Column Archives - Page 4 of 18 - Inside GNSS

Column

May 19, 2016

Re-Baseline This!

So, if everything had gone as planned, we would have a new ground control segment (OCX) operating a new generation of satellites (GPS III) as they launch into an expanded constellation in support of modernized military GPS user equipment (MGUE).

But then the best-laid plans. . . .

Read More >

By Inside GNSS
March 28, 2016

Up in the AIRR

Anyone who has sat through several iterations of a slide presentation by the Federal Aviation Administration (FAA) can’t help but wonder if there isn’t a better way to do things.

As speakers flip through an exhaustively vetted series of PowerPoint slides, squeezing out a new bullet point or two from one version to the next six months later, watching paint dry seems like a more productive — and briefer — use of one’s time. The agency sometimes brings a whole new meaning to the concept of geological time.

Read More >

By Dee Ann Divis
March 18, 2016

GLONASS and PNT in Russia

The legal and regulatory framework of the Russian Federation covers not only the GLONASS system, but the country’s overall positioning, navigation and timing (PNT) system as well.

The term PNT is a synonym for navigation activities as defined in the Federal Law on Navigation Activities. The PNT system in the Russian Federation is defined as the combination of administrative and technical means that provide spatial and time data to all user groups, with GLONASS as a key element.

Read More >

By Ingo Baumann

What are the fundamentals of an effective GNSS test plan?

Q. What are the fundamentals of an effective GNSS test plan?  

A. One aspect of GNSS development that engineers often find challenging is the lack of common testing standards and procedures. This can make life difficult for the engineer tasked with constructing a test plan for a new GNSS-enabled system. How much testing is proportionate, at which stages of development? What are the key performance parameters to measure? What apparatus is best suited to the application, and what are the appropriate pass/fail criteria?

Read More >

By Inside GNSS
January 27, 2016

Making Good Better

SBAS and RNSS: The Unsung Heroes of GNSS

Okay, if I had wanted to pander to GNSS fans, I might have called this, “Making Great Greater.”

But there are only so many superlatives that can be lathered on this remarkable technology before simple praise turns into hagiography.

So, it’s time once more to give a little love to those unsung heroes of GNSS: the augmentations and regional navigation satellite systems.

Read More >

By Inside GNSS
January 19, 2016

Galileo Themes, Threads and Visions

Europe’s space community rang in the New Year with two of its brightest annual fixtures: the European Union (EU) Space Policy conference in Brussels and the European Space Agency (ESA) media briefing in Paris.

The events brought out all of the relevant voices and served to illustrate not only the disposition of materiel and troops but also their intent and even the level of morale. 

Read More >

By Peter Gutierrez
January 18, 2016

What is Doppler collision and is it a problem in GNSS?

Figure 1, 3, 4 & 5

Q: What is Doppler collision and is it a problem in GNSS?

A: Doppler collision is a physical effect in code-division multiple access (CDMA) systems where code measurement errors are observed due to cross-correlation effects. Doppler collision may occur when the Doppler frequency between signals from two different transmitters is smaller than the code lock loop bandwidth. 

Read More >

By Inside GNSS
November 29, 2015

Failure to Communicate

For an organization with its name, the Federal Communications Commission (FCC) is a remarkably opaque public entity. 

Such is the case with the agency’s inaction on requests by foreign GNSS services to waive the so-called FCC Part 25 rules that require licensing of non-Federal receive-only Earth stations (e.g., GNSS receivers) operating with non-U.S. licensed space stations (i.e., satellites). 

Although at least one such request has reportedly been submitted, the FCC has not even acknowledged it, let alone moved to render a decision on the request. 

Read More >

By Inside GNSS
November 19, 2015

Code Shift Keying

Equations 1 – 10

The constant growth and evolution of the positioning, navigation, and timing (PNT) market generate demands for more and more added-value applications and services relying on GNSS signals, with expectations for improved accuracy and availability. Some services may also rely on added-value content other than navigation messages, for example, higher data volume with less latency, such as the data carried by satellite-based augmentation system (SBAS) services and the Galileo Commercial Service.

Read More >

By Günter W. Hein

How Important Is It to Synchronize the Code and Phase Measurements of a GNSS Receiver?

Q: How Important Is It to Synchronize the Code and Phase Measurements of a GNSS Receiver?

A: Precise timing lies at the heart of GNSS implementation and operation and is generally well understood in terms of synchronizing individual satellites and/or receivers. Recent results, however, have demonstrated that timing of code and phase measurements in a receiver can have significant implications for the timing community in particular.

Read More >

By Inside GNSS