Innovation: GNSS Spoofing Detection

June 1, 2013By

It's a hostile (electronic) world out there, people. Our wired and radio-based communication systems are constantly under attack from evil doers. We are all familiar with computer viruses and worms hiding in malicious software or malware distributed over the Internet or by infected USB flash drives. Trojan horses are particularly insidious. These are programs concealing harmful code that can lead to many undesirable effects such as deleting a user’s files or installing additional harmful software. Such programs pass themselves off as benign, just like the “gift” the Greeks delivered to the Trojans as reported in Virgil’s Aeneid. This was a very early example of spoofing. read more

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Innovation: Evil Waveforms

May 1, 2013By

Generating Distorted GNSS Signals Using a Signal Simulator
In this month’s column, our authors discuss a set of GPS and Galileo evil-waveform experiments they have carried out with an advanced GNSS RF signal simulator. Their results will help to benchmark the effects of distorted signals and perhaps lead to improvements in GNSS signal integrity. read more

Innovation: Interfacing Clearly

April 1, 2013By

A New Approach to the Design and Development of Global Navigation Satellite Systems
In this month’s column, a team of authors affiliated with the Galileo project discusses the Interface Communication Modeling Language, an extension of UML that allows engineers to clearly represent SIS interfaces, critical for the design of GNSS receivers. read more

Innovation: A Better Way

March 1, 2013By

Monitoring the Ionosphere with Integer-Leveled GPS Measurements
I am joined by two of my graduate students, who report on an advance in the signal processing procedure for better monitoring of the ionosphere, potentially allowing scientists to get an even better handle on what’s going on above our heads. read more

Innovation: Getting Control

February 1, 2013By

Off-the-Shelf Antennas for Controlled-Reception-Pattern Antenna Arrays
The antenna is a critical component of any GNSS receiving equipment. It must be carefully designed for the frequencies and structures of the signals to be acquired and tracked. Important antenna properties include polarization, frequency coverage, phase-center stability, multipath suppression, the antenna’s impact on receiver sensitivity, reception or gain pattern, and interference handling. While all of these affect an antenna’s performance, let’s just look at the last two here. read more

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Innovation: Getting at the Truth

January 1, 2013By

A Civilian GPS Position Authentication System
When a GPS receiver reports its position to a monitoring center using a radio signal of some kind, how do we know that the receiver or its associated communications unit is telling the truth? It’s not that difficult to generate false position reports and mislead the monitoring center into believing the receiver is located elsewhere — unless an authentication procedure is used. In this month’s column, we look at the development of a clever system that uses the concept of supplicant and authenticator to assess the truthfulness of position reports. read more

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Innovation: Getting Along

November 1, 2012By

Collaborative Navigation in Transitional Environments
In this month’s article, a team of researchers at The Ohio State University discusses a system under development for collaborative navigation in transitional environments — environments in which GPS alone is insufficient for continuous and accurate navigation. Their prototype system involves a land-based deployment vehicle and a human operator carrying a personal navigator sensor assembly, which initially navigate together before the personal navigator transitions to an indoor environment. This system will have multiple applications including helping first responders to emergencies. Read on. read more

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Innovation: Easy Peasy, Lemon Squeezy

October 1, 2012By

Satellite Navigation Using Doppler and Partial Pseudorange Measurements
Have we outgrown the use of Doppler measurements for position fixing? It seems not. In this month’s column, we’ll take a look at a GNSS positioning technique that uses admittedly inaccurate Doppler-based position fixes as a first step in producing an accurate fix using just a snapshot of recorded Doppler frequency and code-phase data with no need to decode the navigation message. Old dog, new tricks. read more

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