MIL-STD-1553: Operation, Application and Revisions
Originally designed for military avionics usage, MIL-STD-1553 is now commonly employed in On-Board Data Handling (OBDH) spacecraft subsystems, both civil and military. MIL-STD-1553 features include:
- Network interface
- Time division multiplexing
- Dual redundant balanced line physical layer
- Half-duplex command/response protocol
- Nearly 31 remote devices
Both the Society of Automotive Engineers (Aerospace branch) and the US DOD now maintain the MIL-STD-1553 standard. A MIL-STD-1553 version that employs optical cabling instead of electrical is referred to as MIL-STD-1773.
MIL-STD-1553, at some time only considered a military data bus standard has now caught the attention of aircraft manufacturers in the commercial sector who are seeking to capitalize on the inherent reliability, maturity, robustness, and superior EMI performance of the standard.
Today, its application has gone further than the traditional domain of US Navy and Air Force aircraft to include applications utilized in combat vehicles, missiles, ships, satellites as well as the International Space Station Program. It’s also being used in advanced commercial avionic applications.
The multi-function interface cards of the MIL-STD-1553 are fully compatible with all common variations of the standard. They are providing a broad variety of features that are normally only found on full-size testers. Simultaneously, the card can operate as a Triggerable Bus Monitor, or as a Bus Controller (BC) or a multiple Remote Terminals (up to 32).
Today, MIL-STD-1553 has turned into one of the principal and basic tools being utilized by the US DoD for integrating weapon systems. The 1553 standard outlines the communication method and the requirements for the electrical interface subsystems that are linked to the data bus. The serial communication 1 Mbps bus is employed to attain stores management (MIL-STD-1760B) and aircraft avionic (MIL-STD-1553B) integration.
The main point of divergence between the MIL-STD-1553A and MIL-STD-1553B revisions is seen in the latter where the options have been clearly spelt out instead of being left open for the benefit of the user as required. The primary 1553B goal was offering flexibility without having to create new designs for each individual new user of the standard. This has been realized through explicitly specifying the electrical interfaces so that compatibility between designs coming from diverse manufacturers is maintained.
Key elements of the MIL-STD-1553B include the bus controller, bus monitor, the stand-alone remote terminal, the embedded remote terminal (a sensor/subsystem providing own internal 1553 interface). Others are 2 devices, part of the MIL-STD-1553 integration, the isolation couplers, and the twisted shielded pair wire data bus that is optional.
Also introduced by the MIL-STD-1553B revision is the optional broadcast transfer concept. A multiplex data bus system of the MIL-STD-1553 comprises of controlling multiple Remote Terminals (RT) and a Bus Controller (BC) all which are linked using a data bus. This provides a single data path between the associated Remote Terminals and the Bus Controller.
Today, similar to the majority of military standards, the MIL-STD-1553 is organized with a foreword, definitions, scope, general requirements, referenced document section, the appendix, as well as a tri-service Notice 2. Since 1978, seven change notices have been published in reference to the 1553 standard.