Unmanned Aerial Vehicle Relays Pictures to Airborne Radar System

May 1999
By Mark H. Kagan

Exercise shows that operators on aircraft can use video to confirm identities of radar images of ground targets.

The U.S. Air Force has demonstrated the ability to provide airborne joint surveillance target attack radar system operators with real-time video ground imagery from an unmanned aerial vehicle. The capability allows positive identification of targets, decreased reporting and response times for attacking critical targets, and reduced fratricide.

This fills two performance gaps of the airborne radar platform: its incapability to distinguish between lethal and nonlethal targets and their activities, and its inability to see targets that are screened by terrain and buildings. It would also allow technicians on the joint surveillance target attack radar system (JointSTARS) to select targets and choose the appropriate ordnance and delivery systems. Under this scenario, JointSTARS would potentially become a battle management platform and not just a surveillance system.

The evolution of JointSTARS into a battle management platform would put it on a path similar to the one followed by the airborne warning and control system (AWACS). Introduced in the late 1970s as a surveillance platform and early warning long-range radar, this system’s mission capabilities evolved along with its technology and matured over time into a battle management platform that also carried aircraft and weapons controllers.

The ground-breaking video transfer capability was displayed in an unmanned aerial vehicle (UAV)/ JointSTARS battlespace imaging demonstration carried out by the Air Force UAV Battlelab at Eglin Air Force Base, Florida. The battle laboratory is part of the Air Force Aerospace Command, Control, Intelligence, Surveillance and Reconnaissance Center and focuses on developing and demonstrating UAV innovations and technology that would produce immediate payoffs for the warfighter. The demonstration also involved the 605th Air Force Test Squadron, Melbourne, Florida; the 11th Air Force Reconnaissance Squadron, Indian Springs Auxiliary Airfield, Nevada; the UAV Joint Program Office, Wright-Patterson Air Force Base, Ohio; the JointSTARS Joint Test Force, Melbourne; the Joint Theater Missile Defense Attack Operations Office, Kirkland Air Force Base, New Mexico; and the Space Warfare Center’s SHIELD office at Colorado Springs, Colorado.

The E-8C JointSTARS is a Boeing 707-300 aircraft modified to furnish near-real-time surveillance and target information on moving and stationary ground targets, and on slow-moving rotary and fixed-wing aircraft. It employs a side-looking phased array radar that provides both moving target indicator wide area surveillance and synthetic aperture radar capabilities.

The RQ-1A Predator UAV provides near-continuous imagery coverage through long-endurance surveillance and reconnaissance missions. It carries three imagery systems: electro-optical, infrared and tactical endurance synthetic aperture radar. The associated ground control station contains the pilot, payload operator, data exploitation, mission planning and communications workstations. The battle laboratory chose the Predator for the demonstration because it is the first operational UAV in the Air Force inventory and could demonstrate operational realism and immediate warfighter payoff, according to the demonstration’s lead Predator pilot, Capt. Thomas Hesterman, USAF, assistant operations officer at the 11th Reconnaissance Squadron.

Although video imagery from Predators is routinely provided to ground intelligence collection sites during operations, it is not furnished to airborne battle management platforms. According to Maj. Scott Wilcoxen, USAF, UAV battle laboratory demonstration program manager, the Air Force and U.S. Army have carried out exercises in which a Predator ground control station was collocated with a JointSTARS common groundstation. This allowed these ground personnel to talk with each other and compare their respective video and radar images.

“However, it was a mechanical man-in-the-loop process, in which they had to go back and forth to tell each other who had what and where they were,” Maj. Wilcoxen emphasizes. “There never was any ability to correlate those two pictures on a single workstation onboard the JointSTARS platform, which is what we showed for the first time in the demonstration in February.”

According to Maj. Philip Pearson, USAF, UAV battle laboratory project manager, the workstation operators on JointSTARS currently see dots on their screens, which indicate that something is there, but they cannot positively identify what the dots represent. With the correlation of real-time UAV imagery, the JointSTARS crew can track, identify and cross-cue radar returns to positively identify moving and stationary ground targets such as tanks, trucks and missile platforms as well as identify the vehicle types and classify them as friend or foe. “Using the sensor capabilities of JointSTARS, they can then track that particular dot and get a wider picture of the battlefield,” Pearson adds.

The battle laboratory carried out the demonstration in two phases. The first phase, in September 1998, evaluated all the components of the system architecture in a laboratory environment at Eglin Air Force Base to prove the system’s capability. Various video processing software, video display quality and crew coordination and workstation procedures were tested. Northrop Grumman Corporation, Surveillance and Battle Management Systems, Advanced Program Office, Melbourne, Florida, which has the support contract for JointSTARS, designed and conducted the multipart laboratory evaluation. The second phase, which was the actual flight portion of the demonstration, took place at both Edwards Air Force Base and Nellis Air Force Base ranges in February.

The laboratory demonstration had three objectives. “First, we needed to configure the communications architecture that would be required to transmit the imagery obtained by Predator to the JointSTARS aircraft,” Maj. Wilcoxen says. “Although there had been some tests in the past, none of the JointSTARS aircraft had done this operationally,” he notes.

“We wanted to determine in the demonstration if we could emulate a global broadcast system [GBS]-type architecture because we saw that the GBS satellite network, which is still under development, is probably the way the Air Force is going,” Maj. Wilcoxen reports. GBS is an extension of the defense information systems network and part of the overall Defense Department military satellite communications architecture. It will employ an open architecture that can accept a variety of input formats and will exploit commercial off-the-shelf technology.

