Broad Area Maritime Surveillance

The Pentagon

The US Navy is planning to acquire a Broad Area Maritime Surveillance (BAMS) UAV system that will provide a persistent maritime surveillance, communication and reconnaissance capabilities, with worldwide access. The complete BAMS system will consist of the UAV platform and onboard sensors, as well as incorporating the command and control network and other supporting elements. The UAV will be capable of operating independently or work in conjunction with other maritime assets, particularly the planned Maritime Multi-mission Aircraft. Around 40 UAVs will be based at five US Navy sites located at Hawaii, Diego Garcia, Florida, Japan and Italy and current plans call for the BAMS UAV to be fully operational by 2013.

The BAMS UAV will need to be able to provide a continuous on-station presence at ranges of 1,000 to 3,000 miles from the launch point and will typically operate at over 40,000 ft whilst tracking targets ranging from ships to a submarines periscope and relaying the data received back to a ground station in near real-time. The broad aim is for the BAMS UAV to provide the command authorities with a persistent and reliable picture of surface threats, without exposing manned assets to any potential threat. To achieve maximum flexibility, the UAV must be capable of sea control and strike support missions as necessary.

Night Hunter II

Typical of the new systems that may find their way onto the BAMS UAV is a collaborative project between Northrop and Sonoma Design Group for a new high performance electro-optical and infra-red system called Night Hunter II. Optimised for passive imaging at stand-off ranges in the visible and IR bands, Night Hunter II is housed in a 21 inch lightweight turret that can accommodate up to six sensors and has a large aperture of 11 inches. Typically the various enhanced day and night sensors onboard would search, auto-detect and track targets over 360 degrees as well as enabling laser ranging and designation for the latest laser guided or GPS guided weapons.

There appear to be three main contenders in the BAMS UAV competition a maritime version of the Northrop Grumman RQ-4A Global Hawk, a maritime version of the General Atomics Predator B known as Mariner and an unmanned version of the Gulfstream G550 business jet known as the Gulfstream RQ-37.

Global Hawk

The Northrop Grumman RQ-4A Global Hawk high altitude, long endurance UAV is the front runner in the competition, as it has a proven track record and the platforms capabilities already closely match the BAMS UAV requirement, particularly the ability to operate at 60,000ft carrying a wide variety of sensors, a range of 10,000 miles and the ability to remain aloft for up to 35 hours. Current USN plans call for a Congress-mandated Global Hawk Maritime Demonstration (GHMD) to begin in Nov 2005 until 2009 and to this end the USN have purchased two Global Hawks designated as RQ-8As. The RQ-8A aircraft will be equipped with the normal Intergrated Sensor Suite, but also with a special maritime-mode radar and an LR-100 electronic support measures suite with 360 degree coverage. The planned 360 degree scan inverse synthetic aperture radar capability was not funded, instead the two aircraft will be equipped with new software that allows the existing SAR sensor to pick up maritime targets identified initially by the LR-100 system. The initial plan for the GHMD calls for the aircraft to support an exercise called Trident Warrior 05, followed by a Joint Expeditionary Forces Exercise starting in Feb 06. However, with the situation in Iraq deteriorating as each month passes, the Department of Defence is investigating the possibility of one of the USN Global Hawks deploying to the United Arab Emirates, joining the single USAF Global Hawk based there, to support US Marine Corps operations in Iraq. If the plan goes ahead this will clearly have a major impact on the GHMD programme, but may also serve to remind the USN of the superb capability of this state-of-the-art UAV.


General Atomics are also keen to demonstrate that a version of their Predator B, known as the Mariner, will be capable of meeting the BAMS UAV requirement and have teamed up with Lockheed Martin in an effort to secure the contract. The Mariner combines the Predator B fuselage with the lengthened wings of the high-altitude Altair version of the Predator. The Mariner can operate for up to 50hrs and climb to above 50,000ft carrying a 800lb internal payload and 3000lbs externally. Production version of Mariner will also be fitted with a conformal fuel tank to increase endurance even further. Equipped with a Raytheon developed electro-optical / infra-red sensor and a new SeaVue multimode maritime radar, the Mariner is certainly capable of providing the real-time, persistent intelligence, surveillance and reconnaissance capability required for the BAMS UAV, however, whether this highly capable UAV will win in a straight fight against the Global Hawk RQ-8A remains to be seen.

Gulfstream RQ-37

Gulfstream have been slow to enter the UAV market and rather than risk the costs associated with developing a completely new UAV to compete for the BAMS UAV contract, instead they have proposed an unmanned version of their successful G550 long-range business jet. Known as the RQ-37 this aircraft would use a fully automated flight control system developed by Sierra Nevada Corporation to convert the aircraft for unmanned flight. The main advantage of the RQ-37 would be its ability to carry a payload of nearly 10,000lbs for 15 hours up to altitudes of 60,000ft, a far greater payload than either of its competitors can manage. A typical configuration for the RQ-37 would include a synthetic aperture radar, an electro-optical / infra-red sensor, an ELINT / ESM suite and a ballistic/theatre missile defence sensor all routing data through a reconnaissance management system to data link and SAT Comms systems. If the payload was reduced around 5000lbs, the RQ-37 could then be fitted with additional fuel tanks and under-wing hard points and could operate for up to 18 hours, but still some way short of the endurance offered by the RQ-8A and Mariner. Despite its many virtues, cost is the real achilles heel of the RQ-37, with a unequipped G550 costing over $10 million more than a RQ-8A and an even greater cost disparity existing against the Mariner. However, with the ACS platform still in doubt, if the USN opted for the G550 as both platform for both the ACS and BAMS UAV, the overall price could be driven down, but this option appears a unlikely possibility.

The battle for the BAMS UAV contract promises to be a long, drawn out contest, in which the usual internal and external politics of US defence procurement will be as much a factor in the final decision as the actual capabilities of the competing platforms. Nevertheless, the various trials that will take place should serve to clearly identify the best platform, with the appropriate mix of specially modified sensors and the ability to disseminate the captured data rapidly to the commanders in the field. Whatever platform is selected will undoubtedly set the standard for a maritime UAV that other many other countries will admire and envy but, given the rules detailing the transfer of sensitive technology, I doubt the BAMS UAV will ever be offered for sale to anyone other than Americas closest allies, even if they can actually afford to buy it!