Operational Requirements

Combined Arms Team (CAT) forwardarea armored maneuver forces are cur-rently deficient in close tactical air andground defense protection. The require-ment for armored formations to be ac-companied by self-propelled air-grounddefense system (AGDS) vehicles, com-parably mobile and ballistically pro-tected, is nowadays widely acknow-ledged. Typically, air defense (AD) sys-tems utilize radar-directed, light to me-dium gun systems or ‘surface-to-air’guided missiles against a variety of aer-ial and ground targets.

Operational needs for an effective andcrucial protective ‘coverage’ for theCAT have substantially escalated overthe last two decades. The predominantrationalization is the proliferation of: a)ground-attack tactical fighter (fixed-wing, low-altitude aircraft) and antitankmissile-launching, advanced attackhelicopters; b) precision guided muni-tions (PGM); c) remotely piloted vehi-cles (RPV) and cruise missiles (CM);and d) a plethora of antitank weaponsystems operated by armored fightingvehicles (AFV) or dismounted infantry.

A modern dual-role hybrid AGDS forthe armored forces, at the brigade ordivision level, must be capable ofkeeping up with forward armored com-bat elements. Additionally, it must sur-vive the extremely hostile ‘armor vis-à-vis armor’ intense battlefield environ-ment. Consequently, an effective air-ground defense role may be accom-plished by providing a timely and pro-tective defense “umbrella” against most

antiarmor threats encountered in themodern battlefield presently and in theforeseeable future.

A highly-effective AGDS is charac-terized by:

• Cost-effectiveness in acquisition,procurement and operational deploy-ment (affordable ‘life cycle cost’-LCC)

• High operational availability andreadiness

• Autonomous rapid fire control andweapon reaction

• Air/ground long-range target iden-tification, acquisition, prioritization,and tracking with high ‘hit and kill’probability

• Ammunition lethality and effectiveengagement range against all air/ground antiarmor designated targets

• All-weather, day/night, extendedfighting capability

• Search and shoot ‘on-the-move’overall capability

• Optimum crew ballistic protection,mobility and agility comparable to theM1-series tank

The typical advanced attack “tank-hunter” helicopter is predominantlyperceived as a major, practically un-challenged threat to the armored forces.In fact, if the CAT is not equipped witheffective antihelicopter ammunition orcounterattack measures, it can do verylittle, if anything at all, to threaten and

encounter this predator on equal terms.The reader will find it hard to conceivethat one or two attack helicopters, ef-fectively operated, may strike havoc,temporarily disrupt, and disable awhole armored formation if the latter isnot provided nor equipped with ade-quate protection and effective counter-measures.

In addition to its enhanced capabili-ties against low-altitude, fixed-wing at-tacking aircraft and antitank helicop-ters, a modern AGDS must be capableof effectively engaging and defeatingmost ground targets, including tanks(!)and heavy armored vehicles (primarilyin a self-defense mode). More oftenthan not, the AGDS will be accompa-nied by tanks, so apparently there is nocategorical need to provide it with apredominant ‘tank kill’ capability.Nonetheless, occasionally, while oper-ating on the battlefield’s forefront, anAGDS may encounter enemy tanks allby itself. In such a scenario, it needs tohave the capability on board to survive.

Furthermore, its inherent antitank ca-pability could be selectively exploitedto engage vital-point, high-priority tar-gets such as command vehicles (tanks),tank destroyers, and other highly sensi-tive targets. Indisputably, the AGDS’sinherent capability to effectively en-gage such “hard” and “soft” groundtargets as mounted or dismounted in-fantry, will substantially enhance theclose-support and protection providedto the CAT.

