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

TL;DR

This paper introduces a novel single-satellite positioning method for the Pulsar LEO navigation system, enabling accurate location estimates even with minimal satellite visibility, suitable for IoT and constrained platforms.

Contribution

It presents the SSP algorithm that estimates user position and clock states using only one or two Pulsar satellites, reducing the need for dense satellite constellations.

Findings

Preliminary tests show meter-level accuracy outdoors and indoors.

Simulation results validate the SSP approach under controlled conditions.

Live sky observations demonstrate practical feasibility.

Abstract

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.