Satellite Aided Inertially Guided Bomb

The FT-1/FT-2 are satellite/inertial guidance kits for a 500 kg / 1,000 lb class general purpose bomb body. Cited range performance for the FT-1 is very close to the GBU-32 JDAM, the cited CEP of ~30 m suggests C/A mode guidance rather than secure Glonass.

The ‘Fei Ting 2’ is Feiting 1 GPS guided bomb (JDAM equivalent) with a strap on wing kit which increases its range from 18km to between 60 to 90 km. The FT-6 is the FT-3 with the strap on folding wing.

The family of streamlined bombs come in 50, 100, 250 and 500kg but only the 250 and 500kg class bombs are used as PGMs. The Feiting 2 and 6 have a realistic combat range of between 40 ~ 60 km¹.

The FT-1 employs strap-on strakes similar to the JDAM series. The FT-2 employs a planar wing kit similar to the Kerkanya/JDAM-ER.

FT-1 on a JH-7A Flying Leopard (Chinese internet).

Luoyang/CASC FT-3/FT-4 Satellite Aided Inertially Guided Bomb

The FT-3/FT-4 are satellite/inertial guidance kits for a 250 kg / 500 lb class general purpose bomb body.

The FT-3 employs a unique cruciform strake arrangement on the tailkit. The variant displayed at Zhuhai 2008 is different in many respects from demonstrators previously displayed, which appeared to use a modification of the LS-6 tailkit. The FT-4 employs a planar wing kit similar to the Kerkanya/JDAM-ER.

Luoyang/CASC FT-5 Satellite Aided Inertially Guided Bomb

The FT-5 is the smallest guidance kit in the Luoyang/CASC FT series, intended for a 100 kg bomb body. The strake kit design and tail kit are modelled on the FT-1 configuration. The bomb casing geometry displayed in 2009 is relatively conventional and evidently not intended for deep penetration of concrete in the manner of the GBU-39/B SDB warhead.

Luoyang/CASC FT-6 Satellite Aided Inertially Guided Bomb

The FT-6 displayed in 2010 at Zhuhai employed a slimline low drag bomb casing, with a set of planar glide wings similar to those employed with the FT-2, FT-4 and LS-6. This weapon would appear to the planar wing derivative of FT-3 variant with a low drag 250 kg / 500 lb bomb body⁵.

Luoyang/CASC LS-6 Satellite Aided Inertially Guided Bomb Family

The LS-6 designation is applied to a family of guidance kits for a range of low drag bomb bodies. Known variants of the tailkit are for 500 kg, 250 kg, 100 kg and 50 kg bombs. The former variants are glidebombs, the latter variants strake equipped analogues to the US GBU-39/B Small Diameter Bomb (SDB).

The 500 kg / 250 kg LS-6 glidebomb design is modelled in many respects on the concept of the Australian developed planar wing Kerkanya glidebomb kit, more recently adapted to form the JDAM-ER. Unlike the Kerkanya which uses a low wing monoplane configuration with a blended adaptor fairing, the LS-6 glide wing kit is much simpler in design and the weapon flight configuration is that of a high wing monoplane. Cited range for an 11 km release altitude at 900 km/h is 60 km, considerably less than the Kerkanya/JDAM-ER design⁴.

In 2010 Luoyang displayed 100 kg and 50 kg derivative designs, which are clearly intended to be analogues to the US GBU-39/B Small Diameter Bomb (SDB) which has developed to fit the weapon bays of the F-22A Raptor³.

These weapons are clearly designed for compact internal carriage, and it is reasonable to conclude that the intended launch platform is the J-20 stealth fighter.

Both the 100 kg and 50 kg derivatives are fitted with nose mounted electro-optical seekers, with high quality planar windows. JDW's Hewson reports this to be a semi-active homing laser seeker, however, such a seeker is not compatible with a weapon intended to be released in multiple round salvos⁵.

The regime of operation is however compatible with a scene matching area correlator seeker, such as that employed in the Russian GNPP KAB-500/1500Kr series, or trialled in the US Navy DAMASK/HART effort. A seeker modelled on the DAMASK or KAB-500/1500Kr would provide high accuracy, and a redundant guidance regime should the satellite navigation channel be successful jammed⁴.

The type of satellite navigation receiver and inertial unit employed in the LS-6 series have not been disclosed to date. While the Luoyang website states the use of GPS, other sources claim the use of Glonass. It is likely the receiver is like a number of Russian designs, a dual mode device which can use C/A GPS or secure Glonass concurrently.

