gr-pocketsdr: Bringing PocketSDR Front-Ends to GNU Radio and GNSS-SDR Ecosystem

Abstract

Open-source software-defined radio (SDR) ecosystems thrive on broad hardware support. Global Navigation Satellite System (GNSS)-SDR, a popular GNSS software receiver based on GNU Radio (GR), is no different. PocketSDR front-ends are an effective alternative to generic commodity SDRs for GNSS research. PocketSDRs are specifically tuned to GNSS bands and share a common clock across multiple radio frequency (RF) channels, enabling coherent multi-band processing. In addition, they are highly cost-effective. This paper presents gr-pocketsdr, a GR out-of-tree (OOT) module that enables open-source PocketSDR front-ends to serve as a GR signal source. Furthermore, we develop a GNSS-SDR adapter that enables use of the gr-pocketsdr module as a GNSS signal source. Experimental results show sustained IQ streaming at 20 Msps without sample loss and provide a real-time PVT (position, velocity, and time) solution. Experimental evaluation demonstrates sustained streaming at 20 Msps without sample loss. During a 328.6 s end-to-end run, GNSS-SDR produced 287 position fixes with no ring-buffer overruns. A controlled comparison with a ZeroMQ-based transport measures the processing cost, pipeline behavior, and end-to-end latency associated with crossing a process boundary. The multi-channel implementation additionally streams two independently tuned RF channels from one device while preserving their sample alignment. Finally, we demonstrate an application of the integrated receiver for characterizing the PocketSDR front-end reference oscillator. The software is released as open source to facilitate reproducible GNSS SDR research.