Exploiting Starlink and OneWeb LEO Satellite Signals for High-Altitude Platform Station Opportunistic Navigation

Will Barrett, Sharbel Kozhaya, Jennifer Sanderson, and Zaher M. Kassas

Peer Reviewed

Abstract:	Conventional navigation methods rely on utilizing signals from global navigation satellite systems (GNSS), and fusing this information waith various other sensors. However, the crucial dependence on these GNSS signals has left significant vulnerabilities in position, navigation, and timing (PNT) sys- tems around the world. These signals can become unreliable or completely unavailable due to (i) intentional jamming ( [1], [2]) and spoofing ( [3], [4]), (ii) multipath intererence and signal obstruction ( [5]), and (iii) unintentional interference from out-of-band sources ( [6]). In the past decade, the usage of SOPs as an alternative navigation source has been expansively studied to reduce the dependence of navigation systems on GNSS. Literature has explored various terrestrial-based ambient signals including: (i) AM/FM radio signals ( [7]), (ii) digital television signals ( [8]) ,and (iii) cellular signals ( [9], [10], [11]). The exploitation of these signals has yielded experimental results achieving meter level navigation accuracy of a ground vehicle ( [12], [13], [14]), and sub-meter level estimation accuracy of an unmanned aerial vehicle (UAV) ( [15]). However, the continuous deployment of low Earth orbit satellites (LEO) in recent years has introduced new non- terrestrial signals and incited tremendous interest in their potential usage as a navigation source ( [16], [17], [18]). These signals offer multiple inherent benefits that could be ideal for PNT purposes. For example, these constellations are up to twenty times closer to the surface of the Earth than GNSS space-vehicles (SVs), implying a significantly higher carrier- to-noise ratio (CNR). Additionally, these LEO SVs occupy various orbital planes at altitudes ranging from 160 to 1000 kilometers, offering improved geometric dilution of precision as compared to GNSS ( [19]). These new constellations also utilize various frequency bands making jamming and spoofing more difficult, and are extremely abundant in the world today ( [20]). While specific LEO constellations may employ dedicated PNT services, such as that of Xona Space Systems, many are currently built primarily for communication signals. In trying to utilize these signals for PNT purposes in an opportunistic fashion, there are multiple significant challenges that must be addressed. For example, these SVs may not broadcast their clock errors, meaning receivers must independently es- timate these parameters ( [21], [22]). Similarly, these SVs may not broadcast their ephemerides, forcing receivers to either rely on erroneous open-loop propagation techniques of publicly available ”two-line element” (TLE) files ( [23], [24]), closed-loop corrections of these propagations ( [25], [26]) or continuously estimate and correct these parameters ( [27]), [28], [29]). Additionally, the signal structure of these non- cooperative LEO constellations may not be publicly available, which complicates the problem of effective receiver design. To address this difficulty, studies have been done to either decode specific symbols ( [30]), or utilize repetitive beacon signals to yield navigation observables ( [31], [32], [33]). Various groups have successfully shown experimental re- sults demonstrating the possibility of non-cooperative LEO navigation ( [34], [35], [36]). These results include stationary localization, ground vehicle navigation, and even low-altitude UAV navigation. However, in the world today there is a need to evaluate alternative navigation approaches at much higher altitudes. One high-altitude platform that is designed for operation in environments exceeding twenty kilometers is a high-altitude platform station. These systems are designed to function as a non-terrestrial network node, that may become pivotal in the operation of next-generation networks ( [37], [38]). This paper will outline the design considerations for a high-altitude balloon experiment, capturing LEO downlink signals of opportunity from the Ku-band spectrum. These experiments created extensive datasets that consist of multiple hours of recorded data at elevations as high as 82,000 feet in a turbulent, dynamic environment. First, it will outline the Starlink received signal model, OneWeb received signal model, and the software-defined radio receiver architecture implemented to yield Doppler observables. The paper will further characterize the received signals as a function of altitude, comparing predicted behavior for parameters such as CNR and tracking performance with experimental results. 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Published in:	2025 IEEE/ION Position, Location and Navigation Symposium (PLANS) April 28 - 1, 2025 Salt Lake Marriott Downtown at City Creek Salt Lake City, UT
Pages:	1388 - 1393
Cite this article:	Barrett, Will, Kozhaya, Sharbel, Sanderson, Jennifer, Kassas, Zaher M., "Exploiting Starlink and OneWeb LEO Satellite Signals for High-Altitude Platform Station Opportunistic Navigation," 2025 IEEE/ION Position, Location and Navigation Symposium (PLANS), Salt Lake City, UT, April 2025, pp. 1388-1393.
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