ARTICLE

August 2003

Army Speeds Up Development Of Mortar Fire Control System

by Frank Colucci

The U.S. Army 1st Cavalry Division at Fort Hood, Texas, began fielding a new digital fire control system that promises to improve the speed, accuracy and survivability of mechanized mortar platoons. The technology also introduces common fire control elements for dismounted mortars and Stryker brigade combat teams.

The program is called mortar fire control system (heavy), managed by the Army Armament Research Development and Engineering Center at Picatinny Arsenal.

Tom Bradley, Army assistant product manager for fire control, said that Honeywell Defense & Space Electronic Systems will produce MFCS under a five-year contract.

Picatinny MFCS development project officer Vince Matrisciano explained that the system “seamlessly integrates mortars into the digital battlefield.”

The M95/96 mortar fire control system (heavy) links the M577 fire direction center (FDC) vehicle with up to 18 M1064 120 mm mortar carriers, without soldiers having to dismount. In operational testing, networked vehicles had first rounds in flight in less than 1.5 minutes and achieved a circular error probable (CEP) of about 75 meters. In contrast, conventional mortar platoons typically require 8 to 12 minutes to set up and have CEPs of 230 meters.

Mortar Measurements
The Army currently uses 120 mm mortars on vehicles and 120, 81, and 60 mm mortars with dismounted troops. Mechanized platoons typically have one FDC and four mortar carriers. To drop rounds on target, the FDC translates coordinates provided by forward observers into mortar tube deflection and elevation adjustments. Aiming points are marked on a plotting board with a paper or Mylar overlay to generate the azimuth. Paper firing tables list elevation to achieve the desired range with a given type of ammunition.

The traditional means of aiming mortars has significant shortcomings. To establish azimuth reference lines, mortar crews leave the protection of armored vehicles to place aiming stakes 50 and 100 meters away. Though mortar teams can now establish their precise locations with the Global Positioning System, they still rely on imprecise manual tube adjustments.

Elevation and other computations are made with an M23 mortar ballistic computer. However, the handheld device is based on 1970s technology that is limited in capability and no longer logistically supportable. “It’s more of a calculator than a computer,” said Matrisciano.

In 1993, the Army sought to give 120 mm heavy mortars the digital fire control capabilities built into the M109A6 Paladin 155 mm self-propelled howitzer. The Paladin was the first platform able to receive fire missions from the so-called Tacfire tactical fire direction system, take up a firing position, calculate accurate ballistic solutions, deliver ordnance accurately and depart rapidly. “Shoot-and-scoot” capability improves survivability by relocating fire units quickly to evade counterfires.

The Picatinny ARDEC and the program manager for mortars built a fire control demonstrator system with components from the Paladin howitzer and Abrams tank integrated by new software. A demonstration took place at Fort Irwin National Training Center, in California. “It was the first time a mortar weapon was digitized,” noted Matrisciano. “It was the springboard for everything else to date.”

Refinements and repackaging for different size mortars led to another successful demonstration in Task Force XXI exercises at Fort Hood in 1997, and to a three-year contract with Allied Signal Integrated Avionics Division for a production fire control system.

However, the contract concluded in 2000 with an unfinished product, and the program manager turned to the Picatinny ARDEC to finish development.

“We re-wrote all the software, upgraded the computers, integrated everything, and completed system testing and qualification,” said Matrisciano. MFCS operational testing wrapped up in November 2002, and production deliveries were scheduled for May 2003. The war with Iraq accelerated fielding to the Army’s 1st Cavalry Division with three brigades staged at Picatinny.

Honeywell has been negotiating the terms of the contract with the Army. Company vice president Ed Goosen said it is not a “defined contract. It’ll be a series of task orders as the PM Mortar Systems decides how to proceed. … Right now, we’re negotiating the procurement and installation on all the vehicles.” The installation requires brackets to hold the MFCS hardware and cables to tie into the vehicle power supplies. Installation will be done at the home bases of fielded units.

MFCS automates the mortar platoon with identical software, computers and displays on both the M577 FDC vehicle and M1064 mortar carriers. The Windows-based software is hosted on Pentium-based ruggedized computers made by Miltope Corp. The integrated hardware uses Rockwell Collins PLGR GPS receivers in the vehicles and Honeywell Talin inertial measurement units on the mortar tubes.

Easy-to-understand graphic display pages and plain text messages coordinate the fire mission. Vehicle displays put the mortar carriers in their precise firing positions. Each driver’s display doubles as an enroute navigation aid showing direction and distance to the firing point. Gunners’ displays show soldiers in the mortar carriers the tube azimuth and elevation corrections calculated by the computer.

The FDC operator receives fire missions via SINCGARS digital and voice links. Frequency-hopping SINCGARS radios also link the vehicles in the mortar platoon.

One FDC can coordinate fires for up to 18 mortar carriers simultaneously. The position of each vehicle is established by the GPS receivers and ring laser gyroscope inertial-navigation pointing device on each weapon. Motion sensors tied to the vehicle odometers correct for IMU drift errors. “All inertial measurement units drift,” explained Eric Judkins, Honeywell business development manager for ground vehicles. “If the IMU knows it’s not moving, it can strip out the drift.”

The precise position of each mortar vehicle is shared with the FDC, enabling the FDC computer to calculate firing solutions. The ballistic engine in the FDC computer compensates for wind and other atmospheric factors automatically. A graphic emplacement page appearing on each display shows target azimuth to be achieved by moving the vehicles, the mortar turntables, or the mortar tubes.

The computer aboard each mortar carrier generates azimuth and elevation corrections with the help of the IMU tube pointing device. Individual gunner displays command the type of ammunition, number of rounds, and manual azimuth and elevation adjustments. A “check-fire” call can stop the entire mission instantly to avert fratricide.

As Version 1 of the mortar fire control system (heavy) is fielded, Picatinny engineers are readying Version 2 software. The improved system does additional fratricide checks as part of its ballistic calculations, and provides the capability for MFCS M1064 operators to function as FDCs.

The MFCS has broader application to other mortars both mounted and dismounted. There will be a development activity to design and develop light systems and integrate the MFCS into the Future Combat System,” said Goosen.

Identical software and the same off-the-shelf components with different mounting brackets and cabling will go aboard the Stryker brigade combat team vehicles. Aboard the Future Combat System, the software could run on a Land Warrior personal data assistant.

The same system running on common hardware and software may give dismounted 81 and 60 mm mortar platoons a rapid-fire capability. However, MFCS for dismounted mortars will require smaller tube pointing devices. “That’s the real challenge,” said Matrisciano. “We’ve got more SBIRs [Small Business Innovative Research contracts] working on that.”

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