Because of a third-party delay, one of Pumpkin's 12U buses has undergone ground-based testing for several months longer than originally planned. This has presented the opportunity to fine-tune Pumpkin's GUTS flight software for enhanced performance. Because this 12U program only purchased one radio (the Flight Model), Pumpkin's software team developed a suite of tools to ensure reliable radio communications without having 24x7 access to the flight hardware.
As part of our testing, a ground-based Engineering Model is used to first validate GUTS, and then new code releases code make their way to the Flight Model. One of the critical GUTS components is the radio service that implements the CCSDS protocol over a commercial S/X-band radio. In order to test the radio service without access to the S/X-band radio, Pumpkin wrote a radio simulator. In the real-time performance plot below, the radio service (running on a Pumpkin 1GHz BeagleBone Black (BBB) SBC in a Pumpkin RS3) is communicating with the radio simulator (on a Xeon-based desktop PC) over a 100Mbps Ethernet link.
By using the simulator to develop and fine-tune the simulator, GUTS's CCSDS radio service can now deliver continuous throughput as high as 45Mbps (limited by the BBB SBC). While the actual radio may limit on-orbit performance, this test setup demonstrates the current upper bound of GUTS' radio service's performance in the existing 12U SUPERNOVA architecture. Further optimizations may raise the radio service's performance even further.