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Topcon Introduces Full-Spectrum GNSS Geodetic Antenna
February 16, 2012

Topcon Introduces Full-Spectrum GNSS Geodetic Antenna

Topcon CR-G5 GNSS antenna

Topcon Positioning Systems (TPS) announced the company’s new CR-G5 high-performance, GNSS choke ring antenna.

Based on the company’s new TA-5 full-spectrum GNSS antenna element, the CR-G5 geodetic antenna offers excellent vertical phase center stability over the GNSS frequency band superior performance in tracking low elevation satellite signals, according to the company.

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By Inside GNSS
Aviation Subcommittee Hearing Moves Beyond LightSquared to GPS Spectrum Protection
February 8, 2012

Aviation Subcommittee Hearing Moves Beyond LightSquared to GPS Spectrum Protection

John Porcari, US DoT Deputy Secretary

U.S. Deputy Secretary of Transportation John Porcari told a congressional committee today (February 8, 2012) that the expenditure of “substantial federal resources” in assisting LightSquared to gain approval for its terrestrial wireless broadband system was “unusual” yet “merited,” but that “further investment cannot be justified at this time.”

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By Inside GNSS
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Big Solar Storm, Little GPS Effect
January 28, 2012

Big Solar Storm, Little GPS Effect

Solar flare viewed January 23, 2012. NASA Solar Dynamics Observatory image.

Although it was billed as the strongest for the past eight years and coincided nicely with the American Meteorological Society (AMS) annual meeting in New Oreans, this week’s solar storm apparently had a limited effect on GPS receivers and users.

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By Inside GNSS
LightSquared GPS Interference Controversy: Senate Investigation Won’t End with FCC Decision
January 27, 2012

LightSquared GPS Interference Controversy: Senate Investigation Won’t End with FCC Decision

A Senate investigation into how the Federal Communications Commission (FCC) handled a request to rezone spectrum adjacent to GPS frequencies for LightSquared’s powerful wireless network will continue whether the FCC nixes the plan or not.

Sen. Chuck Grassley, R-Iowa, has been looking into whether the FCC fast-tracked its review of the Virginia firm’s proposal to build a 4G broadband network with signals that would be, tests now show, powerful enough to interfere dramatically with GPS receivers.

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By Inside GNSS
The Return of SVN49

The Return of SVN49

In an effort to improve constellation sustainment, on or about Feb. 1, 2012, SVN-49 will resume transmitting an L-band signal using PRN24 as a test asset, according to the U.S. Air Force Space Command. Upon completion of the test event, SVN-49 will once again be decommissioned from active service.  PRN24 will then once again be available for future satellite service.

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By Inside GNSS
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Code Tracking and Pseudoranges

Code Tracking and Pseudoranges

FIGURE 2: Pseudorange computation based on transmission. On the left side, the satellites are transmitting mes¬sages synchronously. On the right side, the four subframes are received asynchronously, due to the different propagation time. The TLM word is taken as a referene. The time differences ?i are computed on the basis of the relative arrival times of the front of the first bit of the TLM word.

Q: How can pseudorange measurements be generated from code tracking?

A: Every GNSS receiver processes the received signals to obtain an estimate of the propagation time of the signal from the satellites to the receiver. These propagation times are then expressed in meters to solve for the user position using trilateration.

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By Inside GNSS
Contact!

Contact!

A photo of the NavSAS group (December 2011)

On December 12, 2011, one of the two Galileo in-orbit validation (IOV) satellites launched on October 21 — the Galileo- ProtoFlight Model (PFM) spacecraft — started transmitting its payload signal on the E1 band over Europe.

 

That same day NavSAS researchers were able to acquire and track the E1 signal (Galileo Code Number 11) beginning at 14:46:15 CET. Two days later, on December 14, the E5 signal became available as well.

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By Inside GNSS
ESA Report: Galileo IOV Transmitting on all 3 Frequencies
December 26, 2011

ESA Report: Galileo IOV Transmitting on all 3 Frequencies

The European Space Agency (ESA) has reported its first successful reception of triple-frequency signals from a Galileo in-orbit validation (IOV) spacecraft.

The weekend of December 17 all Galileo signals were activated simultaneously for the first time across the European GNSS system’s three spectral bands, known as E1 (1559–1592 MHz), E5 (1164–1215 MHz), and E6 (1.215–1.300 MHz). The accompanying graphic displays the signals spectral profile.

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By Inside GNSS
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