signal Archives - Page 9 of 22 - Inside GNSS - Global Navigation Satellite Systems Engineering, Policy, and Design

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.

By Inside GNSS

February 15, 2012

NTIA and FCC Agree: No Practical Way to Fix LightSquared’s GPS Interference Problem

[Updated February 15, 2012] The GPS community received a Valentine’s Day message from U.S. regulators today (Feburary 14, 2012): there is “no practical way” to mitigate potential interference posed by terrestrial transmissions from LightSquared’s proposed wireless broadband network.

By Inside GNSS

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.”

By Inside GNSS

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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.

By Inside GNSS

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.

By Inside GNSS

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.

By Inside GNSS

January 13, 2012

Optimal Aligning of the Sums of GNSS Navigation Signals

Working Papers explore the technical and scientific themes that underpin GNSS programs and applications. This regular column is coordinated by Prof. Dr.-Ing. Günter Hein, head of Europe’s Galileo Operations and Evolution.

By Inside GNSS

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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.

By Inside GNSS

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.

By Inside GNSS

January 3, 2012

Newly Signed Appropriations Measure Adds Layer of Political Protection for GPS

When President Obama signed the $1 trillion dollar federal appropriations bill just before Christmas, he also inked into law a provision further protecting GPS receivers from interference from the wireless network proposed by LightSquared.

By Inside GNSS

December 27, 2011

China Publishes Compass /BeiDou “Test Version” of ICD; Key Data Missing

[Updated January 3, 2012] China released a long-awaited “test version” interface control document (ICD) for its Compass (BeiDou-2) GNSS system today (December 27, 2011). The 11-page publication covers its open B1 civil signal centered at 1561.098 MHz.

By Inside GNSS

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.

By Inside GNSS

December 13, 2011

Lockheed Delivers GPS III Pathfinder Spacecraft

GPS III pathfinder satellite testbed. Lockheed Martin photo

The Lockheed Martin team developing the U.S. Air Force’s next-generation GPS satellites (GPS Block III) has delivered the program’s pathfinder spacecraft to the company’s Denver, Colorado–area facility.

The program remains on schedule for a 2014 launch of the first Block III space vehicle (SV).

By Inside GNSS

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signal

Septentrio/QinetiQ Equipment Receives First Gaileo PRS Signal...

Spectracom Offers New Signal Generator for In-Line GNSS Product T...

Topcon Introduces Full-Spectrum GNSS Geodetic Antenna

NTIA and FCC Agree: No Practical Way to Fix LightSquared’s GPS Interference Problem

Aviation Subcommittee Hearing Moves Beyond LightSquared to GPS Spectrum Protection

Big Solar Storm, Little GPS Effect

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

The Return of SVN49

Optimal Aligning of the Sums of GNSS Navigation Signals

Code Tracking and Pseudoranges

Contact!

Newly Signed Appropriations Measure Adds Layer of Political Protection for GPS

China Publishes Compass /BeiDou “Test Version” of ICD; Key Data Missing

ESA Report: Galileo IOV Transmitting on all 3 Frequencies

Lockheed Delivers GPS III Pathfinder Spacecraft