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Army Magazine >> Army Magazine Archive >> ARMY Magazine - September 2004 >> XM32 Lightweight Handheld Mortar Ballistic Computer Email this... Email    Print this Print

XM32 Lightweight Handheld Mortar Ballistic Computer

In response to an urgent need from U.S. Army warfighters serving in Iraq, the U.S. Army’s Research, Development and Engineering Center at Picatinny Arsenal, N.J., has developed and recently fielded the first 36 XM32 lightweight handheld mortar ballistic computers (LHMBCs).

According to David Super, deputy product manager for Mortar Systems (under project manager for Combat Ammunition Systems at Picatinny Arsenal), the new XM32 lightweight handheld mortar ballistic computer is a joint service Marine Corps/Army system that calculates the ballistic solution for the entire family of fielded U.S. mortars and their complete inventory of ammunition.

U.S. mortar systems include the 60 mm, 81 mm and 120 mm mortar weapons. The 60 mm and 81 mm mortars are dismounted systems with the 120 mm fielded in both dismounted and vehicle-mounted configurations. Vehicle-mounted 120 mm mortar configurations include the tracked M1064A3, a variant of the M113A3 armored personnel carrier, and the soon to be fielded wheeled M1129, a Stryker mortar variant.

"The current [dismounted] mortar ballistic computer is the M23," Super explained. "It was built in the 1970s and is the equivalent of a Commodore 64. It is obsolete, unsupportable and cannot be repaired anymore."
Perhaps most serious, the M23’s memory capabilities are exhausted, meaning that recently fielded ammunition options could not be included in the system.

"The memory is depleted," Super said. "We cannot expand it any further."

In addition to supporting all of the currently fielded mortar ammunition, the XM32 also provides warfighters with a more accurate solution, based on a ballistic algorithm that accounts for wind speed, wind temperature and propellant temperature. Moreover, the system features software growth potential to allow incorporation of any future mortar rounds.

"The XM32 also automates a number of different procedures, such as determining ammunition requirements for a given target and calculating firing orders for large target areas in terms of traverse. We do computations much faster and the entire system weighs less than two pounds," Super added.

By contrast, the obsolete M23 weighs approximately eight pounds.

The requirement for the XM32 was derived from an umbrella operational requirements document (ORD) for the M95/M96 mortar fire control system (MFCS), which is the current heavy mortar fire control system fielded in the M1064A3 and M1129.
The main computer in the MFCS is the commander’s interface computer, which weights almost 14 pounds.

"There was also a requirement in the mortar fire control system ORD for a lightweight commander’s interface computer," Super added, "so, Fort Benning [Ga.], who is our user, developed a user’s functional description for the XM32 to formalize the requirement."

"The XM32 is strictly a ballistic calculator," he said. "It does not do weapon pointing like the mortar fire control system does. What we need to do is be able to take that heavy mortar fire control system and develop a dismounted [lightweight] mortar fire control system for dismounted applications. The first step in doing that is the XM32 lightweight handheld mortar ballistic computer. It does not give us weapon pointing/weapon laying capability, but it does give us that exceptional lightweight ballistic calculator."

Based on the user’s functional description, the XM32 LHMBC was developed over an 18-month period. The system relies on a ruggedized personal computer, developed and produced by Talla-Tech (Tallahassee, Fla.). The handheld computer, which is based on the Compaq iPAQ, is equipped with software developed in house at Picatinny.

Noting that the mortar fire control system software was also developed at Picatinny, Super added, "Basically we have taken the mortar fire-control software that we developed for the heavy system and we have ported it and developed it for the smaller screen on the ruggedized PDA."

Picatinny planners are developing three versions of software for the XM32. The initial version (version 1) was fielded in August 2004 to support an urgent need from the Stryker brigade combat team (SBCT) in Iraq. The SBCTs carry 60 mm mortars available for dismounted use at the company level and 81 mm mortars available for dismounted use at the battalion level. New equipment training for the first three dozen systems was conducted in-theater.

Version 2 software, which is still being refined, adds embedded global positioning system information and a digital communications link that will interface with the advanced field artillery tactical data system. Operational testing of the version 2 package will be conducted in the fall of 2004. Version 3 will increase the capabilities with what Super described as "additional software functionality."

In addition to the urgent fielding to the SBCT in Iraq, Super said that current funding profiles cover the fielding of 30 version 3 full capability LHMBC systems to the 75th Ranger Regiment in the spring of 2005.

"Assuming full funding for the system, we will field to all the active light forces in the Army that have 60 mm, 81 mm and 120 mm dismounted mortar systems, including all the Stryker brigades," he added.

Along with application by U.S. Army dismounted mortar units, Super pointed to an expected application of the XM32 by the U.S. Marine Corps.

Emphasizing that the development of the XM32 has been a joint Army and Marine Corps effort," he said, "The Marine Corps requirements are all encapsulated in software version 1 so we would expect the Marine Corps to fund their requirement next year. For their part, the Marine Corps is not that interested in digital communications. The Army requirement is for digital communications. The Marine Corps requirement is strictly for a ballistic calculator with no digital communications, as of yet."

Summarizing the significance of the recent LHMBC fielding in Iraq, Super observed, "The XM32 fills a critical need for accurate, timely and responsive mortar fires, which are vitally important to today’s dismounted warfighters. Because the current M23 [software] does not have all of the modern rounds of ammunition in it, soldiers are reduced to manual calculations on the M16 plotting board, which take a long time. They cannot be as responsive as they would like. They cannot be as accurate. They cannot be as timely."

"It is really critical that we get the LHMBC out there as quickly as possible to light mortar users," he concluded.