Columns and Editorials Archives - Inside GNSS - Global Navigation Satellite Systems Engineering, Policy, and Design

Columns and Editorials

September 14, 2021

Washington View: Big Wheels Keep On Turning – Rolling On The River To 5G

Ligado Networks had an early-year win in the form of a Federal Communications Commission denial of the National Telecommunications and Information Administration Stay Petition involving Ligado’s license for a terrestrial service in the mobile satellite services L-band. The company continues to roll toward deployment of a nationwide 5G network. While filings trickle in from the private sector, the feds work quietly behind the scenes on Congressional due-outs. In short, wheels big and small keep churning down the river to 5G.

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By Dawn M.K. Zoldi (Colonel, USAF, Ret.)

Are Elliptical Galileo Satellites Usable for RTK?

Galileo satellites 5 and 6 (E18, E14) were declared unusable in February 2021 after reports indicating repeatable daily problems with RTK. This article explores the possible impact of deviant elliptical orbits on the performance of RTK and finds that there is no reason to expect any anomalies caused by high orbit eccentricity per se. Thus there is no reason to declare the satellites unhealthy.

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By Inside GNSS
August 5, 2021

Evaluation of Sensor-Agnostic All-Source Residual Monitoring for Navigation

The addition of alternative sensors such as cameras, magnetometers, and small ranging radios increases the likelihood of a mismodeled and/or faulty sensor, affecting the accuracy and performance of the overall navigation solution. Unlike two-sensor systems such as GPS-inertial integration, systems of three or more sensors present the problem of ambiguity as to which sensor is adversely affecting the solution. This presents the need for a robust framework that can maintain navigation integrity despite the additional sensor modalities.

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By Inside GNSS
August 3, 2021

GNSS Interference Mitigation: Modulations, Measurements and Position Impact

Interference mitigation techniques should protect GNSS receivers from interference and jamming without biasing their final position, velocity and timing solution. This column analyses five popular interference mitigation techniques, including the Adaptive Notch Filter (ANF) and Pulse Blanking (PB), evaluating their impact on pseudoranges and on the final position and timing solution. Several GNSS modulations are considered, showing the advantage of using GNSS signals with similar spectral characteristics.

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By Inside GNSS

Washington View – PNT: Nothing to See?

A Department of Homeland (DHS)-chartered May 2021 report concludes that PNT threat and resilience concerns are not as dire as some have made them out to be, and that funds for backup could be spent elsewhere. Why this runs counter to other recent government reports is not clear, nor is the fallout from this divergence of Congressionally mandated views. The Department of Transportation has distanced itself a bit from this report by the RAND Corporation—and even its issuer, the DHS, seems to have done so.

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By Dawn M.K. Zoldi (Colonel, USAF, Ret.)
May 31, 2021

Getting to E5 With Ease: An AltBOC Double-Sideband Receiver Based on Single-Sideband Correlation

A novel method to track Galileo E5 AltBOC signal phase adjusts and then combines the correlation results of the upper sideband and lower sideband signal to form a double-sideband correlation result, which is equivalent to AltBOC wideband receiving to some extent. Thus, a Galileo E5 wideband receiver can be achieved with only minor modification to a traditional GNSS single-sideband receiver. The method can be further applied to other binary offset carrier (BOC) signals.

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By Inside GNSS
May 26, 2021

Seeing and Inertial Integrating Is Believing: Multi-Antenna Vision-and-Inertial-Aided CDGNSS for Micro Aerial Vehicle Pose Estimation

Multi-antenna carrier-phase differential GNSS (CDGNSS)-based pose (position and orientation) estimation aided by monocular visual measurements and a smartphone-grade inertial sensor form the core of a system designed for micro aerial vehicles. It can be applied generally for low-cost, lightweight, high-accuracy, geo-referenced pose estimation.

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By Inside GNSS
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