Nexter (GIAT) CAESAR (CAmion Equipe d'un Systeme d'ARtillerie)
Wheeled Self-Propelled Howtizer (SPH)
The French Nexter CAESAR is part of a growing global military trend towards all-wheeled self-propelled gun artillery systems.
Authored By: JR Potts, AUS 173d AB | Last Edited:
The international market for Self-Propelled Artillery (SPA) systems has been, and will continue to be, a competitive business for the long term. A market forecast produced by the International Weapons Group (IWG) reported the current worldwide environment is set for a production schedule of 4,500 self-propelled artillery systems through 2016 resulting in sales at an estimated $13.5 billion. The marketplace is showing growing interest in wheeled SPA systems for their cost-effectiveness and simplicity when compared to tracked armored types. Examples of the new direction include the American M1128 Stryker Mobile Gun System (MGS) and the French CAESAR Self-Propelled Howitzer (SPH).
The "CAESAR" name is derived from the French "CAmion Equipe d'un Systeme d'ARtillerie" (translating to "Truck Equipped with Artllery System").
The CAESAR fields a 52-caliber, 155mm howitzer gun system mounted on the back of a Sherpa 5 6x6 five-ton truck chassis. While a wide variety of truck chassis can field the gun system itself, primary contractor GIAT (now Nexter) has selected the proven Daimler-Chrysler (Mercedes) UNIversal MOtor Gerat - better known as the "UNIMOG" - for its locally-produced CAESAR design. The CAESAR was originally developed and manufactured by GIAT Industries, a French government-owned company, prior to it becoming Nexter Systems which is headquartered in Versailles, France. The design is categorized as a Self-Propelled Gun (SPG) and features a fully-enclosed crew cab with unfettered engagement angles from its main gun mounting. A typical operating crew is five personnel though three can manage the gun and vehicle functions in an emergency.
The CAESAR gun and transport platform weigh less than 18 tons. GIAT/Nexter coupled its 155m howitzer with the Renault Sherpa 5 series truck to reduce overall procurement, operating and maintenance costs while increases the SPH's speed. The Renault chassis is an all-terrain, six-wheeled truck complete with power steering assist. It is designed to carry up to a 7-ton payload over paved roads or take its cargo offroad over uneven, loose terrains. The CAESAR chassis is fully suspended atop its heavy-duty chassis and utilizes rubber tires set over steel rims as opposed to a steel track-and-wheel arrangement featured in many modern SPHs/SPGs. The wheeled arrangement requires a lower torque-to-power ratio, thusly increasing overall speed when compared to a tracked vehicle. Rubber tires also provide a higher degree of maneuverability versus continuous steel track systems and reduces overall weight with far fewer moving parts - the wheels provide fewer components that can get damaged in-the-field, thusly reducing repair costs. A centralized tire pressure regulation system is fitted in the cab allowing the driver to adjust tire pressure to suit the terrain. The Sherpa 5 is powered by a EURO 4 six-cylinder engine with a power output of 177 kW at 2,300 rpm. The vehicle has an operational range of 370 miles (600 km) with a maximum speed of 62 mph (100 km/h) on paved roads and 31 mph (50 km/h) when going offroad.
CAESAR Firing Set-Up and Armament
When the CAESAR crew is notified to engage a target, the vehicle truck comes to a complete stop. A crewmember engages the hydraulic system at the rear of the truck which enables the gun to be deployed into the firing position by way of two large spades. The spades are dug into the ground to about 14 inches deep. This limits the amount of vehicle movement when firing the main gun. At the same time, the rear four wheels are hydraulically raised to clear the ground enabling the two spades to absorb the entire recoil force, thus limiting pressures on the wheeled axles. The team leader supervises the firing through the on-board GPS computer. In all, the CAESAR can be made ready-to-fire in just seconds. One loader loads the shell projectiles containing high explosive while another loader loads the propellant powder charges. A fifth member screws the fuses into the shells and then aids where needed. This pre-firing process takes less than one minute.
The weapon can fire and place six projectiles onto a target, or target area, in less than two minutes. When the firing mission is complete, the crew reverses the procedure and the vehicle can relocate under its own power, repeating the setup-fire-takedown process as needed. This minimal "shoot and scoot" timeframe increases the difficulty of the enemy engaging the CAESAR in turn through counter- battery fire.
The heart and soul of the CAESAR is, indeed, its 155mm /52 caliber gun. The weight of the gun alone is 17.7 tons (16057.17 kg; 35,400 lbs) and, when affixed to the truck body, total weight is slightly under 18 tons. This overall weight, and the contained dimensions of the vehicle itself, are wholly by design for transportation incentives allow including moving the CAESAR via railway flatcar, naval vessels (including landing craft) or through the air in the belly of aircraft such as the Transall C-160, a Lockheed C-130 Hercules or the new Airbus A400M Atlas (the air transport option is for the CAESAR unit alone for the crew and resupply truck must be flown separately). The gun is cleared to fire NATO-standard 39- or 52-caliber 155mm projectiles as well as Extended Range, Full Bore (ERFB) ammunition which conforms to international JB MoU munition specifications.
