Commercial, Military

RCAT: Testbed for Nextgen

By David Van Cleave, The MITRE Corp. | August 1, 2008
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One of the most important aspects of the Next Generation Air Transportation System (NextGen) is ensuring that Department of Defense (DoD) and civil aviation can operate seamlessly in both national and international airspace. Based on net-centric operations, NextGen will use an enterprise-wide network for quickly sharing air transportation system information to substantially improve situational awareness and shorten decision cycles.

In preparation for addressing NextGen concepts and equipment, the U.S. Air Force’s Electronic Systems Center (ESC) at Hanscom AFB, Mass., connected its real-time avionics laboratory with a laboratory at Raytheon’s Network Centric Systems business in Marlborough, Mass. The ESC/Raytheon lab relationship is unique in its test capabilities, making it ideal for a wide range of experimentation for net-centric air traffic control operations.

The ESC lab, called the Reconfigurable Cockpit Avionics Testbed (RCAT), is located at The MITRE Corp., in Bedford, Mass. The not-for-profit company manages three federally funded research and development centers (FFRDC), including one each for the DoD and FAA. The RCAT is one of only a handful of cockpit simulators in the world with a real tail number — 160414.

At the other end of the connection is Raytheon’s Network Centric Operations Integration Laboratory (NCOIL), where the company experiments with transportation management and interagency real-time information sharing concepts. The RCAT/NCOIL facility has the potential to be an important tool to test NextGen transformation concepts as they get fleshed out and to help explore DoD/National Airspace System interoperability.

The laboratory collaboration is the result of a Cooperative Research and Development Agreement (CRADA) between ESC and Raytheon. The CRADA allows government agencies and collaborators to develop and use shared resources. No money is exchanged and the parties cover the cost of their own contributions to the shared asset.

The CRADA enabled two things to happen. First, it augmented the RCAT with a slimmed down version of Raytheon’s Standard Terminal Automation Replacement System (STARS), which ESC is buying and deploying for the Air Force to monitor approaches and departures. In addition to STARS, ESC also is buying and deploying Raytheon’s ASR-11 Digital Airport Surveillance Radar (ASR).

Second, the CRADA establishes the connectivity between the RCAT lab and Raytheon’s NCOIL to evaluate methods of sharing responsibility for maintaining aircraft separation between the aircraft and ground-based ATC.

"We’re linking the two labs so we can do a wide range of experimentation," said Alexander Kelley, deputy director of the ESC’s 853rd Electronics Systems Group, 653rd Electronic Systems Wing. "Raytheon’s lab can simulate and control airspace, and our RCAT lab can simulate live aircraft flying in that space. With the two, we can share a common air picture, a key enabler in the NextGen concept. And since we can do real-time testing while avoiding the cost of a flight test, we save a ton of money, especially with oil over $100 a barrel."

John Morris, who is MITRE’s global air traffic system project director and serves as director of engineering for the 853rd Electronic Systems Group, agreed. "We have the potential to do a wide range of experimentation with the many government agencies working on NextGen. This lab combination gives us an extensive capability to do risk reduction and test systems without having to fly. It will be a great help in validating NextGen concepts. And it will help us with the development of ATC systems by reducing their integration risks."

Equipment in the RCAT lab, in addition to the STARS terminal, includes a commercial flight management system- (FMS) based cockpit flight simulator, live Aircraft Communication Addressing and Reporting System (ACARS) data link connectivity and a variety of other avionics. The RCAT also has an AviationSimNet node for supporting real-time civil ATC simulations with voice and data communications.

Also installed in the RCAT is Raytheon’s Collaboration Workstation (CWS), a suite of Web-based software applications that run on a PC. The CWS subscribes to standards-based protocols, enabling both new and legacy systems to collaborate by sharing information. This capability helps make better decisions by providing more relevant cross-domain data to decision-makers. For example, CWS users can display all aircraft track updates, a single track, a selection of tracks or only those in a selected area.

Operators can also monitor and exchange public warnings and emergency messages between alerting technologies by using the Common Alerting Protocol (CAP). CAP is a XML-based data format that many agencies use to disseminate information about various warnings and alerts.

Raytheon’s lab uses the Air Force’s Distributed Common Ground System Integration Backbone (DIB). "The lab networks share information using XML and SOA (service-oriented architecture) technologies," said Robert Stamm, senior principal systems architect. "The lab also has databases for track information, alert messages, geospatial volumes of airspace and other types of information. We can publish a warning about an area where there’s a hazard and all connected members can display it on their CWS."

Weather information is provided through Raytheon’s Joint Environmental Toolkit, or JET, and published to subscribers on the network through the DIB. JET was developed for the Air Force, incorporating weather services and applications. It uses SOA technologies to replace legacy weather systems with a single, integrated capability that provides tailored weather products to users. It also ties into command and control systems and is an integral part of the Air Force Weather Weapon System, a "system of systems" that collects and analyzes weather information, then brings it to warfighters worldwide.


