GNSS World

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March 7, 2022

Q: How could GNSS users determine in real time that their received navigation signals are correct? What methods are recommended, and when might they go into operation?

Cryptographic techniques can optimize the trade-off between authentication integrity (minimizing the probability of authenticating a modified message), ease of modification of existing signals (for operator and user acceptance), and minimal impact on existing users who will form the vast majority of the GNSS user population for some time to come.

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By Sam Pullen
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November 30, 2021

Energy-Efficiency Considerations For GNSS Signal Acquisition

Future miniaturized sensors, to be used for example in bee-sized drones, mini-satellites, or wearable devices, are likely to include GNSS chipsets supporting accurate outdoor localization and also offering reduced computational costs and power consumption compared to traditional GNSS receivers. The survey various energy-efficient methods for GNSS acquisition and present a discontinuous-reception acquisition algorithm, analyzed with both simulated and measurement-based data.

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By Inside GNSS
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November 29, 2021

ENTER LEO on the GNSS Stage: Navigation with Starlink Satellites

We are witnessing a space renaissance. Tens of thousands of broadband low Earth orbit (LEO) satellites are expected to be launched by the end of this decade. These planned megaconstellations of LEO satellites along with existing constellations will shower the Earth with a plethora of signals of opportunity, diverse in frequency and direction. These signals could be exploited for navigation in the inevitable event that GNSS signals become unavailable (e.g., in deep urban canyons, under dense foliage, during unintentional interference, and intentional jamming) or untrustworthy (e.g., undermalicious spoofing attacks).

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By Inside GNSS
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September 21, 2021

Smartphone-based GNSS Positioning – Today and Tomorrow

This article reviews some of the recent results analyzing the feasibility of carrier-phase based positioning with smartphone data and highlights limitations largely arising due to the poor antenna quality. It shows how they might be overcome by antenna calibration or coupling to the phone’s inertial sensors. The goal is to perform a successful RTK positioning with the smartphone-quality data.

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By Inside GNSS
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Washington View: Big Wheels Keep On Turning - Rolling On The River To 5G
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.)
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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
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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
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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
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