Development of a Real-Time Software-Defined Receiver for Broadband LEO PNT

W. Jeremy Morrison, Todd E. Humphreys

Abstract:	This paper offers a first look at the development of a software defined radio (SDR) capable of processing signals from lowEarth-orbit (LEO) constellations for time-of-arrival and frequency-of-arrival measurements in real time. LEO signals offer greater potential accuracy and resilience to jamming and spoofing than traditional global navigation satellite system (GNSS) signals, due to their high power and wide bandwidth. SDRs have historically enabled rapid innovation cycles for traditional GNSS. However, the large bandwidth of LEO mega-constellation signals have been prohibitive for using “pure” SDRs— those that perform correlation on a general purpose processor—to process these signals in real-time. This paper showcases the development of LEONARD, the first pure SDR capable of real-time LEO broadband processing. Differences from the real-time tracking of GNSS signals are discussed and preliminary tracking results are shown.
Published in:	Proceedings of the 38th International Technical Meeting of the Satellite Division of The Institute of Navigation (ION GNSS+ 2025) September 8 - 12, 2025 Hilton Baltimore Inner Harbor Baltimore, Maryland
Pages:	2795 - 2803
Cite this article:	Morrison, W. Jeremy, Humphreys, Todd E., "Development of a Real-Time Software-Defined Receiver for Broadband LEO PNT," Proceedings of the 38th International Technical Meeting of the Satellite Division of The Institute of Navigation (ION GNSS+ 2025), Baltimore, Maryland, September 2025, pp. 2795-2803. https://doi.org/10.33012/2025.20458
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