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Columns and Editorials

September 24, 2020

The Time and the Place: Threats From Within

It has become fashionable of late in U.S. government circles to undermine the U.S. defense forces. The General Accounting Office (GAO), the Federal Communication Commission (FCC) and the White House (POTUS) have all pitched in, doing their share to weaken the capability and downgrade the tools with which our warfighters enter conflict.

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By Alan Cameron
August 18, 2020

Novel Anti-Jamming Techniques for GNSS-based ERTMS Train Control

The digital outputs of a four-channel antenna processing chain consisting of a four-element squared phased array and a 4-coherent channels front-end are processed to identify the presence of a jamming signal. The processing unit then implements a spatial filter to minimize jammer impact. The reconstructed signal is input to a COTS/SDR receiver designed to work in a typical railway environment.

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By Inside GNSS
August 3, 2020

Galileo’s High Accuracy Service: Field Experimentation of Data Dissemination Schemes

Galileo will provide a High Accuracy Service (HAS) with positioning performance in the 20-cm range, disseminating Precise Point Positioning (PPP) corrections through the Galileo E6-B signal. Test results of a data encoding and dissemination scheme in different user environments demonstrate a reception time of the corrections in a few seconds in good channel conditions, and less than half a minute with severe channel impairments.

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By Inside GNSS
May 21, 2020

The New Flex Power Mode: From GPS IIR-M and IIF Satellites with Extended Coverage Area

GPS satellites usually transmit their signals with constant power. However, a so-called “Flex Power” is foreseen to increase the strength of individual signals to better fulfill operational constraints. Flex power operations can be detected in carrier-to-noise density ratio (C/N0) observations provided by GNSS receivers of the global tracking network of the International GNSS Service (IGS).

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By Peter Steigenberger, et al.

Positioning, Navigation, and Timing Trust Inference Engine

Critical infrastructure has a compelling need to infer the assurance of PVT estimates—as do users in general. However, traditional PNT platforms do not offer a principled way to infer assurance from multiple anti-spoofing (A-S) techniques, situational awareness (SA) information, and other auxiliary sources such as network data. Here we introduce, a PNT Trust Inference Engine (PNTTING) that can assess PNT trust according to probabilistic models with rigorous semantics.

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By Andras Molina-Markham & Joseph J. Rushanan