Joint Tactical Information Distribution System
The Joint Tactical Information Distribution System (JTIDS) is an L band Distributed Time Division Multiple Access (DTDMA) network radio system used by the United States Department of Defense and their allies to support data communications needs, principally in the air and missile defense community.
The slot assignments, frequencies, and information are all encrypted to provide computer-to-computer connectivity in support of every type of military platform to include Air Force fighters and Navy submarines.
Development is now carried out by Data Link Solutions, a joint BAE/Rockwell Collins company, ViaSat, and the MIDS International consortium.
Link 16, a highly-survivable radio communications design to meet the most stringent requirements of modern combat, provides reliable Situational Awareness (SA) for fast-moving forces.
While principally a data network, Link 16 radios can provide high quality voice channels and navigation services as accurate as any in the inventory.
Every Link 16 user can identify itself to other similarly equipped platforms at ranges well beyond what Mark XII Identification Friend or Foe (IFF) systems can provide.
The capabilities of Link 16 are best represented by the JTIDS or its follow-on Multifunctional Information Distribution System (MIDS) terminals.
The TADIL-J message format forms the basis for the mandates in the DoD Tactical Data Link Management Plan.
There are benefits to the full-scale implementation of the two key elements of Link-16: (1) the message "catalog" and (2) the specific radio waveform (i.e., frequency hopped, Lx-band CPSM, spread-spectrum and Reed–Solomon coding, omni-directional broadcast).
In a typical theater of operations combat forces and elements that are deployed to gather information tend to be scattered, are not always associated with a single unit, may even belong to different services and are not always well coordinated.
With JTIDS people who have information can broadcast it without explicitly knowing where it is going and combat elements can filter the composite data stream to extract exactly what they need (and no more).
At the time this was done, there was concern that operators who were used to dealing with conventional communications would gravitate toward replicating the circuits they were used to over JTIDS at the expense of the new and more responsive architecture.
The study concluded that on the battlefield valuable information was available that was not getting to the combat forces that needed it because of fundamental deficiencies in communications architecture.
This was a significant departure from the circuit-oriented communications architectures then in use and a way to eliminate overcrowding and confusion in the radio nets used to interconnect aircraft and some ground forces.
The advanced planning study was well received both at MITRE and ESD and it was decided to pursue a practical design to see if these ideas could be translated into a usable system.
Early on it became apparent that the CASOFF architecture was sufficiently radical that a "proof of concept" activity was needed to better understand and ultimately demonstrate the feasibility and benefits of such an approach.
The demonstration system used a synchronized Time Division Multiple Access architecture and incorporated position location as an integral part of the communications process.
Ellingson responded in the affirmative and immediately set about to implement the needed interfaces with the various NATO systems and equipping a KC135 aircraft that was to be used as a relay.
John Klotz didn't like acronyms and dubbed the program Tactical Position Location/Common Grid Capability which immediately became Tipplekeg.
In concert with contractor efforts a MITRE team led by Myron Leiter and consisting of communications and digital signal processing engineers refined the JTIDS design to optimize interference rejection and link performance.
