Innovation

Innovation: Getting Closer to Everywhere

October 1, 2013By
FIGURE 1. Functional flow diagrams for a strapdown inertial navigation system (top) and a pedestrian dead-reckoning system (bottom).

Accurately Tracking Smartphones Indoors
If we wish to obtain consistently usable positions indoors using a mobile phone, we can augment its GPS or GNSS receiver with other unfettered sensing technologies such as gyroscopes and accelerometers supplemented by radio signals of opportunity. But is all of this actually feasible? The authors have conducted tests of a multi-system approach to positioning indoors with favorable results. read more

This article is tagged with and posted in Augmentation & Assistance, Innovation

Innovation: Under Cover

September 1, 2013By
FIGURE 1. Artist’s impression of the synthetic-aperture GNSS system for surveying in a forest.

Synthetic-Aperture GNSS Signal Processing
We take a look at a novel GNSS signal-processing technique, which uses the principles of SAR to improve code and carrier-phase observations in degraded environments such as under forest canopy. The technique can simultaneously reject multipath signals while maximizing the direct line-of-sight signal power from a satellite. Along with a specially programmed software receiver, it uses either a single conventional antenna mounted, say, on a pedestrian’s backpack for GIS applications or a special rotating antenna for high-accuracy surveying. Want to learn more? Read on. read more

This article is tagged with , , and posted in Algorithms & Methods, From the Magazine, Innovation

Innovation: Getting a Grip on Multi-GNSS

July 1, 2013By
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The International GNSS Service MGEX Campaign
GPS is almost 40 years old. While mass consumer use of GPS began only within the past decade or so, GPS was "born" during the Labor Day weekend of 1973, when about a dozen military officers and industry analysts under the leadership of Brad Parkinson met to consolidate the concept for a single satellite-based navigation system for the U.S. Department of Defense. Their proposal for NAVSTAR GPS was approved on December 22, 1973. The first satellite to be launched under the GPS program, on July 14, 1974, was the Naval Research Laboratory’s Navigation Technology Satellite (NTS) 1. read more

This article is tagged with and posted in BeiDou/Compass, From the Magazine, Galileo, GLONASS, GPS Modernization, Innovation

Innovation: GNSS Spoofing Detection

June 1, 2013By
In-opener

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

This article is tagged with , and posted in From the Magazine, GNSS, Innovation

Innovation: Evil Waveforms

May 1, 2013By
Innov-evilwave-O2

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
Innov-opener

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

This article is tagged with and posted in From the Magazine, Galileo, GNSS, Innovation

Innovation: A Better Way

March 1, 2013By
In-opener

Monitoring the Ionosphere with Integer-Leveled GPS Measurements
II 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

This article is tagged with and posted in From the Magazine, Innovation

Innovation: Getting Control

February 1, 2013By
I-opener2

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

This article is tagged with , and posted in From the Magazine, GNSS, Innovation