201609 September/October 2016

September 8, 2016

Single Versus Multiple

Dr. Kyle O’Keefe, University of Calgary

In the beginning, there was just one GNSS — the Global Positioning System — and just one fully available signal on the L1 frequency.

Eventually, some clever scientists discovered how to exploit certain characteristics of the encrypted L2 signal to come up with so-called codeless and semi-codeless techniques that enabled dual-frequency positioning. This hastened the development of user equipment that used the carrier phase of signals as well as the code to deliver high-precision results.

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By Inside GNSS

Mikel Miller’s Compass Points

Mikel Miller’s favorite equation

Return to main article: "Mikel Miller: Science, Service, and Family"

COMPASS POINTS

GNSS event that most signified to you that GNSS had ‘arrived’

Testing of the initial handheld units from vendors such as Trimble’s two-channel GPS receiver and Rockwell Collins’ PLGR. “We thought, ‘What an amazing capability to have a handheld device that all you had to do was turn it on and it told you where you were – wow!’”

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By Inside GNSS
September 1, 2016

GNSS Forum: Seven Easy Ways the Administration or Congress Could Get a Quick Win Protecting GPS and America

Dana Goward, President & Executive Director, Resilient Navigation & Timing Foundation

The U.S. Secretary of Defense has said “I hate GPS” and “I want to unplug the military from GPS.” Senior officials at the Department of Homeland Security (DHS) have called GPS “a single point of failure for critical infrastructure.”

GPS signals are used by virtually every technology. Their disruption for more than a brief period of time or over more than a small area could impact cell phone service, financial systems, computer networks, emergency radio systems, and every mode of transportation. It could be catastrophic for America.

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By Inside GNSS

The Particular Importance of Galileo E6C

Equations

The Galileo E6 signal is centered at 1278.75 MHz, and comprises three signals: an authorized signal (E6A, the publicly regulated service, PRS plus two civilian signals), a data component (E6B), and a pilot component (E6C). Both E6B and C are modulated using binary-phase shift keying (BPSK) code division multiple access (CDMA) memory codes, having lengths of 5,115 chips and chipping rates of 5.115 Mcps.

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By Inside GNSS

It’s Time for 3D Mapping–Aided GNSS

Figures 1-6

Real-time position accuracy, achievable in dense urban areas using low-cost equipment, is currently limited to tens of meters. If this could be improved to five meters or better, a host of potential applications would benefit. These include situation awareness of emergency, security and military personnel and vehicles; emergency caller location, mobile mapping, tracking vulnerable people and valuable assets, intelligent mobility, location-based services and charging, augmented reality; and enforcement of curfews, restraining orders and other court orders.

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By Inside GNSS