By Graham Warwick in Nas Patuxent River
Planned to get under way in September, the US Navy’s Broad Area Maritime Surveillance (BAMS) unmanned aircraft competition will be open to a wider range of solutions than expected, but a slight change in requirements could favour a fast UAV.
The revision has changed the key persistence parameter from a vehicle endurance of 24h to an “effective time on station” requiring the system to maintain 24h coverage at 3,700km (2,000nm) range for seven days, with 85% availability. “This is fairly challenging,” says Cdr Robert Dishman, BAMS integrated product team lead.
The revised requirement will drive reliability, force structure and vehicle attributes, including speed, says Dishman. “It is not just persistence – it’s persistence at range. A 200kt [370km/h] aircraft vehicle will take 10h to go 2,000nm. If it fails on station, there is a minimum 10h gap in coverage. But at 500kt there will only be a 4h gap.”
The balance of transit speed and endurance and reliability on station will determine how many air vehicles are needed to meet the system persistence requirement, says Dishman. Companies pursuing BAMS include Northrop Grumman, with the turbofan-powered Global Hawk, and Lockheed Martin with General Atomics Aeronautical Systems’ turboprop-powered Mariner.
A draft specification for BAMS is expected to be released this month, followed by a draft request for proposals in September. The schedule calls for award of a system development and demonstration contract in September 2007. First flight is set for fiscal year 2011 and initial operational capability (IOC) in FY2013.
The IOC requirement is sufficient air vehicles and ground stations to maintain one continuous, year-round orbit, says Dishman. Full operation capability is five orbits, one for each of the deployed fleets. BAMS is expected to be co-located with and operate alongside US Navy Boeing P-8A Multi-Mission Maritime Aircraft.
With the mission to detect, classify, track and identify maritime targets, BAMS will carry a maritime radar, electro-optical (EO) sensor, electronic support measures and have a communications relay capability. The radar will have a 270° scan centred on the nose and will not be capable of synthetic-aperture radar ground imaging.
Dishman says the requirement to identify targets will require “altitude agility” – the ability to descend to within EO sensor range – or the ability “to put on expendables as an option – or they could propose a family of systems, low-altitude and high-altitude. This is a performance-based specification.”
Source: Flight International