“We didn’t want to demonstrate an architecture that the Air Force is never going to use,” Maj. Wilcoxen states. “However, the unfavorable position of the GBS satellite over the mid-Atlantic at the time of the demonstration would have led to significant signal loss during the live flyby.”

Instead, the battle laboratory chose the commercial direct broadcast service (DBS), which closely resembles GBS. The JointSTARS aircraft used for the demonstration already had a DBS antenna and receiver manufactured and installed by The Boeing Company for use in an earlier unrelated test exercise.

Second, demonstrators anticipated the need for a standard Windows-based JointSTARS workstation to receive the video imagery from a Predator. The imagery would be transmitted via its ground control station, ensuring that the video quality would actually be usable by the operator, Maj. Wilcoxen explains.

The battle laboratory reviewed two commercial off-the-shelf and two commercial developmental products that could transmit video images to a personal computer display and manipulate the images. However, because of availability, integration and cost issues, the laboratory ultimately chose to use an analog format for the demonstration because it could display the video transmissions directly on the JointSTARS operator workstation.

The engineers also decided to use the onboard digital capability provided by the motion pictures experts’ group (MPEG)-1 card and its embedded display tool but recommended an MPEG-2 format or other digital capabilities for future demonstrations or actual operations. The MPEG-1 card converts the analog signal to a digital signal and also provides the interface tools for manipulating the imagery, replaying history and planning missions. The converted signal was then displayed on a laptop computer, which sent it through a red-blue-green spectrum display handler to the operator workstation. The handler allowed the mission crew to manipulate both the screen position and size of the video images.

“The digital capability is essential because the JointSTARS operator must be able to replay both the radar and video images in order to build up a situational awareness of what is happening on the battlefield,” James Goodson, SAIC senior analyst, says. The analog video transmitted from the Predator provides better quality images, but they cannot be saved for replay or manipulated, he explains.

The third objective involved establishing procedures for the crew. “We brought in a Predator imagery analyst from the 11th Reconnaissance Squadron, Nellis Range, Nevada, and put him together with a JointSTARS combat intelligence technician,” Maj. Wilcoxen recounts. “They worked out how they would handle the imagery and how they would coordinate with the other crew members on UAV tasking procedures and JointSTARS orbit location issues.”

During the February demonstration, the battle laboratory broke additional ground by arranging for JointSTARS to receive Predator’s exploitation support data (ESD), a telemetry stream broadcast alongside the imagery signal. ESD enabled the JointSTARS workstation to display the aircraft’s position and sensor footprint, which was critical to the operational utility of UAV imagery onboard JointSTARS, according to Northrop Grumman’s Steven Mitchell, project lead technical engineer. “ESD allows us to immediately correlate what the UAV sees with what JointSTARS sees,” Mitchell explains. “If we had to mechanically convert and correlate geographical data for both platforms, it wouldn’t be timely or dynamically workable.”

To test the system rigorously, the demonstration followed a scripted scenario that emulated the surveillance of a large target area with multiple fixed and moving targets. According to the script’s author, Chief Master Sgt. Gary Wildman, USAF, the scenario included two convoys of vehicles. One convoy comprised a Scud transporter erector launcher (TEL), some 2.5-ton trucks and six passenger-pickup trucks simulating the TEL’s support vehicles. The other convoy also included identical types of trucks but was led by a decoy TEL designed to draw attention away from the other convoy.

When JointSTARS began its reconnaissance orbit, it contacted the 11th Reconnaissance Squadron via a very high frequency radio link, requesting Predator imagery support at designated target areas. The imagery was downlinked to the ground control station that was cross-linked to DBS terminals. The terminals, in turn, laterally broadcast the transmission to a DBS injection site and uplinked it to the DBS network. The DBS antenna and receiver onboard JointSTARS then intercepted the imagery transmission and fused it to the operator workstation. JointSTARS and 11th Reconnaissance Squadron mission and intelligence specialists analyzed the imagery to identify the targets and determine battle management utility.

“The Space Warfare Center detected a Scud missile launch by means of unattended measurement and signature intelligence sensors that had been placed on the target area earlier,” Pearson recounts. “The center then cued JointSTARS [operators], which looked for that launch point on their radar; JointSTARS then cued Predator to find the launch TEL so that it could later track the Scud vehicles.”

“They didn’t actually launch any Scuds,” Maj. Wilcoxen points out. “We thought it would be much more realistic to look at an actual battlefield scenario, rather than just looking at trucks on I-15, which would therefore be much more useful to potential users of the system.” SAIC Deputy Group Manager Nicholas Gritti adds, “The whole point of the demonstration was to show what military utility is derived from doing this sort of thing. Using the Scud missile scenario, which was developed out of current crisis situations, would give those people who viewed the demonstration or who will read about it, an idea about why this is being done and the military utility of its success.”

According to Maj. Wilcoxen, the next step is to determine how to exploit this new capability. “If JointSTARS has reliable and continual access to Predator imagery during a contingency situation, it is conceivable that the combat identification, data exploitation, and the targeting and attack function used to strike ground targets can be drastically improved,” he declares.

“In addition, the latency built into decision making can be significantly reduced,” he contends. “However, this all depends on JointSTARS being outfitted with GBS-compatible antennas, receivers and associated hardware and software.”

The JointSTARS Joint Program Office, Hanscom Air Force Base, Massachusetts, is developing a transition plan to employ this technology to meet current and future JointSTARS operational requirements. The office contends that as GBS becomes standard Air Force equipment, it would be easy to install the necessary equipment for providing Predator imagery not only to JointSTARS, but possibly to other command and control platforms as well.