MEASUREMENTS OF SIGNAL DELAYS IN SOFTWARE DEFINED RADIO WITH USE OF GNSS MODULES

Oskar Mężyk 1, Michał Doligalski 2, Ryszard Rybski 3

1Institute of Metrology, Electronics and Computer Science, University of Zielona Góra

2Institute of Metrology, Electronics and Computer Science, University of Zielona Góra

DOI: 10.1515/aon-2019-0010

ABSTRACT

In the work a method of latency measurement in software defined radio (SDR) is proposed and validated. The test setup uses customer grade GNSS modules as reference time sources and enables relative delay calculation between signals received directly and those bypassed through SDR platform. The method is hardware agnostic in a sense, that it does not involve any custom software or hardware modifications. Tests that compare reported carrier-to-noise ratio and positioning errors were performed to prove functionality of such system. Additionally, authors measured several gnuradio blocks with respect to their impact on total latency introduced into signal path. All tests were performed on a bladeRF low-cost RF front-end. Minimum observed latency for the signal was below 10 ms.

KEYWORDS

GNSS, SDR

REFERENCES

[1] Falone R., Stallo C., Gambi E., Spinsante S., „SDR GNSS receivers: A comparative overview of different approaches,” 2014 IEEE Metrology for Aerospace, Benevento, 2014, pp. 326-331. doi: 10.1109/MetroAeroSpace.2014.6865943
[2] Müller M., “Behind the Veil: A Peek at GNU Radio’s Buffer Architecture”, The GNU Radio Foundation, 5 Jan 2017, www.gnuradio.org/blog/2017-01-05-buffers/
[3] Nuand LLC, “bladeRF USB 3.0 Software Defined Radio”, 23 Mar 2019, www.nuand.com/bladeRF-brief.pdf,
[4] Schmid T., Sekkat O., B. Srivastava M., “An experimental study of network performance impact of increased latency in software defined radios.”, Proceedings of the second ACM international workshop on Wireless network testbeds, experimental evaluation and characterization (WinTECH ’07), ACM, New York, 59-66. doi:10.1145/1287767.1287779
[5] Suganuma, H., Suzuki, M., Morikawa, H., “A Buffer Size Tuning Mechanism for Software-Defined Radios”, IEEE INFOCOM 2012, Hilton Orlando Lake Buena Vista
[6] Truong, N.B., Yu, C. „Investigating Latency in GNU Software Radio with USRP Embedded Series SDR Platform,” 2013 Eighth International Conference on Broadband and Wireless Computing, Communication and Applications, Compiegne, 2013, pp. 9-14. doi: 10.1109/BWCCA.2013.11
[7] U-blox AG, “u-blox 8 / u-blox M8 Receiver Description”, 6 Mar 2018, ubx-13003221