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Session A11: Satellite Experimentation: Commercial Satellite Sources 1

Single-Satellite Positioning from LEO PNT Signals: Elevation, Arc Length, and Observable Selection
Furqan Ahmed, Patrick Shannon, Anil Goparaju, TrustPoint, Inc.
Location: Room 1-3
Date/Time: Wednesday, Jun. 3, 2:50 p.m.

Single-satellite navigation is attractive for early constellation rollout, sparse-sky coverage, and resilience when multi-satellite geometry is unavailable. However, single-satellite PVT is intrinsically under-determined at a single epoch and becomes practical only when time history, dynamics models, and/or prior information are exploited. This presentation evaluates the achievable performance of single-satellite PVT using TrustPoint LEO PNT waveforms across three complementary data sources: (1) a real capture from an operational TrustPoint LEO PNT satellite, (2) two simulated TrustPoint satellites produced with a prototype receiver signal chain, and (3) software simulations of single-satellite operation derived from full-constellation scenarios. We analyze three observable sets commonly available in modern navigation receivers: pseudorange only, pseudorange plus Doppler (range-rate), and pseudorange plus Doppler plus Doppler-rate. Both static and moving receiver scenarios are considered to illuminate when single-satellite methods can provide stable solutions and when additional observables or priors become necessary.
Our approach uses batch and filtering formulations that ingest a time window (“arc”) of measurements centered around the point of strongest geometry and signal quality. For each observable set and scenario, we quantify position and time accuracy as a function of pass peak elevation, arc length, and other influential factors such as tracking quality, measurement noise assumptions, and receiver dynamics. The results show that elevation and arc length are first-order drivers: higher peak elevation and longer arcs markedly improve solution robustness and reduce tail risk, while low-elevation passes exhibit stronger sensitivity to measurement errors and modeling assumptions. Adding Doppler generally improves observability and reduces the minimum arc length required for stable solutions, particularly for moving receivers and in the presence of clock drift. Doppler-rate can further tighten dynamics constraints when measurement quality supports it, but its benefit is conditional on achievable measurement stability and robust modeling of satellite and receiver dynamics.
These findings provide concrete guidance for early deployment modes and hybrid architectures, including when to rely on single-satellite navigation, when to incorporate additional observables, and how to select arc length and geometry gates to deliver predictable performance during phased constellation rollout.

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