The barrel is fitted with a double-baffle muzzle brake which extends beyond the roof of the cab by 1.5 meters. During standard transport, the barrel is held in position by a clamp just behind the cab. When loaded onto an aircraft, the roof of the cab and windshield separate while the barrel is lowered inside the cab. The roof is then closed over the barrel. The barrel chamber has a real-time sensor checking temperature system indicating heat levels in an effort to prevent "cook off" of entered projectiles (inadvertent firing/detonation). The cab features a self-contained, onboard ordnance ballistic and navigation computer system for modern battlefield accuracy at range. The muzzle velocity measurement radar can be integrated into any Fire Control System (FCS) which is appealing to foreign buyers.No survey team is required for target acquisition due to the installation of a SAGEM SIGMA 30 onboard position data system within the cab. Mounted on the gun is a Global Positioning System (GPS)which interacts with the SAGEM SIGMA 30. The CS 2002-G onboard fire-control computer is located in the cab and sports its own printer. The gun battery receives target information on a 3-D display based on ballistic computation taking place from combined systems. The CS 2002-G computer has a management program to monitor gun status, onboard ammunition status and ammunition resupply needs.
Projectiles are manually placed by a crew member on the automatic projectile loader system mounted on the right side of the gun breech. The 100+ pound 155mm shell is loaded onto the feed tray and then hydraulically rammed into the breech. This arrangement increases the firing rate of the weapon over a manual loading process. The conventional type, or modular type, propellant charges are manually placed on the shell tray and hydraulically pushed behind the shell. The screw breech mechanism automatically closes. The gun captain places a round primer drum the size of a softball into the breech block that rotates automatically when firing the 155mm shells.
The CAESAR system is designed for a sustained fire rate of six-to-eight rounds per minute. The gunnery crew is capable of three rounds in an eighteen second burst for the short-term. A regiment of eight CAESAR vehicles can, therefore, volley fire more than 2,000 pounds of projectiles per minute on a target or target area. Aiming is automatically controlled by the onboard computer in the cab plus a station at the rear along the left side of the gun. Optical sights are provided but not necessarily designed for "shoot and scoot" actions. Elevation and traverse are hydraulically controlled though manual management is provided if the hydraulic system fails. Indirect firing elevation ranges from +17 to +66 degrees with traverse being 17 degrees to the left or right. The crew also has the option of manually relocating the vehicle to a more proper firing angle. Direct firing elevation ranges from -3 to +10 degrees with traverse between 21 degrees left and 27 degrees right.
CAESAR Ammunition Versatility
The 155mm Maximum range depends of the nature of ammunition used but firing a 155 mm Extended Range Full Bore-Base Bleed(ERFB-BB)round features a maximum range of 26 miles (42 km). The French Army has integrated the CAESAR with the Thales Land and Joint Systems Atlas artillery C4I system. This integration improves Command & Control (C&C) communications and intelligence. The system provides the onboard terminals in the cab and on the vehicle management screen at the rear with real-time firing sequences. The C4I system accepts forward fire-support requests and selects firing orders based on the nature of the target while also selecting the ammunition type.
The conventional high-explosive (HE) round is the most common shell fired by the CAESAR and all 155mm guns of the modern age. The NATO HE 155mm round weighs 96lbs, 11.8oz (43.88 kg). The 155mm NATO-standard powder charge weighs 55 lbs, 1.8oz (25 kg). The CAESAR also fires the new-generation French made "Ogre" cargo round. The high explosive round was designed to pin point and destroy hard fixed targets like fortifications, concrete-reinforced bunkers or large entrenched infantry concentrations like those seen in World War 1. The Ogre delivers greater accuracy and firepower against targets over a large area as the hollow shell is filled with 63 "bomblets", each having a fragmentation explosive mechanism that detonates on contact. This munition is useful when mission targets are dispersed or moving vehicles such as light tanks, light armored vehicles, command shelters and dispersed buildings over the battlefield - making them impractical for a single, high explosive round to be used.
