Session
Technical Session XI: Advanced Subsystems and Components II
Abstract
The use of the MIL-STD-1553B (1553) communications bus and Consultative Committee for Space Data Systems (CCSDS) standards are becoming increasingly popular in the design of small satellite command and data handling systems. Experience has been gained in the use of these two standards on a number of missions, which could be of benefit to those faced with integrating them into new spacecraft. The 1553 bus presents a number of advantages and disadvantages, both from electrical and data protocol perspectives. The 1553 bus is sometimes specified in the design of systems without considering these issues and without understanding the fundamental characteristics of the 1553 bus. The historical use of the 1553 bus provides important insights into these characteristics. The pros and cons of the 1553 bus must be considered when specifying the communications bus for a satellite. The use of the 1553 bus is often weighed against other communication protocols such as RS-422 in the design of command and data handling systems. The CCSDS standards are now maturing and are realizing increased use in explorer-class satellites. In addition to spacecraft-to-ground communications, CCSDS data units are being used as the format for the communication of commands, messages, and telemetry data among the instruments and the spacecraft controller. Because of the common use of the 1553 bus, techniques for implementing CCSDS over the 1553 bus must be derived. Experience has produced a list of “dos and don’ts” in implementing 1553 bus command and telemetry protocols. A number of missions have developed successful strategies for integrating CCSDS and the 1553 bus.
Designing Command and Telemetry Systems using MIL-STD-1553 and CCSDS
The use of the MIL-STD-1553B (1553) communications bus and Consultative Committee for Space Data Systems (CCSDS) standards are becoming increasingly popular in the design of small satellite command and data handling systems. Experience has been gained in the use of these two standards on a number of missions, which could be of benefit to those faced with integrating them into new spacecraft. The 1553 bus presents a number of advantages and disadvantages, both from electrical and data protocol perspectives. The 1553 bus is sometimes specified in the design of systems without considering these issues and without understanding the fundamental characteristics of the 1553 bus. The historical use of the 1553 bus provides important insights into these characteristics. The pros and cons of the 1553 bus must be considered when specifying the communications bus for a satellite. The use of the 1553 bus is often weighed against other communication protocols such as RS-422 in the design of command and data handling systems. The CCSDS standards are now maturing and are realizing increased use in explorer-class satellites. In addition to spacecraft-to-ground communications, CCSDS data units are being used as the format for the communication of commands, messages, and telemetry data among the instruments and the spacecraft controller. Because of the common use of the 1553 bus, techniques for implementing CCSDS over the 1553 bus must be derived. Experience has produced a list of “dos and don’ts” in implementing 1553 bus command and telemetry protocols. A number of missions have developed successful strategies for integrating CCSDS and the 1553 bus.
