Spacecraft computing systems with high-level specifications and FPGAs

Abstract

A typical modem spacecraft requires computer processing in every major subsystem. The most popular method to carry out these processing requirements involves the use of a primary computer based on microprocessors. To carry out each spacecraft's unique processing requirements, custom software is specified, written, compiled, and executed by the microprocessors. The current process leads to a dedicated group of software engineers to design and create spacecraft software. This process is expensive and error-prone. Errors that occur during the translation of subsystem specifications into software specifications have led to failures and anomalies. This thesis describes a new methodology and toolsets that allow spacecraft subsystem engineers to capture and analyze typical spacecraft processing requirements in a unified and formal specification methodology. Subsystem engineers capture processing requirements with a pair of formal high-level specification languages specifically designed for spacecraft requirements. Control-oriented requirements such as fault detection and isolation features are captured with SpecTRM-RL, while data-oriented requirements such as control law algorithms are captured in a new language and toolset called Octavia.

(cont.) Once subsystems engineers have completed the high-level specifications, the specifications are automatically converted into a combination of software code and hardware descriptions using a set of autocode generators. Using recent advances in Field Programmable Gate Array (FPGA) technology, a unique computing system can be synthesized from the autocode generated components.