Software glitch causes F-35 to incorrectly detect targets in formation

Engineers are trying to fix the F-35’s software package after it was discovered the sensors for the Joint Strike Fighter malfunction when detecting targets when the aircraft flies in formation.

Air Force Lt. Gen. Christopher Bogdan, Program Executive Officer, F-35, said he didn’t have a date when the correction would be made. However, he said the problem would not delay the declaration of the Marine variant of the aircraft, the F-35B, ready for combat.

“When you have two, three or four F-35s looking at the same threat, they don’t all see it exactly the same because of the angles that they are looking at and what their sensors pick up,” Bogdan told reporters Tuesday. “When there is a slight difference in what those four airplanes might be seeing, the fusion model can’t decide if it’s one threat or more than one threat. If two airplanes are looking at the same thing, they see it slightly differently because of the physics of it.”

For example, if a group of F-35s detect a single ground threat such as anti-aircraft weaponry, the sensors on the planes may have trouble distinguishing whether it was an isolated threat or several objects, Bogdan explained.

As a result, F-35 engineers are working with Navy experts and academics from John’s Hopkins Applied Physics Laboratory to adjust the sensitivity of the fusion algorithms for the JSF’s 2B software package so that groups of planes can correctly identify or discern threats.

“What we want to have happen is no matter which airplane is picking up the threat – whatever the angles or the sensors – they correctly identify a single threat and then pass that information to all four airplanes so that all four airplanes are looking at the same threat at the same place,” Bogdan said.

The F-35 is engineered to fuse relevant information from a variety of sources into one common operating picture for the pilot to view – such as digital maps, radar information and sensor information all combined into a single set of screens, JSF officials said.

The F-35’s Electro-Optical Target System, or EOTS, is an infra-red sensor able to assist pilots with air and ground targeting at increased standoff ranges while also performing laser designation, laser range-finding and other tasks.

In addition, the plane’s Distributed Aperture System, or DAS, is a series of six electro-optical sensors able to give information to the pilot. The DAS includes precision tracking, fire control capabilities and the ability to warn the pilot of an approaching threat or missile.

The F-35s also have an Active Electronically Scanned Array Radar which is able to track a host of electromagnetic signals, including returns from Synthetic Aperture Radar, or SAR. SAR paints a picture of the contours of the ground or surrounding terrain and Ground Moving Target Indicator, or GMTI, locates something on-the-move-on the ground and airborne objects or threats.

Overall, information from all of the JSF sensors is fused through the aircraft’s computer, providing the pilot with clear, integrated view of the battlefield. The aircraft also have a data link enabling them to share information with one another in real time.

The F-35 software, which shows images on display screens in the cockpit as well as on a pilot’s helmet-mounted-display, is designed to fuse results from various radar capabilities onto a single screen for the pilot.

The Marine Corps plans to declare their short-take-off-and-landing F-35B variant ready for combat by June of this year by declaring what’s called Initial Operating Capability, or IOC, with the 2B version of the software.

Software Block 2B, while still short of the full final 3F software configuration, can provide data link capabilities and early fused sensor integration, program officials have said.

Block 2B can provide basic close air support and fire an AMRAAM (Advanced Medium Range Air to Air Missile), JDAM [Joint Direct Attack Munition] or GBU 12 [laser-guided aerial bomb], JSF program officials said.

“We will declare IOC with an older version of the software that does not have all the fixes in it. They (Marine Corps) have ways of mitigating those problems which they feel are sufficient for them to go to war,” Bogdan said.

Bogdan explained how F-35B pilots will be able to use concepts of operation to work around the sensor fusion problems until the software fixes are in place. Some of these tactics could include turning off certain sensors or flying in groups of two instead of four planes, Bogdan explained.

“We want to fix this so it is inherent in the airplane. We have always said that fusion was going to be tough. We are going to work through this,” Bogdan said.

– Kris Osborn can be reached at Kris.Osborn@military.com