NextGen’s initial demonstrations are overseen by the Joint Network Enabled Operations (NEO) Program, a public-private partnership sponsored by the multi-agency Joint Planning and Development Office (JPDO). The program is funded by FAA, DoD and the Department of Homeland Security. The NEO industry team, led by Boeing, includes Computer Sciences Corp., Lockheed Martin and Raytheon.

The Joint NEO Program is the first NextGen activity where government policies, technical developments and shared funding decisions are brought together for integrated operations. The NEO Spiral One demonstration includes a hurricane disaster recovery operation and security operations during a terrorist attack.

"Our understanding of NextGen concepts, capabilities and interagency integration issues brings a perspective to help ensure success in this partnership with ESC," said Teh-Kuang Lung, program manager in Raytheon’s Airspace Management and Homeland Security group.

In the future, the RCAT/NCOIL lab could be used to define new procedures that permit access by unmanned aircraft to the NAS. For example, new net-centric approaches could test the interaction of remotely located UAV pilots with ATC procedures. To help maintain worldwide airspace access and mobility for DoD aircraft, Automatic Dependent Surveillance-Broadcast (ADS-B) could be tested as part of an Identification Friend or Foe system. The joint labs could also be used for end-to-end testing of the interface between Mode-S Digital Airport Surveillance Radar and STARS, among other possibilities.

As NextGen laboratory concepts and prototypes become available, one way to couple them to RCAT/NCOIL is via the AviationSimNet software from MITRE’s Center for Advanced Aviation System Development. AviationSimNet is a community-defined standard for interconnecting simulation labs that can be used to help evaluate concepts for NextGen. It’s a framework that allows aviation labs around the world to conduct distributed simulations in real time over the Internet.

The AviationSimNet specification covers the use of standards such as IP, VoIP, DIS 1278 for voice communications and DoD’s high-level architecture (HLA), which enable simulations to run across the public Internet and connect with those hidden behind firewalls. AviationSimNet also includes simulation hub and gateway software that facilitates laboratory connectivity.

Said Kelley: "We like the idea of using CRADAs to leverage infrastructures and technologies that already exist. By using existing resources like the RCAT for NextGen, we can promote collaboration between industry, the military and FFRDCs so that we can do our job better."

RCAT Reduces Risk Of Integrating COTS Systems

The ESC’s Reconfigurable Cockpit Avionics Testbed (RCAT) provides the U.S. Air Force with a hands-on demonstration, experimentation, training and test facility.

ESC currently leverages the RCAT in its support role to the Air Force for its Communications, Navigation, Surveillance/Air Traffic Management (CNS/ATM) modernization effort to help reduce the risk of integrating commercial off-the-shelf (COTS) air-traffic control subsystems into military aircraft.

The CNS/ATM modernization effort is all about getting CNS systems in Air Force platforms upgraded to facilitate seamless access to civil airspace. Otherwise, Air Force platforms may be restricted to slower air routes and altitudes that could impede their missions. KC-135 and C-5 mobility aircraft are some of the first to go through the CNS/ATM upgrade program.

"Among the many RCAT CNS capabilities is a completely qualified aircraft simulator with its own tail number," said Mike Bernock, MITRE’s RCAT testbed manager.

"In the RCAT, we can exercise live ATC communications links in real time so that we can observe end-to-end performance. When we have everything properly coordinated, it’s possible for an air-traffic controller sitting at a workstation in the Oakland or Gander Oceanic Flight Information Regions to communicate directly with the cockpit simulator of RCAT and view its simulated position. Since the RCAT appears on air-traffic control displays as a real aircraft, actual air-traffic control networks can be used to check communication system availability, integrity, throughput and delays."

Other labs that test avionics subsystems by simulating air-traffic control communications with computers cannot test as completely.

"Unlike other labs where the communications systems are often simulated, the RCAT has real aircraft avionics," said Bernock. "They are essentially the same boxes that are installed in Boeing, Airbus and other commercial aircraft."

In addition to integrating COTS avionics systems into military aircraft, the RCAT also helps the Air Force identify and track datalink network quality-of-service issues and is helping Air Force Guard and Reserve units train on oceanic datalink communications procedures.

STARS Brings Fusion, Airspace Adaptability

The Standard Terminal Automation Replacement System (STARS) is designed for use at medium to large terminal areas and the airports they service. The RCAT uses a slimmed-down version for use at medium- and low-density airports called STARS Local Integrated Tower Equipment (LITE).

The STARS terminal has a fusion tracking system that can receive inputs from 16 radar sensors to accurately depict aircraft location, even in mountainous areas. The STARS open architecture allows it to expand and adapt to new functional requirements and changing system configurations due to airspace changes and runway modifications. STARS can track up to 1,350 airborne aircraft simultaneously within a terminal area.

The system interfaces with multiple radars (up to 16 short- and long-range), 128 controller positions, 20 remote towers and a 512-by-512 mile area of coverage.

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