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June 23, 2010

Russian Company Offers ‘Preliminary’ Specifications for GLONASS CDMA Signal

Illustration of GLONASS-K satellite

A provisional specification for the planned GLONASS CDMA signal has been defined and is available to receiver manufacturers interested in experimenting with the demonstration signal that will be broadcast from the GLONASS-K satellite to be flight-tested later this year.

Mark Shmulevich, head of business development for Russian Space Systems (RSS), extended the offer at the Asia Pacific Economic Cooperation GNSS Implementation Team (APEC-GIT) meeting in Seattle, Washington, this week. RSS is an amalgamation of 10 former Russian federal state unitary enterprises — that is, government corporations — and other Russian institutes and agencies established last year, with the former Russian Institute of Space Device Engineering (RISDE) serving as the lead.

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By Inside GNSS
June 22, 2010

Lockheed Martin Team Completes Requirements Review for GPS IIIB Program

Lockheed Martin has announced successful completion of a key requirements review for the GPS IIIB satellite series under the U.S. Air Force’s next-generation GPS III Space Segment program.

Lockheed Martin Space Systems, Newtown, Pennsylvania, is working under a $3 billion development and production contract from the U.S. Air Force to produce up to 12 GPS IIIA satellites, with first launch projected for 2014. The contract includes a Capability Insertion Program (CIP) designed to mature technologies and perform rigorous systems engineering for the future IIIB and IIIC increments planned as follow-on procurements.

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By Inside GNSS

Generating Carrier Phase Measurements

Q: What is the carrier phase measurement? How is it generated in GNSS receivers?

A: Simply put, the carrier phase measurement is a measure of the range between a satellite and receiver expressed in units of cycles of the carrier frequency. This measurement can be made with very high precision (of the order of millimeters), but the whole number of cycles between satellite and receiver is not measurable.

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By Inside GNSS
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GLONASS CDMA

For the complete story, including figures, graphs, and images, please download the PDF of the article, above.

The decades of successful exploitation of satellite navigation systems GPS and GLONASS have confirmed their unique status as a basic resource for reliable worldwide, all-weather, all-season, round-the-clock positioning and timing. Nevertheless, the permanently widening sphere of their practical applications — as well as challenging requirements emerging from potential new users — give these systems a momentum for further evolution and progress.

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By Inside GNSS

On the Air

With the launch of the Delta IV rocket on May 27 from Cape Canaveral Air Force Station the first satellite (space vehicle number 62 or SVN62) of the latest GPS generation Block IIF (F, for “follow-on”) was carried into earth orbit — a major step with roots in the past.

Eight years ago in August 2002 the United States decided in coordination with the International Telecommunication Union (ITU-R) to transmit a new civil signal on a third frequency known as L5.

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By Inside GNSS
June 18, 2010

First Look at GPS L5 Signal

GPS L5 Signal Spectrum. German Aerospace Center image

The German Aerospace Center (DLR) has tracked and recorded the first operational L5 GPS signal as transmitted by the first GPS Block IIF satellite launched on May 27. The accompanying spectral image of the signal was received at about 15:10 UTC (GMT) today (June 17, 2010).

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By Inside GNSS
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June 7, 2010

DLR, Stanford Track First GPS IIF Signals; Tests Begin on L5

GPS IIF SV1 Spectral Flux Density on L1. DLR figure

[Updated June 10] The U.S. Air Force announced today (June 10) that it has begun
testing the new operational L5 signal transmitted by the first GPS IIF satellite (space vehicle 1 or SV1 — designated SVN-62 in the overall GPS system), which was launched May 27.

On June 7, 2010, a team of experts from the German Aerospace Center (DLR) and Stanford University in California reported results of their tracking of the first navigation signals from the satellite, the pseudorandom noise code 25 (PRN25) on L1 and L2 — C/A and P(Y).

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By Inside GNSS
April 14, 2010

EC Liberates Galileo ICD Signal Specification

Today’s (April 13) release of an updated “Galileo Open Service Signal-In-Space Interface Control Document” (OS SIS ICD) freed the key specification document in two senses of the word: receiver manufacturers, application developers and service providers may now use the ICD as an official — not draft — guide to their work, and they may do so at no cost

The t’s have been crossed and the i’s dotted to the satisfaction of lawyers and politicians — and the relief of designers and system integrators eager to begin work on Galileo-capable products without fear of having substantive changes in the specifications and legal or financial difficulties for moving ahead.

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By Inside GNSS
April 10, 2010

U.S. Invites Comments for Easing GPS SVN49 Signal Anomaly

(This article first appeared in the March 31 Inside GNSS SIGNALS eNewsletter)

The GPS Wing is in the middle of a yearlong process designed to sort out the trade-offs among a set of at least nine options that may be undertaken to reduce the effects of a signal anomaly on the GPS satellite known as SVN49.

In a March 26 teleconference, the first of two scheduled to discuss the options, Lt. Col. James Lake, the wing’s deputy chief engineer, emphasized that some of the options could well improve the performance of some receivers while decreasing that of others.

He underlined the Air Force’s concern that receivers that don’t conform to the specification for GPS space segment/navigation user interfaces (IS-GPS-200) "greatly complicate the issue."

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By Inside GNSS
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