Design & Test

CAST Navigation Introduces Handheld Simulator

April 9, 2012By

  CAST Navigation of Tewksbury, Massachusetts introduced its SGX GPS Satellite Simulator. With its compact size — 7 × 11× 3 inches — and weighing in at just over 4 pounds, the SGX is CAST’s newest and smallest fully capable simulator to date. The new SGX replaces the CAST-SIMCOM Simulator which was a 17-inch, 50-pound simulator. The SGX lightweight portability... read more

The System: eLoran Gets Trials, Possibly a New Life

April 1, 2012By

eLoran Gets Trials, Possibly a New Life As result of a Cooperative Research and Development Agreement (CRADA) between the U.S. Coast Guard and UrsaNav, Inc., on-air tests are being conducted from the former Loran Support Unit site in New Jersey. One of the CRADA’s goals is to research, evaluate, and document a wireless technical approach as an alternative to GPS... read more

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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

The Kinematic GPS Challenge: First Gravity Comparison Results

March 14, 2012By

By Theresa Diehl The National Geodetic Survey (NGS) has issued a “Kinematic GPS Challenge” to the community in support of NGS’ airborne gravity data collection program, called Gravity for the Redefinition of the American Vertical Datum (GRAV-D). The “Challenge” is meant to provide a unique benchmarking opportunity for the kinematic GPS community by making available two flights of data from... read more

UrsaNav Testing Wide-Area Timing Alternative

March 5, 2012By

As a result of a Cooperative Research and Development Agreement (CRADA) between the U.S. Coast Guard and UrsaNav, Inc., on-air tests are being conducted from the former Loran Support Unit site in New Jersey. One of the CRADA’s goals is to research, evaluate, and document a wireless technical approach as an alternative to GPS for providing precise time. The ability... read more

The System: NTIA, FCC Waiver No More on LS

March 1, 2012By

“We conclude that LightSquared’s proposed mobile broadband network will impact GPS services and that there is no practical way to mitigate the potential interference at this time.” These words from Lawrence Strickling, U.S. assistant secretary for communications and information and head of the National Telecommunications and Information Administration (NTIA), appear to signal the end of LightSquared’s run. Strickling’s letter to... 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

A Comparison of Lidar and Camera-Based Lane Detection Systems

February 3, 2012By

By Jordan Britt, David Bevly, and Christopher Rose Nearly half of all highway fatalities occur from unintended lane departures, which comprise approximately 20,000 deaths annually in the United States.  Studies have shown great promise in reducing unintended lane departures by alerting the driver when they are drifting out of the lane. At the core of these systems is a lane... read more

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