Implementation of an actor framework for a ground station

Abstract

This paper describes an implementation for a ground station framework based on the actor model and software-defined radios (SDRs), allowing for a highly scalable system that can operate on low-cost receivers or scale to a collection of servers. The actor model defines a concurrent system where the individual unit of computation is the actor and communication between components is handled through a message passing interface. Pystation is an actor framework written in Python that implements a message-passing scheme where each actor has the ability to communicate with local actors or actors across a network. This paper describes some historical and background information on the actor model followed by details of its implementation and examples of use at a ground station. GNU Radio is utilized as the software for physical layer and signal processing, allowing for a highly robust and flexible ground station that can be altered without tedious hardware modifications. The purpose of this framework is to provide the software foundation to the Virginia Tech Ground Station (VTGS) in order to increase reliability and flexibility. The Virginia Tech Ground Station project is meant to serve as a ground station operations and communications sandbox for educational activities, such as student labs and space-based research projects.