Imaging seekers are one technique which provides satellite aided inertially guided bombs with genuine precision capability. The US Navy DAMASK/HART effort is a good example. A typical design for such a seeker will see the bomb seeker take a snapshot of the target surroundings, which is then compared with a preprogrammed image to fix the bomb's position. Once the error is found, the target aimpoint is corrected and the bomb dives into the target. MilliMetric Wave Imaging (MMWI) techniques were demonstrated in the Orca program, while DAMASK demonstrated an uncooled low cost IIR seeker, based on automotive technology. Both techniques have growth potential for attacks on moving targets such as vehicles or shipping (Author/USAF)⁴.

Luoyang Description for 500/250 kg Variants (Cite):

LS-6 guided glide bomb is a low-cost but highly effective air to surface weapon for standoff precise attack on fixed ground targets, such as airports, seaports, bridges, commander centers, etc. With a wing kit and GPS/INS guidance unit, the conventional low-drag aerial bombs are modified into precision guided bombs with standoff attack ability.

System features：

Launched outside mid/short range air defense firepower
All-weather, day & night attack capability
Low cost but highly effective
Fire and forget capability
Excellent anti-interference capability
Modular guidance and control unit
Single target or multiple targets attack capability

Weapon delivery:

The LS-6 standoff guided glide bomb (SOGGB) utilizes high-altitude and high-speed launching, high lift-drag ratio aerodynamic configuration and suitable control scheme to ensure a remote gliding control. Before the bomb is dropped, its on-board INS coordinate system must be aligned with that of the aircraft and the fire control system downloads the mission planning into the bomb. Within a specified period of time after the bomb being dropped, the stabilizing system of the bomb starts to work to ensure the bomb and the aircraft being separated safely. And then, the folded-wings expand, putting the bomb into the autonomous flight course, and the on-board control system of the bomb starts to operate to keep the bomb body stable. A combined GPS/INS navigation is adopted during this course. The guidance system translates and calculates the guidance commands and outputs to the autopilot to ensure the bomb flying in a planned trajectory. Based on the relative position of the bomb to the target, the bomb will enter its terminal guidance at a preset distance from the target. On the terminal course of the trajectory, attitude control will be performed via a vertical lead-bias to improve the kill effect.

Technical data：

a) Kill Area：
   For normal target：5,000 - 10,000 m²
   For armored targe：100 - 500 m²
b) Operational Altitude and Speed：
   Launch altitude：4,000 - 11,000 m
   Launch speed：600 - 1,000 km/h

c) Maximum Launch Range：No less than 60 kilometers with a launch altitude of 11,000 meters and an initial speed of 900 km/h.

d) Guidance Mode：Combined GPS/INS guidance.
e) Guidance Accuracy： ≤15 meters CEP

LS-6 prototype glidebomb under a J-8F Finback.

The Australian HdH JDAM-ER was designed for very low mass production unit cost, which is reflected in a number of design features. The most evident is the revival of the DSTO GTV untapered wing planform, which sacrifices a little range performance but is significantly easier to manufacture. The baseline GBU-31/32/35/38 tailkit is used, with software alterations to support the changed aerodynamics and wing deployment functions (HdH).

References

‘Zhuhai hangzhan Zhongguo jizai zhidao zhadan’, Bingqi Zhishi (Ordnance Knowledge) 1A/2011 No. 308 ,pp. 32 & 33.
LT2 laser guided bomb, Luoyang Optoelectro Technology Development Center, URL: http://www.loec.cn/e32.html
Kopp C., GBU-39/B Small Diameter Bomb I / GBU-40/42/B Small Diameter Bomb II, Technical Report APA-TR-2007-0106, URI: http://www.ausairpower.net/APA-SDB.html.
Kopp C., JDAM Matures, Parts 1 and 2, Australian Aviation, December 2002, URI: http://www.ausairpower.net/TE-JDAMPt1.html.
Hewson R., Briefing: Teeth of the dragon, China is setting its sights on expanding its air-to-air and air-to-surface weapon inventory, Jane's Defence Weekly, 19 January 2011, URI: http://www.janes.com/news/defence/jdw/jdw110119_1_n.shtml.

Imagery Sources: Zhenguan Studio, Xinhua; PLA-AF; MilitaryPhotos.net; other Internet sources.

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