February 25, 2014
Lockheed Martin has demonstrated a secretly developed capability to fix one of the shortfalls of its stealthy F-22 and F-35 fighters: their inability to link to one another, or to legacy fighters, for air campaigns.
The company recently showcased a new datalink capability for the fighters through Project Missouri, a proprietary program. During the demonstration, Lockheed validated the use of a Link 16 transmit capability from the twin-engine F-22 Raptor as well as showcased a waveform developed by L-3 Communications and optimized for low-probability-of-intercept/low-probability-of-detection transmissions (LPI/LPD), says Ron Bessire, vice president of technology and innovation at the company’s Skunk Works.
The demonstration required 8 hr. of flight time and took place Dec. 17 and 19, Bessire tells Aviation Week. The trials required the use of an Air Force Raptor as well as the F-35 Cooperative Avionics Testbed (CATbird), a 737-based flying laboratory that is used to test F-35 software standing in as a Joint Strike Fighter surrogate. The F-22 was able to transmit to a Link 16 terminal on the ground.
The F-22 was designed to communicate only with other Raptors in an effort to reduce emissions from the aircraft to maintain signal stealth in the event of a peer-to-peer engagement. However, because of a dramatic cutback in the number of Raptors purchased — 187 operational — the aircraft must now communicate with F-35s expected to enter service next year as well as legacy “fourth-generation” fighters such as the F-15, F-16 and F-18 families.
This so-called fourth-to-fifth capability was highlighted as a need last week by Air Force Chief of Staff Gen. Mark Welsh at the annual Air Force Association Air Warfare Symposium in Orlando, Fla., but a firm requirement and funding are lacking. Describing the technology as “nothing cosmic,” Welsh said such a link would extend the range and improve the effectiveness of each platform; ultimately what is needed is handoff of weapons-quality data, meaning data from one aircraft can be used by another to accurately fire a weapon.
“We demonstrated the data was being transmitted at a high rate, [enough] to support rapid update of the air tracks to whomever was on Link 16,” Bessire says.
Should such a capability be fielded, the F-22 could be used to enhance the effectiveness of F-15s and F-16s in an air battle though most of the older fighters lack the use of an active, electronically scanned array radar. The F-22’s Northrop Grumman radar is able to detect airborne threats at ranges far exceeding those of radars on the older fighters.
Bessire said the “LPI/LPD waveform still needs some additional maturation,” but he declined to discuss whether it is in use in another platform. Such a waveform would be useful for the B-2, new unmanned aircraft such as the Northrop Grumman RQ-180 and any system hoping to reduce radio frequency emissions to conduct stealthy operations. Equipment and the optics for the waveform are at a technology readiness level of 9, he said, indicating more work needs to be done before it can be proven in a relevant environment and garner full programmatic status at the Pentagon. The F-22 is, however, able to use its existing apertures to operate the waveform, he said.
Installation of a so-called “open system architecture” (OSA) rack and the radio took place within a year of starting the effort to add Link 16 to the Raptor, Bessire said. The OSA racks can also can enable other operations, such as distributed electronic attack, though this was not demonstrated. “What we learned out of this demonstration is that there is tremendous power in the Air Force open mission architecture standard,” Bessire says. The equipment was installed in the F-22’s avionics bay.