Forward Area Air-Ground Defense

Do We Need A Dual-Role Hybrid Air-Ground Defense Systemfor the Armored Forces?

by Dr. Asher H. Sharoni

and Lawrence D. Bacon

ARMOR — July-August 1996 15

A Proposed Solution: The Hybrid AGDS for the CAT

As a viable, cost-effective and practi-cal solution to the above mentionedthreats, a hybrid AGDS must be capa-ble of providing adequate defense fortanks and armored formations by creat-ing an effective and close “fire screen.”A hybrid AGDS epitomizes the best ofboth AD worlds — missiles and guns.Though ‘surface-to-air’ guided missilesdemonstrate high kill probability atlong ranges (10-12 km), they are ex-pensive to operate and vulnerable toElectronic Warfare (EW) and Elec-tronic Counter Measures (ECM). Con-sequently, it is essential to include acomplementary weapon system, com-prised of automatic barreled weaponsagainst low-level aircraft, RPVs, heli-copters, and various ground targets op-erating at short ranges (2.5-3 km).Thus, a modern AGDS must beequipped with a hybrid, completely in-tegrated weapon system, optimized toengage air and ground targets/threats atrequired ranges under all adverse bat-tlefield conditions.

History: Division Air Defense Gun System (DIVAD)

The U.S. Army recognized the needfor a new AD system two decades ago.In January 1978, the DIVAD (“Ser-geant York”) program was embarkedupon by the U.S. Army for the design,development, fabrication, and test oftwo prototypes. The reasoning for theprogram was that the Army’s forwardmaneuver forces were recognized to beseverely lacking in air-defense cover-age. Prototypes were scheduled for de-livery to the U.S. Government in mid-

1980 for a comparative test and evalu-ation.

Development contractors employedexisting European cannons and U.S.-made fire control systems and radars.The chassis, as prescribed by the U.S.Army, was a modified, GovernmentFurnished Equipment (GFE), M48A5tank. The U.S. Army planned to opera-tionally deploy the first DIVAD units inthe mid-1980s. Contractors were givenample flexibility to encourage designof a cost-effective system that couldsuccessfully achieve operational re-quirements commensurate with thethreats. One prototype had as the mainarmament twin 40-mm L70 Bofors(Sweden) guns, while the other twin35-mm KDA Oerlikon (Swiss) guns.

For various reasons, the DIVAD pro-gram did not live to see actual deploy-ment. Nevertheless, the operationalneed did not vanish nor diminish. Con-versely, it has steadily and persistentlyevolved to a degree that constitutes aclear and present threat to the CAT.The authors believe it is high time thatthe threat definition and present air-ground defense operational capabilitiesbe reassessed, the operational require-ments revisited and updated, and sub-sequently, an AGDS be fielded.

AGDS/M1 Major Operational Capabilities Overview

The proposed AGDS/M1 is an ar-mored, self-propelled, mobile, autono-mous, cost-effective, technologicallysuperior, and economically affordableintegrated weapon system. It is de-signed to function as a dual-role, hy-brid Air-Ground Defense System for

the CAT. The AGDS/M1 is a self-con-tained “fire unit” employing its ownsurveillance/tracking radars, fire controlsystems and main armaments for earlydetection and destruction of low-flyingground attack aircraft and aerials, an-tiarmor attack helicopters, and antiar-mor ground targets. The AGDS/M1 isbased on the battle proven, highly reli-able M1 Abrams tank chassis.

The AGDS/M1 concept represents anextremely potent weapon systemwhich, through effective sub-system in-tegration, constitutes a significant leap-ahead in current armored air-grounddefense conception and capabilities. Itutilizes available proven weapon sys-tems and mature technologies to ad-dress a pressing operational need. Thefollowing is an overview of its majoroperational capabilities related to themain armaments:

• Primary Weapon System Candi-date: ‘Surface-to-Air’ and “Surface-to-Surface” Guided Missile: Air De-fense, Anti-Tank System (ADATS)‘type’ missile system is selected as thebest overall ‘system’ choice for a pri-mary weapon because of its inherentadvantageous characteristics. ADATSwas developed as an international pri-vate joint-venture undertaken by Mar-tin Marietta (USA) under contract toOerlikon-Bührle (Switzerland). ADATSis a single-stage, multipurpose, highlyaccurate, day/night and adverseweather missile system. It has a trueand unique dual-target capability forengaging low-flying aircraft, advancedattack antitank helicopters, and ar-mored vehicles.