The bomblets can penetrate more than 90mm of armor. Six CAESARs firing a volley of six Ogre shells at a range of 35 km releases a total of 378 bomblets over an area of 3-hectares covering 30,000 meters squared (35,879 yards squared). For targets such as tanks and medium-to-heavy armored vehicles, Nexter Ammunition of France has developed the "Bonus" 155mm projectile filled with two smart sub-munition bomblets consisting of shaped charges able to reach 34 km. The warhead explodes above ground, shooting the two smart bombs into the nearest tanks or armored vehicles, penetrating from the top where the armor of a vehicle is typically minimal and then exploding the munitions once inside the vehicle's first level of protection. For targets at the maximum range of the gun (up to 26 miles (42km)) the "Base Bleed" round (ERFB-BB) was developed. The fuse is set to airburst on a point approximately 300 meters above ground. The projectile is used against personnel, artillery positions, supply dumps, and light armored vehicles. The 56 bomb-lets are not "smart" weapons by definition but are designed as a saturation weapon with multiple CAESARs intended to fire at a singular target area. The cost of each 155mm NATO ERFP-BB shell is $3,930 US and each weighs 103.6 pounds (47.3 kg).
Minimal ammunition and charges are carried on the CAESAR vehicle proper. These are held along two storage boxes located on either side of the truck (aft of the cab). The area along the driver's side holds 18 powder propellant charges with primer discs and the storage boxes along the passenger side hold 18 x 155mm projectiles - within proximity of the automatic breech loader. To support its high-rate firepower, Nexter developed a resupply vehicle using the same truck cab and body used for the CAESAR. The ammunition hauler is equipped with a hydraulic crane at the rear of the truck bed. This leaves the bulk of the trailer bed for the six containers holding 12 rounds or propellant (or charges) for a total of 72 x 155mm rounds and charges. The resupply vehicle has a crew of three - a driver, crane operator and assistant and also carries spare vehicle parts such as tires. The crane is designed to quickly unload the containers of ammunition projectiles and charges.
The truck's cab has a number of modular designs available to the prospective customer. The cab is the nerve center for the main fire-control computer and all associated systems needed for autonomous mission support. The cab is air-conditioned and armored against shell fragments and small arms fire with windows six inches thick of bulletproof glass. The computers provide aiming, ballistic calculations, navigation and command aids. An optional 12.7mm heavy machine-gun (as a secondary weapon) can be mounted using a ring turret on top of the cab. The cab's modular design allows the customer to select a variety of features to suit mission requirements - Newsteel and fiberglass, closed or open-air, desert environment, three- or five-seat models etc.
The swap-cab concept designed by Renault for its Kerax 8x8 truck line of rigid logistic and tactical vehicles. These come complete with armored cabs and self-defense weapon kits and are expected to be integrated into the Sherpa 5 design. A "top-up" cab protection kit is also on the drawing board and includes upgrades for armored doors, mine-resistant floors, armored roof and new armored hinged forward windscreen flaps. The upgraded C-section chassis has enhanced axles and leaf-spring suspension systems. Brakes can be a disc or drum and both with anti-lock protection. The customer can choose between inter-axle differential locks or full cross.
Orders, Operators and Combat Service to Date
The first order of five CAESARs went to the French Army in June 2003. The purpose of the limited delivery schedule proved two-fold: first to develop a standard order-of-battle for the gun crews going forward and, second, to test the gun's systems as designed for glitches and report possibly needed improvements. By late 2004, the testing had been completed the French Army purchased an additional 72 CAESARs. By April 2007, the French Army started receiving its first units for firing trials. CAESARs are now in quantitative use by French Army forces as of this writing (2013).
The French Army has purchased 77 Caesars and 77 ammunition supply trucks to date (November 2013). The next logical evolution is in acquiring a reserve stock pile of all types of 155mm projectile rounds and their applicable propellant. In 2012, the French Army entered into a multi-year contract for ammunition for its CAESAR units. This commitment by the French Army convinced global customers to also invest in the CAESAR. To date (2013), export sales have been made to Saudi Arabia, which ordered 132 units, Indonesia (2), Thailand (6) and Denmark (18). The average cost of all export contracts is $5.5 million per CAESAR unit and one re-supply truck per vehicle is included.
In 2009, France sent eight of its CAESARs to Afghanistan to support French forces at firebases Tora, Tagab and Nijrabthe - this marked the first time the weapon system served in an official combat capacity. With roads in Afghanistan - mostly goat paths - the CAESAR has proven up to the challenge. In 2011, the French Foreign Legion engaged in Operation Servalin Mali with four CAESAR vehicles.
On the other side of the globe, Thailand has used its six CAESARs in a combat during 2011 when they claimed a pair of Cambodian BM-21 122mm Multiple Launch Rocket Systems (MLRSs) of Soviet origin. In December of 2012, France contributed troops to the UNIFIL peacekeeping force in Lebanon, taking two CAESARs with them. Renault is developing future prototypes on the CAESAR concept - the larger Sherpa 10 mounted on a UNIMOG 6x6 chassis is one such initiative. The Sherpa 10 payload would be in the 8- to 10-ton range with a platform body capable of handling a 20 foot long ISO containers - almost double the Sherpa 5 capability which sports a 5- to 7-ton payload range capacity.