Connectivity breakdowns during early tests of the US Navy's newest cruise missile have exposed the complexity of the US military's hopes to integrate datalinks on thousands of long-range munitions. A two-way link installed on the Raytheon Tactical Tomahawk Block IV missile worked only half the time during a developmental test cycle last year - a performance record deemed "insufficient" by Keith Sanders, deputy programme executive officer for navy weapons.
"To make [beyond line of sight (BLOS) communications] work for weapons is not going to be easy and is going to be a stretch," Sanders told the Precision Strike Technology Symposium in Laurel, Maryland on 12 October. The Tomahawk's performance record will probably catch the attention of the US Air Force, which is pursuing an ambitious strategy to integrate a Link 16-like communications device on all future stand-off weapons, such as the developmental Boeing Small Diameter Bomb (SDB) and the newly operational Lockheed Martin AGM-158 JASSM stand-off missile.
In each case, two-way communications can update the weapon with new target co-ordinates after launch and allow the weapon to report back on its health status, as well as pass surveillance data from onboard sensors. JASSM and the Block IV Tomahawk can be fired more than 465km (250nm) and about 1,850km, respectively, while the SDB can glide more than 110km to its target.
Sanders says the navy has traced the Tactical Tomahawk's connection problems to the limitations of a 5kHz modem and bottlenecks created by the military's system for regulating BLOS transmissions. Military satellite transmissions must be assigned by a separate controller, who strictly allots and enforces time limits on message relays, says Sanders. Onboard modems, meanwhile, are limited to three channels, which further restrict the ability to send and receive large amounts of data.
Sanders says the complexity of the transmission process for Tomahawk means adjustments must be made before the military can manage dozens of datalinked munitions simultaneously, as envisaged in air force and navy plans. The USN is interested in providing the Block IV Tomahawk for export, but is awaiting government clearance.
STEPHEN TRIMBLE / WASHINGTON DC
Source: Flight International