The proposed AGDS/M1 consists of apassive electro-optical sensor retract-able head containing a FLIR, TV, a la-

The ill-fated DIVAD (“Sergeant York”). Proposed AGDS turret on M1 tank chassis.

16 ARMOR — July-August 1996

ser rangefinder and a laser beam guid-ance sensor. Two banks of six missileretractable launchers each (12 missilesin a ‘ready-to-fire’ mode) are locatedand integrated at either side of the tur-ret. ADATS was originally designed topermit flexible installation on a varietyof wheeled and tracked vehicles andtherefore could be modified andadapted to the AGDS/M1 configurationwithout major difficulty. The additional‘surface-to-surface’ antiarmor capabil-ity of the ADATS is considered essen-tial, but complementary to its principalantiair role. It can penetrate the equiva-lent of 900+ mm (with growth poten-tial) rolled homogeneous armor steel,sufficient to defeat most armored tar-gets (composite/reaction) today and inthe foreseeable future. In its varioustest programs, ADATS has undergonehighly successful operating trials in alltypes of conditions and environments.

AGDS/M1 Individual Mode of Op-eration: On detection of an aerial tar-get, it is handed off to the passive opti-cal tracking system (high-resolution TVor thermal imaging IR) which is im-mune to both anti-radiation missilesand ECM. Following passive tracking

of the target in the Line of Sight(LOS), the missile is launched whenthe target is within range, subsequentand final guidance only being by en-coded laser beam radiated from thelaunching vehicle or an external source.In an antitank ‘surface-to-surface’ op-eration, the target is acquired andtracked with FLIR/TV and a laserrangefinder ensures optimal engage-ment. Launch and guidance of the mis-sile is performed with an encoded laserbeam. AGDS/M1 could receive infor-mation on targets from a Skyguard firecontrol station.

The passive guidance system, com-bined with a smokeless, solid fuelrocket motor propellant, further en-hance the system’s survivability on thebattlefield. The dual-purpose warhead,with fragmentation effects against airtargets and shaped-charge against ar-mored vehicles, is detonated by a nose-mounted, impact/crush fuze. An elec-tro-optical proximity fuze is used foraerial targets only. The ADATS missileweapon system will be deployed to in-tercept air targets at ranges between 3to 10 km and ground targets between500 meters and 10 km.

AGDS/ADATS Operating as an AirDefense ‘Network’: A ‘network’ of sixAGDS/M1, at the division level, canprioritize and engage up to 20 aerialand vital-point ground targets at anygiven time. The regional AD com-mander has a complete and expedientpicture of the surrounding tactical areawith inputs from all subordinateAGDS/M1s. The commander transmitsinformation and targeting assignmentsto the individual AGDS/M1 over a datalink. One or more surveillance radarsof the AD network can provide neces-sary target information to other vehi-cles, which can then track and engagetargets in a ‘radar-silent’ mode to mini-mize exposure.

ADATS Missile Major Specifica-tions: Length: 2.08m; Diameter:152mm; Weight: 51 kg (at launch);Dual-Purpose Heavy Warhead: shaped(hollow) charge and HE fragmentation(12.5 kg); Fuze: electro-optical range-gated laser proximity fuze with vari-able fuze delay and nose-mountedcrush/impact fuse; Propulsion: solid,smokeless, rocket motor; Max. Speed:Mach 3+; Max. Intercept Range: 10km (slow-air/ground targets), high

ARMOR — July-August 1996 17

speed maneuverable aerial targets: 8km; Max. altitude: 7 km.

• Secondary Weapon System Can-didate: Air-Ground Defense Auto-matic Guns:

Two Bushmaster III 35-mm automaticcannons were selected as the best over-all ‘system’ choice for a secondaryweapon because of their inherent ad-vantageous characteristics: American-designed and to be produced in theUSA; near end of development; firesNATO standard 35-mm ammunition;demonstrates high reliability, superiordurability, exceptional accuracy, andsafe operation under all firing condi-tions. Bushmaster III is virtually an‘upscaled’ design and incorporates allthe battle-proven features of the Bush-master 25-mm M242 gun which servesas the primary armament on theArmy’s Bradley Fighting Vehicle.

