One of the US Air Force's goals is to reduce the time needed to strike timesensitive targets, thus minimizing the adversary's perceived mobility advantage and leaving concealment as that enemy's primary defensive measure. One potential way to meet this challenge relies on a capability to redirect and update weapons with new target coordinates while they are in flight—a solution that requires weapons developers to outfit weapons with a data link enabling communications between warfighters operating in the air and on the ground. This Weapon Data Link (WDL) approach would allow the warfighter to directly communicate with and control air-launched weapons to strike moving or otherwise time-sensitive targets, while continually gathering information about the weapon's performance against those targets. The scenario could involve something as simple as a weapon communicating its position and system status back to the release aircraft, or something as complex as a weapon operating in the Global Information Grid (GIG), wherein a secondary ground/air controller assumes the weapon's control after a positive handoff from the release platform, with the weapon's sensor and video information autonomously distributed throughout the GIG.

Figure 1. Depiction of WDL
AFRL engineers recently accomplished a critical step in demonstrating the WDL approach. Held at Langley Air Force Base (AFB), Virginia, the demonstration's primary objective was to show that two WDL terminals, connected to Tactical Air Control Party (TACP) laptop computers, could successfully transmit and receive J-series messages within a Link-16 network (see Figures 1 and 2). The network included a legacy Fighter Data Link (FDL) terminal provided by the 46th Test Squadron (Eglin AFB, Florida), two WDL terminals, and local aircraft equipped with Link-16 radios.

Engineers from AFRL and Rockwell Collins partnered to develop the 50 in3, software-defined WDL radio used in the demonstration. This radio provides multiple operators with the flexibility to port and upload communication waveforms. The device has three software waveforms loaded into its memory; the operator can switch between these waveforms as required. Although the test team limited this demonstration to Link-16 operation, future demonstrations will highlight the radio's capacity to receive and transmit ultra-high-frequency satellite communications and line-of-sight waveforms as well. The TACP Modernization program supplied the TACPCASS (Close Air Support System) software, laptop computers, and a trained operator. During the first part of the demonstration, one TACP computer generated target coordinates and transmitted them as J-series messages from one WDL terminal to the other. The TACP-CASS software on the second TACP computer interpreted and displayed the transmitted messages as target tracks. This test showed that messages generated by the TACP-CASS software could be correctly interpreted by the two networked WDL terminals and that this information could be shared between them. In the second phase of the demonstration, test engineers integrated the FDL terminal into the network. One of the TACP computers transmitted target information via Link-16 network protocol to the FDL terminal, which correctly interpreted and displayed the information on the Improved Multilink Translator and Display System (IMTDS). In the next phase, both computers correctly received, interpreted, and displayed target messages transmitted by the FDL terminal. In a final demonstration of system capability, several aircraft from Langley AFB joined the network for short periods of time, transmitting information that was subsequently displayed on both the TACP and IMTDS computers.

Figure 2. Setup of WDL demonstration equipment
All demonstration participants gained valuable insight into using Link-16 networks for passing J-series messages between aircraft, weapons, and ground troops. The test team did not intend for the demonstration to provide an in-depth look at integrating weapons into battlefield networks. Rather, its purpose was to provide a rudimentary understanding of how an aircraft, weapon, and TACP could join and operate in an existing Link-16 network, while specifically demonstrating the capability of a software-defined WDL radio to transmit and receive J-series messages. The demonstration achieved its twofold purpose, both providing overall insight regarding the system and establishing the flexibility of a softwaredefined WDL radio in processing J-series messages within a representative network.

Ms. Michelle White, of the Air Force Research Laboratory's Munitions Directorate, wrote this article. For more information, contact TECH CONNECT at (800) 203-6451 or place a request at http://www.afrl.af.mil/techconn/index.htm. Reference document MN-H-05-14.

Reference

1 "China-America: The Great Game." Interview With Lt Gen Liu Yazhou. Eurasian Review of Geopolitics, Gruppo Editoriale L'Espresso/Cassan Press-HK, Jan 05.