Project Biarri and the Namuru V3.2 Spaceborne GPS Receiver

The Namuru V3.2 GPS receiver is an Australian developed FPGA-based GPS receiver designed specifically for the Biarri Project; a multi-lateral Colony 2 cubesat defence project that Australia is participating in via the Defence Science and Technology Organisation. In this paper, a brief introduction to the Biarri mission requirements is provided, as are the various design features of the receiver that has been developed to satisfy those requirements. In particular, we focus on describing the features relating to operation of the receiver in low-earth orbit, in-orbit reprogramming of the receiver, and the provision of precise timing signals. GPS simulator test results using the latest generation of Namuru V3.2 receiver are also presented. These results show in-orbit positional accuracies within 10 m, velocity accuracies within 1 m/s and timing accuracies within 50 ns, while the warm-start time-to-first fix typically (90%) occurs within one minute.