Bushmaster III combines design sim-plicity, external operation, positiveround control, ease of maintenance andconstant velocity feed to enhance reli-ability of gun and feed systems. Firedcases are ejected forward (overboard).Longer dwell after firing eliminatesgun gas buildup ‘under armor.’ Bush-master III capitalizes on the use of ex-ternally powered operation to separatemechanism motion from cartridge bal-listics, This allows for a preciselytimed and fully controllable operatingcycle. A key feature assuring outstand-ing reliability is 100% positive car-tridge control from the time the ammu-nition enters the feeder until the firedcase is ejected from the weapon. It isreadily adaptable to advanced, highperformance, antiair and antiarmorpenetrating rounds currently being de-veloped to defeat present and projectedfuture threats.

Utilization of the ‘twins’ will be lim-ited to targets at ranges not greater than2.5-3.0 km. To be effective, and yetpreserve ammunition, single fire burstsmust take no longer than 1.5-2.0 sec-onds. A very high rate of fire is notnecessarily a decisive and mandatoryfactor at such a short range. Nowadayswe have stabilized, highly accuratefire-control systems with enhancedcomputerized tracking and ‘smart’ pro-grammed proximity fuses. These renderthe philosophy of “filling the sky withbullets...” — to increase hit probability— obsolete. The rate of fire is alsoadequate for engaging relatively slowmoving ground targets. Therefore, arate of fire of 250 rounds per minute,

500 rounds per min-ute total on target,should be suffi-ciently effective inhitting and killingair/ground targetswithin the desig-nated ranges.

Bushmaster IIIGun Major Specifi-cations: Caliber:35mm; Muzzle ve-locity: 4540 fps;Peak recoil: 14,000lb; Total weight: 535lb; Overall length:158.1 inch; Rate offire: Single shot, 250spm; Power re-quired: 3.0 hp @ 28VDC; Clearingmethod (‘cookoff’safe): open-bolt;Safety: AbsoluteHangfire Protection;Case ejection: for-ward (overboard).

Ammunition(NATO Standard35mm): Antiair andsoft to mediumground armored tar-gets-HEI/T (HighExplosive Incendi-ary, T-tracer);SAPHEI-T (Semi-Armor Piercing+HEI); FAPDS (Frangible ArmorPiercing Discarding Sabot). Oerlikon-Contraves has recently developed theAHEAD antiair/missile ammunition tokeep abreast of the ever escalatingthreat scenario.

The essence of the AHEAD conceptis the high-precision determination oftime and projectile location in space towithin 1/1000 of a second and one me-ter of distance from target. The actualvelocity of each projectile leaving themuzzle is measured by muzzle velocitymeasuring coils and processed instantlyby the fire control computer. Time offlight is calculated and impartedthrough electronic induction via frontcoil to the projectile’s base fuse. Whenthe projectile’s timer hits the ‘zero’mark, the fuse detonates the payloadejection charge, erecting a ‘cone’ of 100-200 heavy-metal, spin stabilized sub-projectiles that are directed towards thetarget with devastating terminal effects.This type of ammunition reduces theneed for a high rate of fire to achieve a‘hit and kill’ of an aerial target.

Anti-Armor - FAPDS, APDS-T (Ar-mor Piercing Discarding Sabot),APFSDS-T (Armor Piercing Fin Stabi-lized Discarding Sabot) to combat ar-mored targets. Evidently, if BushmasterIII is selected, 35-mm NATO standardammunition must be produced in theU.S. under license. NATO 35-mmstandard ammunition, when fired toranges up to 3 km, is characterized bya short time of flight which ensures flattrajectories with resultant high hit prob-ability.

It has excellent armor-piercing per-formance by use of discarding sabotshell and excellent final ballistics. Stor-age, transportation, handling and firingcriteria are all in full compliance withthe U.S. Army and NATO specifica-tions.

