Navigation and ionosphere characterization using high‐frequency signals: Models and solution concepts

Abstract

A navigation concept is being developed that relies on passive one-way ranging using pseudorange and beat carrier-phase measurements of high-frequency (HF) beacon signals that travel along non-line-of-sight paths via ionosphere refraction. This concept is being developed as an alternative to GNSS positioning services.If the set of signals that reaches a user receiver has sufficient geometric diversity, then the position of that receiver can be determined uniquely. Ionospheric modeling uncertainty causes errors in the deduced user position, but these errors are compensated by estimating corrections to a parametric model of the ionosphere as part of the navigation solution. A batch filter estimates the user position and corrections to an a priori ionosphere model. In simulated case studies involving significant errors in the a priori ionospheric parameters, the total positioning error is on the order of tens of meters in the horizontal plane and on the order of meters vertically.

Navigation and Ionosphere Characterization Using High-Frequency Signals: A Performance Analysis

“…A solution for this coupled positioning/ ionosphere characterization problem is obtained using a method that combines an a-priori ionosphere model, ray-tracing calculations for propagating signals, and model inversion calculations to compute an enhanced estimate for the unknown quantities. The details of this technique are provided in Baumgarten et al (2021), which also demonstrates the feasibility of the proposed concept.…”

“…calculations through a three-dimensional model of the ionosphere's free-electron density profile and models of signal reflection off the Earth's surface. The needed models have been introduced and developed in Baumgarten et al (2021). This reference also discusses and demonstrates how uncertainties in the electron density profile can induce significant errors in the computation of signal trajectories.…”

“…The present paper focuses on the potential performance of the batch filter of Baumgarten et al (2021) and on its sensitivity to problem parameters. In particular, a key question concerns the way that positioning accuracy varies with the set of parameters that characterize a given estimation scenario.…”

“…A comprehensive description of the fundamental models that lie in the core of this study is provided by Baumgarten et al (2021). This includes physical models of propagating RF signals in the ionosphere that are implemented using refractive ray-tracing techniques of the Earth's geometry and magnetic field as well as of the three-dimensional electron density distribution in the ionosphere.…”

“…This includes physical models of propagating RF signals in the ionosphere that are implemented using refractive ray-tracing techniques of the Earth's geometry and magnetic field as well as of the three-dimensional electron density distribution in the ionosphere. Baumgarten et al (2021) also derived mathematical models for single-hop and multi-hop ray paths. These models combine to yield the batch filter's models of the measured observables.…”