Excalibur Unitary PGM down range in Iraq.

Coalition Forces often observe insurgents but cannot engage them because they lack timely, precision responses for use in an urban environment.

Precision munitions currently in theater lack the scalability and responsiveness to engage these targets that have low dwell time. Cannon munitions have the responsiveness and warhead scalability, but their inherent inaccuracies raise the potential for collateral damage to unacceptable levels. Consequently, the use of Field Artillery in contemporary urban operations has been reduced, forcing many guns to sit silent.

Urgent Need for a Cannon Precision-Guided Munition (PGM). In August 2004, the MultiNational Corps, Iraq (MNC-I) submitted an urgent needs statement (UNS) requesting a precision-guided cannon munition with greater range and lethality than current munitions, a round that has a circular error probable (CEP) independent of range and a fire-and-forget capability.

On 6 November and 18 December 2004 at Yuma Proving Ground, Arizona, two Excalibur Unitary rounds were fired at targets 20 kilometers away and landed 3.4 meters and 6.9 meters from the targets, respectively. Excalibur's precision demonstrated by these tests and its extended range and fire-and-forget capability made it a possible solution for the UNS. In March 2005, the Army Resource and Requirements Board at the Pentagon decided to accelerate Excalibur to satisfy the UNS. Deliveries in Iraq will begin in the Second Quarter of FY06.

What is Excalibur? Excalibur is a GPS-guided 155-mm unitary high-explosive (HE) cannon munition. It uses an inductively set fuze with three modes--point detonation, variable time and delay--and base bleed to achieve extended ranges, 35 to 40 kilometers, from digitized 155-mm platforms. Excalibur maintains a 10-meter CEP at all ranges and combines a naturally fragmenting steel warhead with a near-vertical terminal trajectory to achieve greater lethality than current HE rounds. The non-ballistic trajectory and near-vertical terminal trajectory make it ideal for complex and urban terrain.

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Excalibur was chosen as a solution because of the overall maturity of the program. Originally scheduled for fielding in FY08, the program was accelerated to synchronize with the fielding of the M777A2 155-mm lightweight howitzer in the 5th Stryker Brigade Combat Team (SBCT) in mid FY07.

Technical Challenges of Accelerating the Program. Accelerating Excalibur is not without risks and tradeoffs. To meet the specified delivery date, deviations from the program were necessary. Time constraints forced base bleed to be removed from consideration for the early fielding round, reducing the maximum range to 22 kilometers. The test schedule also was condensed, allowing little room for program slip-pages or delays.

When Excalibur arrives in-theater, a total system will be delivered, not just a round. In addition to the round, firing units must have an updated version of the advanced FA tactical data system (AFATDS) software, an up-date to the forward observer system (FOS) software and the enhanced portable inductive artillery fuze setter (EPIAFS). Accelerating Excalibur also required accelerating these other systems or producing an interim solution.

To field the round on time, the AFATDS software update will be released as a service pack before Software Block 2. Also, an interim stand-alone fuze setter will be required to breach the gap between AFATDS software and the current automatic fire control system (AFCS) software on the Paladin. Both interim solutions are needed only for the early fielded rounds and will be unnecessary when the round associated with the program of record is fielded.

Despite the constraints on introducing the round to Iraq, an incredibly capable munition will be placed in the hands of maneuver commanders. Excalibur's responsiveness and suitability for complex terrain allows commanders to engage the enemy in today's contemporary urban environment. Its non-ballistic trajectory will deny the enemy sanctuary in his current surroundings, forcing him either to abandon his sanctuary or find increasingly risky means of delivering his harassing fires.

Excalibur will change the dynamics of current operations and reinforce the impact of Field Artillery on the urban and complex terrain battlefield.

MAJ J. Riley Durant, FA

Assistant TSM Cannon

Fort Sill, OK