• Surveillance/Scanning Radar: Adual beam, X-band, pulse Doppler sur-veillance radar, 25 km range with en-hanced ECM resistance; High-elevationangle search armored antenna ensureslong-range rapid target detection, IFFinterrogation, acquisition and trackingwith high survivability.

18 ARMOR — July-August 1996

• Primary (ADATS) Fire ControlSystem: Comprised of Forward Look-ing Infra-Red (FLIR) and TV trackers,a Nd-YAG laser rangefinder and a laserbeam rider using digitally encodedcarbon-dioxide laser which provides aguidance beam for the beam-ridingADATS missile. It is fitted with search‘on-the-move’ (preferably fire ‘on-the-move’), ‘track-while-scan’ and auto-matic threat IFF interrogation, acquisi-tion and prioritization for up to 10 tar-gets.

• Secondary (Guns) Fire ControlSystem: High-powered armored track-ing radar transmitter in the J/X-band(preferably ‘off-the-shelf’) provides en-hanced performance against enemythreat and Electronic Warfare (EW)countermeasures; precision angle radartracking for enhanced direct hit capa-bility; rapid search, track and fire ‘on-the-move’; target identification, acqui-sition and IFF interrogation by radar;Passive tracking FLIR, TV and opticalsight; Active tracking by radar.

• Gun Optical Sight and OpticalTarget Designator: Stabilized, dual-power sight for search, track, identifi-cation, and kill assessment while sta-tionary or ‘on-the-move’; Computeraided optical tracking against evasivemaneuvering targets; Integrated nightsight (FLIR) capability; Dual-beamwidthlaser rangefinder for accurate air/groundtarget engagements; open hatch opera-tion would require an optical targetdesignator which provides quick targetdesignation to the tracking radar or theoptical sight.

• Command Control and Commu-nications (C3): C3 net allows theAGDS/M1 to be linked with higherechelon defenses and command cen-ters, other radars and weapon systemsfor automatic response to saturationand time-compressed coordinated at-tacks.

• Armored Turret: The turret’s ex-ternal envelope configuration and levelof ballistic protection will resemble anM1 tank but it is not an M1 turret. Thiswill make it more difficult for the en-emy to ‘single-out’ the AGDS/M1 fromthe M1-series tank fleet as a high prior-ity target. To enhance crew and vehiclesurvivability, “blow-off” panels will beinstalled in the magazine compart-ments.

• Gun Ammunition Handling Sys-tem (AHS): The AGDS/M1 utilizes aunique Ammunition Handling System(AHS). This system is comprised of a

linear-linkless magazine, transfer unit(“Twister”) and a 4-bar mechanical ac-cumulator. It is a high-density systemthat minimizes the required volumesuch that the AHS approximately fitsinto an existing M1 tank turret enve-lope. The unique feed system also per-mits the elimination of flexible chuteswhich take up large volume, introducemechanical complexity and substan-tially reduce reliability. Linear Linkless(LL) AHS is characterized by 60-70%increase in ready ammunition, en-hanced operational effectiveness, lowerLCC, less susceptibility to jammingand less chance of round damage.

• Dual Feed Capability: Bushmas-ter III has a dual feed capability. An-tiair ammunition is stored in the mainmagazines (2x500 rounds total). Antiar-mor ammunition is stored in two addi-tional small magazines (40-50 roundscapacity each), both located above theguns and each elevating with one gunto allow switching and immediate feed-ing of antiarmor ammunition in emer-gency situations. This dual feed ar-rangement reduces cost and volume,keeps the design simple, and maintainsthe highest possible system reliability.

• Crew: 3-man crew (commander, gun-ner and driver) with one man full arma-ment non-intense operation. Commanderand gunner can interchange roles.

