Signal Processing

Directions 2013: Doing More with Less to Advance GNSS

December 1, 2012By

The history of GNSS shows each year has always been more successful than the year prior, and in 2013 we expect the trend to continue. In the United States, the role of GPS will continue to expand, and the applications for our technology will reach sectors we never imagined. As our international partner countries continue to launch GNSS satellites, and user equipment develops further, our community will increase its globalization, and international cooperation will reach new heights. read more

This article is tagged with , and posted in From the Magazine, GNSS, Opinions, Signal Processing

Directions 2013: Dealing with Interference

December 1, 2012By

In my vision of the future of GNSS, I see a pressing need to manage radio-frequency spectrum more efficiently. This will drive the creation of official standards for GNSS receivers, and better design of those receivers with better filters at lower cost, to protect against out-of-band and near-band interference. This in turn will enable user to undertake widespread monitoring and reporting of in-band interference, and create the freedom for many technologies to explore wider and more productive use of all bands of the radio-frequency spectrum. read more

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

Innovation: The Devil Is in the Details

July 1, 2012By
FIGURE 4. A CPSE observed on SVN48 (PRN07) on September 15, 2010, at 19:21:42 GPS Time. (Click to enlarge.)

Looking Closely at Received GPS Carrier Phase
The stability of a received GPS signal determines how well the receiver can track the signal and the accuracy of the positioning results it provides. While the satellites use a very stable oscillator and modulation system to generate their signals, just how stable are the resulting phase-modulated carriers? In particular, do received signals always conform to the published system specifications? In this month’s column we take a look at a specially designed receiver for analyzing GPS carrier phase and some of the interesting results that have been obtained. read more

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

Reminder: Leap Second This Weekend

June 29, 2012By

News courtesy of CANSPACE Listserv. Likely none of us needs a reminder as the upcoming leap second has been all over the news outlets for the past few days. But just to provide the details again, read this article. Presumably, all GPS receiver manufacturers have checked to make sure their receivers will handle the leap second properly. However, at least... read more

This article is tagged with , and posted in Featured Stories, Signal Processing, Timing

Hemisphere GPS Introduces A325 GNSS Smart Antenna

June 27, 2012By

Today, Hemisphere GPS introduced the A325 GNSS Smart Antenna. It incorporates professional-level centimeter and sub-meter positioning accuracy powered by Hemisphere GPS' Eclipse receiver technology and includes L-band and Bluetooth communications support. A325 is designed for a variety of applications including agriculture, construction, straddle carriers, robotics, marine, survey, and GIS, Hemisphere GPS said. read more

This article is tagged with , , and posted in Signal Processing, Survey

Innovation: Simulating GPS Signals

May 1, 2012By
FIGURE 3. Signal Architect simulation flow. (Click to enlarge.)

It Doesn't Have to Be Expensive
GNSS signal simulators can be expensive and beyond the limited budgets of many researchers. In this month’s column, we look at one company’s approach to providing GNSS signal simulation at a low cost — one that virtually any researcher can afford.GNSS signal simulators can be expensive and beyond the limited budgets of many researchers. In this month’s column, we look at one company’s approach to providing GNSS signal simulation at a low cost — one that virtually any researcher can afford. read more

Innovation: Ionospheric Scintillations

April 1, 2012By
FIGURE 1 Global occurrence characteristics of scintillation. (Figure courtesy of P. Kintner)

How Irregularities in Electron Density Perturb Satellite Navigation Systems
In this month’s column, the international Satellite-Based Augmentation Systems Ionospheric Working Group presents an abridged version of their recently completed white paper on the effect of ionospheric scintillations on GNSS and the associated augmentation systems. read more

Sensing Location: Software Receiver Estimates Signal States During Outages

March 1, 2012By
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Future safety-relevant driver assistant systems demand vehicle state estimations accurate enough to match the position within a road lane, which cannot be provided by standalone GPS. A promising approach to meet the requirements is the fusion of standalone or differential GNSS measurements with vehicle sensor data like odometers or accelerometers. To achieve deeper sensor integration, a software GNSS receiver was developed at the Institute of Flight Guidance (IFF) that is able to use dead reckoning sensors to support its signal acquisition. This article presents an approach to estimate the signal states during outages based on the tightly coupled vehicle state, which reduces the reacquisition time and significantly increases the signal availability. read more