arXiv subjects

Thyagaraja Marathe

Publications and source records attributed to Thyagaraja Marathe.

2 recordsLinked to original sources

arXiv2026

Xona Pulsar Single-Satellite Positioning: System Perspective and Experimental Validation

Xona is deploying Pulsar, a low Earth orbit (LEO) commercial navigation system designed to deliver resilient positioning, navigation, and timing (PNT) where traditional solutions fall short. Pulsar satellites broadcast dedicated signals optimized for commercial users. This brings rapid geometry change, strong Doppler observability, and robust timing, enabling new approaches to positioning even when only one satellite is visible. Internet of Things (IoT) applications often prioritize availability over sub-meter accuracy in urban canyons, semi-indoor spaces, and other constrained environments. Many platforms are battery-powered, have strict size, weight, and power (SWaP) limits, and cannot support complex multi-sensor architectures. Leveraging LEO dynamics and signal strength, Pulsar can maintain navigation capability under these conditions without specialized user hardware. Here we present a single-satellite positioning (SSP) concept that uses available Pulsar measurements to estimate user position and receiver clock states without external aiding. Early in Pulsar deployment, only one or two satellites may be in view, yet this still benefits stationary or near-stationary users, including in semi-indoor and indoor settings. We discuss algorithmic details and system implications: SSP enables positioning with minimal satellite visibility, reduces reliance on dense constellations, and supports integration into resource-constrained platforms. We present simulation and live sky results. High-fidelity constellation simulations configured for Pulsar provide controlled performance assessment. We also present early findings from a Pulsar-enabled receiver using observations from the Pulsar-0 satellite on orbit. Preliminary tests demonstrate meter-level accuracy outdoors and indoors, highlighting potential under varied reception conditions.

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arXiv2025

Insights into Xona Pulsar LEO PNT: Constellation, Signals, and Receiver Design

The landscape of global navigation satellite systems (GNSS) is expanding with the emergence of low Earth orbit (LEO) constellations such as Pulsar, which are expected to play a key role in the future of positioning, navigation, and timing (PNT). LEO-based systems provide advantages including stronger signals for greater robustness, faster dynamics that aid convergence and multipath mitigation, and shorter time to first fix (TTFF) enabled by high data rates. These benefits, however, come with changes in signal behavior and constellation geometry that require careful consideration in receiver design. This paper investigates Pulsar properties using a GNSS simulator, analyzing parameters such as satellite pass duration, elevation, Doppler shift, Doppler rate, range, and number of satellites in view. Comparisons with GPS highlight the differences introduced by LEO operation. The analysis examines temporal evolution, statistical distributions, and maximum and minimum values. Beyond these statistical insights, the study explores interdependencies between parameters and differences across satellites, providing additional perspective. Evaluations are performed at multiple latitudes to ensure a worldwide perspective, and the impact of applying different elevation masks is discussed where relevant. Building on these findings, the paper assesses Pulsar's impact on receiver design from two standpoints: design considerations, addressing expanded Doppler ranges, higher Doppler rates, and unique constellation structure; and design optimizations, exploiting parameter analyses and interdependencies (e.g., Doppler rate vs Doppler) to refine acquisition strategies and applying prediction and prioritization techniques to avoid unnecessary computations. Together, these optimizations can reduce acquisition time and lower receiver power consumption.

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