• Crew-Served Weapon System(CSWS): The CSWS (currently underdevelopment) delivers a heavier vol-ume of fire than contemporary crew-served weapons. It is primarily em-ployed to defeat or suppress area-tar-gets such as: personnel under cover andconcealment, protected and unprotectedpersonnel, unarmored and lightly ar-mored vehicles, slow flying aircraft andground emplacements. The CSWS willbe installed on a stabilized, remotelyoperated turret with ‘under-armor’loading capability (100-rd. magazine) Itwill be utilized as a day/night supple-mentary suppressive weapon systemagainst enemy infantry operating an-tiarmor weapons. Specifications:Weight: 38 lb; Effective Range: 2000m; Suppression: high at all ranges; Hitprobability: high up to 2000 m; Opera-tional Environment: all-weather, 24-hour, against air and ground targets.

• M1-Series Tank Chassis: The pre-ferred chassis for the AGDS is ostensi-

35mm GunAmmunitionTransfer Unit

ARMOR — July-August 1996 19

bly the M1-series tank. If the AGDS isto provide close and immediate supportto the CAT, it stands to reason that itshould equally share the same levels ofballistic protection, mobility, and agilityas the forces it is designated to protect.Otherwise, it will not survive, or not bethere when its critical support is re-quired. Oftentimes, we tend to makethe misconceived decision of selectinga ‘degraded’ chassis for weapon sys-tems that assume a combat supportrole. Over the life of the system, it gen-erally proves to be erroneous, both op-erationally and economically. The M1tank chassis will require only minormodifications to allow adaptation to theAGDS turret. The AGDS/M1, based onan M1 tank chassis, will benefit fromimminent and future fightability andmaintainability improvements plannedfor the M1-series tank fleet.

The M1A2 chassis provides mobility,agility, and maneuverability. It cankeep up with armored formations andprovide optimum crew ballistic protec-tion with an inherent 20-25% weight

and combat load growth potential. AnAGDS/M1, if not heavier than 55-60tons, will have better mobility and agil-ity than the M1-series tanks it is desig-nated to protect. This unprecedentedmobility and agility will permit theAGDS/M1 to exploit its firepower po-tential to the utmost and provide thenecessary ‘coverage’ when and whereit is required.

Concluding Remarks

This article was written to capture theattention and imagination of the readerand trigger a creative and productivethought process within the defensecommunity. The AGDS/M1 conceptpresented herein, may not be the opti-mized solution after all. Detailed, quan-titative system engineering analysesmay indicate alternative choices ofguns and missiles. The operational re-quirement for a dual-role AGDS for thearmored forces is more valid todaythan ever before. The authors believe

that prototypes could be feasibly devel-oped in about 30-36 months and thefirst systems deployed within 48-60months if an AGDS/M1 is devised anddeveloped as proposed herein. For thisto occur, the U.S. Government mustadopt a true “hands-off” approach forprocurement in the old spirit of “Proto-typing for Production” and vigorouslyimplement the new policy for stream-lining the procurement and acquisitionprocesses.

Potential sales of the AGDS/M1 inter-nationally should be another paramounteconomic consideration in the develop-ment process. Foreign sales preservethe industrial base, keep productionlines alive, and ultimately reduce thecost of procurement to the Govern-ment. An AGDS/M1 is likely to beprocured by those foreign countriesthat operate the M1-series tank andhave the logistic infrastructure alreadyin place.

35mm Linear Linkless Magazine Details

20 ARMOR — July-August 1996

Western Design Howden(WDH), is a small defense com-pany in Irvine, California, whichspecializes in the design, devel-opment, and production of am-munition and material handlingsystems for the U.S. and Inter-national military markets. WDH’strack record includes a variety ofair, land, and seaborne weaponsystems which require auto-mated feed, resupply, and opti-mized ammunition packaging.

Mr. Lawrence D. Bacon is theDirector of Graphic Arts at WDHwhere, for the past 16 years, hehas been responsible for creat-ing numerous concepts for auto-matic ammunition handling,loading, and storage systems.

Dr. Asher H. Sharoni is the Di-rector of Engineering at WDH.He holds a Sc.D. in MechanicalEngineering from MIT and anM.Sc. and B.Sc. from the Tech-nion, Israel Institute of Technol-ogy. Dr. Sharoni is a formercolonel in the Israeli DefenseForces in which he was involvedin various major armored weap-ons developments.